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Molecular epidemiology of Candida parapsilosis sepsis from outbreak investigations in neonatal intensive care units
Abstract
The DNA probe, Cp3-13, was used in a Southern blot assay for genotyping Candida parapsilosis (CP) from 3 fungemia outbreaks in neonatal intensive care units (NICUs) in the southeastern U.S. Genotyping, in 2 outbreaks, supplied evidence of horizontal transmission of CP. In the third outbreak, bloodstream isolates (BSIs) of 2 genotypes circulated in the NICU, one was shared by a BSI and a healthcare worker's hand culture. A fourth cluster of recurrent episodes of fungemia occurred in outpatients of a children's hospital receiving total parenteral nutrition (TPN) at home. Each child was infected with a different CP genotype which persisted during recurrences. These genotypes were included in a dendrogram from a CDC population-based surveillance for candidemia consisting of 73 clone-corrected Cp3-13 genotypes (overall SAB = 0.36). Analysis revealed a cluster of 11 genotypes (mean SAB = 0.66) including 3 pairs with identical hybridization profiles. A second cluster of 8 genotypes contained clones from 3 outbreaks (mean SAB = 0.76) but no clustering of genotypes specific for neonates was identified. No decreased susceptibility to azole and polyene antifungal agents was detected in this collection of CP. The frequent occurrence of transmission of CP in this vulnerable population underlines the relevance of Cp3-13 subtyping to investigate suspected transmission and persistence of CP strains in the NICU.
... These markers were applied to a collection of 40 CP isolates from three NICUs in different US states, and a collection of CP isolates from the general population in two of the hospitals. The objectives were to: (i) refine an optimal set of microsatellites to aid in infection control measures since clusters of related CP strains have been reported to persist and circulate in the hospital environment (Reiss et al., 2008;Sarvikivi et al., 2005); (ii) detect potentially unrecognized clusters of related CP strains within a NICU; and (iii) compare the genotypic diversity of CP isolates among geographically separated hospitals. ...
... The use of five PMMs allowed discrimination of all 40 CP isolates from the three NICU collections. The resulting multiplex D value, 0.997, compares favorably with similar D values reported by Reiss et al. (2008) and Sabino et al. (2010). Hospital C is a referral center and almost all of their neonates are born at hospitals from a wide geographic region in the central Atlantic states. ...
... Highly related genotypes have caused outbreaks of CP candidemia in NICUs (Reiss et al., 2008) and individual strains or a small number of related CP strains may persist in a hospital for a period of years, making the patient population we studied relevant to hospital infection control. A bloodstream CP isolate with a singular genotype persisted in a Finland NICU for a 7-year period (Sarvikivi et al., 2005). ...
Candida parapsilosis (CP) (n=40) isolated from an unselected patient population in the neonatal intensive care units (NICUs) of three US hospitals were collected over periods of 3.5-9years. Two previously published microsatellite markers and three additional trinucleotide markers were used to produce multiplex genotypes, which revealed broad strain diversity among the NICU isolates with a combined index of discrimination (D)=0.997. A cluster of eight related CP strains from four infants in a single NICU was observed. An extended collection of 24 CP isolates from the general population of that hospital showed that the cluster of NICU isolates was related to three isolates from general hospital patients. This microsatellite marker set is suitable to investigate clusters of colonizing and infecting strains of CP.
... C. parapsilosis is known for the ability to form biofilms on catheters and other implanted devices Kuhn et al. 2004;Levy et al. 1998;Trofa et al. 2008), for nosocomial spread by hand carriage, and for persistence in the hospital environment Fridkin. 2005;Kwon-Chung et al. 2002;Perlroth et al. 2007;Reiss et al. 2008;Safdar et al. 2002;San Miguel et al. 2005;Sarvikivi et al. 2005;Trofa et al. 2008;Van Asbeck et al. 2007). It is also well known for causing infections in infants and neonates (Table 9) Kuhn et al. 2004;Levy et al. 1998;Lupetti et al. 2002;Pfaller et al. 2008d;Reiss et al. 2008;Saiman et al. 2000;Sarvikivi et al. 2005;Saxen et al. 1995;Trofa et al. 2008;Van Asbeck et al. 2007;Zaoutis et al. 2005;Zaoutis et al. 2007). ...
... 2005;Kwon-Chung et al. 2002;Perlroth et al. 2007;Reiss et al. 2008;Safdar et al. 2002;San Miguel et al. 2005;Sarvikivi et al. 2005;Trofa et al. 2008;Van Asbeck et al. 2007). It is also well known for causing infections in infants and neonates (Table 9) Kuhn et al. 2004;Levy et al. 1998;Lupetti et al. 2002;Pfaller et al. 2008d;Reiss et al. 2008;Saiman et al. 2000;Sarvikivi et al. 2005;Saxen et al. 1995;Trofa et al. 2008;Van Asbeck et al. 2007;Zaoutis et al. 2005;Zaoutis et al. 2007). C. parapsilosis affects critically ill neonates and ICU patients likely because of its association with parenteral nutrition and central venous catheters Hachem et al. 2008;Horn et al. 2009;Kuhn et al. 2004;Sarvikivi et al. 2005). ...
The incidence of invasive mycoses is increasing, especially among patients who are immunocompromised or hospitalized with serious underlying diseases. Such infections may be broken into two broad categories: opportunistic and endemic. The most important agents of the opportunistic mycoses are Candida spp., Cryptococcus neoformans, Pneumocystis jirovecii, and Aspergillus spp. (although the list of potential pathogens is ever expanding); while the most commonly encountered endemic mycoses are due to Histoplasma capsulatum, Coccidioides immitis/posadasii, and Blastomyces dermatitidis. This review discusses the epidemiologic profiles of these invasive mycoses in North America, as well as risk factors for infection, and the pathogens' antifungal susceptibility.
... In line with our findings, two recent studies in Brazil identified different C. parapsilosis genotypes among pediatric patients [31,32], but their results also confirmed whether these genotypes are phylogenetically related or not. Moreover, highly related genotypes have caused outbreaks of C. parapsilosis candidemia in neonatal intensive care units in the USA [33]. Furthermore, other studies have also documented the occurrence of clonal complexes of closely related genotypes as a result of microevolution caused by the inherent instability of microsatellite loci [34]. ...
Non-albicans Candida infections have recently gained worldwide attention due to their intrinsic resistance to different antifungal agents and the limited therapeutic options for treating them. Although the Candida parapsilosis complex is reported to be the second or third most prevalent Candida spp., little information is available on the prevalence of antifungal resistance along with genotyping of the C. parapsilosis complex. In this study, we aimed to evaluate the prevalence of antifungal resistance, the genetic basis of such resistance, and the genotyping of C. parapsilosis complex isolates that were recovered from hospitalized patients in Japan from 2005 to 2019. Our results indicated that, with the exception of one single C. metapsilosis isolate that was dose-dependently susceptible to fluconazole, all other isolates were susceptible or showed wild phenotypes to all tested antifungals, including azoles, echinocandins, amphotericin B, and flucytosine. Molecular analyses for azole and echinocandin resistance via evaluating ERG11 mutation and FKS1 hotspot one (HS1) and hotspot two (HS2) mutations, respectively, confirmed the phenotypic results. Genotyping of our isolates confirmed that they belong to 53 different but closely related genotypes, with a similarity percentage of up to 90%. Our results are of significant concern, since understanding the genetic basis of echinocandin resistance in the C. parapsilosis complex as well their genotyping is essential for directing targeted therapy, identifying probable infection sources, and developing strategies for overcoming epidemic spread.
... ) while infections with C.parapsilosis are mostly associated with pediatric populations(Bouza & Munoz 2008;Reissa et al. 2008;Singhi, Rao, & Chakrabarti 2008). Candida species that cause candidemia are markedly different in their response to anti-fungal treatment. ...
THE UNIVERSITY OF MANCHESTER
Candidate: Huda. H. Algriw
Degree: Doctor of Philosophy
Year: 2011
Molecular Detection of Bloodstream Pathogens in Critical Illness
Background: Critically ill patients are at particular risk of developing bloodstream infection. Such infections are associated with the development of sepsis, leading to a marked increase in mortality rate. Early detection of the causative organism and appropriate antibiotic treatment are therefore critical for optimum outcome of patients with nosocomial infection. Current infection diagnosis is based on standard blood culture techniques. However, microbiological culture has a number of limitations, not least that it takes several days to confirm infection and is therefore not useful in directing the early treatment with antibiotics. New techniques based on the detection of pathogen DNA using real-time polymerase chain reaction (PCR) technology have the potential to address these limitations but their clinical utility is still to be proved.
Objectives: Develop and evaluate novel PCR-based approaches to bloodstream infection diagnosis in critical illness based on detection and identification of bacterial and fungal DNA in blood.
Methods: A range of commercial and “in-house” PCR-based assays for detection of bacterial and fungal DNA were developed and/or optimised for use in clinical blood samples. These included LightCycler SeptiFast, a CE-marked multi-pathogen assay for common bloodstream pathogens, BactScreen and GramScreen, broad spectrum bacterial assays based on 16S rRNA gene and real-time PCR assays developed to detect a range of clinically important fungal pathogens. Novel approaches to speciation of pathogen DNA using melting temperature (Tm) profiling and high resolution melting analysis (HRMA) were developed. Clinical evaluation of assays was either on blinded clinical isolates or blood samples from critically ill patients with clinical suspicion of bloodstream infection against conventional microbiological culture. Several techniques aimed at improving extraction of pathogen DNA from blood were also investigated.
Results: The CE-marked commercial assay SeptiFast showed analytical sensitivity and specificity of 79% and 83% respectively. Concordance with positive culture results was good but high levels of “false positives” were detected possibly attributed to detection of free pathogen DNA not associated with viable pathogens. The predictive value of a negative SeptiFast test was 98% suggesting that absence of pathogen DNA is a strong indicator of absence of infection. Further studies were aimed at detailed optimisation and validation of 16S rRNA gene real-time PCR assays for bacterial DNA. BactScreen and GramScreen were able to detect a broad range of clinically important bacteria down to <50 CFU/ml blood. A preliminary comparative evaluation against SeptiFast showed BactScreen gave excellent concordance with blood culture results with minimal false positive results compared to SeptiFast. Efficient extraction of pathogen DNA was shown to be a key factor in determining analytical sensitivity and several protocols were evaluated. Low cost approaches to speciation of bacterial DNA were developed by combining broad range real-time PCR with HRMA. A novel HRMA method based on Tm profiling was shown to identify 89% and 96% of blinded clinical isolates at species or genus level respectively. Real-time PCR/HRMA approaches were also successfully developed for detection and identification of fungal pathogens including a range of Candida and Aspergillus species associated with bloodstream fungal infection.
Conclusions: These studies have highlighted some of the key factors that need to be considered when developing and validating PCR based assays for pathogen DNA detection in blood. A set of novel tools have been developed for rapid detection and identification of bacterial and fungal pathogens that could address the challenges of infection diagnosis based on pathogen DNA detection. Further work is required, not least in development of more efficient pathogen DNA extraction and detailed clinical validation but the tools described here have the potential to provide cost effective solutions to aid infection diagnosis that would be complementary to current culture-based methods. The provision of time critical information could have a positive impact on clinical decision-making leading to more effective management and treatment of patients with suspected bloodstream infection
... The use of RAPD-PCR method has identified the source of contamination from particular work stations where it was prepared (Marais et al., 2004). In addition, the source of infections can be determined by molecular typing methods, especially incidences of C. parapsilosis outbreaks in neonatal intensive care unit (NICU) (Reissa et al., 2008) and systemic infections due to C. parapsilosis (Paluchowska et al., 2014). The use of central intravascular catheters, prior exposure to haemodialysis or antibiotics remain to be the main cause of systemic infections (Binelli et al., 2006;Pittet et al., 1994). ...
The purpose of this study is to characterize 3 non-albicans Candida spp. that were collected from two major hospitals in a densely populated area of Kuala Lumpur for their
susceptibilities to azole and genetic background. Fifteen non-albicans Candida clinical isolates in two major hospitals in Kuala Lumpur area of Malaysia were collected by convenience sampling during 2007 and 2010. The genetic diversity of 15 non-albicans Candida species comprising C. glabrata (n = 5), C. parapsilosis (n = 5) and C. rugosa (n = 5) were assessed by RAPD-PCR typing. Strains were initially identified using biochemical tests and CHROMagar Candida medium. Fluconazole and voriconazole susceptibilities were determined by E-test method. Commercial kits were used for DNA extraction and amplification with RAPD primers (OPA02, OPA03 and OPA08). PCR conditions were optimized and simultaneous identification was possible by agarose gel electrophoresis of PCR products and the bands obtained were analyzed using BioNumerics Applied Maths v.6.6 software. The RAPD primers used in this study generated 100% polymorphic profile. Cluster analysis using the RAPD-PCR profile showed 12.5-25% similarity among the strains. The genetic diversity was based on the strain susceptibility towards both the azoles, site of isolation and place according to their unique banding patterns. In contrast, strains susceptible to azoles were found to be genetically similar with clonal dissimilarity. The use of OPA02, OPA03 and OPA08 primers in differentiating non-albicans Candida spp. underscores the higher resolution of RAPD-PCR as a reliable tool for strain/species level differentiation.
... Since 2006, MLP has thus been used to study outbreaks of C. parapsilosis especially in neonatal intensive care unit (NICU) [7,[12][13][14]. Other studies have addressed the overall population structure, genetic diversity, suggesting that inheritance in C. parapsilosis is mainly clonal [11,15,16]. ...
Candida parapsilosis is a human commensal yeast, frequently involved in infection worldwide and especially in neonates. It is the second species responsible for bloodstream infections in Uruguay and the third species in France. We were interested in knowing whether the population structure of isolates responsible for candidemia in France and in Uruguay was different. Genotyping methods based on microsatellite length polymorphism (MLP) have been described and are especially used for investigation of local outbreaks. We therefore determined the genotypes of 159 C. parapsilosis isolates recovered from 122 patients (84 French patients from 43 hospitals and 38 Uruguayan patients from 10 hospitals) using three microsatellites markers previously described. Our results confirmed that C. parapsilosis population has a high genetic diversity, clonal inheritance and that majority of patients were infected by a single isolate. But we described recurrent infections due to related or unrelated genotypes resulting from isolates harboring loss or gain of heterozygosity. We also described three cases of coinfections due to unrelated genotypes. We did not uncover geographic specificity but observed two linked genotypes that seem to be associated with voriconazole resistance. Finally, among eight isolates involved in grouped cases, the genotypes were similar in six cases supporting the hypothesis of inter-patient transmission. These results confirmed the usefulness of performing MLP genotyping analysis for grouped cases of C. parapsilosis isolates in order to reinforce preventive hygiene measures.
... Since 2006, STR markers have been frequently used to study outbreaks of C. parapsilosis, especially in neonates. Studies based on STRs, together with other tools such as Cp3-13 DNA probes, suggested persistence of genotypes during recurrent infection, horizontal transmission in intensive care units, and microevolution of C. parapsilosis (7,206,208,(214)(215)(216)(217)(218). ...
Genotyping studies of medically important fungi have addressed elucidation of outbreaks, nosocomial transmissions, infection routes, and genotype-phenotype correlations, of which secondary resistance has been most intensively investigated. Two methods have emerged because of their high discriminatory power and reproducibility: multilocus sequence typing (MLST) and microsatellite length polymorphism (MLP) using short tandem repeat (STR) markers. MLST relies on single-nucleotide polymorphisms within the coding regions of housekeeping genes. STR polymorphisms are based on the number of repeats of short DNA fragments, mostly outside coding regions, and thus are expected to be more polymorphic and more rapidly evolving than MLST markers. There is no consensus on a universal typing system. Either one or both of these approaches are now available for Candida spp., Aspergillus spp., Fusarium spp., Scedosporium spp., Cryptococcus neoformans , Pneumocystis jirovecii , and endemic mycoses. The choice of the method and the number of loci to be tested depend on the clinical question being addressed. Next-generation sequencing is becoming the most appropriate method for fungi with no MLP or MLST typing available. Whatever the molecular tool used, collection of clinical data (e.g., time of hospitalization and sharing of similar rooms) is mandatory for investigating outbreaks and nosocomial transmission.
... This high rate of C. parapsilosis infections may reflect the ability of this species to form biofilms on catheters and to contaminate glucosecontaining solutions, including those used in parenteral nutrition (15). In addition, because the C. parapsilosis complex is a commensal of human skin (horizontal transmission), its transmission from the hands of healthcare workers to neonates has been suggested in cases of CVC-related infections (13,16). ...
Background:
Candidemia has become an increasingly important problem in infants hospitalized in the Neonatal Intensive Care Units (NICUs). Candida species are the third most common agents of late-onset infections in critically ill neonates and they are associated with high morbidity and mortality rates. In this study we evaluated the epidemiology of Candida bloodstream infections in the NICU of an Italian university hospital during a 15-year period. Our specific aims were to analyze the change in species distribution and the vitro susceptibility of these yeasts to fluconazole (FCZ) and amphotericin B (AmB).
Methods:
A retrospective study of candidemia in the NICU of a university hospital in southern Italy, covering the years 2000-2014 was carried out. The isolates were identified using the VITEK2 yeast identification system and antifungal susceptibility was determined using the E-test method.
Results:
Among the 57 patients with confirmed candidemia, 60% were males (n = 34 cases) and 82% (n = 47) had a gestational age of 24-32 weeks. Twenty-seven neonates (47%) had a very low birth weight (<1500 g), 20 (35%) an extremely low birth weight (<1000 g), and 10 (18%) a low birth weight (<2500 g). The most important potential risk factors were the placement of a central venous catheter, total parenteral nutrition, and endotracheal intubation (100%, each). Candida albicans was the most frequent yeast (47%), followed by Candida parapsilosis (44%). The proportion of Candida non-albicans increased slightly, from 46% in 2000-2004 to 71% in 2010-2014 (χ2 test for trend, p = 0.030). All isolates were susceptible to FCZ and AmB.
Conclusions:
The detection in this epidemiologic study of an increase in Candida non-albicans highlights the importance of correct species-level identification in the rapid diagnosis for an efficient treatment of candidemia. Knowledge of the local epidemiological trends in Candida species isolated in blood cultures will facilitate therapeutic decision-making.
... Patients were both adult and paediatric, although neonates were also frequently involved. Typing of isolates from the patients involved and from the environment (including health care personnel) showed that genotypes from patients were commonly found on the hands of the health care workers, which are a common source of exogenous isolates [42,45,46,[48][49][50][51]. Patients' skin or central venous catheters can become infected by exogenous isolates after manipulation of medical devices by health care workers, particularly in the adult and neonatal ICU. ...
Only 5 species account for 92% of cases of candidemia (Candida albicans, C. glabrata, C. tropicalis, C. parapsilosis, and C. krusei); however their distribution varies in population-based studies conducted in different geographic areas. C. albicans is the most frequent species, but considerable differences are found between the number of cases caused by C. glabrata and the number caused by C. parapsilosis. Studies from Northern Europe and the USA reported a high number of cases caused by C. glabrata, whereas studies from Spain and Brazil demonstrated a lower number of cases caused by C. glabrata and a higher number of cases attributed to C. parapsilosis. Although C. albicans remains the most common species worldwide, its frequency is decreasing. In the case of C. glabrata and C. krusei, frequency is stable, although that of C. parapsilosis and C. tropicalis is increasing. The kind of patient and the antifungal agents received also have a considerable influence on the distribution and frequency of Candida spp., regardless of the geographic area. C. albicans is more frequent in patients aged up to 18 years. Interestingly, the frequency of C. parapsilosis decreases with age, whereas C. glabrata is more common in the elderly. Finally, the presence of horizontal transmission of Candida spp. isolates (reported mainly in patients from the adult medical and post-surgical ICU, patients from oncology-hematology units, and neonates) can affect species distribution. This article is protected by copyright. All rights reserved.
... previously not been noticed and the clonality of infection [12,13]. Although some investigators have reported large outbreaks of C. parapsilosis bloodstream infections among adults [14], the majority have occurred among neonates [15][16][17]. ...
Candida is the second leading cause of sepsis related death in the neonatal intensive care unit (NICU). Using the C. parapsilosis paradigm, the endogenous and exogenous routes of infection were simulated in order to enhance prevention among neonates at highest risk. A deterministic model was constructed with transmission parameters calculated from the basic reproductive number (), derived from the mean serial interval from two published outbreaks. Uncertainty and sensitivity analyses were performed via Latin hypercube sampling. Prevention measure effects were ascertained by incorporating percent coverage and efficacies into the existing model. The colonized and infected neonatal prevalence peaked at 17.4% and 39.4%, respectively, and reduction was achieved by compartmental replacement with susceptibles. Containment of greater than 60% of the cohort had minimal effect on the effective reproductive number () unless hand hygiene compliance dropped below 40% at a fixed ratio of nurses to neonates. Antifungal prophylaxis in combination with hand hygiene and cohorting extinguished an outbreak 14 days sooner than baseline. The critical proportion () requiring prophylaxis in order to stop an outbreak increases, as rises, and the prophylaxis efficacies decrease. Internal and external sources of Candida lead to invasive disease in neonates differentially. Optimal prevention is dependent upon understanding the dynamics of this disease process under diverse circumstances.
... C andida parapsilosis is one of the most common non-albicans Candida species that cause human infections. In some regions in Latin America and Spain, C. parapsilosis occurs at the same or even a higher frequency than does Candida albicans, particularly in bloodstream infections in young children and premature neonates (1)(2)(3)(4)(5)(6). C. parapsilosis is considered a normal or transient inhabitant of the skin and is found on the hands of health care workers who install central venous catheters and other medical devices, thus suggesting a nosocomial route of transmission (7)(8)(9)(10). ...
Inteins are coding sequences that are transcribed and translated with flanking sequences and then are excised by an autocatalytic
process. There are two types of inteins in fungi, mini-inteins and full-length inteins, both of which present a splicing domain
containing well-conserved amino acid sequences. Full-length inteins also present a homing endonuclease domain that makes the
intein a mobile genetic element. These parasitic genetic elements are located in highly conserved genes and may allow for
the differentiation of closely related species of the Candida parapsilosis (psilosis) complex. The correct identification of the three psilosis complex species C. parapsilosis, Candida metapsilosis, and Candida orthopsilosis is very important in the clinical setting for improving antifungal therapy and patient care. In this work, we analyzed inteins
that are present in the vacuolar ATPase gene VMA and in the threonyl-tRNA synthetase gene ThrRS in 85 strains of the Candida psilosis complex (46 C. parapsilosis, 17 C. metapsilosis, and 22 C. orthopsilosis). Here, we describe an accessible and accurate technique based on a single PCR that is able to differentiate the psilosis
complex based on the VMA intein. Although the ThrRS intein does not distinguish the three species of the psilosis complex
by PCR product size, it can differentiate them by sequencing and phylogenetic analysis. Furthermore, this intein is unusually
present as both mini- and full-length forms in C. orthopsilosis. Additional population studies should be performed to address whether this represents a common intraspecific variability
or the presence of subspecies within C. orthopsilosis.
... In fact, it is particularly frequent in newborns (Tortorano et al., 2006; Trofa et al., 2008; van Asbeck et al., 2009b ) and in a recent multicentre regional study from southern Italy it accounted for 60% of bloodstream infections among neonatal intensive care unit (NICU) patients, surpassing even Candida albicans (Montagna et al., 2010). In addition, C. parapsilosis also represents the predominant species which causes nosocomial outbreaks of infections, especially in NICU settings (van Asbeck et al., 2007; Reissa et al., 2008; Hernández-Castro et al., 2010; Vaz et al., 2011; Reiss et al., 2012). Since 2007 there has been an increased frequency of isolation of C. parapsilosis from blood cultures of patients hospitalized in the NICU of the University Hospital ''Policlinico G. Martino'' Infection, Genetics and Evolution 13 (2013) 105–108 ...
In this study, using multilocus microsatellite analysis, we report the genetic characterization of 27 Candida parapsilosis isolates recovered in two different periods of time (2007-2009 and 2011-2012) from infants hospitalized in the neonatal intensive care unit of a hospital in Messina, Italy. The results revealed the persistence and dominance of a particular infectious genotype among NICU patients and highlight the power of the used microsatellite markers in clarifying epidemiologic associations, detect micro-evolutionary variations and facilitating the recognition of outbreaks.
... Infection rates are particularly high in premature neonates and in young children [2]. C. parapsilosis is found on the hands of health-care workers [3] and has been associated with major outbreaks of infection, particularly in neonatal intensive care units [4,5,6,7]. The presence of central venous catheters (CVCs) and receiving parenteral nutrition are also major risk factors [8,9]. ...
Candida orthopsilosis is closely related to the fungal pathogen Candida parapsilosis. However, whereas C. parapsilosis is a major cause of disease in immunosuppressed individuals and in premature neonates, C. orthopsilosis is more rarely associated with infection. We sequenced the C. orthopsilosis genome to facilitate the identification of genes associated with virulence. Here, we report the de novo assembly and annotation of the genome of a Type 2 isolate of C. orthopsilosis. The sequence was obtained by combining data from next generation sequencing (454 Life Sciences and Illumina) with paired-end Sanger reads from a fosmid library. The final assembly contains 12.6 Mb on 8 chromosomes. The genome was annotated using an automated pipeline based on comparative analysis of genomes of Candida species, together with manual identification of introns. We identified 5700 protein-coding genes in C. orthopsilosis, of which 5570 have an ortholog in C. parapsilosis. The time of divergence between C. orthopsilosis and C. parapsilosis is estimated to be twice as great as that between Candida albicans and Candida dubliniensis. There has been an expansion of the Hyr/Iff family of cell wall genes and the JEN family of monocarboxylic transporters in C. parapsilosis relative to C. orthopsilosis. We identified one gene from a Maltose/Galactoside O-acetyltransferase family that originated by horizontal gene transfer from a bacterium to the common ancestor of C. orthopsilosis and C. parapsilosis. We report that TFB3, a component of the general transcription factor TFIIH, undergoes alternative splicing by intron retention in multiple Candida species. We also show that an intein in the vacuolar ATPase gene VMA1 is present in C. orthopsilosis but not C. parapsilosis, and has a patchy distribution in Candida species. Our results suggest that the difference in virulence between C. parapsilosis and C. orthopsilosis may be associated with expansion of gene families.
... Although C.albicans is the most frequent aetiological agent, infections due to C. non-albicans have increased in frequency in recent years [8][9][10]. In many NICUs C.parapsilosis is the main pathogen causing clusters and nosocomial outbreaks [11][12][13]. Numerous risk factors for invasive candidiasis (IC) have been identified in NICU patients: some are related to host factors (immunodeficiency resulting from decreased numbers of neutrophils and T cells, immature skin structure, Candida colonization), others to medical care (central venous catheters, total parenteral nutrition, mechanical ventilation, broad spectrum antibiotic therapy, use of 3 rd generation cephalosporin, administration of H2-blockers) [7,[14][15][16][17]. The mortality rate is high (25-60%) [17] and it is related to the difficulty to make an early diagnosis because of reduced sensitivity of diagnostic tests, non-specific clinical signs and to inadequate and / or delayed treatments [18,19]. ...
During the past years invasive fungal infections (IFIs) have become an increasingly important problem in infants hospitalized in the Neonatal Intensive Care Unit (NICU). Candida species is the third most-common agent of late-onset infections in critically ill neonates, with an estimated incidence of 2.6-10% in very low birth weight and 5.5-20% in extremely low birth weight infants. The aim of this observational study is to evaluate the epidemiology of IFIs among infants admitted to NICUs of one Italian region by a multicenter surveillance (Aurora Project).
The IFIs surveillance was carried out prospectively in Apulia (Southern Italy) between February 2007 and August 2008. This report focuses on the results from 6 enrolled NICUs.
Twenty-one neonates developed IFIs: the overall incidence was 1.3% and crude mortality was 23.8%. Infants weighing < or = 1500 g (4.3%) showed a significantly higher incidence than those > or = 2500 g (0.2%). C. parapsilosis (61.9%) was the most frequent isolated species. The main potential risk factors were having a central venous catheter placed, length of stay in NICU > 7 days and total parenteral nutrition for > 5 days. The (1,3)-beta-D glucan (BDG), mannan antigens and anti-Candida antibodies' evaluation was performed in 7 neonates. All neonates were positive to the BDG; the mannan antigen result was positive in 5 newborns, the anti-mannan antibodies were always negative. All isolates were amphotericin B and fluconazole-susceptible.
This first prospective study on neonatal fungal infection in one Italian region gives evidence of a preponderance of non-albicans Candida spp and indicates potential utility of BDG as an adjunct diagnostic test.
Nosocomial clusters of fungal infections, whilst uncommon, cannot be predicted and are associated with significant morbidity and mortality. Here, we review reports of nosocomial outbreaks of invasive fungal disease to glean insight into their epidemiology, risks for infection, methods employed in outbreak detection including genomic testing to confirm the outbreak, and approaches to clinical and infection control management. Both yeasts and filamentous fungi cause outbreaks, with each having general and specific risks. The early detection and confirmation of the outbreak are essential for diagnosis, treatment of affected patients, and termination of the outbreak. Environmental sampling, including the air in mould outbreaks, for the pathogen may be indicated. The genetic analysis of epidemiologically linked isolates is strongly recommended through a sufficiently discriminatory approach such as whole genome sequencing or a method that is acceptably discriminatory for that pathogen. An analysis of both linked isolates and epidemiologically unrelated strains is required to enable genetic similarity comparisons. The management of the outbreak encompasses input from a multi-disciplinary team with epidemiological investigation and infection control measures, including screening for additional cases, patient cohorting, and strict hygiene and cleaning procedures. Automated methods for fungal infection surveillance would greatly aid earlier outbreak detection and should be a focus of research.
A reliable estimate of Candida parapsilosis antifungal susceptibility in candidemia patients is increasingly important to track the spread of C. parapsilosis bloodstream infections and define the true burden of the ongoing antifungal resistance. A systematic review and meta-analysis (SRMA) were conducted aiming to estimate the global prevalence and identify patterns of antifungal resistance. A systematic literature search of the PubMed, Scopus, ScienceDirect and Google Scholar electronic databases was conducted on published studies that employed antifungal susceptibility testing (AFST) on clinical C. parapsilosis isolates globally. Seventy-nine eligible studies were included. Using meta-analysis of proportions, the overall pooled prevalence of three most important antifungal drugs; Fluconazole, Amphotericin B and Voriconazole resistant C. parapsilosis were calculated as 15.2% (95% CI: 9.2–21.2), 1.3% (95% CI: 0.0–2.9) and 4.7% (95% CI: 2.2–7.3), respectively. Based on study enrolment time, country/continent and AFST method, subgroup analyses were conducted for the three studied antifungals to determine sources of heterogeneity. Timeline and regional differences in C. parapsilosis prevalence of antifungal resistance were identified with the same patterns among the three antifungal drugs. These findings highlight the need to conduct further studies to assess and monitor the growing burden of antifungal resistance, to revise treatment guidelines and to implement regional surveillance to prevent further increase in C. parapsilosis drug resistance emerging recently.
Objective:
To evaluate the clinical value of droplet digital PCR (ddPCR) in rapid and accurate diagnosis of invasive fungal infection (IFI) in neonates.
Methods:
The highly conserved sequence of fungi 18S RNA was selected as the target sequence, and primers were designed to establish a ddPCR fungal detection system. Blood samples were collected from 83 neonates with high-risk factors for IFI and/or related clinical symptoms in the neonatal intensive care unit (NICU) of a hospital in Shenzhen, China. Blood culture and ddPCR were used for fungal detection.
Results:
The ddPCR fungal detection system had a specificity of 100% and a sensitivity of 3.2 copies/μL, and had a good reproducibility. Among the 22 blood samples from neonates with a confirmed or clinical diagnosis of IFI, 19 were detected positive by ddPCR. Among the 61 blood samples from neonates who were suspected of IFI or had no IFI, 2 were detected positive by ddPCR.
Conclusions:
The ddPCR technique can be used for the detection of neonatal IFI and is a promising tool for the screening and even diagnosis of neonatal IFI.
Background:
Candida parapsilosis is a common agew2nt of fungemia, but few outbreaks of Candida parapsilosis infection have been reported in China.
Aim:
This study aimed to elaborate an outbreak of nosocomial Candida parapsilosis sensu stricto fungemia in a neonatal intensive care unit (NICU) of a comprehensive hospital in China from July to October 2017.
Methods:
Epidemics and characteristics of fungemia cases were investigated. Surveillance samples were collected. VITEK 2 Compact System, internal transcribed spacer sequencing, and Random Amplified Polymorphic DNA (RAPD) typing were conducted to identify the isolates. Antifungal susceptibility test was performed for all bloodstream isolates.
Findings:
Sixteen neonates were diagnosed as Candida parapsilosis sensu stricto fungemia during this period. Presenting symptoms included leukopenia, thrombocytopenia, and respiratory crackles. Fifteen cases were cured while one case who suffered from severe concomitant diseases died. The isolates were susceptible to fluconazole, amphotericin B, itraconazole, voriconazole, and 5-fluorocytosine. A total of 313 surveillance samples were collected, and Candida parapsilosis sensu stricto was identified from 16 environmental samples and one sample from an ultrasonographer's hand. The colonized locations included wiping cloths, faucets, sinks, operating table, puddles in the bathroom, a ventilator, and an ultrasonic probe. The RAPD patterns of all the Candida parapsilosis sensu stricto isolates from bloodstream and surveillance samples were identical. The outbreak was controlled after a series of infection control measures.
Conclusions:
Contaminated environment was associated with this outbreak. Close attention to immunocompromised patients, thorough environmental disinfection and hand hygiene should be strengthened in NICU.
Topics not Covered, or Receiving Secondary Emphasis Biosafety Considerations: Before You Begin Work with Pathogenic Fungi… Fungi Defined: Their Ecologic Niche Medical Mycology A Brief History of Medical Mycology Rationale for Fungal Identification Sporulation Dimorphism Sex in Fungi Classification of Mycoses Based on the Primary Site of Pathology Taxonomy/Classification: Kingdom Fungi General Composition of the Fungal Cell Primary Pathogens Endemic Versus Worldwide Presence Opportunistic Fungal Pathogens Determinants of Pathogenicity General References in Medical Mycology Selected References for Introduction to Fundamental Medical Mycology Websites Cited Questions
Invasive infections have emerged over the past decades as important causes for morbidity and mortality. Favorable outcome is associated with early and appropriate antifungal treatment. Therefore, rapid and correct diagnosis is of utmost importance. The clinical mycology field has evolved over the past decade. Reference methods for susceptibility testing and associated clinical breakpoints for Candida and Aspergillus have been developed, and several commercial susceptibility tests have been marketed. New diagnostic tests have become available including ELISA and lateral flow devices for the detection of Aspergillus, Candida, and Cryptococcus antigens; β-d-glucan detection test; diagnostic PCRs; and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) techniques for identification and perhaps in the future also for susceptibility screening (testing). Finally, molecular sequencing and genotyping methods have been described and increasingly used for outbreak and resistance detection. Some of these tests are straightforward to implement in the routine laboratory for clinical microbiology, whereas others require mycological expertise. Here, we present an overview of the newer diagnostic options, review options for improving sensitivity of classical diagnostic techniques, and also comment on which levels of mycological expertise are required for the different diagnostic tests. The goal of this review is to summarize current diagnostic options and discuss benefits and pitfalls on how these are best implemented in order to obtain state-of-the-art mycology service.
Candidiasis or thrush is a fungal infection (mycosis) of any of the Candida species. Also commonly referred to as a yeast infection, candidiasis encompasses infections that range from superficial, such as oral thrush and vaginitis, to systemic and potentially life-threatening diseases. In this book, the authors discuss the epidemiology, symptoms and treatment options of candidiasis. Topics include invasive candidiasis and candida parapsilosis complex diagnoses and treatment; conventional and alternative treatment options for oral candidiasis; candida spp. in the oral cavity of children with immunodeficiencies; oxidative stress and the development of antifungal agents for the treatment of candidiasis; inhalation and topical steroid therapy and oral candidiasis; and fluorescent staining for the diagnosis of oral erythematous candidiasis. (Imprint: Nova Biomedical)
INTRODUCTION: There are few epidemiological studies on candidaemia in the paediatric population in Spain. We sought to determine the epidemiology of candidaemia in these patients. METHODS: Prospective, observational and multicentre study in 44 Spanish hospitals. All candidaemia episodes in paediatric patients from 0 to 15 years old between January 2009 and February 2010 were studied. RESULTS: There were 197 episodes and 200 species were isolated. The most frequent species was Candida parapsilosis sensu stricto (43%), followed by C. albicans (36%), C. tropicalis (6%), C. orthopsilosis, and C. glabrata (4%) respectively. C. albicans was the most prevalent in newborns, and C. parapsilosis was most frequent in the other age groups. As regards the regions of Spain, C. albicans was most prevalent in patients from Catalonia, the Balearic Islands and Canary Islands, and C. parapsilosis in patients from Andalusia, Castilla-León, Galicia, Valencia, and Madrid. The rate of resistance to fluconazole was 1.5% (4.1% with the new species-specific Clinical and Laboratory Standards Institute [CLSI] criteria). Fluconazole resistance was lower in neonates than the other age groups. The Neonatal Wards were the areas with most episodes (31.5%). In the multivariate analysis, the variables associated independently with candidaemia due to C. albicans were: catheter (OR: 5.967; 95% CI: 1.614-22.057; P=.007) and prematurity (OR: 2.229; 95% CI: 1.141- 4.631; P=.020). CONCLUSIONS: The epidemiology of paediatric candidaemia varies between Spanish regions, but, globally, C. parapsilosis and C. albicans, are respectively, the first and second most frequently isolated species, and they show resistance rates to fluconazole of less than 5%.
Background:
Few studies exist on prevalence of fungemia by Candida orthopsilosis, with variable results.
Aims:
To study the incidence, epidemiology and antifungal susceptibility of C. orthopsilosis strains isolated from fungemias over two years at a tertiary hospital.
Methods:
Candidemia episodes between June 2007 and June 2009 in a university hospital (Puerta del Mar, Cádiz, Spain) were studied. The strains initially identified as Candida parapsilosis were genotypically screened for C. parapsilosis sensu stricto, C. orthopsilosis and Candida metapsilosis, and their antifungal susceptibility was evaluated.
Results:
In this period 52 cases of candidemia were documented. Of the 19 strains originally identified as C. parapsilosis, 13 were confirmed as C. parapsilosis sensu stricto and 6 as C. orthopsilosis. Of the 52 isolates, the most frequent species were Candida albicans (30.8%), C. parapsilosis sensu stricto (25%), C. orthopsilosis, Candida tropicalis and Candida glabrata in equal numbers (11.5%). C. orthopsilosis isolates were susceptible to amphotericin B, caspofungin, voriconazole and fluconazole, with no significant differences in MIC values with C. parapsilosis sensu stricto. The source of isolates of C. orthopsilosis were neonates (50%) and surgery (50%), and 100% were receiving parenteral nutrition; however C. parapsilosis sensu stricto was recovered primarily from patients over 50 years (69.2%) and 46.1% were receiving parenteral nutrition.
Conclusions:
These findings show that C. orthopsilosis should be considered as human pathogenic yeast and therefore its accurate identification is important. Despite our small sample size our study suggests that a displacement of some epidemiological characteristics previously attributed to C. parapsilosis to C. orthopsilosis may be possible.
INTRODUCTION: There are few epidemiological studies on candidaemia in the paediatric population in Spain. We sought to determine the epidemiology of candidaemia in these patients. METHODS: Prospective, observational and multicentre study in 44 Spanish hospitals. All candidaemia episodes in paediatric patients from 0 to 15 years old between January 2009 and February 2010 were studied. RESULTS: There were 197 episodes and 200 species were isolated. The most frequent species was Candida parapsilosis sensu stricto (43%), followed by C. albicans (36%), C. tropicalis (6%), C. orthopsilosis, and C. glabrata (4%) respectively. C. albicans was the most prevalent in newborns, and C. parapsilosis was most frequent in the other age groups. As regards the regions of Spain, C. albicans was most prevalent in patients from Catalonia, the Balearic Islands and Canary Islands, and C. parapsilosis in patients from Andalusia, Castilla-León, Galicia, Valencia, and Madrid. The rate of resistance to fluconazole was 1.5% (4.1% with the new species-specific Clinical and Laboratory Standards Institute [CLSI] criteria). Fluconazole resistance was lower in neonates than the other age groups. The Neonatal Wards were the areas with most episodes (31.5%). In the multivariate analysis, the variables associated independently with candidaemia due to C. albicans were: catheter (OR: 5.967; 95% CI: 1.614-22.057; P=.007) and prematurity (OR: 2.229; 95% CI: 1.141- 4.631; P=.020). CONCLUSIONS: The epidemiology of paediatric candidaemia varies between Spanish regions, but, globally, C. parapsilosis and C. albicans, are respectively, the first and second most frequently isolated species, and they show resistance rates to fluconazole of less than 5%.
The incidence of candidemia in the overall population ranges from 1.7 to 10 episodes per 100,000 inhabitants and Candida is one of the ten leading causes of bloodstream infections in developed countries. An estimated 33-55% of all episodes of candidemia occur in intensive care units (ICU) and are associated with mortality rates ranging from 5% to 71%. Candida fungemia may have an endogenous or an exogenous origin, and in recent years a growing proportion of episodes of candidemia have been caused by Candida species other than albicans. The most important independent conditions predisposing to candidemia in ICU patients include prior abdominal surgery, intravascular catheters, acute renal failure, parenteral nutrition, broad-spectrum antibiotics, a prolonged ICU stay, the use of corticosteroids and mucosal colonization with Candida. In recent years, several studies have shown that ICU patients with mucosal Candida colonization, particularly if multifocal, are at a higher risk for invasive candidiasis, and that colonization selects a population amenable to antifungal prophylaxis or empirical therapy. Candidemia in ICUs is associated with a considerable increase in hospital costs and length of hospital stay.
Neutral lipid storage in lipid droplets (LDs) is a conserved process across diverse species. Although significant attention has focused on LDs in the biology of obesity, diabetes, and atherosclerosis, there is limited information on the role of LDs in pathogenic fungi. We have disrupted the Fat storage-Inducing Transmembrane (FIT) protein 2 genes of the emerging pathogenic fungus Candida parapsilosis and demonstrated that LD formation is significantly reduced in the mutant cells. Disruption of FIT2 genes also reduced accumulation of triacylglycerols. The production of other lipids such as phospholipids and steryl esters were also affected in the mutant strain. Inhibition of de novo fatty acid biosynthesis by triclosan in the FIT2 disruptants reduced fungal growth in rich medium YPD, indicating that TAGs or fatty acids from the LDs could be important for cell proliferation. FIT2 disruption was associated with enhanced sensitivity to oxidative stress. Furthermore, we showed that FIT2 deletion yeast cells were significantly attenuated in murine infection models, suggesting an involvement of LDs in the pathobiology of the fungus.
Candida parapsilosis was recently reclassified into 3 closely related species, C. parapsilosis sensu stricto, Candida orthopsilosis, and Candida metapsilosis. Variation in susceptibility characteristics and prevalence of the 3 genomic species could have therapeutic and epidemiologic implications. The aim of this study is to characterize the genetic and antifungal susceptibility profiles of 97 C. parapsilosis isolates from 71 patients. Among the 71 nonduplicate isolates, 85.9% (61/71) were identified as C. parapsilosis sensu stricto, 5.6% (4/71) as C. metapsilosis, and 8.5% (6/71) as C. orthopsilosis species based on sequences of the internal transcribed spacer (ITS) region. The delineation of these 3 species is concordant with that achieved by pulsed-field gel electrophoresis of BssHII restriction fragments at 75% similarity. Antifungal susceptibility tests showed that most isolates were susceptible to flucytosine, azoles, amphotericin B, and echinocandins, whereas 3 C. metapsilosis isolates from 1 patient showed resistance and susceptible-dose dependence to fluconazole. The C. metapsilosis isolates exhibited significantly higher MIC values to both fluconazole and voriconazole than those of C. parapsilosis sensu stricto and C. orthopsilosis. On the other hand, the C. metapsilosis isolates showed significantly lower MIC values on 24 h to caspofungin than those of C. parapsilosis sensu stricto and C. orthopsilosis. For micafungin, the isolates of C. parapsilosis sensu stricto had significantly higher MIC values on 24 h than those of C. orthopsilosis and C. metapsilosis. Compared to Candida albicans, mutations from proline to alanine were identified on the hot spot 1 of Fks1 in all these C. parapsilosis sensu lato isolates regardless of their MIC levels. Some of the C. orthopsilosis and C. metapsilosis isolates expressed the isoleucine to valine substitution on the hot spot 2 region. However, the amino acid variations in these isolates did not correlate to their MIC values of echinocandin.
Candida albicans, a diploid yeast commensal and opportunist pathogen, has evolved unusual mechanisms for maintenance of genetic diversity in the absence of a complete sexual cycle. These include chromosomal polymorphisms, mitotic recombination events, and gains and losses of heterozygosity, superimposed on a fundamentally clonal mode of reproduction. Molecular typing of C. albicans strains shows geographical evolutionary associations but these have become partially blurred, probably as a result of extensive human travel. Individual patients usually carry a single C. albicans strain type, but this may undergo microvariation leading to detection of mixtures of closely related types. Associations have been found between clade 1, the most common multilocus sequence typing cluster of related C. albicans strains, and resistance to flucytosine and terbinafine. There are also clade-related associations with lengths of tandem repeats in some cell-surface proteins, but not with virulence or type of infection.
Antecedentes: La candidiasis invasora (CI) es la enfermedad fúngica oportunista más frecuente, tanto en niños como en adultos.
Objetivos: Se presenta una revisión actualizada sobre los aspectos epidemiológicos en neonatos, niños y adultos ingresados en unidades de cuidados intensivos, así como en pacientes oncohematológicos y receptores de trasplantes de órgano sólido.
Métodos: Se ha realizado una búsqueda bibliográfica en la base de datos PubMed/Medline. Se presenta una revisión actualizada.
Resultados y conclusiones: La CI se asocia a una elevada morbimortalidad y costes económicos. En las últimas décadas, la enfermedad invasora debida a Candida spp. ha aumentado de forma significativa en pacientes críticos, ha disminuido en pacientes oncohematológicos, aunque en todas las distintas subpoblaciones son más prevalentes las especies de Candida diferentes de C. albicans.
The yeast Candida parapsilosis is an opportunistic human pathogen frequently associated with nosocomial infections in neonates and patients with diminished immunity. A growing number of studies powered by recent advances in molecular genetics and genomics provide a background for uncovering the molecular basis of its virulence that suggests promising avenues for therapeutic intervention against this pathogen. Importantly, these studies also revealed several unique genetic and physiological features absent in model organisms, such as baker's and fission yeasts. Hence, besides the clinical impact, C. parapsilosis represents an interesting non-conventional model suitable for investigations of several fundamental biological phenomena in cellular physiology, morphogenesis, and genome maintenance. In this study, we provide a concise review on C. parapsilosis biology and highlight its interesting biological features. In addition, we summarize approaches for genetic manipulation, which have enhanced research on this species by overcoming limitations of conventional genetic analysis caused primarily by an apparent absence of a sexual cycle and the diploid state of its genome.
Invasive candidiasis (IC) is the most frequent fungal disease in children and adults.
To critically review and update the current epidemiology of Candida spp. disease in neonates, children and adults (critically ill patients and in oncohematologic patients and in solid organ transplant recipients).
We searched the PubMed/Medline, discussing the current data.
IC is associated with high attributable morbimortality and increased healthcare costs. In the last decades the incidence of invasive Candida spp. disease has increased in critically ill patients, has decreased in oncohematologic patients, although currently the involvement of non-albicans Candida species in the etiology of this disease is increasing steadily.
The ability of Candida parapsilosis to form biofilms on indwelling medical devices is correlated with virulence. To identify genes that are important for biofilm
formation, we used arrays representing approximately 4,000 open reading frames (ORFs) to compare the transcriptional profile
of biofilm cells growing in a microfermentor under continuous flow conditions with that of cells in planktonic culture. The
expression of genes involved in fatty acid and ergosterol metabolism and in glycolysis, is upregulated in biofilms. The transcriptional
profile of C. parapsilosis biofilm cells resembles that of Candida albicans cells grown under hypoxic conditions. We therefore subsequently used whole-genome arrays (representing 5,900 ORFs) to determine
the hypoxic response of C. parapsilosis and showed that the levels of expression of genes involved in the ergosterol and glycolytic pathways, together with several
cell wall genes, are increased. Our results indicate that there is substantial overlap between the hypoxic responses of C. parapsilosis and C. albicans and that this may be important for biofilm development. Knocking out an ortholog of the cell wall gene RBT1, whose expression is induced both in biofilms and under conditions of hypoxia in C. parapsilosis, reduces biofilm development.
OBJECTIVE: To analyze the secular trends of candidemia in a large tertiary-care hospital to determine the overall incidence, as well as the incidence by ward and by species, and to detect the occurrence of outbreaks. DESIGN: Retrospective descriptive analysis. Secular trends were calculated using the Mantel-Haenszel test. SETTING: A large tertiary-care referral center in Spain with a pediatric intensive care unit (ICU) to which more than 500 children with congenital cardiac disease are admitted annually. PATIENTS: All patients with candidemia occurring from 1988 to 2000 were included. Cases were identified from laboratory records of blood cultures. RESULTS: There were 331 episodes of candidemia. The overall incidence of nosocomial candidemia was 0.6 episode per 1,000 admissions and remained stable throughout the study period (P = .925). The species most frequently isolated was Candida albicans, but the incidence of C. parapsilosis candidemia increased (P = .035). In the pediatric ICU, the incidence of C. parapsilosis was 5.6 episodes per 1,000 admissions and it was the predominant species. Outbreaks occurred occasionally in the pediatric ICU, suggesting nosocomial transmission. CONCLUSIONS: During this 13-year period, the incidence of candidemia remained stable in this hospital, but C. parapsilosis increased in frequency. Occasional outbreaks of candidernia suggested nosocomial transmission of Candida species.
When microbial strain-typing methods are compared, the most important characteristics are typeability, reproducibility, and discriminatory power. While typeability and reproducibility can be presented as numerical values, indices of discriminatory power have only recently been described. This paper examines the relationship between reproducibility and indices of discriminatory power. In an individual typing method, an inverse relationship between reproducibility and discriminatory power appears as the number of test differences required in order to distinguish between strains is increased. A method of standardizing the discriminatory power of a typing method to a predetermined reproducibility is presented. In this way the discriminatory powers of different typing methods can be compared while being standardized for the effect of reproducibility.
Candida parapsilosis accounts for a significant number of nosocomial fungemias, but in fact, no effective and verified genetic fingerprinting
method has emerged for assessing the relatedness of independent isolates for epidemiological studies. A complex 15-kb DNA
fingerprinting probe, Cp3-13, was therefore isolated from a library ofC. parapsilosis genomic DNA fragments. The efficacy of Cp3-13 for DNA fingerprinting was verified by a comparison of its clustering capacity
with those of randomly amplified polymorphic DNA analysis and internally transcribed spacer region sequencing, by testing
species specificity, and by assessing its capacity to identify microevolutionary changes both in vitro and in vivo. Southern
blot hybridization of EcoRI/SalI-digested DNA with Cp3-13 provides a fingerprinting system that (i) identifies the same strain in independent isolates, (ii)
discriminates between unrelated isolates, (iii) separates independent isolates into valid groups in a dendrogram, (iv) identifies
microevolution in infecting populations, and (v) is amenable to automatic computer-assisted DNA fingerprint analysis. This
probe is now available for epidemiological studies.
This report describes the nosocomial acquisition of Candida parapsilosis candidemia by one of the six premature newborns housed in the same room of a neonatal intensive care unit at the Ospedale
Santa Chiara, Pisa, Italy. The infant had progeria, a disorder characterized by retarded physical development and progressive
senile degeneration. The infant, who was not found to harbor C. parapsilosis at the time of his admission to the intensive care unit, had exhibited symptomatic conjunctivitis before the onset of a severe
bloodstream infection. In order to evaluate the source of infection and the route of transmission, two independent molecular
typing methods were used to determine the genetic relatedness among the isolates recovered from the newborn, the inanimate
hospital environment, hospital personnel, topically and intravenously administered medicaments, and indwelling catheters.
Among the isolates collected, only those recovered from the hands of two nurses attending the newborns and from both the conjunctiva
and the blood of the infected infant were genetically indistinguishable. Since C. parapsilosis was never recovered from indwelling catheters or from any of the drugs administered to the newborn, we concluded that (i)
horizontal transmission of C. parapsilosis occurred through direct interaction between nurses and the newborn and (ii) the conjunctiva was the site through which C. parapsilosis entered the bloodstream. This finding highlights the possibility that a previous C. parapsilosis colonization and/or infection of other body sites may be a predisposing condition for subsequent C. parapsilosis hematogenous dissemination in severely ill newborns.
To determine the incidence of Candida bloodstream infections (BSI) and antifungal drug resistance, population-based active laboratory surveillance was conducted
from October 1998 through September 2000 in two areas of the United States (Baltimore, Md., and the state of Connecticut;
combined population, 4.7 million). A total of 1,143 cases were detected, for an average adjusted annual incidence of 10 per
100,000 population or 1.5 per 10,000 hospital days. In 28% of patients, Candida BSI developed prior to or on the day of admission; only 36% of patients were in an intensive care unit at the time of diagnosis.
No fewer than 78% of patients had a central catheter in place at the time of diagnosis, and 50% had undergone surgery within
the previous 3 months. Candida albicans comprised 45% of the isolates, followed by C. glabrata (24%), C. parapsilosis (13%), and C. tropicalis (12%). Only 1.2% of C. albicans isolates were resistant to fluconazole (MIC, ≥64 μg/ml), compared to 7% of C. glabrata isolates and 6% of C. tropicalis isolates. Only 0.9% of C. albicans isolates were resistant to itraconazole (MIC, ≥1 μg/ml), compared to 19.5% of C. glabrata isolates and 6% of C. tropicalis isolates. Only 4.3% of C. albicans isolates were resistant to flucytosine (MIC, ≥32 μg/ml), compared to <1% of C. parapsilosis and C. tropicalis isolates and no C. glabrata isolates. As determined by E-test, the MICs of amphotericin B were ≥0.38 μg/ml for 10% of Candida isolates, ≥1 μg/ml for 1.7% of isolates, and ≥2 μg/ml for 0.4% of isolates. Our findings highlight changes in the epidemiology
of Candida BSI in the 1990s and provide a basis upon which to conduct further studies of selected high-risk subpopulations.
Candida parapsilosis is an important cause of bloodstream infections in the health care setting. We investigated a large C. parapsilosis outbreak occurring in a community hospital and conducted a case-control study to determine the risk factors for infection.
We identified 22 cases of bloodstream infection with C. parapsilosis: 15 confirmed and 7 possible. The factors associated with an increased risk of infection included hospitalization in the
intensive care unit (adjusted odds ratio, 16.4; 95% confidence interval, 1.8 to 148.1) and receipt of total parenteral nutrition
(adjusted odds ratio, 9.2; 95% confidence interval, 0.9 to 98.1). Samples for surveillance cultures were obtained from health
care worker hands, central venous catheter insertion sites, and medical devices. Twenty-six percent of the health care workers
surveyed demonstrated hand colonization with C. parapsilosis, and one hand isolate was highly related to all case-patient isolates by tests with the DNA probe Cp3-13. Outbreak strain
isolates also demonstrated reduced susceptibilities to fluconazole and voriconazole. This largest known reported outbreak
of C. parapsilosis bloodstream infections in adults resulted from an interplay of host, environment, and pathogen factors. Recommendations for
control measures focused on improving hand hygiene compliance.
Two new species, Candida orthopsilosis and C. metapsilosis, are proposed to replace the existing designations of C. parapsilosis groups II and III, respectively. The species C. parapsilosis is retained for group I isolates. Attempts to construct a multilocus sequence typing scheme to differentiate individual strains
of C. parapsilosis instead revealed fixed DNA sequence differences between pairs of subgroups in four genes: COX3, L1A1, SADH, and SYA1. PCR amplicons for sequencing were obtained for these four plus a further seven genes from 21 group I isolates. For nine
group II isolates, PCR products were obtained from only 5 of the 11 genes, and for two group III isolates PCR products were
obtained from a different set of 5 genes. Three of the PCR products from group II and III isolates differed in size from the
group I products. Cluster analysis of sequence polymorphisms from COX3, SADH, and SYA1, which were common to the three groups, consistently separated the isolates into three distinct sets. All of these differences,
together with DNA sequence similarities <90% in the ITS1 sequence, suggest the subgroups should be afforded species status. The near absence of DNA sequence variability among isolates
of C. parapsilosis and relatively high levels of sequence variability among isolates of C. orthopsilosis suggest that the former species may have evolved very recently from the latter.
Candida parapsilosis is an increasing cause of bloodstream infections (BSIs) in neonatal intensive care units (NICUs). It has been a persistent
problem in the NICU of Hospital for Children and Adolescents, Helsinki University Central Hospital, Helsinki, Finland, since
1987. Fluconazole prophylaxis has been used to control the problem. The number of new infections has, however, increased markedly
since September 2000. We assessed fluconazole consumption and occurrence of all Candida species in the NICU from 1991 to 2002. C. parapsilosis bloodstream isolates obtained in the NICU from 1990 to 2002 (n = 26) were genotyped and their fluconazole susceptibility was defined. A low rate of C. parapsilosis BSIs was correlated with high rates of consumption of fluconazole. No emergence of Candida species with primary resistance to fluconazole was detected. However, genotyping with a complex DNA fingerprinting probe
revealed that a single strain of C. parapsilosis with decreasing susceptibility to fluconazole was responsible for cross-infections that caused BSIs in the NICU over a 12-year
period. The emergence of fluconazole resistance in that strain was observed after more than 10 years of fluconazole prophylaxis.
To analyze the secular trends of candidemia in a large tertiary-care hospital to determine the overall incidence, as well as the incidence by ward and by species, and to detect the occurrence of outbreaks.
Retrospective descriptive analysis. Secular trends were calculated using the Mantel-Haenszel test.
A large tertiary-care referral center in Spain with a pediatric intensive care unit (ICU) to which more than 500 children with congenital cardiac disease are admitted annually.
All patients with candidemia occurring from 1988 to 2000 were included. Cases were identified from laboratory records of blood cultures.
There were 331 episodes of candidemia. The overall incidence of nosocomial candidemia was 0.6 episode per 1,000 admissions and remained stable throughout the study period (P = .925). The species most frequently isolated was Candida albicans, but the incidence of C. parapsilosis candidemia increased (P = .035). In the pediatric ICU, the incidence of C. parapsilosis was 5.6 episodes per 1,000 admissions and it was the predominant species. Outbreaks occurred occasionally in the pediatric ICU, suggesting nosocomial transmission.
During this 13-year period, the incidence of candidemia remained stable in this hospital, but C. parapsilosis increased in frequency. Occasional outbreaks of candidemia suggested nosocomial transmission of Candida species.
Candida parapsilosis, a pathogenic yeast, is composed of three newly designated genomic species that are physiologically and morphologically indistinguishable. Nosocomial infections caused by group I C. parapsilosis are often associated with the breakdown of infection control practices and the contamination of medical devices, solutions, and indwelling catheters. Due to the low levels of nucleotide sequence variation that are observed, an investigation of the size polymorphisms in loci harboring microsatellite repeat sequences was applied for the typing of C. parapsilosis group I isolates. PCR primer sets that flank the microsatellite repeats for seven loci were designed. Following amplification by PCR, the size of each amplification product was determined automatically by capillary electrophoresis. A total of 42 C. parapsilosis group I isolates were typed by microsatellite analysis, and their profiles were compared to the hybridization profiles obtained by use of the Cp3-13 DNA probe. A high degree of discrimination (discriminatory power = 0.971) was observed by microsatellite analysis. The number of different alleles per locus ranged from 14 for locus B to 5 for locus C. Microsatellite analysis detected 30 different microsatellite genotypes, with 24 genotypes represented by a single isolate. Comparison of the genotypes obtained by microsatellite analysis and those obtained by analysis of the Cp3-13 hybridization profiles showed that they were similar, and these methods were able to identify related and unrelated isolates. Some discrepancies were observed between the methods and may be due to higher mutation rates and/or homoplasy by microsatellite markers. Identical results were observed between microsatellite analysis and Cp3-13 DNA hybridization profile analysis for C. parapsilosis isolates obtained from two patients, demonstrating the reproducibilities of the methods in vivo. Identical microsatellite profiles were observed for isolates displaying different phenotypic switching morphologies. Indistinguishable Cp3-13 DNA hybridization profiles were observed for six epidemiologically related isolates; however, only three of six primary isolates had identical microsatellite profiles. Size variation at a single locus was observed for three of six isolates obtained either after the outbreak period or from a different body site, suggesting the potential of the method to detect microevolutionary events. Interestingly, for most loci a single allele per strain was observed; in contrast, two alleles per locus were observed for some strains, and consistent with the findings for natural isolates, some isolates may be aneuploid. Due to the potential for high throughput, reproducibility, and discrimination, microsatellite analysis may provide a robust and efficient method for the genotyping of large numbers of C. parapsilosis group I isolates.
Despite advances in supportive care and use of antibiotics, sepsis preserves its importance due to its high mortality and morbidity for neonates. Identifying the causative agents and antibiotic resistance yearly in a neonatal intensive care unit (NICU) helps the physician to choose the most appropriate empirical therapy. In this study we aimed to evaluate positive blood cultures and antibiotic susceptibilities of newborns with proven sepsis during the years 2000-2002 in our NICU. The charts of babies with sepsis were evaluated for clinical characteristics, positive cultures and antimicrobial susceptibilities, retrospectively. Although most of the admitted patients were premature (76.5%), the frequency of proven sepsis was quite low, at 9.1% among 909 newborns. Mortality rate in sepsis was 16%. The most commonly isolated micro-organisms were coagulase-negative staphylococci (CoNS) (31.3%), fungi (19.2%), Staphylococcus aureus (13%) and Klebsiella pneumoniae (10.5%). Methicillin resistance for CoNS was 92.3% and for S. aureus was 72.7%. In the last year, a significant increase in the frequency of Klebsiella pneumoniae (8.3 vs 14.2%), CoNS (27.1 vs 37.1%), Pseudomonas aeruginosa (2.1 vs 8.6%) and fungal infections (18.8 vs 20%) was observed compared to the previous years. An initial empirical antibiotic therapy for late-onset sepsis was designed with teicoplanin + piperacillin-tazobactam/meropenem + antifungal (fluconazole or amphotericin B) as the best combination to cover this spectrum until the culture results arrive. However, this combination is only compatible with our results and may not be applied in all units. Every unit must follow the bacterial spectrum and antibacterial resistance patterns to choose their specific empirical treatment strategy for nosocomial infections.
Recent reports suggest that candidemia caused by fluconazole-resistant strains is increasing in certain adult populations. We evaluated the annual incidence of neonatal candidemia and the frequency of disease caused by different species of Candida among neonates in the United States.
The study included neonates admitted to 128 NICUs participating in the National Nosocomial Infections Surveillance system from January 1, 1995, to December 31, 2004 (study period).
Reports of bloodstream infection (BSI) with Candida spp.; Candida BSIs, patient admissions, patient-days, and central venous catheter days were pooled by birth weight category. The number of Candida BSIs per 100 patients (attack rate) and per 1000 patient-days (incidence density) was determined. Both overall and species-specific rates were calculated; data were pooled over time to determine the differences by birth weight category and by year to determine trends over time.
From the 130,523 patients admitted to NICUs during the study period, there were 1997 Candida spp. BSIs reported. Overall, 1472 occurred in the <1000-g birth weight group. Candida albicans BSIs were most common, followed by Candida parapsilosis, Candida tropicalis, Candida lusitaniae, Candida glabrata, and only 3 Candida krusei. Among neonates <1000 g, incidence per 1000 patient-days decreased from 3.51 during 1995-1999 to 2.68 during 2000-2004 but remained stable among heavier neonates. No increase in infections by species that tend to demonstrate resistance to fluconazole (C glabrata or C krusei) was observed.
Although Candida BSI is a serous problem among neonates <1000 g, incidence has declined over the past decade, and disease with species commonly resistant to azoles was extremely rare.
Almost one-third of patients with bloodstream infections with Candida species (candidemia) have onset of disease that occurs outside of the hospital or < or = 2 days after hospital admission (i.e., community-onset candidemia). We compared the characteristics of patients who developed candidemia by the timing of onset of infection.
Incident episodes of candidemia were identified through active, population-based surveillance in Connecticut and in Baltimore and Baltimore County, Maryland, during 1 October 1998-30 September 2000. The molecular subtypes of a sample of 45 Candida parapsilosis isolates were evaluated using Southern blots hybridized with the complex probe Cp3-13.
Overall, 356 (31%) of the 1143 incident episodes of candidemia were classified as community-onset disease (occurring < or = 2 days after hospital admission), and 132 (37%) were caused by Candida albicans, 89 (25%) were caused by Candida glabrata, 57 (16%) were caused by C. parapsilosis, and 53 (15%) were caused by Candida tropicalis. Community-onset disease was less likely to be associated with concurrent immunosuppressive therapy, recent surgery, or use of a central venous catheter, compared with inpatient disease. Among patients with community-onset disease, the median time from blood culture to initiation of antifungal treatment was 2.7 days, the 30-day case-fatality rate was 26%, and 262 patients (75%) had been hospitalized at least once in the previous 3 months. Although there were few differences between patients with very recent hospitalization (in the previous 1 month), less recent hospitalization (previous 1-3 months), and no documented past hospitalization, C. parapsilosis was more frequently associated with community-onset disease as hospitalization became more distant. C. parapsilosis strains tended to be unique to the patient, with little similarity found between strain types, on the basis of epidemiologic classification of patients.
We report that community-onset candidemia is common and occurs in patients with extensive contact with the health care system. Disease caused by C. parapsilosis tends to involve unique strains.
In order to determine the local epidemiology of candidemia, Candida strains isolated between 1994 and 2000 were identified to species level; antifungal resistance patterns and DNA fingerprints were analyzed. Identification of Candida strains (n: 140) was performed with germ tube test and carbohydrate assimilation reactions. Minimal inhibitory concentrations were determined using a commercial test for 5-flucytosine and the broth macrodilution method according to NCCLS for fluconazole and amphotericin B. Molecular relatedness was determined by restriction endonuclease analysis of genomic DNA followed by probe hybridization. C. albicans (37.2%), C. parapsilosis (32.2%), and C. tropicalis (12.2%) comprised 114 (81.4%) of 140 isolates. Susceptibility tests did not reveal resistance to amphotericin B in any of the Candida isolates. Fluconazole resistance was detected in one isolate of C. krusei, and 5-flucytosine resistance in two C. tropicalis isolates and one C. albicans isolate. Significantly higher frequency of clusters with identical strains in C. parapsilosis and C. tropicalis was detected compared to C. albicans. Pediatric wards are particularly important in the nosocomial transmission of non-albicans candida species.
Invasive candidiasis (IC) is a leading cause of mycosis-associated mortality in the United States. We examined data from the National Center for Health Statistics and reviewed recent literature in order to update the epidemiology of IC. IC-associated mortality has remained stable, at approximately 0.4 deaths per 100,000 population, since 1997, while mortality associated with invasive aspergillosis has continued to decline. Candida albicans remains the predominant cause of IC, accounting for over half of all cases, but Candida glabrata has emerged as the second most common cause of IC in the United States, and several less common Candida species may be emerging, some of which can exhibit resistance to triazoles and/or amphotericin B. Crude and attributable rates of mortality due to IC remain unacceptably high and unchanged for the past 2 decades. Nonpharmacologic preventive strategies should be emphasized, including hand hygiene; appropriate use, placement, and care of central venous catheters; and prudent use of antimicrobial therapy. Given that delays in appropriate antifungal therapy are associated with increased mortality, improved use of early empirical, preemptive, and prophylactic therapies should also help reduce IC-associated mortality. Several studies have now identified important variables that can be used to predict risk of IC and to help guide preventive strategies such as antifungal prophylaxis and early empirical therapy. However, improved non-culture-based diagnostics are needed to expand the potential for preemptive (or early directed) therapy. Further research to improve diagnostic, preventive, and therapeutic strategies is necessary to reduce the considerable morbidity and mortality associated with IC.
The neonate, whether premature or of normal gestational age, is a unique host from an immunologic perspective. Many components of the immune system function less well in neonates compared with adults, giving rise to the concept of an 'immunodeficiency of immaturity.' The adaptive significance of these alterations for neonatal survival remains obscure. This review highlights some of the most prominent quantitative and qualitative differences between neonatal and adult immune systems. From a clinical standpoint, the most important differences appear to be (1) reduction in the available bone marrow reserve of granulocyte precursors, (2) reduction in serum complement activity, (3) decreased ability to produce antibodies against bacterial polysaccharide antigens, and (4) increased percentage of T lymphocytes bearing an antigenically 'naive' cell surface phenotype and a correspondingly naive functional program.
Infant skin differs from adult skin in several ways. These important differences place infants at increased risk for fluid electrolyte imbalance, thermal instability, skin damage, percutaneous infection, and percutaneous toxicity from topically applied agents. This article includes a review of skin development, as well as the details of current skin care practices in the neonatal nursery. A better understanding of the principles of infant skin care and a more uniform approach to skin care in the neonatal nursery can minimize risks and costs to this special population of patients.
Background. Candida species are important nosocomial pathogens in neonatal intensive care unit (NICU) patients.
Methods. A prospective cohort study was performed in six geographically diverse NICUs from 1993 to 1995 to determine the incidence of and risk factors for candidemia, including the role of gastrointestinal (GI) tract colonization. Study procedures included rectal swabs to detect fungal colonization and active surveillance to identify risk factors for candidemia. Candida strains obtained from the GI tract and blood were analyzed by pulsed field gel electrophoresis to determine whether colonizing strains caused candidemia.
Results. In all, 2847 infants were enrolled and 35 (1.2%) developed candidemia (12.3 cases per 1000 patient discharges or 0.63 case per 1000 catheter days) including 23 of 421 (5.5%) babies ≤1000 g. After adjusting for birth weight and abdominal surgery, forward multivariate logistic regression analysis demonstrated significant risk factors, including gestational age <32 weeks, 5-min Apgar <5; shock, disseminated intravascular coagulopathy, prior use of intralipid, parenteral nutrition, central venous catheters, H2 blockers, intubation or length of stay >7 days before candidemia (P < 0.05). Catheters, steroids and GI tract colonization were not independent risk factors, but GI tract colonization preceded candidemia in 15 of 35 (43%) case patients.
Conclusions. Candida spp. are an important cause of late onset sepsis in NICU patients. The incidence of candidemia might be decreased by the judicious use of treatments identified as risk factors and avoiding H2 blockers.
A national surveillance program of nosocomial blood stream infections (BSI) in the USA between April 1995 and June 1996 revealed that Candida was the fourth leading cause of nosocomial BSI, accounting for 8% of all infections. Forty-eight percent of 379 episodes of candidemia were due to species other than Candida albicans. The rank order of non-C. albicans species was C. glabrata (20%) > C. tropicalis (11%) > C. parapsilosis (8%) > C. krusei (5%) > other Candida spp. (4%). The species distribution varied according to geographic region, with non-C. albicans species predominating in the Northeast (54%) and Southeast (53%) regions, and C. albicans predominating in the Northwest (60%) and Southwest (70%) regions. In vitro susceptibility studies demonstrated that 95% of non-C. albicans isolates were susceptible to 5-fluorocytosine, and 84% and 75% were susceptible to fluconazole and itraconazole, respectively. Geographic variation in susceptibility to itraconazole, but not other agents, was observed. Isolates from the Northwest and Southeast regions were more frequently resistant to itraconazole (29–30%) than those from the Northeast and Southwest regions (17–18%). Molecular epidemiologic studies revealed possible nosocomial transmission (five medical centers). Continued surveillance for the presence of non-C. albicans species among hospitalized patients is recommended.
Random amplified polymorphic DNA (RAPD) was used to better characterize the genotypic relatedness among medically important Candida species. By using short oligomer primers (10-mers) with arbitrarily chosen sequences in the polymerase chain reaction, distinctive and reproducible sets of polymerase chain reaction products were observed for isolates of C. albicans, C. lusitaniae, C. tropicalis, and Torulopsis (Candida) glabrata. The RAPD analysis differentiated a physiologically homogeneous panel of C. parapsilosis into three distinct groups and showed genetic diversity within C. haemulonii. Intraspecies DNA-length polymorphisms were seen for RAPD profiles derived from different isolates of each species. Analysis of RAPDs from a panel of C. albicans, which included 16 laboratory derivatives of two reference strains, showed that the profiles of unrelated strains differed and that the derivatives of each reference strain were identifiable. Minor differences in the RAPD profiles, suggestive of mutations that had occurred during the long-term maintenance of the strains, were detected. Because of its ease and reliability, RAPD analysis should be useful in providing genotypic characters for taxonomic descriptions, for confirming the identities of stock isolates, for typing Candida species in epidemiologic investigations, and for use in the rapid identification of pathogenic fungi.
Late-onset sepsis (occurring after 3 days of age) is an important problem in very low birth weight (VLBW) infants. To determine the current incidence of late-onset sepsis, risk factors for disease, and the impact of late-onset sepsis on subsequent hospital course, we evaluated a cohort of 7861 VLBW (401 to 1500 gm) neonates admitted to the 12 National Institute of Child Health and Human Development (NICHD) Neonatal Research Network centers during a 32-month period (1991 to 1993).
The NICHD Neonatal Research Network maintains a prospectively collected registry of all VLBW neonates cared for at participating centers. Data from this registry were analyzed retrospectively.
Of 6911 infants who survived beyond 3 days, 1696 (25%) had one or more episodes of blood culture-proven sepsis. The vast majority of infection (73%) were caused by gram-positive organisms, with coagulase-negative staphylococci accounting for 55% of all infections. Rate of infection was inversely related to birth weight and gestational age. Complications of prematurity associated with an increased rate of infection included intubation, respiratory distress syndrome, prolonged ventilation, bronchopulmonary dysplasia, patent ductus arteriosus, severe intraventricular hemorrhage, and necrotizing enterocolitis. Among infants with bronchopulmonary dysplasia, those with late-onset sepsis had a significantly longer duration of mechanical ventilation (45 vs 33 days; p <0.01). Late-onset sepsis prolonged hospital stay: the mean number of days in the hospital for VLBW neonates with and without late-onset sepsis was 86 and 61 days, respectively (p <0.001). Even after adjustment for other complications of prematurity, including intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia, infants with late-onset sepsis had a significantly longer hospitalization (p <0.001). Moreover, neonates in whom late-onset sepsis developed were significantly more likely to die than those who were uninfected (17% vs 7%; p <0.000 1), especially if they were infected with gram-negative organisms (40%) or fungi (28%). Deaths attributed to infection increased with increasing chronologic age. Whereas only 4% of deaths in the first 3 days of life were attributed to infection, 45% of deaths after 2 weeks were related to infection.
Late-onset sepsis is a frequent and important problem among VLBW preterm infants. Successful strategies to decrease late-onset sepsis should decrease VLBW mortality rates, shorten hospital stay, and reduce costs.
Candida parapsilosis is a common cause of sporadic and epidemic infections in neonatal intensive care units (NICUs). When a cluster of C. parapsilosis bloodstream infections occurred in NICU patients in a hospital in Louisiana, it provided us with the opportunity to conduct an epidemiologic investigation and to apply newly developed molecular typing techniques.
A case-patient was defined as any NICU patient at Louisiana State University Medical Center, University Hospital, with a blood culture positive for C. parapsilosis during July 20 to 27, 1991. To identify risk factors for C. parapsilosis bloodstream infection, a cohort study of all NICU infants admitted during July 17 to 27, 1991, was performed. Electrophoretic karyotyping was used to assess the relatedness of C. parapsilosis isolates.
The receipt of liquid glycerin given as a suppository was identified as a risk factor (relative risk, 31.2; 95% confidence intervals, 4.3 to 226.8). Glycerin was supplied to the NICU in a 16-oz multidose bottle. Bottles used at the time of the outbreak were not available for culture. All six available isolates from four case-patients had identical chromosomal banding patterns; six University Hospital non-outbreak isolates had different banding patterns.
This study demonstrates the utility of combined epidemiologic and laboratory techniques in identifying a novel common source for a C. parapsilosis bloodstream infection outbreak and illustrates that extreme caution should be exercised when using multidose medications in more than one patient.
Candida species are frequently encountered as part of the human commensal flora. Colonization mostly precedes candidemia and is an independent risk factor for the development of candidemia. Genotyping methods showed the similarity between colonizing and infecting strains, thus making endogenous origin likely, though exogenous sources like total parenteral nutrition also have been described. Health care workers (HCWs) play an important role in the transmission of yeasts. Candida species are frequently isolated from the hands of HCWs and can be transmitted from hands to patients. Granulocytopenia and damage of the mucosal lining resulting from intensive chemotherapy due to cancer, the increasing use of broad spectrum antibiotics, and the use of intravenous catheters are other important risk factors for the development of candidemia. Candidemia is associated with a high mortality and prolonged hospitalization. Therefore, and because of the high frequency of dissemination, all candidemias should be treated. Amphotericin B was considered the standard drug for the systemic treatment of candidemia. Fluconazole has been shown to be an effective and safe alternative in non-neutropenic patients. 5-Fluorocytosine has been used in combination with amphotericin B in the treatment of deep-seated infections. Liposomal formulations of amphotericin B and other new antifungal drugs currently are under investigation. C. albicans is the most frequently isolated Candida species, although the proportion of infections caused by non-C. albicans species is increasing. Also, there are reports of development of resistance to amphotericin B. C. lusitaniae is known for primary resistance and the development of resistance to amphotericin B. Development of resistance to fluconazole is mainly seen in AIDS patients with recurrent oropharyngeal candidiasis who receive longer courses of therapy.
Candida species are important nosocomial pathogens in neonatal intensive care unit (NICU) patients.
A prospective cohort study was performed in six geographically diverse NICUs from 1993 to 1995 to determine the incidence of and risk factors for candidemia, including the role of gastrointestinal (GI) tract colonization. Study procedures included rectal swabs to detect fungal colonization and active surveillance to identify risk factors for candidemia. Candida strains obtained from the GI tract and blood were analyzed by pulsed field gel electrophoresis to determine whether colonizing strains caused candidemia.
In all, 2,847 infants were enrolled and 35 (1.2%) developed candidemia (12.3 cases per 1,000 patient discharges or 0.63 case per 1,000 catheter days) including 23 of 421 (5.5%) babies < or =1,000 g. After adjusting for birth weight and abdominal surgery, forward multivariate logistic regression analysis demonstrated significant risk factors, including gestational age <32 weeks, 5-min Apgar <5; shock, disseminated intravascular coagulopathy, prior use of intralipid, parenteral nutrition, central venous catheters, H2 blockers, intubation or length of stay > 7 days before candidemia (P < 0.05). Catheters, steroids and GI tract colonization were not independent risk factors, but GI tract colonization preceded candidemia in 15 of 35 (43%) case patients.
Candida spp. are an important cause of late onset sepsis in NICU patients. The incidence of candidemia might be decreased by the judicious use of treatments identified as risk factors and avoiding H2 blockers.
Candidaemia caused by Candida parapsilosis (CP) is being increasingly reported among infants in neonatal intensive care units (NICU). To assess relative severity, clinical manifestations of candidaemia caused by C. albicans (CA) and CP in a NICU were compared.
Between January 1994 and July 1997, episodes of candidaemia occurring among infants hospitalized in the NICU were identified in a children's hospital. The demographic characteristics, associated risk factors, clinical manifestations and outcome of the infants with CP fungaemia were collected and compared with those of the infants with CA fungaemia.
Twenty-four episodes caused by CA and 22 episodes caused by CP were included in this study. No significant differences were found between the two groups for gestational age, birth weight, male gender, post-natal age at onset of candidaemia, frequency of antecedent neonatal events, prior duration of antibiotic therapy and hyperalimentation, as well as presence of central venous catheter (CVC). Infants with CA fungaemia were significantly more likely than those with CP fungaemia to present with hypoxaemia, bradycardia and respiratory distress requiring intubation, and have a longer prior duration of indwelling CVC and a higher dissemination rate. The eradication rate of candidaemia and overall case fatality rate were comparable in both groups. but CP fungaemia did not appear to cause acute lethal events.
The presenting signs of CP fungaemia are relatively not so severe, but CP fungaemia, which is relatively difficult to eradicate, increases the morbidity and mortality of the infants.
To determine the epidemiology of candidemia in our neonatal intensive care unit; to compare risk factors, clinical presentation, and outcomes for neonates infected with Candida albicans, Candida parapsilosis, and coagulase-negative staphylococcus (CoNS); and to suggest a rational approach to empiric antifungal therapy of neonates at risk for nosocomial infection.
Retrospective chart review of all neonatal intensive care unit patients with systemic candidiasis or CoNS infection between January 1, 1995 and July 31, 1998 at Duke University Medical Center.
Fifty-one patients were reviewed. Nine of 19 patients infected with C parapsilosis and 5 of 15 patients infected with C albicans died of fungemia. Seventeen neonates had >2 positive cultures for CoNS obtained within 96 hours and 1 died. There was no statistically significant difference in birth weight, gestational age, or age at diagnosis between patient groups; however, candidemic patients had a sevenfold higher mortality rate. Before diagnosis, candidemic patients had greater exposure to systemic steroids, antibiotics, and catecholamine infusions. Of the 51 patients, 32 received third-generation cephalosporins in the 2 weeks before diagnosis and 19 did not. Twenty-nine of the 32 who were treated with third-generation cephalosporins subsequently developed candidemia, while candidemia occurred in only 5 of 19 patients who were not treated with cephalosporins. At the time of diagnosis, candidemic patients were more likely to have required mechanical ventilation and were less likely to be tolerating enteral feeding. Multivariate clustered logistic regression analysis revealed that candidemic patients had more exposure to third-generation cephalosporins. Once the clinician was notified of a positive blood culture for Candida, patients infected with C parapsilosis retained their central catheters longer than patients infected with C albicans.
In this retrospective review, we were able to identify aspects of the clinical presentation and medication history that may be helpful in differentiating between candidemia and CoNS bacteremia. Those key features may be used by clinicians to initiate empiric amphotericin B therapy in premature neonates at risk for nosocomial infections. Prolonged use of third-generation cephalosporins was strongly associated with candidemia. There was no statistically significant difference in the morbidity and mortality between patients infected with C parapsilosis and those infected with C albicans. Observed delays in removal of the central venous catheter may have contributed to finding a mortality rate from C parapsilosis that was higher than was previously reported.
Candida albicans strain diversity and fluconazole resistance were prospectively analyzed in oral strains from 29 adult human immunodeficiency virus (HIV)-positive patients followed for > 1 year who had five or more culture-positive clinic visits. Molecular typing consisted of genomic blots probed with the Ca3 repetitive element. Sixteen patients had one or more episodes of oropharyngeal candidiasis (OPC), 12 (75%) maintained the original genotype, whereas the remaining four patients had a succession of 2-3 genotypes. The original genotype, either alone or mixed with another strain or with non-C. albicans Candida spp., was recovered from oral lesions in 13 of 15 evaluable (86.7%) patients. C. dubliniensis was the infecting yeast in the remaining two patients. Different patterns of fluconazole resistance occurred in three OPC patients. One patient's infecting strain became less susceptible. A second patient was infected with a resistant genotype and a progressively more susceptible minor genotype variant. C. dubliniensis isolates from the third patient varied in susceptibility. Thirteen colonized patients who never developed OPC harbored a greater variety of C. albicans genotypes (2-6) than their infected counterparts (P = 0.35). OPC patients maintained their original endogenous C. albicans strains for prolonged periods, whether or not they demonstrated decreased in vitro susceptibility to fluconazole. The adaptation and maintenance of an endogenous C. albicans strain within its host may be linked to as yet uncharacterized factors.
Candida infections have become an increasingly frequent problem in neonatal intensive care units, particularly among extremely low birth weight infants. Transmission occurs both vertically and horizontally, with Candida albicans and C. parapsilosis as the predominant species. Multiple risk factors have been identified with prior antibiotic exposure, presence of a central line, endotracheal intubation, and prior fungal colonization reported most frequently. The primary site of infection can involve the bloodstream, meninges, or urinary tract, but disease is frequently disseminated to multiple organ systems. Amphotericin is the most commonly used antifungal agent, although fluconazole is being used more frequently. The potential role of antifungal prophylaxis is not yet clearly defined, but has been the topic of recent investigative efforts. The crude mortality rate among neonates with systemic candidiasis remains approximately 30%.
This is a cohort study of pediatric outpatients receiving total parenteral nutrition (TPN) and follow-up care in a Tennessee hospital between January and June 1999. The study was conducted following an increase in the incidence of candidemia. Of 13 children receiving home TPN, five had candidemia; three were due to Candida parapsilosis. Case patients were more likely to have an underlying hematologic disease (P = 0.02) as well as previous history of fungemia (P = 0.02). Two case patients had successive candidemia episodes 3 months apart; karyotypes and RAPD profiles of each patient's successive C. parapsilosis isolates were similar. Candida spp. were frequently detected in hand cultures from cohort members (four of 10) and family member caregivers (nine of 11); C parapsilosis was isolated from five caregivers. Our findings underscore the challenges of maintaining stringent infection control practices in the home health care setting and suggest the need for more intensive follow-up and coordination of home TPN therapy among pediatric patients.
Candida spp. are increasingly important hospital-acquired pathogens in neonatal intensive care units (NICU) and cause considerable mortality in preterm infants. Most studies have been limited to a single institution. The aim of this study was to determine the epidemiology of candidemia in all Barcelona NICUs.
We conducted prospective population-based surveillance for candidemia in Barcelona, Spain, during 2002-2003. This report focuses on the results from 5 participating hospitals with NICUs.
We detected 24 cases, resulting in an annual incidence of 32.6 cases per 100,000 live births and 1.1 cases per 100 NICU discharges. Median gestational age was 27.5 weeks (range, 24-40.5), and there were 21 cases among very low birth weight infants. Among the 20 (83%) cases evaluated for the presence of end organ infection, endophthalmitis occurred in 2 cases, and endocarditis, meningitis and peritonitis occurred in 1 case each. Candida parapsilosis was the most frequent species isolated (67%). All isolates were fluconazole-susceptible. Crude mortality was 21%.
The preponderance of C. parapsilosis candidemias observed in Barcelona NICUs is similar to reports from the literature. Morbidity and mortality associated with neonatal candidemia remain high.
ME-2-4 ME-2-4 a Cp3-13 genotype as shown in Figs. 1 and 2
- Hand
Hand, caregiver patient 2 ME-2-4 ME-2-4 a Cp3-13 genotype as shown in Figs. 1 and 2. E. Reiss et al. / Infection, Genetics and Evolution 8 (2008) 103–109 References
GA-11 GA-11 MC 60 Skin non-case infant GA-12 GA-12 Outpatients of a Children's Hospital, Memphis TN
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GA-11 GA-11 MC 60 Skin non-case infant. GA-12 GA-12 Outpatients of a Children's Hospital, Memphis TN, 1998-1999 Cano et al. (2005) Y0884-99
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