Pathogenic Aspergillus species recovered from a hospital water system: a 3-year prospective study

Contamination of a purified water system by Aspergillus fumigatus in a new endoscopy reprocessing unit

Use of purified water for the final rinse stage of disinfected endoscopes is an important element of quality control. We describe the detection and management of Aspergillus fumigatus contamination of a new reverse osmosis unit supplying 10 automated endoscope reprocessor basins. Prompt detection and reaction to this contaminant were possible because of the introduction of a comprehensive program for microbiological monitoring of rinse waters, which included total viable counts, endotoxin, conductivity, and Pseudomonas spp.

A comprehensive water management program for multicampus healthcare facilities

OBJECTIVE

Develop and implement an effective program for hazard analysis and control of waterborne pathogens at a multicampus hospital with clinics.

DESIGN

A longitudinal study. Several-year study including analysis of results from monitoring and tests of 26 building water systems.

SETTING

Outpatient and inpatient healthcare facilities network.

METHODS

The hazard analysis and critical control point (HACCP) process was used to develop a water management program (WMP) for the hospital campuses. The HACCP method systematically addressed 3 questions: (1) What are the potential waterborne hazards in the building water systems of these facilities? (2) How are the hazards being controlled? (3) How do we know that the hazards have been controlled? Microbiological and chemical tests of building water samples were used to validate the performance of the WMP; disease surveillance data further validated effective hazard control.

RESULTS

Hazard analysis showed that waterborne pathogens were generally in good control and that the water quality was good in all facilities. The hospital network has had several legionellosis cases that were identified as presumptive hospital acquired, but none was confirmed or substantiated by water testing in follow-up investigations. Building water system studies unrelated to these cases showed that pressure tanks and electronic automatic faucets required additional hazard control.

CONCLUSIONS

Application of the HACCP process for long-term building water systems management was practical and effective. The need for critical control point management of temperature, flow, and oxidant (chlorine) residual concentration was emphasized. The process resulted in discovery of water system components requiring additional hazard control.

Antifungal prophylaxis among allogeneic hematopoietic stem cell transplant recipients: current issues and new agents

Invasive candidiasis and invasive mold infections cause significant morbidity and mortality in the hematopoietic stem cell transplant population, in particular in recipients of allografts. The introduction of a variety of new antifungal compounds over the past decade has focused attention on prophylactic strategies as a means to decrease the burden of invasive fungal infections (IFIs). Until recently, fluconazole has been the standard agent for prophylaxis before and after engraftment. In 2005, the echinocandin micafungin received US FDA approval for prophylaxis against IFIs in stem cell transplant recipients during the neutropenic period prior to engraftment. In patients with substantial risk for invasive mold infection, many centers now use a mold-active antifungal agent (e.g., a triazole such as itraconazole, voriconazole or posaconazole, or an echinocandin) as prophylaxis after engraftment. Several recent studies have highlighted the efficacy of these newer agents in preventing IFIs in these highly immunocompromised patients. This review will discuss current issues in IFI and new agents available for prophylaxis in allogeneic hematopoietic stem cell transplant recipients.

Fungal infections in cancer patients

Invasive fungal infections (IFI) have become a leading cause of morbidity and mortality in cancer patients. Infections with these organisms are often difficult to diagnose and treat. Appropriate and timely diagnosis requires a high index of suspicion and invasive procedures, including biopsy, to confirm the diagnosis. Treatment may be difficult, secondary to variable susceptibility and difficulty with exact and specific characterization of the fungal pathogen. The pathogens that are seen range from yeasts to invasive molds. Fortunately newer, noninvasive diagnostic techniques are available to aid in the diagnosis and treatments have become better tolerated and more efficacious.

[Aspergillus species in hospital environments with pediatric patients in critical condition]

BACKGROUND

Aspergillus is a group of opportunistic fungi that cause infections, with high morbimortality in immunosuppressed patients. Aspergillus fumigatus is the most frequent species in these infections, although the incidence of other species has increased in the last few years.

AIMS

To evaluate the air fungal load and the diversity of Aspergillus species in hospitals with pediatric patients in critical condition.

METHODS

The Intensive Care Unit and Burns Unit of a pediatric hospital were sampled every 15 days during the autumn and spring seasons. The air samples were collected with SAS Super 100(®) and the surface samples were collected by swab method.

RESULTS

The UFC/m(3) counts found exceeded the acceptable levels. The UFC/m(3) and the diversity of Aspergillus species found in the Intensive Care Unit were higher than those found in the Burns Unit. The fungal load and the diversity of species within the units were higher than those in control environments. The use of both methods -SAS and swab- allowed the detection of a higher diversity of species, with 96 strains of Aspergillus being isolated and 12 species identified. The outstanding findings were Aspergillus sydowii, Aspergillus niger, Aspergillus flavus, Aspergillus terreus and Aspergillus parasiticus, due to their high frequency. Aspergillus fumigatus, considered unacceptable in indoor environments, was isolated in both units.

CONCLUSIONS

Aspergillus was present with high frequency in these units. Several species are of interest in public health for being potential pathogenic agents. Air control and monitoring are essential in the prevention of these infections.

Prevention of Infections in Patients with Hematological Malignancies

Infection is a frequent complication and a leading cause of morbidity and mortality in patients with hematological malignancies. Problems associated with the management of infections in these patients include difficulties in early diagnosis because the clinical signs of infection are subtle, the low performance of diagnostic tests, and suboptimal response to treatment because recovery of host defenses is a key factor for resolution of infection. Preventing these infections relies on infection control measures and antimicrobial chemoprophylaxis. While infection control measures are safe (but not always effective), the use of antimicrobial agents for prophylaxis of infection is not devoid of problems. Its wide use may increase the possibility of the development of resistance, select for resistant organisms, and increase toxicity and cost. Therefore, any attempt to administer an antimicrobial agent should be accompanied by a reflection of the potential benefits and risks of prophylaxis.

Nontuberculous mycobacteria, fungi, and opportunistic pathogens in unchlorinated drinking water in The Netherlands

The multiplication of opportunistic pathogens in drinking water supplies might pose a threat to public health. In this study, distributed unchlorinated drinking water from eight treatment plants in the Netherlands was sampled and analyzed for fungi, nontuberculous mycobacteria (NTM), and several opportunistic pathogens by using selective quantitative PCR methods. Fungi and NTM were detected in all drinking water samples, whereas Legionella pneumophila, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Aspergillus fumigatus were sporadically observed. Mycobacterium avium complex and Acanthamoeba spp. were not detected. Season had no influence on the occurrence of these organisms, except for NTM and S. maltophilia, which were present in higher numbers in the summer. Opportunistic pathogens were more often observed in premise plumbing water samples than in samples from the distribution system. The lowest number of these organisms was observed in the finished water at the plant. Thus, fungi, NTM, and some of the studied opportunistic pathogens can multiply in the distribution and premise plumbing systems. Assimilable organic carbon (AOC) and/or total organic carbon (TOC) had no clear effects on fungal and NTM numbers or on P. aeruginosa- and S. maltophilia-positive samples. However, L. pneumophila was detected more often in water with AOC concentrations above 10 μg C liter(-1) than in water with AOC levels below 5 μg C liter(-1). Finally, samples that contained L. pneumophila, P. aeruginosa, or S. maltophilia were more frequently positive for a second opportunistic pathogen, which shows that certain drinking water types and/or sampling locations promote the growth of multiple opportunistic pathogens.

Ultraviolet irradiation: An effective inactivation method of Aspergillus spp. in water for the control of waterborne nosocomial aspergillosis

Invasive aspergillosis is the second most common cause of nosocomial fungal infections and occurring mainly by Aspergillus fumigatus, Aspergillus flavus, and Aspergillus niger. There is evidence that nosocomial aspergillosis may be waterborne. This study was conducted to evaluate the ultraviolet (UV) irradiation efficiency in terms of inactivating the most important Aspergillus species in water since these are potential sources for nosocomial aspergillosis. A continuous flow UV reactor which could be used as a point-of-use (POU) system was used to survey Aspergillus inactivation by UV irradiation. The inactivation efficiency of UV fluence (4.15-25 mJ/cm(2)) was measured by determination of fungal density in water before and after radiation. Because turbidity and iron concentration are two major water quality factors impacting UV disinfection effectiveness, the potential influence of these factors on UV inactivation of Aspergillus spp. was also measured. The 4 log inactivation for A. fumigatus, A. niger and A. flavus at a density of 1000 cfu/ml was achieved at UV fluences of 12.45 mJ/cm(2), 16.6 mJ/cm(2) and 20.75 mJ/cm(2), respectively. The inactivation efficiency for lower density (100 cfu/ml) was the same as for the higher density except for A. flavus. The removal efficiency of Aspergillus spp. was decreased by increasing the turbidity and iron concentration. UV disinfection could effectively inactivate Aspergillus spores from water and eliminate potential exposure of high-risk patients to fungal aerosols by installation of POU UV systems.

Soil eukaryotic microorganism succession as affected by continuous cropping of peanut--pathogenic and beneficial fungi were selected

Peanut is an important oil crop worldwide and shows considerable adaptability but growth and yield are negatively affected by continuous cropping. Soil micro-organisms are efficient bio-indicators of soil quality and plant health and are critical to the sustainability of soil-based ecosystem function and to successful plant growth. In this study, 18S rRNA gene clone library analyses were employed to study the succession progress of soil eukaryotic micro-organisms under continuous peanut cultivation. Eight libraries were constructed for peanut over three continuous cropping cycles and its representative growth stages. Cluster analyses indicated that soil micro-eukaryotic assemblages obtained from the same peanut cropping cycle were similar, regardless of growth period. Six eukaryotic groups were found and fungi predominated in all libraries. The fungal populations showed significant dynamic change and overall diversity increased over time under continuous peanut cropping. The abundance and/or diversity of clones affiliated with Eurotiales, Hypocreales, Glomerales, Orbiliales, Mucorales and Tremellales showed an increasing trend with continuous cropping but clones affiliated with Agaricales, Cantharellales, Pezizales and Pyxidiophorales decreased in abundance and/or diversity over time. The current data, along with data from previous studies, demonstrated that the soil microbial community was affected by continuous cropping, in particular, the pathogenic and beneficial fungi that were positively selected over time, which is commonplace in agro-ecosystems. The trend towards an increase in fungal pathogens and simplification of the beneficial fungal community could be important factors contributing to the decline in peanut growth and yield over many years of continuous cropping.

The importance of cleanrooms for the treatment of haemato-oncological patients

The main purpose of cleanrooms in health care centres is to prevent hospital infections or leakage of a highly infectious agent (the source of haemorrhagic fevers, SARS, etc.) into the ambient environment and subsequently possibly threatening other individuals. Patients with haematological malignancies or after autologous or allogeneic haematopoietic stem cell transplantation (HSCT) rank among immunosuppressed individuals. Prolonged and deep neutropenia is considered a key risk factor of the occurrence of an exogenous infection. One of the possibilities of preventing an exogenous infection in these patients is to place them in a "cleanroom" for the crucial period of time. Cleanrooms are intensive care units with reverse isolation. The final part of the general article below provides an overview of the technology and types of cleanrooms for immunosuppressed patients in compliance with the current recommendations and technical standards.

Hospital environment and invasive aspergillosis in patients with hematologic malignancy

BACKGROUND

To determine whether there is a correlation between sources of Aspergillus spores in a high-efficiency particulate air (HEPA)-filtered environment and nosocomial invasive aspergillosis (IA), we performed a detailed environmental assessment and case review.

METHODS

From April to October 2004, 626 bioaerosol samples, 1,257 surface samples, and 607 water samples were obtained from 74 HEPA-filtered air hospital rooms occupied by 458 patients with hematologic malignancies. Samples were collected prospectively from the room before and after cleaning within 1 hour of patient admission or discharge. Aspergillus spp was isolated from 21 surface samples and 46 bioaerosol samples. Interestingly, Aspergillus spp was not isolated from any water samples.

RESULTS

Aspergillus spp was isolated from 21 surface samples and 46 bioaerosol samples. Interestingly, Aspergillus spp were not isolated from any water samples. The majority (90%) of the positive bioaerosol samples had ≤ 10 colony-forming units of Aspergillus/m3 of air. Only 2 patients developed nosocomial IA. No correlations were found between Aspergillus species isolated from the hospital rooms and those causing IA.

CONCLUSION

The risk of hematologic malignancy patients acquiring nosocomial aspergillosis from water or HEPA-filtered air is very low.

Widespread occurrence of diverse human pathogenic types of the fungus Fusarium detected in plumbing drains

It has been proposed that plumbing systems might serve as a significant environmental reservoir of human-pathogenic isolates of Fusarium. We tested this hypothesis by performing the first extensive multilocus sequence typing (MLST) survey of plumbing drain-associated Fusarium isolates and comparing the diversity observed to the known diversity of clinical Fusarium isolates. We sampled 471 drains, mostly in bathroom sinks, from 131 buildings in the United States using a swabbing method. We found that 66% of sinks and 80% of buildings surveyed yielded at least one Fusarium culture. A total of 297 isolates of Fusarium collected were subjected to MLST to identify the phylogenetic species and sequence types (STs) of these isolates. Our survey revealed that the six most common STs in sinks were identical to the six most frequently associated with human infections. We speculate that the most prevalent STs, by virtue of their ability to form and grow in biofilms, are well adapted to plumbing systems. Six major Fusarium STs were frequently isolated from plumbing drains within a broad geographic area and were identical to STs frequently associated with human infections.

Aspergillus species identification in the clinical setting

Multiple recent studies have demonstrated the limited utility of morphological methods used singly for species identification of clinically relevant aspergilli. It is being increasingly recognised that comparative sequence based methods used in conjunction with traditional phenotype based methods can offer better resolution of species within this genus. Recognising the growing role of molecular methods in species recognition, the recently convened international working group meeting entitled "Aspergillus Systematics in the Genomic Era" has proposed several recommendations that will be useful in such endeavors. Specific recommendations of this working group include the use of the ITS regions for inter section level identification and the beta-tubulin locus for identification of individual species within the various Aspergillus sections.

In vitro antimicrobial activity of methanolic leaf extract of Psidium guajava L

AIM

This study was designed to examine the chemical composition and in vitro antimicrobial potential of methanolic extract of Psidium guajava Linn (Myrtaceae).

MATERIALS AND METHODS

The inhibitory effect of methanolic extract of P. guajava was tested against three bacterial and two fungal strains by using the paper disc diffusion method.

RESULTS

The methanolic extract exhibited antibacterial activity against E. coli with minimum inhibitory concentration, 0.78 μg/ml, minimum bactericidal concentration of 50 μg/ml, and appreciable antifungal activity with minimum inhibitory concentration of 12.5 μg/ml. Preliminary phytochemical analysis of methanolic extract revealed the presence of antimicrobial compounds such as flavonoids, steroids, and tannins, which may contribute for the antimicrobial action of P. guajava.

CONCLUSION

The extract was found to be bacteriostatic and fungistatic in action.

Microbiological monitoring of mineral water commercialized in Brazil

The quality of mineral water commercialized in Brazil regarding the microbial content was analyzed and the results were compared with the standards established by the current legislation. Results demonstrated there was no bacterial contamination, but several types of fungi were found. Therefore, bottled mineral water could be considered a possible route for the transmission of filamentous fungi and yeasts.

Nosocomial fungal infections: epidemiology, infection control, and prevention

Fungal infections are an increasing cause of morbidity and mortality in hospitalized patients. This article reviews the current epidemiology of nosocomial fungal infections in adult patients, with an emphasis on invasive candidiasis and aspergillosis. Recently published recommendations and guidelines for the control and prevention of these nosocomial fungal infections are summarized.

Fungal microbiota in air-conditioning installed in both adult and neonatal intensive treatment units and their impact in two university hospitals of the central western region, Mato Grosso, Brazil

To evaluate fungal microbiota in air-conditioning units installed in intensive care units in two university hospitals in Cuiaba city, Mato Grosso, central western region of Brazil, 525 solid environmental samples were collected, 285 from Hospital A and 240 from Hospital B. Collections were performed using sterile swabs on air-conditioning unit components: cooling coils, ventilators, and filters. Mycelial fungi identification was achieved by observation of the macroscopic and micromorphological characteristics in different culture mediums (maize meal, oatmeal and potato dextrose agars and malt extract) using the Ridell technique. Eleven genera and 27 distinct species belonging to the hyphomycetes and ascomycetes classes were isolated and identified. The most frequently detected genera in both hospitals were Aspergillus spp, Penicillium spp, and Cladosporium spp. Values for colony-forming units per gram were 64 and 75%, well above the limits recommended by Health Ministry resolution 176/00 at the locations selected for analysis in Hospitals A and B, respectively. In conclusion, evaluation of fungal microbiota in the air-conditioning units indirectly determined that the air quality was compromised in both university hospitals analyzed, which constitutes a risk factor for the acquisition of infection in the intensive care units.

Three potential sources of microfungi in a treated municipal water supply system in sub-tropical Australia

Some microfungi are known to be opportunistic human pathogens, and there is a body of scientific opinion that one of their routes of infection may be water aerosols. Others have been implicated as causative agents of odours and off-tastes in drinking water. This study was undertaken to investigate three potential sources of microfungi in a treated, oligotrophic municipal water supply system in sub-tropical Australia. Formation of the microfungal component of developing biofilm on hard surfaces in water storage reservoirs was also assessed. Inside and outside air samples were collected from two reservoirs using two types of Burkard air samplers. Biofilm and soft sediment samples were collected from the inner surfaces of asbestos cement water pipes and from pipe dead ends respectively. These were analysed for microfungal growth and sporulation using Calcofluor White stain and epifluorescent microscopy. Artificial coupons of glass, PVC and concrete were immersed in two reservoirs to assess microfungal biofilm formation. This was analysed periodically using Calcofluor White stain and epifluorescent microscopy, cultures of coupon swabs and scanning electron microscopy. Fungal spores were recovered from all air samples. The number of colonies and the genera were similar for both inside and outside air. Microfungal filaments and sporulating structures were recovered from most of the pipe inner surface biofilm and dead end sediment samples, but were sparser in the biofilm than in the sediment samples. No recognisable, vegetative filamentous fungi were found in the slowly developing biofilm on coupons. This study indicates that airborne spores are an important potential source of microfungi found in water storage reservoirs. It has also demonstrated conclusively that filamentous microfungi grow and sporulate on water pipe inner surfaces and in soft sediments within the water distribution system.

Study on fungal flora of tap water as a potential reservoir of fungi in hospitals in Sari city, Iran

OBJECTIVE

The aim of the present investigation was to evaluate the fungal flora of tap water from university hospitals of Sari city, Iran.

MATERIALS AND METHODS

During a 1-year period, 240 water samples were collected from four university hospitals. All water samples were collected in sterile polystyrene bottles. A volume of 100ml of the samples passed through sterile 0.45-micrometer filters. The filters were placed directly on malt extract agar and incubated at 27°C for 3 to 7 days. Routine mycological techniques were applied to identification of grown fungi.

RESULTS

Out of 240 plates, 77.5% were positive for fungal growth. Twelve different genera were identified. Aspergillus (29.7%), Cladosporium (26.7%) and Penicillium (23.9%) were the most common isolated. Among Aspergillus species, A. flavus had the highest frequency. Highest colony counts were found in autumn. Aspergillus predominated in autumn, Cladosporium in winter and spring and Penicillium in summer.

CONCLUSION

The results of our study showed that hospital water should be considered as a potential reservoir of fungi particularly Aspergillus.

Hospital epidemiology and infection control in acute-care settings

Health care-associated infections (HAIs) have become more common as medical care has grown more complex and patients have become more complicated. HAIs are associated with significant morbidity, mortality, and cost. Growing rates of HAIs alongside evidence suggesting that active surveillance and infection control practices can prevent HAIs led to the development of hospital epidemiology and infection control programs. The role for infection control programs has grown and continues to grow as rates of antimicrobial resistance rise and HAIs lead to increasing risks to patients and expanding health care costs. In this review, we summarize the history of the development of hospital epidemiology and infection control, common HAIs and the pathogens causing them, and the structure and role of a hospital epidemiology and infection control program.

Megacities as sources for pathogenic bacteria in rivers and their fate downstream

Poor sanitation, poor treatments of waste water, as well as catastrophic floods introduce pathogenic bacteria into rivers, infecting and killing many people. The goal of clean water for everyone has to be achieved with a still growing human population and their rapid concentration in large cities, often megacities. How long introduced pathogens survive in rivers and what their niches are remain poorly known but essential to control water-borne diseases in megacities. Biofilms are often niches for various pathogens because they possess high resistances against environmental stress. They also facilitate gene transfers of antibiotic resistance genes which become an increasing health problem. Beside biofilms, amoebae are carriers of pathogenic bacteria and niches for their survival. An overview about our current understanding of the fate and niches of pathogens in rivers, the multitude of microbial community interactions, and the impact of severe flooding, a prerequisite to control pathogens in polluted rivers, is given.

Design of the environment of care for safety of patients and personnel: does form follow function or vice versa in the intensive care unit?

We review the context of the environment of care in the intensive care unit setting in relation to patient safety and quality, specifically addressing healthcare-associated infection issues and solutions involving interdisciplinary teams. Issues addressed include current and future architectural design and layout trends, construction trends affecting intensive care units, and prevention of construction-associated healthcare-associated infections related to airborne and waterborne risks and design solutions. Specific elements include single-occupancy, acuity-scalable intensive care unit rooms; environmental aspects of hand hygiene, such as water risks, sink design/location, human waste management, surface selection (floor covering, countertops, furniture, and equipment) and cleaning, antimicrobial-treated or similar materials, ultraviolet germicidal irradiation, specialized rooms (airborne infection isolation and protective environments), and water system design and strategies for safe use of potable water and mitigation of water intrusion. Effective design and operational use of the intensive care unit environment of care must engage critical care personnel from initial planning and design through occupancy of the new/renovated intensive care unit as part of the infection control risk assessment team. The interdisciplinary infection control risk assessment team can address key environment of care design features to enhance the safety of intensive care unit patients, personnel, and visitors. This perspective will ensure the environment of care supports human factors and behavioral aspects of the interaction between the environment of care and its occupants.

Incidence and distribution of microfungi in a treated municipal water supply system in sub-tropical Australia

Drinking water quality is usually determined by its pathogenic bacterial content. However, the potential of water-borne spores as a source of nosocomial fungal infection is increasingly being recognised. This study into the incidence of microfungal contaminants in a typical Australian municipal water supply was carried out over an 18 month period. Microfungal abundance was estimated by the membrane filtration method with filters incubated on malt extract agar at 25 °C for seven days. Colony forming units were recovered from all parts of the system and these were enumerated and identified to genus level. The most commonly recovered genera were Cladosporium, Penicillium, Aspergillus and Fusarium. Nonparametric multivariate statistical analyses of the data using MDS, PCA, BEST and bubble plots were carried out with PRIMER v6 software. Positive and significant correlations were found between filamentous fungi, yeasts and bacteria. This study has demonstrated that numerous microfungal genera, including those that contain species which are opportunistic human pathogens, populate a typical treated municipal water supply in sub-tropical Australia.

Epidemiology of invasive mycoses in North America

The incidence of invasive mycoses is increasing, especially among patients who are immunocompromised or hospitalized with serious underlying diseases. Such infections may be broken into two broad categories: opportunistic and endemic. The most important agents of the opportunistic mycoses are Candida spp., Cryptococcus neoformans, Pneumocystis jirovecii, and Aspergillus spp. (although the list of potential pathogens is ever expanding); while the most commonly encountered endemic mycoses are due to Histoplasma capsulatum, Coccidioides immitis/posadasii, and Blastomyces dermatitidis. This review discusses the epidemiologic profiles of these invasive mycoses in North America, as well as risk factors for infection, and the pathogens' antifungal susceptibility.

Prophylactic Antifungal Agents Used After Lung Transplantation

Objective:

To review the data supporting available antifungal agents and compare regimens utilized to prevent fungal infection in lung transplant recipients.

Data Sources:

Literature retrieval was accessed through MEDLINE (1950 through October 2009) and United Network for Organ Sharing online database (available data through October 2009), using the terms lung transplantation, prophylaxis, and fungal infection. In addition, reference citations from publications identified were reviewed.

Study Selection And Data Extraction:

All articles or related abstracts in English identified from the data sources above were evaluated. Literature including adult lung transplant recipients who received systemic antifungal prophylaxis to prevent invasive fungal infections (IFIs) was included in the review.

Data Synthesis:

IFIs after lung transplantation remain a common postoperative problem and are associated with high mortality. The lung is the most vulnerable solid organ to be transplanted, as it is the main organ responsible for gas exchange and therefore the high risk for pulmonary-related IFIs. It is most susceptible to developing an IFI, as it serves as a medium for organisms traveling from air to human tissue, potentially causing life-threatening infections. Such infections typically involve Candida and Aspergillus spp. and tend to occur within the first 12 months after transplant. Although there has been an increase in lung transplants performed over the past decade, no standard antifungal prophylactic regimen exists. Literature describing antifungals used to prevent IFI after transplant is scarce, which may be due to a lack of consistency in regimens used between transplant centers. Several regimens have been described utilizing different antifungal agents as both monotherapy and combination therapy. The majority of the literature reviewed here describes aerosolized amphotericin B formulations and azole antifungals demonstrating an overall decreased risk of fungal infection after lung transplantation. It has become the standard of practice to initiate some form of antifungal prophylaxis in these patients.

Conclusions:

The risk of fungal infection after lung transplant is multifactorial and optimal prophylactic regimens should include agents with adequate activity against the most pathogenic fungi.

The changing face of febrile neutropenia-from monotherapy to moulds to mucositis. Prevention of mould infections

Isolation of patients at risk of invasive mould infection might be suitable for the reduction of invasive aspergillosis or zygomycosis, if combined with high-efficiency particulate air filtration. Prophylactic wearing of filtering masks of N95 or FFP2 standards has not yet been demonstrated to be efficacious in reducing invasive mould infections outside of scenarios with excessive contamination of room air by fungal spore-loaded dust. The oral broad-spectrum antifungal azoles posaconazole and voriconazole offer protection against invasive Aspergillus infections in severely neutropenic leukaemia patients and allogeneic haematopoietic stem cell transplant recipients; however, their routine use might result not only in considerable side effects, but also in the spread of multi-azole-resistant Aspergillus species, so that careful selection of suitable high-risk patient populations is mandatory.

[Aspergillus spp. in risk areas of transplant patients in a university hospital]

As a consequence of the increase in the number of immunocompromised patients, cases of aspergillosis, due to the opportunist character of this fungus, have increased considerably. Aspergillus fumigatus, Aspergillus flavus, and Aspergillus niger have been found in air and water samples of the majority of investigated hospitals. The aim of the present study was to investigate the presence of aspergilli in transplant patients areas at the Hospital Universitario of Bogotá, Colombia. Samples of air were collected using the MAS-100 Air Sampler from each of the investigated areas. A sample of 100 ml of water was also recovered from these areas. All samples were taken for triplicate and were cultured in 2% Sabouraud Dextrose Agar. The average of aspergilli in air samples was 2.8 CFU/l corresponding to A. flavus, A. niger, Aspergillus versicolor and Aspergillus terreus. In water samples, the average was 17.1 CFU/l corresponding to A. flavus and Aspergillus clavatus. Because potentially pathogenic Aspergillus species were found in the hospital areas were transplant patients are usually kept, active surveillance and a high clinical suspicion should be considered in those patients. Since Aspergillus infections haven't been found so far, a higher fungal load and other host factors might be needed to facilitate the infection.

The study of fungi in drinking water

The occurrence of fungi in drinking water has received increased attention in the last decades, and fungi are now generally accepted as drinking water contaminants. The knowledge about the occurrence and diversity of fungi in water has increased considerably from a low knowledge base. However, the relevance of waterborne fungi for water quality and human health is poorly understood and still conflicting. Scientific reports on effective treatment against fungi in water are also few. This article presents a review of the literature on fungal water studies, including some general results, and considerations of significance, limits, contradictions, precautions, and practical consequences.

Occurrence and hygienic relevance of fungi in drinking water

Fungi, above all filamentous fungi, can occur almost everywhere, even in water. They can grow in such a quantity in water that they can affect the health of the population or have negative effects on food production. There are several reports of fungal growth in water from different countries, but to our knowledge none from Austria so far. The aim of this study was to gain an overview of the spectrum of filamentous fungi and yeasts in drinking water systems. Thirty-eight water samples from drinking water and groundwater were analysed. Fungi were isolated by using membrane filtration and plating method with subsequent cultivation on agar plates. The different taxa of fungi were identified using routine techniques as well as molecular methods. Fungi were isolated in all water samples examined. The mean value for drinking water was 9.1 CFU per 100 ml and for groundwater 5400 CFU per 100 ml. Altogether 32 different taxa of fungi were found. The taxa which occurred most frequently were Cladosporium spp., Basidiomycetes and Penicillium spp. (74.6%, 56.4% and 48.7%, respectively). This study shows that drinking water can be a reservoir for fungi, among them opportunists, which can cause infections in immunosuppressed patients.

Occurrence of fungi in water used at a haemodialysis centre

AIMS

The aim of this study was to identify and determine the diversity, occurrence and distribution of fungi in water used at a haemodialysis centre.

METHODS AND RESULTS

Samples in the hydraulic circuit for the distribution of the water, dialysate samples and samples of sterilization solution from dialysers were collected over a 3-month period, and 500 ml of each sample was filtered through membranes. All together 116 isolates of fungi were recovered from 89% of all water samples collected inside the haemodialysis unit, with prevalence of moulds in tap water samples and of yeasts in dialysate samples. Fusarium spp. was the most abundant genus found, whereas Candida parapsilosis was the predominant yeast species.

CONCLUSIONS

This study demonstrated that various fungi were present in the water system. These data suggest the inclusion of the detection and quantification of fungi in the water of haemodialysis.

SIGNIFICANCE AND IMPACT OF THE STUDY

The recovery of fungi from aqueous haemodialysis environments implies a potential risk for haemodialysis patients and indicates the need for continuous maintenance and monitoring. Further studies on fungi in haemodialysis water systems are required to investigate the organism ability to persist, their role in biofilm formation and their clinical significance.

[Prevention of fungal infections related to the water supply in French hospitals: proposal for standardization of methods]

OBJECTIVES

The aims of this study were to assess the risk of fungal infections related to the water supply in several hospitals and to clarify the appropriate methodology in order to standardize the technical conditions of the controls and develop guidelines. It was conducted in 10 university hospital centers across the country from February 2004 through March 2005.

METHOD

A preliminary study allowed us to optimize the mycological analysis. The study was conducted under the same conditions as for bacteriological controls: water filtration through a cellulose acetate membrane cultured on agar. Departments with the highest patient risk were selected, including hematology, organ transplantation, and burn units. We selected 98 sites and sampled both water and water-related surfaces at each: three one-liter water samples (the first flow, cold and hot water) and two or three surface samples (inside the tap, pommel of the shower and siphon). At each site, a form was filled to specify its location in the unit, any water treatment (chlorine or other), filtering, and temperature. Water from taps equipped with sterilized filtration was sampled without the filter.

RESULTS

There was a significant difference (p=0.039) in the number of positive cultures between the three types of water sampled: hot water (>50 degrees C) was colonized less often than first flow or cold water. Only 4% of the hot-water samples had positive cultures, compared to the 52% of the cold-water samples. Except in two hospitals with generalized contamination of the water pipes (one with Exophiala spp and the other with Fusarium spp), colonization was usually slight. Cold water was more colonized than hot water, but 79% of the samples yielded fewer than 5CFU/L. Dematiaceous hyphomycetes were isolated; Aspergillus spp were rare. The number of CFU in surface samples (that is, biofilms) was higher (mean=15 CFU per sample) but surfaces were positive less often than water (13% compared with 43% of all water samples). Sampling from siphons was productive more often than from taps (23%), but the molds isolated differed from those in the related water. Relations to bacterial flora and P. aeruginosa were also studied, together with the effects of chemical treatment.

CONCLUSION

Current regulations require only bacteriological survey. The absence of knowledge about the threshold of contamination at which there is a risk of nosocomial invasive fungal infections makes it difficult to impose routine monitoring. Mycological surveys of water are required during hospital renovation, plumbing work, pipe maintenance and when air samples are negative during nosocomial infection investigations.

[Isolation of filamentous fungi from water used in a hemodialysis unit]

Despite the relative frequency of opportunistic fungal infections among hemodialysis patients, the reservoirs for these microorganisms in the environment remain unknown, although some recent studies have made correlations with the water supply as their source. The objective of the present study was to monitor the mycological quality of the water system of a hemodialysis unit in the interior of the State of São Paulo, Brazil, over the period from April to July 2006. Fifteen samples of 1000 ml were collected from seven water distribution points using the membrane filtration technique (0.45 microm). A total of 116 filamentous fungus specimens were isolated, including 47 Trichoderma sp (40.5%), 29 Cladosporium sp (25%), 16 Aspergillus sp (13.8%) and 11 Fusarium sp (9.5%). The results suggest that the water supply for hemodialysis units should also be monitored for mycological contamination, and that effective prophylactic measures should be adopted for minimizing the exposure of these immunodeficient patients to contaminated water sources in the environment.