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Health care-acquired aspergillosis and air conditioning systems
... Airborne diseases have been linked to poorly functioning HVAC system: improper function of temperature control, humidity control, air distribution and filtration of HVAC systems [16][17][18][19][20][21][22][23][24][25][26][27][28]. Lutz et al. reported an outbreak of Aspergillus infection among inpatients who had been operated in the same operating room in a 12-day period. ...
... They also found contaminated diffusers, duct work and other duct materials which were cultured for Aspergillus species. Similar outbreaks of Aspergillus infections were reported in health care systems linked to air conditioning plants [18]. ...
... This is achieved either by 'diluting' the pathogen (dilution ventilation) or by removing the pathogen (exhaust ventilation) [3,16,30,32,33]. An improperly maintained HVAC system can be a continuing source of contamination, an example of which is the growth of moulds and other fungi in damp and wet surfaces such as cooling coils, humidifiers, condensate pans and filters [17][18][19][20][21][22][23]. Poorly designed and maintained HVAC systems in the ICU can lead to 'sick building syndrome' (SBS), characterized by suffocation which can lead to decreased staff performance in addition to various hospital-acquired infections and occupational hazards [34]. ...
The aim of this review is to describe variation in standards and guidelines on 'heating, ventilation and airconditioning (HVAC)' system maintenance in the intensive care units, across the world, which is required to maintain good 'indoor air quality' as an important non-pharmacological strategy in preventing hospital-acquired infections. Health Technical Memorandum 2025 (HTM) and Healthcare Infection Control Practices Advisory Committee (HICPAC) along with various national expert committee consensus statements, regional and hospital-based protocols available in a public domain were retrieved. Selected publications and textbooks describing HVAC structural aspects were also reviewed, and we described the basic structural details of HVAC system as well as variations in the practised standards of HVAC system in the ICU, worldwide. In summary, there is a need of universal standards for HVAC system with a specific mention on the type of ICU, which should be incorporated into existing infection control practice guidelines.
... Hospital environment often has microorganisms in the air, floor, walls, surgical equipment, hospital furniture, refrigeration systems and employees, preferentially infecting immunocompromised patients who use catheters and dialysis, as well as newborns and elderly, causing severe intrahospital infections (Cristina et al., 2009;Setlhare et al., 2014). Therefore, indoor air quality procedures in hospital environments are critical factors in preventing infections (Azimi et al., 2013). ...
... Due to the pathogenic potential of airborne fungi, especially in neonates cared in hospital air-conditioned environments (Cristina et al., 2009), the aim of this study was to evaluate airborne fungal contamination in two neonatal intensive care units (ICU) of a public hospital before and after cleaning. ...
... The presence of pathogenic fungi is associated with various diseases, among them the aspergillosis; determining specific pathological conditions, especially in immunocompromised patients, neonates and children (Cristina et al., 2009). Furthermore, fungi contamination of the indoor atmosphere may influence the occurrence of invasive aspergillosis in intensive care units (Boff et al., 2013). ...
Fungi are opportunistic organisms with wide geographical distribution and can also be found in the hospital environment. These microorganisms can cause infections, especially in immunocompromised patients. The aim of this study was to evaluate airborne fungal contamination in two neonatal intensive care units (ICU) of a public hospital before and after cleaning. The technique of Petri dishes exposure containing Sabouraud agar with 50mg/L chloramphenicol was used for sample collection. Air conditioning filters were also sampled using a sterile swab for fungal collection. The identification of fungal isolates was performed by observing macroscopic and microscopic structures. A total of 1305 colony forming units was isolated, where: 718 (55.0%) were isolated before neonatal ICU cleaning and 587 (45.0%) after cleaning. Forty-two species belonging to 24 genera were identified, being Cladosporium cladosporioides, Penicillium aurantiogriseum and Aspergillus oryzae the most frequent species in the analyzed samples. The presence of pathogenic fungi in ICUs demonstrates the need for constant monitoring of indoor air quality in order to better control airborne contamination in hospital environments. K e y w o r d s Air quality,
... Both the reservoirs and the methods of transmission of Aspergillus and Zygomycetes are similar. In hospitals, the sources of Aspergillus are contaminated air filtering systems, ventilation systems contaminated with dust accumulated during renovation or construction, carpets, food and plants [125,126]. The species of the genus Aspergillus most commonly causing nosocomial infections are A. fumigatus, A. flavus and A. terreus. ...
... Invasive Aspergillus sp. infections may occur after immunosuppression or surgery, which may even result in death [126]. Research by Neely A. and Orloff M. indicates plastics and materials commonly used in hospitals as important reservoirs and vectors for the transmission of fungal infections. ...
The carriers of nosocomial infections are the hands of medical personnel and inanimate surfaces. Both hands and surfaces may be contaminated as a result of contact with the patient, their body fluids, and touching contaminated surfaces in the patient’s surroundings. Visually clean inanimate surfaces are an important source of pathogens. Microorganisms have properties thanks to which they can survive in unfavorable conditions, from a few days to several months. Bacteria, viruses and fungi are able to transmit from inanimate surfaces to the skin of the patient and the medical staff. These pathogens include SARS-CoV-2, which can survive on various types of inanimate surfaces, being a potential source of infection. By following the recommendations related to washing and disinfecting hands and surfaces, and using appropriate washing and disinfecting agents with a broad biocidal spectrum, high material compatibility and the shortest duration of action, we contribute to breaking the chain of nosocomial infections.
... Species of the genus Aspergillus are common in hospitals and play a relevant part as agents of opportunistic nosocomial infections; these species potentially affect any organ, but the lungs are more frequently affected because Aspergillus spores are easily inhaled (Chuaybamroong et al., 2008;Ortiz et al., 2009;Quadros et al., 2009) and have been associated with outbreaks (Lutz et al., 2003;Cristina et al., 2009;Ortiz et al., 2009). However, outbreaks can be performed retrospectively, and are generally defined by epidemiological methods (Tang et al., 2015). ...
... However, outbreaks can be performed retrospectively, and are generally defined by epidemiological methods (Tang et al., 2015). Rare events have been properly documented by sampling or laboratory tests associating the presence of conidia in the air and illness of patients (Lutz et al., 2003;Cristina et al., 2009). However, a multidisciplinary team of public health specialists, epidemiologists, microbiologists and engineers could contribute to the understanding of how any event of transmission of pathogens may have occurred and how to intervene to prevent its recurrence (Tang et al., 2015). ...
Invasive fungal infection is an important cause of mortality and morbidity in neonates, especially in low-birthweight neonates. The contribution of fungi in the indoor air to the incidence of mucocutaneous colonization and to the risk of invasive fungal infection in this population is uncertain. This review aimed to identify and to summarize the best available evidence on the fungal contamination in the indoor air of critical hospital areas with an emphasis on pediatric/neonatal ICUs. Publications from 2005 to 2019 were searched in the databases Scientific Electronic Library Online (SciELO), US National Library of Medicine National Institutes of Health Search (PubMed), and Latin American Caribbean Health Sciences (LILACS). Descriptors in Health Sciences (DeCS) were used. Research papers published in Portuguese, English, and Spanish were included. Twenty-nine papers on all continents except Australia were selected. The results showed that the air mycobiota contained several fungal species, notably Aspergillus, Penicillium, Cladosporium, Fusarium, and yeast (Candida) species. The selected papers point out the risks that fungi pose to neonates, who have immature immune system, and describe simultaneous external factors (air humidity, seasonality, air and people flow, use of particulate filters, and health professionals’ hand hygiene) that contribute to indoor air contamination with fungi. Improving communication among health professionals is a great concern because this can prevent major health complications in neonates, especially in low-birthweight neonates. The results reinforced the need to monitor environmental fungi more frequently and efficiently in hospitals, especially in neonatal ICUs.
... Although numerous factors, including diseases such as acute myeloid leukemia (AML) and myelodysplasia syndrome (MDS) [9], disease status (untreated or non-remission disease) [10], prolonged neutropenia [11], previous history of IFD [12], age [13], comorbidity such as diabetes and pulmonary disease [14,15], treatment with corticosteroid or other immune-suppression drugs [15][16][17][18], genetic factors related to host innate immunity [19,20], and environmental variables [21,22], have been reported as the main risk factors of IFD, the precise prediction of IFD incidence has remained difficult. ...
... In the literature, numerous risk factors have been reported to be associated with IFD [6,[9][10][11][12][13][14][15][16][17][18][19][20][21]. The most commonly reported variables included hematological disease (AML/MDS vs. others), disease status (newly diagnosed and relapse/refractory vs. clinical remission), type of treatment (chemotherapy vs. transplantation or induction vs. consolidation chemotherapy), development of neutropenia and its duration, graft versus host diseases (GVHD) with steroid treatment in case of allogeneic HSCT, and previous history of IFD. ...
Invasive fungal disease (IFD) is a major infectious complication in patients with hematological malignancies. In this study, we examined 4889 courses of chemotherapy in patients with hematological diseases to establish a training dataset (n = 3500) by simple random sampling to develop a weighted risk score for proven or probable IFD through multivariate regression, which included the following variables: male patients, induction chemotherapy for newly diagnosed or relapsed disease, neutropenia, neutropenia longer than 10 days, hypoalbuminemia, central-venous catheter, and history of IFD. The patients were classified into three groups, which had low (0–10, ~1.2%), intermediate (11–15, 6.4%), and high risk ( > 15, 17.5%) of IFD. In the validation set (n = 1389), the IFD incidences of the groups were ~1.4%, 5.0%, and 21.4%. In addition, we demonstrated that antifungal prophylaxis offered no benefits in low-risk patients, whereas benefits were documented in intermediate (2.1% vs. 6.6%, P = 0.007) and high-risk patients (8.4% vs. 23.3%, P = 0.007). To make the risk score applicable for clinical settings, a pre-chemo risk score that deleted all unpredictable factors before chemotherapy was established, and it confirmed that anti-fungal prophylaxis was beneficial in patients with intermediate and high risk of IFD. In conclusion, an objective, weighted risk score for IFD was developed, and it may be useful in guiding antifungal prophylaxis.
... The primary route of acquiring Aspergillus infections is through the inhalation of spores; the respiratory tract is therefore the most common portal of entry of Aspergillus spp. spores [26,27]. Airborne fungal spores can penetrate deep along the respiratory tree; indeed, the small diameter of the spores allows them to reach the pulmonary alveolar spaces where they may germinate to form hyphae [19]. ...
Aspergillus spp. are ubiquitous fungi present in soil, organic debris, water, decaying vegetation and dust produced in renovation and/or building work. Several studies have shown the presence of aspergilli in various healthcare environments. Typically, thousands of fungal spores are inhaled every day, but if spore clearance fails (typically in immunocompromised patients), fungi can grow and invade lung tissue, causing invasive aspergillosis (IA) which is one of the most frequent infections in highly immunocompromised patients. Aspergillus fumigatus is the most common species involved; this species can be attributed to about 80% of the cases of aspergillosis. According to the WHO, Aspergillus fumigatus is one of four critical priority fungi. The first-line treatment of diseases caused by Aspergillus, in particular IA, is based on triazole antimycotics. Unfortunately, resistance to antimycotics is increasing, partly due to their widespread use in various areas, becoming a significant concern to clinicians who are charged with caring for patients at high risk of invasive mycoses. A recent WHO report emphasised the need for strategies to improve the response, and in particular strengthen laboratory capacity and surveillance, support investment in research and strengthen public health interventions for the prevention and control of fungal infections through a One Health approach.
... The most common fungal species reported in HVAC systems belong to the ubiquitous airborne genera Aspergillus, Cladosporium, and Penicillium. Of particular concern are the opportunistic species Aspergillus flavus and A. fumigatus, which are responsible for recurrent infection outbreaks in hospitals that have been linked to HVAC failures (Cristina, Sartini, & Spagnolo, 2009). During the COVID-19 pandemic, it has been observed that aspergilli can cause coinfections with SARS-CoV-2 in patients who did not have known risk factors of invasive aspergillosis (Lai & Yu, 2021). ...
The variability of individual immunity, the interaction of microbial substances in indoor air, and the performance of measurement tools make it exceedingly difficult to establish specific fungal thresholds in relation to the development of fungal diseases. However, even if one or more correlations between diseases and fungal concentrations were established, this would not mean a causal link.
In this chapter, we propose to discuss the impact of molds upon human health, tools for measuring fungal exposures, major studies proposing thresholds, state guidelines for acceptable thresholds, and the issues involved in setting thresholds for risk.
... The most common fungal species reported in HVAC systems belong to the ubiquitous airborne genera Aspergillus, Cladosporium, and Penicillium. Of particular concern are the opportunistic species Aspergillus flavus and A. fumigatus, which are responsible for recurrent infection outbreaks in hospitals that have been linked to HVAC failures (Cristina, Sartini, & Spagnolo, 2009). During the COVID-19 pandemic, it has been observed that aspergilli can cause coinfections with SARS-CoV-2 in patients who did not have known risk factors of invasive aspergillosis (Lai & Yu, 2021). ...
Fungi can cause deterioration of building materials and adverse health effects on its occupants. However, knowledge of the mycobiome (fungal biome) from the built environment is still incomplete, and most surveys available in the literature have focused on airborne molds. These molds grow on indoor damp materials and can produce abundant conidia (spores) that get easily aerosolized. From indoor environments, they can be transmitted to outdoor air and enter other buildings. One emerging fungal group that has generally been overlooked are the black yeasts, characterized by the conspicuous dark pigmentation due to melanin, and by being adapted to various extreme conditions. This chapter provides an updated review on the accounts of black fungi into the built environment and describes the most common types of extremophilic environments from where they have regularly been isolated. A total of 83 species have been compiled and analyzed in relation to their known ecophysiology and updated phylogeny. We also discuss current hypotheses for the entry and colonization of black fungi into the indoor environment, as well as their potential impacts on human health and on the deterioration of man-made materials.
... The studies conducted show that one of the reasons why the air in a hospital room is contaminated with microorganisms is the hospital staff's activities and the number of staff members inside the room [25]. Some studies have also reported that Acinetobacter and Aspergillus species as well as Clostridium difficile spores are transmitted through air conditioners in ICUs and that these organisms are further disseminated by the movement of heavily contaminated hospital bed curtains [21,[26][27][28]. ...
Background
Effective design and operation of Intensive Care Unit (ICU) ventilation systems is important to prevent hospital-acquired infections. Air purifiers may contribute to that.
Aim
In this study we aimed at detecting the number and types of microorganisms present in the air and on the high touch surfaces in the ICU; evaluating the effectiveness of the air purifying device in reducing the microbial load and thus the rate of nosocomial infections in the ICU.
Method
This interventional study was conducted in two similar ICUs between December 2019 and May 2020. Novaerus brand air purifiers were located in the “intervention ICU” for two months. Routine cleaning procedures and HEPA filtered ventilation continued in “control ICU” as well as in the “Intervention ICU”. After two months the units were moved to the other ICU for the next two months to reduce any possible bias in the results. Air and surface samples were evaluated.
Findings
The evaluation of the change in the interventional ICU over time revealed a significantly lower colony concentration in the air and on surfaces on Day 60 compared to Day 1 (pair<0.001 and psurface<0.001). There was a significant positive correlation between the number of colonies detected and the rate of hospital-acquired infections in the interventional ICU (r:0.406, p:0.049) and in the control ICU (r:0.698, p:0.001).
Conclusion
Using air purifiers in addition to the hospital HVAC systems might be an effective way to reduce the microbial load in the air and surfaces and thus hospital-acquired infections.
... Indoor airborne diseases have been associated with inefficient and badly managed HVAC systems: wrong air distribution (Nazarian and Kleissl, 2016), filtration, humidity, and temperature controls of HVAC systems often lead to disastrous outcomes (Cabral, 2010;Cristina et al., 2009). An outbreak of Aspergillus in an operating room, which infected patients who have been operated on in the same operating theater within a 12-day period, is a classic example of the danger of poorly managed HVAC systems. ...
As the world continues to grapple with the reality of coronavirus disease, global research communities are racing to develop practical solutions to adjust to the new challenges. One such challenge is the control of indoor air quality in the COVID-19 era and beyond. Since COVID-19 became a global pandemic, the “super spread” of the virus has continued to amaze policymakers despite measures put in place by public health officials to sensitize the general public on the need for social distancing, personal hygiene, etc. In this work, we have reviewed the literature to demonstrate, by investigating the historical and present circumstances, that indoor spread of infectious diseases may be assisted by the conditions of the HVAC systems. While little consideration has been given to the possibility of indoor airborne transmission of the virus, the available reports have demonstrated that the virus, with average aerodynamic diameter up to 80-120 nm, is viable as aerosol in indoor atmosphere for more than 3 hours, and its spread may be assisted by the HVAC systems. Having reviewed the vulnerability of the conventional ventilation systems, we recommend innovative air circulation concept supported by the use of UVGI in combination with nanoporous air filter to combat the spread of SARS-CoV-2 and other harmful microbes in enclosed spaces.
... The most common fungal species reported in HVAC systems belong to the ubiquitous airborne genera Aspergillus, Cladosporium, and Penicillium. Of particular concern are the opportunistic species Aspergillus flavus and A. fumigatus, which are responsible for recurrent infection outbreaks in hospitals that have been linked to HVAC failures (Cristina, Sartini, & Spagnolo, 2009). During the COVID-19 pandemic, it has been observed that aspergilli can cause coinfections with SARS-CoV-2 in patients who did not have known risk factors of invasive aspergillosis (Lai & Yu, 2021). ...
Implementation of high-quality ventilation strategies play a key role in maintaining good indoor environment or indoor air quality (IAQ) in hospitals and other healthcare facilities. IAQ is important in all buildings, especially in hospitals. Hospital buildings with heating, ventilating and air conditioning (HVAC) systems may have an increased risk of different diseases with various symptoms, causing irritation in mucous membranes, tiredness, vertigo, dermatosis, headaches, reduced memory, decreased concentration and intellectual work ability, cancers and respiratory diseases (including asthma). The main objective of this chapter is to provide information on the ventilation strategies for maintenance of healthy IAQ in hospitals. The purpose of this chapter is the provision of useful information for both healthcare staff and mechanical engineers to minimize the risk of microbiological pathogens (bacteria and fungi) in the hospital environment, in connection with adequate ventilation systems. Clear control strategies implemented in hospital may reduce the risk of microbiological (bacterial and fungal) infections among hospital staff and patients, with the greatest risk of infection and disease caused by microorganisms from indoor air.
... During this study, different species of Aspergillus were isolated. Cristina et al. (2009) and Boff et al. (2013) described them as "pathogenic". They suggested the possibility of development of various symptoms that can lead to illness in lung as well as an emerging risk factor in immunocompromised patients, neonates and children. ...
... However, while the crucial role of the patient's environment during hospitalization has been clearly demonstrated, the role of the environment outside the hospital is more difficult to evaluate. 19,20 We assumed that some variables (location of residence, type of house, presence of potted plants, etc.) may be a surrogate indicator of the patient's exposure to spores in the air. 21 Not surprisingly, we found a strong correlation (confirmed by multivariate analysis) between a recent house renovation and the onset of an invasive mold infection. ...
... However, while the crucial role of the patient's environment during hospitalization has been clearly demonstrated, the role of the environment outside the hospital is more difficult to evaluate. 19,20 We assumed that some variables (location of residence, type of house, presence of potted plants, etc.) may be a surrogate indicator of the patient's exposure to spores in the air. 21 Not surprisingly, we found a strong correlation (confirmed by multivariate analysis) between a recent house renovation and the onset of an invasive mold infection. ...
Correct definition of the level of risk of invasive fungal infections is the first step in improving the targeting of preventive strategies. We investigated the potential relationship between pre-hospitalization exposure to sources of fungi and the development of invasive fungal infections in adult patients with newly diagnosed acute myeloid leukemia after their first course of chemotherapy. From January 2010 to April 2012, all consecutive acute myeloid leukemia patients in 33 Italian centers were prospectively registered. Upon first admission, information about possible pre-chemotherapy risk factors and environmental exposure was collected. We recorded data regarding comorbid conditions, employment, hygienic habits, working and living environment, personal habits, hobbies, and pets. All invasive fungal infections occurring within 30 days after the first course of chemotherapy were recorded. Of the 1,192 patients enrolled in this study, 881 received intensive chemotherapy and were included in the present analysis. Of these, 214 developed an invasive fungal infection, including 77 proven/probable cases (8.7%). Of these 77 cases, 54 were proven/probable invasive mold infections (6.1%) and 23 were proven yeast infections (2.6%). Upon univariate analysis, a significant association was found between invasive mold infections and age, performance status, diabetes, chronic obstructive pulmonary disease, smoking, cocaine use, job, hobbies, and a recent house renovation. Higher body weight resulted in a reduced risk of invasive mold infections. Multivariate analysis confirmed the role of performance status, job, body weight, chronic obstructive pulmonary disease, and house renovation. In conclusion, several hospital-independent variables could potentially influence the onset of invasive mold infections in patients with acute myeloid leukemia. Investigation of these factors upon first admission may help to define a patient's risk category and improve targeted prophylactic strategies.
Copyright© Ferrata Storti Foundation.
Worldwide, according to the official data, there is an increase in number of
newly diagnosed cases of oncological diseases. This is also the trend in our country. These
patients are usually immunosuppressed and at risk of a wide range of opportunistic and
nosocomial infections (NI). Both malignancy itself and concomitant chemotherapy can
influence negatively the risk of infectious complications. The aim of this article is to provide overview of some aspects of nosocomial infections in cancer patients, based on an
analysis of 51 full text articles published in the period 2000-2018 in the English-language
literature. Levels, etiology, main risk factors and NI prevention and control measures have
been reviewed. Given their vulnerability, these patients need safe and high-quality treatment, and the utmost attention to NI prevention is fully justified.
The operating theatre complex is the heart of any major surgical hospital. Good operating theatre design meets the functional needs of theatre care professionals. Operating theatre design must pay careful consideration to traffic patterns, the number and configuration of nearby operating rooms, the space required for staff, administration and storage, provisions for sterile processing and systems to control airborne contaminants (Wan et al 2011). There have been infection control issues with private finance initiative built operating theatres (Unison 2003, Ontario Health Coalition 2005). The aim of this article is to address these issues as they relate to infection control and prevention.
Patient characteristics, antifungal prophylaxis, and other factors appear to have contributed to a change in the spectrum
of invasive fungal pathogens. Infections with Candida glabrata, Aspergillus terreus, and non-Aspergillus moulds appear to be on the rise, at least among certain populations. These species are resistant or less susceptible to some
commonly used antifungal agents. Non-Aspergillus moulds are particularly lethal. This article reviews the spectrum of invasive mycoses and risk factors for infection with
these pathogens.
Invasive pulmonary aspergillosis is a leading cause of mortality and morbidity in bone marrow transplant recipients. Establishing the diagnosis remains a challenge for clinicians working in acute care setting. However, prompt diagnosis and treatment can lead to favourable outcomes
We report a case of invasive aspergillosis occurring in a 39-year-old Caucasian female 10 years after an allogeneic haematopoietic bone marrow transplant, and 5 years after stopping all immunosuppression. Possible risk factors include bronchiolitis obliterans and exposure to building dust (for example, handling her husband's dusty overalls). There are no similar case reports in the literature at this time.
High clinical suspicion, especially in the setting of failure to respond to broad-spectrum antibiotics, should alert clinicians to the possibility of invasive pulmonary aspergillosis, which, in this case, responded to antifungal therapy.
Inhalation of conidia is the main cause of invasive pulmonary aspergillosis (IPA) and the respiratory epithelium is the first line of defence. To explore the triggering factor for the inflammatory response to Aspergillus fumigatus, the species mainly responsible for IPA, this study analysed the differential expression of three inflammatory genes in A549 cells after challenge with live and killed conidia. The influence of steroids, one of the main risk factors for developing IPA, was also investigated. Quantification of mRNAs of the inflammatory mediator genes encoding interleukin (IL)-8, tumour necrosis factor (TNF)-alpha and granulocyte-monocyte colony-stimulating factor (GM-CSF) was carried out using real-time PCR. Ingestion rates were studied for the conidia of A. fumigatus and Penicillium chrysogenum using a fluorescence brightener. Similar results were obtained for both species, with ingestion rates ranging from 35 to 40 %. Exposure of A549 cells to live A. fumigatus conidia only induced a four- to fivefold increase in the mRNA levels of the three genes, starting 8 h after the initial contact. Both inactivation of live A. fumigatus conidia and treatment by dexamethasone (10(-7) M) prevented the overexpression of TNF-alpha, IL-8 and GM-CSF. Fungal growth, rather than conidia ingestion, appears to be the main stimulus for the production of inflammatory mediators by epithelial cells, and this production is inhibited by steroid therapy. These results underline the role that the epithelium plays in the innate response against IPA.
In order to determine whether water or water-related surfaces are a reservoir for opportunistic filamentous fungi, water sampling in the paediatric bone marrow transplantation (BMT) unit of the National Hospital University of Oslo, Norway was performed. During a six-month period 168 water samples and 20 samples from water-related surfaces were taken. The water samples were taken from the taps and showers in the BMT unit and from the main pipe supplying the paediatric department with water. In addition, 20 water samples were taken at the intake reservoir supplying the city of Oslo with drinking water. Filamentous fungi were recovered from 94% of all the water samples taken inside the hospital with a mean colony forming unit (cfu) count of 2.7/500mL of water. Aspergillus fumigatus was recovered from 49% and 5.6% of water samples from the taps and showers, respectively (mean 1.9 and 1.0cfu/500mL). More than one third (38.8%) of water samples from the main pipe revealed A. fumigatus (mean 2.1cfu/500mL). All water samples taken at the intake reservoir were culture positive for filamentous fungi, 85% of the water samples showed A. fumigatus (mean 3.1cfu/500mL). Twenty-five percent of water-related surfaces yielded filamentous fungi, but A. fumigatus was recovered from only two samples. We showed that filamentous fungi are present in the hospital water and to a lesser extent on water-related surfaces. The recovery of filamentous fungi in water samples taken at the intake reservoir suggests that the source of contamination is located outside the hospital.
Reports have focused on the emergence of moulds as pathogens in recipients of hematopoietic stem cell transplants. To review
the incidence of and risks for mould infections, we examined the records of 5589 patients who underwent hematopoietic stem
cell transplantation at the Fred Hutchinson Cancer Research Center (Seattle) from 1985 through 1999. After 1992, the incidence
of invasive aspergillosis increased in allograft recipients and remained high through the 1990s. Infections with non-fumigatus Aspergillus species, Fusarium species, and Zygomycetes increased during the late 1990s, especially in patients who received multiple transplants. Although
infection caused by Scedosporium species was common in patients who had neutropenia, infection caused by Zygomycetes typically occurred later after transplantation,
when patients had graft-versus-host disease. The overall 1-year survival rate was equally poor (∼20%) for all patients with
mould infections. The results of the present study demonstrate the changing epidemiology of mould infections, emphasizing
the increasing importance of amphotericin B–resistant organisms and the differences in risks and outcome of infection with
different filamentous fungi.
To assess the ability of hospital air handling systems to filter Aspergillus, other fungi, and particles following the implosion of an adjacent building; to measure the quantity and persistence of airborne fungi and particles at varying distances during a building implosion; and to determine whether manipulating air systems based on the movement of the dust cloud would be an effective strategy for managing the impact of the implosion.
Air sampling study.
A 976-bed teaching hospital in Baltimore, Maryland.
Single-stage impactors and particle counters were placed at outdoor sites 100, 200, and 400 m from the implosion and in five locations in the hospital: two oncology floors, the human immunodeficiency virus unit, the cardiac surgical intensive care unit, and the ophthalmology unit. Air handling systems would operate normally unless the cloud approached the hospital.
Wind carried the bulk of the cloud away from the hospital. Aspergillus counts rose more than tenfold at outdoor locations up to 200 m from the implosion, but did not increase at 400 m. Total fungal counts rose more than sixfold at 100 and 200 m and twofold at 400 m. Similar to Aspergillus, particle counts rose several-fold following the implosion at 100 and 200 m, but did not rise at 400 m. No increases in any fungi or particles were measured at indoor locations.
Reacting to the movement of the cloud was effective, because normal operation of the hospital air handling systems was able to accommodate the modest increase in Aspergillus, other fungi, and particles generated by the implosion. Aspergillus measurements were paralleled by particle counts.
The demolition of a maternity building at our institution provided us with the opportunity to study the load of filamentous fungi in the air. External (nearby streets) and internal (within the hospital buildings) air was sampled with an automatic volumetric machine (MAS-100 Air Samplair) at least daily during the week before the demolition, at 10, 30, 60, 90,120, 180, 240, 420, 540 and 660 min post-demolition, daily during the week after the demolition and weekly during weeks 2, 3 and 4 after demolition. Samples were duplicated to analyse reproducibility. Three hundred and forty samples were obtained: 115 external air, 69 'non-protected' internal air and 156 protected internal air [high efficiency particulate air (HEPA) filtered air under positive pressure]. A significant increase in the colony count of filamentous fungi occurred after the demolition. Median colony counts of external air on demolition day were significantly higher than from internal air (70.2 cfu/m(3) vs 35.8 cfu/m(3)) (P < 0.001). Mechanical demolition on day +4 also produced a significant difference between external and internal air (74.5 cfu/m(3) vs 41.7 cfu/m(3)). The counts returned to baseline levels on day +11. Most areas with a protected air supply yielded no colonies before demolition day and remained negative on demolition day. The reproducibility of the count method was good (intra-assay variance: 2.4 cfu/m(3)). No episodes of invasive filamentous mycosis were detected during the three months following the demolition. Demolition work was associated with a significant increase in the fungal colony counts of hospital external and non-protected internal air. Effective protective measures may be taken to avoid the emergence of clinical infections.
An outbreak of Aspergillus infection at a tertiary care hospital was identified among inpatients who had amputation wounds, peritonitis, allograft nephritis,
or mediastinitis. During a 2-year period, 6 patients were identified, all of whom had Aspergillus species recovered from samples from normally sterile sites. All cases clustered in the operating theater during a single
12-day period. To assess operating theater air quality, particle counts were measured as surrogate markers for Aspergillus conidia. A substantial increase in the proportion of airborne particles ⩾3 µm in size (range, 3-fold to 1000-fold) was observed
in many operating rooms. A confined space video camera identified moisture and contamination of insulating material in ductwork
and variable airflow volume units downstream of final filters. No additional invasive Aspergillus wound infections were identified after the operating theater air-handling systems were remediated, suggesting that this unusual
outbreak was due to the deterioration of insulating material in variable airflow volume units.
This report updates, expands, and replaces the previously published CDC "Guideline for Prevention of Nosocomial Pneumonia". The new guidelines are designed to reduce the incidence of pneumonia and other severe, acute lower respiratory tract infections in acute-care hospitals and in other health-care settings (e.g., ambulatory and long-term care institutions) and other facilities where health care is provided. Among the changes in the recommendations to prevent bacterial pneumonia, especially ventilator-associated pneumonia, are the preferential use of oro-tracheal rather than naso-tracheal tubes in patients who receive mechanically assisted ventilation, the use of noninvasive ventilation to reduce the need for and duration of endotracheal intubation, changing the breathing circuits of ventilators when they malfunction or are visibly contaminated, and (when feasible) the use of an endotracheal tube with a dorsal lumen to allow drainage of respiratory secretions; no recommendations were made about the use of sucralfate, histamine-2 receptor antagonists, or antacids for stress-bleeding prophylaxis. For prevention of health-care--associated Legionnaires disease, the changes include maintaining potable hot water at temperatures not suitable for amplification of Legionella spp., considering routine culturing of water samples from the potable water system of a facility's organ-transplant unit when it is done as part of the facility's comprehensive program to prevent and control health-care--associated Legionnaires disease, and initiating an investigation for the source of Legionella spp. when one definite or one possible case of laboratory-confirmed health-care--associated Legionnaires disease is identified in an inpatient hemopoietic stem-cell transplant (HSCT) recipient or in two or more HSCT recipients who had visited an outpatient HSCT unit during all or part of the 2-10 day period before illness onset. In the section on aspergillosis, the revised recommendations include the use of a room with high-efficiency particulate air filters rather than laminar airflow as the protective environment for allogeneic HSCT recipients and the use of high-efficiency respiratory-protection devices (e.g., N95 respirators) by severely immunocompromised patients when they leave their rooms when dust-generating activities are ongoing in the facility. In the respiratory syncytial virus (RSV) section, the new recommendation is to determine, on a case-by-case basis, whether to administer monoclonal antibody (palivizumab) to certain infants and children aged <24 months who were born prematurely and are at high risk for RSV infection. In the section on influenza, the new recommendations include the addition of oseltamivir (to amantadine and rimantadine) for prophylaxis of all patients without influenza illness and oseltamivir and zanamivir (to amantadine and rimantadine) as treatment for patients who are acutely ill with influenza in a unit where an influenza outbreak is recognized. In addition to the revised recommendations, the guideline contains new sections on pertussis and lower respiratory tract infections caused by adenovirus and human parainfluenza viruses and refers readers to the source of updated information about prevention and control of severe acute respiratory syndrome.
Invasive aspergillosis presents a formidable problem for both diagnosis and therapy. Therefore, prevention is a very important strategy in controlling this disease. Preventing invasive aspergillosis demands a clear understanding of the environmental sources of Aspergillus spp. and how this mould is transmitted to patients. Insight into the sources of exposure, mechanisms of transmission, and host susceptibility to infection are vital to appropriately direct preventive strategies to those settings where the risk of infection is the highest and consequently the impact of prevention the greatest.
While invasive aspergillosis occurs typically in severely immunocompromised patients, cases of surgical site infection have been reported in immunocompetent individuals. The Medline, LILACS and EMBASE databases were searched for descriptions of cases of post-operative aspergillosis, and references from relevant articles and conference abstracts were reviewed. More than 500 cases of post-operative aspergillosis were found. Cardiac surgery (n = 188), ophthalmological surgery (n > 90) and dental surgery (n > 100) were associated with the majority of cases. Other cases involved wound infections (n = 22), bronchial infections (n = 30), mediastinitis (n = 11), pleural aspergillosis (n = 1), infections following orthopaedic surgery (n = 42), vascular prosthetic surgery (n = 22), breast surgery (n = 5), abdominal surgery (n = 10) and neurosurgery (n = 25). In most patients, the source was presumed to be airborne infection during the surgical procedure. Prevention of these infections requires special care of the ventilation system in the operating room. Successful treatment requires rapid diagnosis, surgical debridement and antifungal therapy, often with voriconazole. In order to improve the outcome, better diagnostic methods are needed, particularly for cases of endocarditis and aortitis.
Invasive fungal infections (IFIs) continue to cause considerable morbidity and mortality in haematopoietic stem cell transplant recipients. The epidemiology of IFI has changed since the late 1980s, with a trend towards a reduction in invasive infection due to opportunistic yeasts and an increase in invasive mould infections, particularly by Aspergillus spp. Since the introduction of fluconazole for prophylaxis, the incidence rate of invasive candidiasis is close to 5% and the risk factors related to invasive candidiasis are gastrointestinal tract colonisation, cytomegalovirus disease and a prior episode of bacteraemia. The highest risk for invasive aspergillosis was observed in older patients and patients with graft-versus-host disease and immunosuppressive therapy, steroid use (>1-2 mg/kg/day), persistent neutropenia and certain types of transplantation (cord blood transplant, allogeneic mismatched or T-cell depletion). In those cases, rational preventive measures must be implemented and vigilance is necessary in order to diagnose infection as soon as possible.
● Diagnosing the range of pulmonary disorders caused by Aspergillus spp can be challenging. In instances of hyper- sensitivity responses to Aspergillus spp (ie, allergic bron- chopulmonary aspergillosis, bronchocentric granulomato- sis, and hypersensitivity pneumonitis), the surgical pathol- ogist must be cognizant of their relationship to infection, as fungal organisms may be rare or absent from the biopsy specimens. Within the spectrum of opportunistic infection, it is critical to distinguish Aspergillus spp from other fungal mimics, as well as to discern whether infection is limited, progressive, or immanently life threatening. However, the surgical pathologist who establishes expertise in this area will be rewarded by the satisfaction of having contributed primarily to an important area of patient care. This article reviews the spectrum of pulmonary disorders due to infec- tion by Aspergillus spp, with emphasis on the clinical im- plications of diagnosis. (Arch Pathol Lab Med. 2008;132:606-614)
Unfiltered outside air averages 1-15 pathogenic Aspergillus sp. colony forming units (cfu) m-3 although short-term fluctuations are substantial. Seasonal variation reflects increased spore prevalence during periods of greater availability of non-viable matter. In hospital, airborne spores reflect incomplete filtration, infiltration of outside air and shedding of adherent spores from introduced objects. In highly protected hospital areas supplied with air filtered at high efficiency, where aspergillus cfus may be as low as 0.01 cfu m-3, infiltration and shedding contribute a high fraction of ambient spores. Nosocomial aspergillosis occurs in linear proportion to the mean ambient hospital airborne spore content. An analysis presuming a steady-state dynamic equilibrium is imperfect because repeated sampling produces occasional high counts which violate a Poisson distribution. 'Mini-bursts' arise from disturbance of settled spores in dust, shedding spores from clothes or other subtle sources. These sources are best mitigated by increasing the air change rate. It is most important to protect bone marrow transplant patients, leukaemia and lymphoma patients undergoing intensive, potentially curative therapy. The optimal protective environments include high filtration efficiency, point-of-use filters, protection against infiltration and filter bypass, elimination of in-hospital sources, and high air change rates.
Aspergillosis refers to any of the illnesses caused by fungi that are members of the genus Aspergillus. The diseases range from allergic responses that occur in the absence of fungal growth (asthma, hypersensitivity pneumonitis), to colonization with or without an allergic component (allergic bronchopulmonary aspergillosis, aspergilloma, saprophytic involvement of infarcted tissue), to invasion and destruction of lung parenchyma (invasive aspergillosis, chronic necrotizing pulmonary aspergillosis). The development of lung infection and/or disease depends on interaction among three factors: the characteristics of the fungus (virulence factors), the status of host defense mechanisms, and the type of exposure. The purpose of this article is to review these factors and their relationship to the clinical syndromes of aspergillosis.
By comparing natural immunity to Aspergillus fumigatus (AF) in vivo with the action of human or mouse phagocytes against AF in vitro, we delineated two sequential lines of defense against AF. The first line of defense was formed by macrophages and directed against spores. Macrophages prevented germination and killed spores in vitro and rapidly eradicated conidia in vivo, even in neutropenic and athymic mice. The second was the neutrophilic granulocyte (PMN), which protected against the hyphal form of AF. Human and mouse PMN killed mycelia in vitro. Normal, but not neutropenic mice, stopped hyphal growth, and eradicated mycelia. Either line of defense acting alone protected mice from high challenge doses. Natural immunity collapsed only when both the reticuloendothelial system and PMN were impaired. These findings are in keeping with the clinical observation that high doses of cortisone and neutropenia are the main risk factors for invasive aspergillosis. Cortisone inhibited the conidiacidal activity of mouse macrophages in vivo and of human or mouse mononuclear phagocytes in vitro. Cortisone damaged this first line of defense directly and not through the influence of T lymphocytes or other systems modifying macrophage function as shown in athymic mice and in vitro. In addition, daily high doses of cortisone in mice reduced the mobilization of PMN so that the second line of defense was also impaired. Thus, cortisone can break down natural resistance on its own. Myelosuppression rendered mice susceptible only when the first line of defense was overpowered by high challenge doses, by activated spores that cannot be killed by macrophages, or by cortisone suppression of the conidiacidal activity of macrophages. The host, thus, can call upon two independent phagocytic cell lines that form graded defense systems against aspergillus. These lines of defense function in the absence of a specific immune response, which seems superfluous in the control and elimination of this fungus.
The official German guidelines for prevention of nosocomial pneumonia were published by the Bundesgesundheitsamt, now called Robert-Koch-Institut, twelve years ago. The recently published official "guidelines for prevention of nosocomial pneumonia" of the Centers for Disease Control and Prevention (CDC) are categorized according to scientific evidence. The American guidelines are very detailed and differ in some aspects from the official German guidelines. The purpose of the present paper is to inform the German anaesthesiologist about the official CDC guidelines and to provide a renewed background for the prevention of nosocomial pneumonia.
Objective:
To evaluate efficacy of laminar airflow facilities plus high-efficiency particulate air (HEPA) filtration and HEPA filtration alone in preventing environmental Aspergillus contamination during hospital renovation. To show the usefulness of environmental surveillance to facilitate protection of patients at risk for invasive pulmonary aspergillosis.
Design:
Prospective sampling of air and surfaces for Aspergillus conidia during 2-year period.
Setting:
A hematological department adjacent to building renovation at a university hospital.
Results:
1,047 air samples and 1,178 surface samples were collected from January 1996 to December 1997. Significantly more air samples were positive for Aspergillus species during the period of building renovation than during the periods before and after renovation in a unit without a protected air supply adjacent to the building work area (51.5% vs 31.7%; odds ratio [OR], 2.3; 95% confidence interval [CI95], 1.4-3.7; P<.001). A major increase in the frequency of positive air samples was also found in another adjacent unit that was protected with HEPA filtration alone (from 1.8% to 47.5%; OR, 48.9; CI95, 12-229; P<10(-7)). In addition, in this unit, the mean count of Aspergillus conidia in positive air samples increased significantly during construction (4 colony-forming units [CFU]/m3 to 24.7 CFU/m3; P=.04) and the proportion of positive surface samples showed a significant increase during renovation (from 0.4% to 9.7%; OR, 28.3; CI95, 3.4-623; P=10(-4)). However, none of 142 air samples collected during renovation in the area protected with laminar airflow plus HEPA filtration showed Aspergillus conidia. In a unit distant from the building renovation site, the results of air and surface samples were not affected by renovation.
Conclusion:
This study showed a strong association between building renovation and an increase in environmental Aspergillus contamination. Results confirmed the high efficacy of laminar airflow plus HEPA filtration and a high air-change rate. Although filtration with HEPA was effective during normal conditions, it alone was unable to prevent the rise of Aspergillus contamination related to building renovation. This study emphasized the necessity of an environmental survey of airborne contamination related to construction, to facilitate prevention of nosocomial aspergillosis outbreaks. A standardized protocol for aerobiological surveillance is needed.
Between September 1993 and December 1993, during extensive hospital construction and indoor renovation, a nosocomial outbreak of invasive pulmonary aspergillosis occurred in acute leukemia patients treated in a regular ward that has only natural ventilation. The observed infection rate was 50%. Chemoprophylaxis with intravenous continuous low-dose amphotericin B was then instituted as a preventive measure. During the next 18 months invasive pulmonary aspergillosis developed in 43% of acute leukemia patients. After that period a new hematology ward was opened with an air filtration system through high-efficiency particulate air filtration (HEPA) filters, and a bone marrow transplantation program was started on the hematology service. During the following three years, none of the acute leukemia or bone marrow transplantation patients who were hospitalized exclusively in the hematology ward developed invasive pulmonary aspergillosis, although 29% of acute leukemia patients who were housed in a regular ward, because of shortage of space in the new facility, still contracted invasive pulmonary aspergillosis. Overall, 31 patients were diagnosed with invasive pulmonary aspergillosis during almost five years: 74% of patients recovered from invasive pulmonary aspergillosis, and 42% are long-term survivors; 26% of patients died of resistant leukemia with aspergillosis, but no one died of invasive pulmonary aspergillosis alone. In conclusion, during an on-going construction period, an extremely high incidence rate of invasive pulmonary aspergillosis in acute leukemia patients undergoing intensive chemotherapy was observed. Institution of low-dose intravenous amphotericin B prophylaxis marginally reduced the incidence rate of invasive pulmonary aspergillosis. Keeping patients in a special ward with air filtration through a HEPA system eliminated invasive pulmonary aspergillosis completely. Among patients who developed invasive pulmonary aspergillosis, early diagnosis and treatment are probably the explanation for the favorable outcome.
Invasive mold infections (IMIs) are an important cause of morbidity and mortality in patients who are undergoing bone marrow
transplantation (BMT). To examine the epidemiology, risk factors, and outcome of IMIs in allogeneic BMT recipients, all cases
of mold infection among 94 adult patients who underwent allogeneic BMT at this institution from 1 January 1997 through 31
December 1998 were reviewed retrospectively. Fifteen cases of IMI were identified; infection occurred a median of 102 days
after BMT. Aspergillus species was the most common cause of disease, and species other than Aspergillus fumigatus were present in 53% of patients. By multivariate analysis, the variable associated with infection risk was systemic glucocorticosteroid
use. Prophylactic antifungal therapy that was targeted to high-risk patients had little effect on disease incidence. These
observations suggest that early identification of high-risk patients and better approaches to prevention should be explored,
to reduce incidence and severity of disease in this population.
Filamentous fungal infections are associated with high morbidity and mortality in solid organ transplant patients, and prevention is warranted whenever possible. An increase in invasive aspergillosis was detected among solid organ transplant recipients in our institution during 1991-92. Rates of Aspergillus infection (18.2%) and infection or colonization (42%) were particularly high among lung transplant recipients. Epidemiologic investigation revealed cases to be both nosocomial and community-acquired, and preventative efforts were directed at both sources. Environmental controls were implemented in the hospital, and itraconazole prophylaxis was given in the early period after lung transplantation. The rate of Aspergillus infection in solid organ transplant recipients decreased from 9.4% to 1.5%, and mortality associated with this disease decreased from 8.2% to 1.8%. The rate of Aspergillus infection or colonization among lung transplant recipients decreased from 42% to 22.5%; nosocomial Aspergillus infection decreased from 9% to 3.2%. Cases of aspergillosis in lung transplant recipients were more likely to be early infections in the pre-intervention period. Early mortality in lung transplant recipients decreased from 15% to 3.2%. Two cases of dematiaceous fungal infection were detected, and no further cases occurred after environmental controls. The use of environmental measures that resulted in a decrease in airborne fungal spores, as well as antifungal prophylaxis, was associated with a decrease in aspergillosis and associated mortality in these patients. Ongoing surveillance and continuing intervention is needed for prevention of infection in high-risk solid organ transplant patients.
Preventive measures are important in the control of invasive aspergillosis (IA) because diagnosis is difficult and the outcome
of treatment is poor. If effective strategies are to be devised, it will be essential to have a clearer understanding of the
sources and routes of transmission of Aspergillus species. Nosocomial outbreaks of IA highlight the fact that Aspergillus spores are common in the hospital environment. However, in general, such outbreaks are uncommon. Most cases of IA are sporadic
in nature, and many of them are now being acquired outside of the hospital setting. Housing patients in high-energy particulate
air—filtered hospital rooms helps prevent IA, but it is feasible and cost-effective only for the highest-risk groups and for
limited periods. Control measures, which are designed to protect patients from exposure to spores outside the hospital, are
even more difficult. Nevertheless, now that high-risk patients are spending more time outside of the hospital, the cost benefits
of antifungal prophylaxis and other preventive measures require careful evaluation.
The term “aspergillosis” comprises several categories of infection: invasive aspergillosis; chronic necrotizing aspergillosis;
aspergilloma, or fungus ball; and allergic bronchopulmonary aspergillosis. In 24 medical centers, we examined the impact of
a culture positive for Aspergillus species on the diagnosis, risk factors, management, and outcome associated with these diseases. Most Aspergillus culture isolates from nonsterile body sites do not represent disease. However, for high-risk patients, such as allogeneic
bone marrow transplant recipients (60%), persons with hematologic cancer (50%), and those with signs of neutropenia (60%)
or malnutrition (30%), a positive culture result is associated with invasive disease. When such risk factors as human immunodeficiency
virus infection (20%), solid-organ transplantation (20%), corticosteroid use (20%), or an underlying pulmonary disease (10%)
are associated with a positive culture result, clinical judgment and better diagnostic tests are necessary. The management
of invasive aspergillosis remains suboptimal: only 38% of patients are alive 3 months after diagnosis. Chronic necrotizing
aspergillosis, aspergilloma, and allergic bronchopulmonary aspergillosis have variable management strategies and better short-term
outcomes.
Disseminated aspergillus infection has a poor prognosis, but few reports have been published on extra-pulmonary involvement in aspergillosis. We reviewed 107 autopsy records of patients with invasive aspergillosis. Fifty-five patients had extra-pulmonary aspergillosis. Organs involved included heart, kidney, central nervous system, gastrointestinal tract, spleen, liver, thyroid gland and pancreas. Extra-pulmonary aspergillosis produces different manifestations according to involved organs. Risk factors associated with dissemination included cytotoxic chemotherapy within a month of death (P=0.0087). Lack of response to empiric or preemptive treatment of amphotericin B predicted IA dissemination (P=0.0328). To improve prognosis of IA, it is important to recognize clinical features of extra-pulmonary aspergillosis and to institute the aggressive anti-fungal treatment.
To describe and investigate the cause of an outbreak of 10 cases of nosocomial invasive infection with Aspergillus flavus in a hematologic oncology patient care unit.
A retrospective cohort study.
The hematologic oncology unit of a comprehensive cancer center.
Ninety-one patients admitted to the hematologic oncology service between January 1 and December 31, 1992, for 4 or more consecutive days were included in the study.
Ten (18%) of 55 patients admitted from July to December 1992 were diagnosed as having invasive aspergillosis compared with 0 (0%) of 36 patients admitted from January to June 1992 to the same patient care units. Patient characteristics, mortality rate, autopsy rate, and admitting location did not change significantly during the course of the year to result in a sudden increase in the number of aspergillosis cases. The source of the outbreak was the high counts of Aspergillus conidia determined from air sampling in the non-bone marrow transplant wing during the outbreak. After high-efficiency particulate air (HEPA) filters were installed as an infection control measure, there were only two additional cases of nosocomial aspergillosis in the 2 years following the outbreak.
This outbreak occurred among hematologic oncology patients with prolonged granulocytopenia housed in an environment with neither HEPA filters nor laminar air flow units. Our data demonstrate that in the setting of an outbreak of aspergillosis, HEPA filters are protective for highly immunocompromised patients with hematologic malignancies and are effective at controlling outbreaks due to air contamination with Aspergillus conidia.
The health-care facility environment is rarely implicated in disease transmission, except among patients who are immunocompromised. Nonetheless, inadvertent exposures to environmental pathogens (e.g., Aspergillus spp. and Legionella spp.) or airborne pathogens (e.g., Mycobacterium tuberculosis and varicella-zoster virus) can result in adverse patient outcomes and cause illness among health-care workers. Environmental infection-control strategies and engineering controls can effectively prevent these infections. The incidence of health-care--associated infections and pseudo-outbreaks can be minimized by 1) appropriate use of cleaners and disinfectants; 2) appropriate maintenance of medical equipment (e.g., automated endoscope reprocessors or hydrotherapy equipment); 3) adherence to water-quality standards for hemodialysis, and to ventilation standards for specialized care environments (e.g., airborne infection isolation rooms, protective environments, or operating rooms); and 4) prompt management of water intrusion into the facility. Routine environmental sampling is not usually advised, except for water quality determinations in hemodialysis settings and other situations where sampling is directed by epidemiologic principles, and results can be applied directly to infection-control decisions. This report reviews previous guidelines and strategies for preventing environment-associated infections in health-care facilities and offers recommendations. These include 1) evidence-based recommendations supported by studies; 2) requirements of federal agencies (e.g., Food and Drug Administration, U.S. Environmental Protection Agency, U.S. Department of Labor, Occupational Safety and Health Administration, and U.S. Department of Justice); 3) guidelines and standards from building and equipment professional organizations (e.g., American Institute of Architects, Association for the Advancement of Medical Instrumentation, and American Society of Heating, Refrigeration, and Air-Conditioning Engineers); 4) recommendations derived from scientific theory or rationale; and 5) experienced opinions based upon infection-control and engineering practices. The report also suggests a series of performance measurements as a means to evaluate infection-control efforts.
High incidence of aspergillosis on transplant units or hematological wards without HEPA air conditioning during periods of demolishing or construction has been reported by several investigators. Here we report monitoring of fungal air contamination during a period of construction on a stem cell transplantation ward using the gravity air-setting plate (GASP) method. Fungal air contamination in HEPA-conditioned patient rooms was constantly low, independent from construction activity. Outside of the patient rooms at the ward's corridor, the fungal load was significantly higher with some peak values. Outside the transplant unit measures of construction led to a significant increase of fungal spore concentration in air. Transplant activity was not reduced during construction and patients were nursed strictly under HEPA conditions. Patients were monitored prospectively for incidence of infections since 1990 and data of patients grafted during construction (n = 28) were compared to those grafted outside building activity (n = 652). An increase of aspergillosis during construction could be clearly excluded. It can be concluded: Nursing of patients undergoing stem cell transplantation in HEPA-conditioned rooms is an effective protection against acquisition of aspergillus-infection, even under environmental conditions with increased air contamination by conidia. The gravity air-setting plate (GASP) method is not expensive and easy to use and allows reliable and quantitative aerobiological spore monitoring.
Since the 1990s, opportunistic fungal infections have emerged as a substantial cause of morbidity and mortality in profoundly immunocompromised patients. Hypercortisolaemic patients, both those with endogenous Cushing's syndrome and, much more frequently, those receiving exogenous glucocorticoid therapy, are especially at risk of such infections. This vulnerability is attributed to the complex dysregulation of immunity caused by glucocorticoids. We critically review the spectrum and presentation of invasive fungal infections that arise in the setting of hypercortisolism, and the ways in which glucocorticoids contribute to their pathogenesis. A better knowledge of the interplay between glucocorticoid-induced immunosuppression and invasive fungal infections should assist in earlier recognition and treatment of such infections. Efforts to decrease the intensity of glucocorticoid therapy should help to improve outcomes of opportunistic fungal infections.
With the continuing increase in the number of severely immunocompromised patients, hospitals are faced with the growing problem of invasive aspergillosis and other opportunistic fungal infections. Since treatment of these infections are difficult and outcome is often fatal, preventive measures are of major importance in the control of invasive filamentous fungal infections. Until recently, inhalation of airborne conidia was believed to be the primary route of acquiring Aspergillus infection. Despite the fact, that efforts to filter the hospital air has led to a reduction of airborne conidia paralleled by a decrease in the frequency of invasive infections, the correlation between the concentration of Aspergillus conidia in hospital air and the risk of invasive infections remains unclear. Furthermore, alternative modes of transmission may exist and should be recognized and investigated. The discovery of hospital water as a potential source of Aspergillus fumigatus and other filamentous fungi may suggest a new route for the transmission of invasive filamentous fungal infections. Epidemiological studies, based on molecular characterization and comparisons of fungal isolates recovered from patients and environment, are needed to expand our understanding of these alternative routes of transmission.
Nosocomial aspergillosis represents a serious threat for severely immunocompromised patients and numerous outbreaks of invasive aspergillosis have been described. This systematic review summarizes characteristics and mortality rates of infected patients, distribution of Aspergillus spp. in clinical specimens, concentrations of aspergillus spores in volumetric air samples, and outbreak sources. A web-based register of nosocomial epidemics (outbreak database), PubMed and reference lists of relevant articles were searched systematically for descriptions of aspergillus outbreaks in hospital settings. Fifty-three studies with a total of 458 patients were included. In 356 patients, the lower respiratory tract was the primary site of aspergillus infection. Species identified most often were Aspergillus fumigatus (154 patients) and Aspergillus flavus (101 patients). Haematological malignancies were the predominant underlying diseases (299 individuals). The overall fatality rate in these 299 patients (57.6%) was significantly greater than that in patients without severe immunodeficiency (39.4% of 38 individuals). Construction or demolition work was often (49.1%) considered to be the probable or possible source of the outbreak. Even concentrations of Aspergillus spp. below 1 colony-forming unit/m(3) were sufficient to cause infection in high-risk patients. Virtually all outbreaks of nosocomial aspergillosis are attributed to airborne sources, usually construction. Even small concentrations of spores have been associated with outbreaks, mainly due to A. fumigatus or A. flavus. Patients at risk should not be exposed to aspergilli.
A total of 1,030 microbiological samples were taken in 3 hospital wards with different air-conditioning features: no conditioning system (ward A), a conditioning system equipped with minimum efficiency reporting value (MERV) filters (ward B), and a conditioning system thoroughly maintained and equipped with high-efficiency particulate air (HEPA) filters (absolute) (ward C). The air in each ward was sampled, and the bacterial and fungal concentrations were determined by active and passive methods. The concentration of fungi on surfaces was also determined. Active sampling showed positive samples in wards A and B only, with average values of 0.50 colony-forming units (CFU)/m(3) (95% CI, 0.30 to 0.70) in A and 0.16 CFU/m(3) (95% CI, 0.13 to 0.20) in B. Passive sampling was positive only in ward A (mean, 0.14 CFU/cm(2)/h; 95% CI, 0.13 to 0.15). Aspergillus was found in 27% and 22% of sampled surfaces in wards A and B, respectively, but in no samples from ward C. The most commonly found species was A. fumigatus (76% of cases in A and 34% of cases in B). The results show that the use of air-conditioning systems markedly reduces the concentration of aspergilli in the environment. Proper maintenance of these systems is clearly fundamental if their efficacy is to be ensured.
Infections by Aspergillus species present a particular challenge. The organism, which is ubiquitous in the environment, causes allergic disease in otherwise healthy individuals and devastating disease in the immunosuppressed. This article examines the range of infections caused by Aspergillus species, the challenges of diagnosis, and current treatment options.
To evaluate filamentous fungi with respect to environmental load and potential drug resistance in a tertiary care teaching hospital.
Monthly survey in 2 buildings of the hospital during a 12-month period.
Hippokration Hospital in Thessaloniki, Greece.
Air, surface, and tap water sampling was performed in 4 departments with high-risk patients. As sampling sites, the solid-organ transplantation department and the hematology department (in the older building) and the pediatric oncology department and the pediatric intensive care unit (in the newer building) were selected.
From January to May of 2000, the fungal load in air (FLA) was low, ranging from 0 to 12 colony-forming units (cfu) per m(3) in both buildings. During the summer months, when high temperature and humidity predominate, the FLA increased to 4-56 cfu/m(3). The fungi commonly recovered from culture of air specimens were Aspergillus niger (25.9%), Aspergillus flavus (17.7%), and Aspergillus fumigatus (12.4%). Non-Aspergillus filamentous fungi, such as Zygomycetes and Dematiaceous species, were also recovered. The pediatric intensive care unit had the lowest mean FLA (7.7 cfu/m(3)), compared with the pediatric oncology department (8.7 cfu/m(3)), the solid-organ transplantation department (16.1 cfu/m(3)), and the hematology department (22.6 cfu/m(3)). Environmental surfaces were swabbed, and 62.7% of the swab samples cultured yielded filamentous fungi similar to the fungi recovered from air but with low numbers of colony-forming units. Despite vigorous sampling, culture of tap water yielded no fungi. The increase in FLA observed during the summer coincided with renovation in the building that housed the solid-organ transplantation and hematology departments. All 54 Aspergillus air isolates randomly selected exhibited relatively low minimum inhibitory or effective concentrations for amphotericin B, itraconazole, voriconazole, posaconazole, micafungin, and anidulafungin.
Air and surface fungal loads may vary in different departments of the same hospital, especially during months when the temperature and humidity are high. Environmental Aspergillus isolates are characterized by lack of resistance to clinically important antifungal agents.
High-efficiency particulate air (HEPA) filters do not completely prevent nosocomial fungal infections. The first aim of this study was to evaluate the impact of different filters and access conditions upon airborne fungi in hospital facilities. Additionally, this study identified fungal indicators of indoor air concentrations.
Eighteen rooms and wards equipped with different air filter systems, and access conditions were sampled weekly, during 16 weeks. Tap water samples were simultaneously collected.
The overall mean concentration of atmospheric fungi for all wards was 100 colony forming units/m(3). We found a direct proportionality between the levels of the different fungi in the studied atmospheres. Wards with HEPA filters at positive air flow yielded lower fungal levels. Also, the existence of an anteroom and the use of protective clothes were associated to the lowest fungal levels. Principal component analysis showed that penicillia afforded the best separation between wards' air fungal levels. Fungal strains were rarely recovered from tap water samples.
In addition to air filtration systems, some access conditions to hospital units, like presence of anteroom and use of protective clothes, may prevent high fungal air load. Penicillia can be used as a general indicator of indoor air fungal levels at Hospital S. João.
Diagnosing the range of pulmonary disorders caused by Aspergillus spp can be challenging. In instances of hypersensitivity responses to Aspergillus spp (ie, allergic bronchopulmonary aspergillosis, bronchocentric granulomatosis, and hypersensitivity pneumonitis), the surgical pathologist must be cognizant of their relationship to infection, as fungal organisms may be rare or absent from the biopsy specimens. Within the spectrum of opportunistic infection, it is critical to distinguish Aspergillus spp from other fungal mimics, as well as to discern whether infection is limited, progressive, or immanently life threatening. However, the surgical pathologist who establishes expertise in this area will be rewarded by the satisfaction of having contributed primarily to an important area of patient care. This article reviews the spectrum of pulmonary disorders due to infection by Aspergillus spp, with emphasis on the clinical implications of diagnosis.
Hospital-acquired (nosocomial) infections (HAIs) increase morbidity, mortality and medical costs. In the USA alone, nosocomial infections cause about 1.7 million infections and 99 000 deaths per year. HAIs are spread by numerous routes including surfaces (especially hands), air, water, intravenous routes, oral routes and through surgery. Interventions such as proper hand and surface cleaning, better nutrition, sufficient numbers of nurses, better ventilator management, use of coated urinary and central venous catheters and use of high-efficiency particulate air (HEPA) filters have all been associated with significantly lower nosocomial infection rates. Multiple infection control techniques and strategies simultaneously ('bundling') may offer the best opportunity to reduce the morbidity and mortality toll of HAIs. Most of these infection control strategies will more than pay for themselves by saving the medical costs associated with nosocomial infections. Many non-pharmacological interventions to prevent many HAIs will also reduce the need for long or multiple-drug antibiotic courses for patients. Lower antibiotic drug usage will reduce risk of antibiotic-resistant organisms and should improve efficacy of antibiotics given to patients who do acquire infections.
Positive-pressure ventilation implies a sealed room, usually with an anteroom to facilitate the donning of protective clothing, airflows of at least 12 air changes per hour and high-efficiency particulate air (HEPA) to prevent infection in susceptible patients. Laminar airflow (LAF) involves much greater air changes, expense and inconvenience to the patient due to noise and draughts. There are few, if any, truly controlled trials on the impact of positive-pressure ventilation and the prevention of invasive aspergillosis (IA); most are observational studies conducted during an outbreak or retrospective analyses of the incidence of IA over periods of time when a variety of preventative interventions were introduced. Therefore, it is often difficult to determine the specific impact of positive-pressure ventilation with HEPA in leading to a reduction in IA. During periods of hospital demolition or construction, HEPA significantly reduces the aspergillus spore counts and in many studies, the incidence of IA, but other measures such as enhanced cleaning, the sealing of windows and the use of prophylactic anti-fungal agents are also important. On balance, the additional expense and inconvenience of LAF does not appear to be justified. Where positive-pressure ventilation is installed, it is imperative that the system be monitored to ensure that the pressure differentials and air changes are appropriate. Whilst there is a role for positive-pressure ventilation in reducing the incidence of IA, we need a better definition of the importance of hospital-acquired IA compared with community-acquired infection and of the relationship between strains of Aspergillus species isolated from the environment and those strains causing infection.
Invasive aspergillosis
- Dw Denning
Denning DW. Invasive aspergillosis. Clin Infect Dis
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Construction-related Nosocomial Infections in Patients in Health Care Facilities. CCDR. Web site: http://www.phacaspc .gc.ca Hospital sources of Aspergillus: New routes of transmission?
- A Voss
- Pe Verweij
Construction-related Nosocomial Infections in Patients in
Health Care Facilities. CCDR. Web site: http://www.phacaspc.gc.ca/publicat/ccdr-rmtc/01pdf/27s2e.pdf
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New routes of transmission? Rev Iberoam Micol 2001;18:156-62.