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ABSTRACT: Aspergillus flavus is the second most important Aspergillus species associated with aspergillosis and the incidence of infections caused by it are increasing in the immunocompromised population. This species is of major epidemiological importance in regions with a dry and hot climate. Despite the growing clinical significance of A. flavus, data on its molecular epidemiology are scarce. This study was aimed at examining whether isolates from distinct genotypes were involved in distinct clinical forms of aspergillosis. Sixty-three clinical isolates of A. flavus recovered from 35 patients with various clinical presentations of aspergillosis were characterized by microsatellite typing. The highest discriminatory power for a single locus was obtained with the AFLA1 marker, which had 14 distinct alleles and a 0.903 D value. The combination of all six markers yielded 48 different genotypes with a 0.994 D value. There was a considerable genetic diversity in the isolates and patients with invasive aspergillosis were usually colonized by multiples genotypes. There was no evidence that a given genotype was associated with a particular clinical presentation of A. flavus aspergillosis. The occurrence of more than one genotype in clinical samples indicates that a patient may be infected by multiple genotypes and that any particular isolate from a clinical specimen may not necessarily be the one causing aspergillosis.
Medical mycology: official publication of the International Society for Human and Animal Mycology 01/2013; · 2.13 Impact Factor
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ABSTRACT: In recent years, an increase of systemic Candida infections was noted. Thus, identification and susceptibility testing to antifungals became of considerable importance. The technique of dilution in liquid medium developed by « National committee for clinical laboratory standards » NCCLS or more recently named CLSI « Clinical and laboratory standards institute » is the reference method most used. The European committee "European committee on antibiotic susceptibility testing" or EUCAST has made progress by determining the susceptibility of strains within a shorter time. However, the use of these techniques is limited especially in clinical microbiology laboratories. Indeed, others techniques for determining the sensitivity have been developed such as those based on agar diffusion (E-test and disk diffusion), on microdilution (Sensititre yeastOne, Vitek 2 AST-YS01), on flow cytometry techniques and the MALDI-TOF.
Annales de biologie clinique. 12/2012; 70(6):635-642.
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ABSTRACT: Aspergillosis is one of the most common causes of death in captive birds. A. fumigatus accounts for approximately 95% of the cases of aspergillosis and Aspergillus flavus is the second most frequent organism associated with avian infections. In the present study, the fungal detection was performed in environmental samples (eggs, food, and litter of birds) (n=150). In addition, avian clinical samples were isolated post mortem by plating lung material. A. flavus was identified in both avian clinical isolates and in environmental samples (19%). Except A. flavus, even higher distribution was established for Penicillium (39%) and Cladosporium (21%) in environmental samples. Microsatellite typing of A. flavus was used to analyze 7 clinical avian isolates and 22 environmental isolates. All avian clinical isolates were A. flavus, and from eggs, food, and litter this species occupied the third place (19%) after Penicillium (39%) and Cladosporium (21%). Upon the microsatellite analysis, 5 to 8 distinct alleles were detected for each microsatellite marker. The highest discriminatory power for a single locus was obtained with the AFPM7 marker, which had 8 distinct alleles and a 0.852 D value. The combination of all 6 markers yielded 25 different haplotypes with a 0.991 D value. In one case, an identical genotype was found in a clinical avian isolate (lung biopsy) and an environmental isolate (egg). Microsatellite analysis of A. flavus performed in avian isolates and environmental samples displayed an excellent discriminatory power. This method showed a very good reproducibility (100%). Results of this study, revealed an interesting clustering of clinical samples (biopsy) and environmental samples (eggs) with a clear separation between isolates. Based on these results, aspergillosis in birds may be induced by a great diversity of isolates.
Journal of Medical Microbiology 09/2012; · 2.50 Impact Factor
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ABSTRACT: Whether in vitro antifungal susceptibility findings correlate with the outcome of patients with invasive aspergillosis (IA) remains debated. This study aimed to test whether IA patients' outcomes were associated with in vitro susceptibility results. To do so, we determined the in vitro susceptibility to amphotericin B (AMB) of 37 Aspergillus flavus isolates from 14 patients with haematological malignancies diagnosed with proven or probable IA, of which 13 were treated with AMB deoxycholate. Minimal inhibitory concentrations (MICs) were determined by Etest with the isolates classified as in vitro sensitive (AMB-S) or resistant (AMB-R) if their MICs were < 2 or ≥ 2 mg/l, respectively. The association of the patients' death with primary disease, administered antifungal treatment, and infection with AMB-R A. flavus was tested using generalized estimating equations logistic regression. We assessed AMB-R in 31/37 (84%) isolates. In the patients treated with AMB, the survival rate was 2/3 (67%) and 2/9 (22%) for those infected with AMB-S or AMB-R A. flavus, respectively. Both infection with AMB-R A. flavus (P = 0.014) strain and acute myelocytic leukaemia as the underlying primary disease (P = 0.036) were independent predictors of death. Our findings indicate that in vitro resistance predicts a poor outcome in patients with A. flavus invasive disease treated with AMB. Recent advances in non-culture-based microbiological methods should not discourage efforts to obtain in vitro antifungal susceptibility results, which are critical for the choice of antifungal therapy in patients with IA.
Medical mycology: official publication of the International Society for Human and Animal Mycology 05/2012; 50(8):829-34. · 2.13 Impact Factor
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ABSTRACT: Although the arsenal of agents with anti-Aspergillus activity has expanded over the last decade, mortality due to invasive aspergillosis remains unacceptably high. Resistance of the Aspergillus spp. species to antifungal drugs increased in the last 20 years with the increase in antifungal drugs use and might partially account for treatment failures. Recent advances in our understanding of mechanisms of antifungal drug action in Aspergillus, along with the standardization of in vitro susceptibility testing methods, have brought resistance testing to the forefront of clinical mycology. Recent modifications in taxonomy and understanding of the acquired resistance mechanisms of Aspergilli to drugs should support a better management of Aspergillus infections. In this paper, we review the current knowledge on epidemiology and underlying mechanisms involved in antifungal resistance in Aspergillus.
Mycopathologia 02/2012; 174(2):131-41. · 1.65 Impact Factor
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Dong Ying Wang,
Leila Hadj-Henni,
Simon Thierry,
Pascal Arné,
René Chermette,
Françoise Botterel,
Inès Hadrich, Fattouma Makni,
Ali Ayadi,
Stéphane Ranque,
Wei Yi Huang,
Jacques Guillot
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ABSTRACT: Aspergillus flavus is second only to A. fumigatus in causing invasive aspergillosis and it is the major agent responsible for fungal sinusitis, keratitis and endophthalmitis in many countries in the Middle East, Africa and Southeast Asia. Despite the growing challenge due to A. flavus, data on the molecular epidemiology of this fungus remain scarce. The objective of the present study was to develop a new typing method based on the detection of VNTR (Variable number tandem repeat) markers. Eight VNTR markers located on 6 different chromosomes (1, 2, 3, 5, 7 and 8) of A. flavus were selected, combined by pairs for multiplex amplifications and tested on 30 unrelated isolates and six reference strains. The Simpson index for individual markers ranged from 0.398 to 0.818. A combined loci index calculated with all the markers yielded an index of 0.998. The MLVA (Multiple Locus VNTR Analysis) technique proved to be specific and reproducible. In a second time, a total of 55 isolates from Chinese avian farms and from a Tunisian hospital have been evaluated. One major cluster of genotypes could be defined by using the graphing algorithm termed Minimum Spanning Tree. This cluster comprised most of the isolates collected in an avian farm in southern China. The MLVA technique should be considered as an excellent and cost-effective typing method that could be used in many laboratories without the need for sophisticated equipment.
PLoS ONE 01/2012; 7(9):e44204. · 4.09 Impact Factor
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ABSTRACT: Cryptococcus neoformans is an encapsulated yeast-like fungus that causes life-threatening infections, particularly in immunocompromised patients. The formation of brown pigment on many media described in the literature, such as that in Niger seed (Guizotia abyssinica) agar, has been used to identify C. neoformans. The present study compares melanin production by clinical and environmental isolates of C. neoformans and other medically important yeast on two new media, Pinus halepensis seed (PHS) agar and blackberry (BlaB) agar, and the classic medium Niger seed agar. Results obtained after the culture of 46 strains of C. neoformans, for 4, 24 and 48 h at 37 °C on these three media, showed that at 24 h, 100% of strains were pigmented on BlaB agar, 91.3% on PHS agar but only 34.8% on Niger seed agar. In conclusion, PHS and BlaB agar are two interesting new media for the rapid identification of C. neoformans isolates.
Mycoses 07/2011; 54(4):350-3. · 2.25 Impact Factor
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ABSTRACT: Aspergillus flavus is the second most important Aspergillus species causing human infections. The importance of this fungus increases in regions with a dry and hot climate. Small phylogenetic studies in Aspergillus flavus indicate that the morphological species contains several genetically isolated species. Different genotyping methods have been developed and employed in order to better understand the genetic and epidemiological relationships between environmental and clinical isolates. Understanding pathogen distribution and relatedness is essential for determining the epidemiology of nosocomial infections and aiding in the design of rational pathogen control methods. Typing techniques can also give us a deeper understanding of the colonization pattern in patients. Most of these studies focused on Aspergillus fumigatus because it is medically the most isolated species. To date, there has not been any publication exclusively reviewing the molecular typing techniques for Aspergillus flavus in the literature. This article reviews all these different available methods for this organism.
Mycopathologia 03/2011; 172(2):83-93. · 1.65 Impact Factor
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ABSTRACT: This study aimed at comparing a real-time PCR assay and a PCR-ELISA assay of both serum and bronchoalveolar lavage (BAL) samples for the diagnosis of invasive aspergillosis (IA) in patients with hematological malignancies. Using a nested case-control design, 163 patients at risk were prospectively monitored and PCR assays were performed on frozen aliquots of 459 sera which were prospectively sampled twice weekly and 42 BAL specimens sampled from 43 probable and one proven IA cases and 47 matched controls. The data from three patients classified as possible IA were excluded from the nested case-control study. The sensitivity of real-time PCR and PCR-ELISA assays in serum was 73% and 86%, respectively and specificity was 100% for both. In BAL, sensitivity was 64% for real-time PCR, 71% for PCR-ELISA and 86% for Galactomannan antigen (GMA) assays with specificities of 96%, 96%, and 93%, respectively. While slightly less sensitive, the real time-PCR assay was highly specific and considerably faster and more workable than PCR-ELISA. Combining real-time PCR and GMA detection for both serum and BAL samples enhances routine laboratory IA diagnosis.
Medical mycology: official publication of the International Society for Human and Animal Mycology 11/2010; 49(5):489-94. · 2.13 Impact Factor
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ABSTRACT: Assessing the relatedness of strains isolated from patients and their environment is instrumental in documenting the source of preventable health care-associated life-threatening Aspergillus flavus human infection clusters. The present study aimed at identifying and selecting suitable microsatellite markers for A. flavus typing. This typing scheme was then applied to investigate the A. flavus epidemiology within a hematology unit in Sfax, Tunisia. Use of a combination of five markers made it possible to discern clusters of isolates and to substantiate the genetic diversity of A. flavus within clusters. Isolates from Tunisia and Marseille, France, displayed distinct haplotypes, indicating a highly significant geographical structuring of A. flavus. The typing of clinical and environmental A. flavus isolates in a hematology unit provided insights into its hospital epidemiology. From a heterogeneous genetic background, a cluster indicative of a clonal propagation episode within the unit could be identified. In two patients with invasive aspergillosis, the same genotype was found in clinical and environmental isolates, indicating hospital-acquired colonization and infection. In further studies, this novel microsatellite typing scheme might be instrumental in illuminating important epidemiological issues about A. flavus population genetics or epidemiology, including tracing the sources and routes of transmission.
Journal of clinical microbiology 07/2010; 48(7):2396-401. · 4.16 Impact Factor
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ABSTRACT: The distribution of dermatophytes varies in different countries and geographical areas depending on several factors. To determine the frequency of aetiological agents and the clinical variants of dermatophytoses, we carried out a study between 1998 and 2007. Out of 25 432 subjects suspected to have superficial mycoses, 9960 (39.2%) were affected with dermatophytoses; 14957 positive samples were obtained. The mean age was 35.7 years (range: 21 days to 97 years). Sex ratio was 0.9. Our patients were from urban regions in 81.9% of cases. The most common type of infection was onychomycosis (30.3%), followed by tinea pedis (24.8%), intertrigo (21.7%), tinea corporis (11.4%) and tinea capitis (9.6%). Fifteen patients had generalised dermatophytosis. Hadida and Schousboe disease was diagnosed in one case with lethal evolution. The most isolated dermatophyte was Trichophyton rubrum (74.5%), followed by T. violaceum (7.9%), T. mentagrophytes (7.5%), Microsporum canis (3.8%), Epidermophyton floccosum (0.7%) and T. verrucosum (0.54%). Other species were occasionally isolated: T. schoenleinii, T. tonsurans, M. audouinii and M. ferrugineum. The prevalence of dermatophytoses remains high in our country (996 cases/year). Trichophyton rubrum is the predominant causal agent. However, zoophilic agents become more prevalent. Epidemiological surveys are an essential tool for developing strategies for infection control.
Mycoses 02/2009; 52(6):534-8. · 2.25 Impact Factor
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ABSTRACT: In Western Europe and the USA, the presence of anti-Saccharomyces cerevisiae antibodies (ASCAs) in Crohn's disease (CD) patients and their healthy relatives suggests that ASCAs may be influenced by genetic and/or environmental factors.
To assess the prevalence of ASCAs in Tunisian patients with CD or ulcerative colitis (UC), and unaffected family members, in relation to clinical phenotype. Patients and methods. Seventy-seven patients (39 CD, 38 UC), 66 healthy relatives of CD patients, 16 relatives of UC patients and 70 healthy controls were studied. ASCAs were quantified with a new isotype-specific ELISA test involving an antigenic extract from S. cerevisiae strain W303 and by the original test which detects total immunoglobulins against S. cerevisiae Su1 mannan.
The specificity of the two tests was identical (91%). The isotype-specific ASCA W303 test was more sensitive than the ASCA Su1 test for immunoglobulin detection, but some CD patients were positive only with this latter test. A high percentage of patients with CD (72%) and their unaffected family members (35%) were ASCA-positive in contrast to UC patients (16%) and their relatives (0%) and controls (8.6%). ASCAs were shown to be independent of rural or urban living, disease activity, but were associated with ileal location. The antigen of S. cerevisiae strain W303 discriminated patients depending on age at onset or location of the disease.
This study confirms the antigenic heterogeneity of S. cerevisiae strains in their ability to detect ASCA. It suggests that ASCAs are markers of immunoregulatory disturbance in CD, independently of ethnic/cultural differences between Europe, the USA and North Africa.
Scandinavian Journal of Gastroenterology 07/2007; 42(6):717-25. · 2.02 Impact Factor
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Joint Bone Spine 03/2003; 70(1):71-2. · 2.27 Impact Factor
