Relationship between environmental fungal contamination and the incidence of invasive aspergillosis in haematology patients

Rapid detection and quantification of Aspergillus fumigatus in environmental air samples using solid-phase cytometry

Aspergillus fumigatus is an ubiquitous fungus capable of causing severe infections such as aspergilloma, allergic bronchopulmonary aspergillosis, and invasive aspergillosis, especially in immunocompromised patients. Monitoring the number of Aspergillus fumigatus spores in the air is crucial for infection control. In the present study, a novel approach for the quantification of Aspergillus fumigatus, based on solid-phase cytometry (SPC) and immunofluorescent labeling, was developed. The sensitivity and specificity of the assay were confirmed by testing pure cultures. Paecilomyces variotii and Rhizopus stolonifer were codetected but could be excluded on the basis of morphology of the microcolonies. The SPC method has considerable advantages compared to the culture-based method, including its low detection limit (4 cells/m3), its speed (results are obtained within 24 h), and the straightforward microscopic identification of Aspergillus fumigatus. Additionally, comparison of results obtained with both methods demonstrated that they are equally accurate for the quantification of Aspergillus fumigatus in environmental air samples.

A prospective survey of air and surface fungal contamination in a medical mycology laboratory at a tertiary care university hospital

BACKGROUND

Invasive filamentous fungi infections resulting from inhalation of mold conidia pose a major threat in immunocompromised patients. The diagnosis is based on direct smears, cultural symptoms, and culturing fungi. Airborne conidia present in the laboratory environment may cause contamination of cultures, resulting in false-positive diagnosis. Baseline values of fungal contamination in a clinical mycology laboratory have not been determined to date.

METHODS

A 1-year prospective survey of air and surface contamination was conducted in a clinical mycology laboratory during a period when large construction projects were being conducted in the hospital. Air was sampled with a portable air system impactor, and surfaces were sampled with contact Sabouraud agar plates. The collected data allowed the elaboration of Shewhart graphic charts.

RESULTS

Mean fungal loads ranged from 2.27 to 4.36 colony forming units (cfu)/m(3) in air and from 0.61 to 1.69 cfu/plate on surfaces.

CONCLUSIONS

Strict control procedures may limit the level of fungal contamination in a clinical mycology laboratory even in the context of large construction projects at the hospital site. Our data and the resulting Shewhart graphic charts provide baseline values to use when monitoring for inappropriate variations of the fungal contamination in a mycology laboratory as part of a quality assurance program. This is critical to the appropriate management of the fungal risk in hematology, cancer and transplantation patients.

A study of air microbe levels in different areas of a hospital

Airborne transmission is an important route for many microbial pathogens in outdoor and indoor environments, including hospitals. A 2-year-long survey of bioaerosol quality in operating theatres (OT), hospital rooms (HR) and maternity wards (MW) at a hospital in Murcia, Spain, was performed. Total aerobic counts (TAC) and fungal load (FL) were assessed using a microbiological air sampler (MAS-100 single-stage impactor). While fungal levels were below 1 cfu/m(3) (0-7.33 cfu/m(3)) in OT, they were higher in MW (mean, 6.9 cfu/m(3); range 0.44-44.67 cfu/m(3)) and in HR (mean, 10.6 cfu/m(3); range, 0-266 cfu/m(3)). In OT the aerobic counts were considerably higher, with a mean of 25.6 cfu/m(3) (range, 1.67-157 cfu/m(3)). MW and HR also showed higher means for total aerobic counts compared to OT. Seasonal changes were not detected in mould and bacteria levels in OT. Hospital renovation occurred during this study and OT adjacent to renovated areas were closed. A survey of TAC and FL in OT resumed when renovation was completed. We observed an outstanding increase in FL (more than 100 cfu/m(3)), particularly Aspergillus spp., during this period, but no significant changes in TAC were observed after renovation.

Environmental sampling of particulate matter and fungal spores during demolition of a building on a hospital area

Demolition or renovation works adjacent to hospitals pose risks of fungal airborne infections. During November 2005 and March 2006 an old building with three floors was demolished on the area of University Hospital of Essen. To prevent dust exposure the building was sealed up by impermeable plastic foil and mechanical disruption of structures was accomplished using excavators. Dust emission was minimised by water jet. To determine if there were any infectious risks for patients from emissions from the demolition work we monitored particle and fungal concentration of the air before and during demolition. Air sampling was performed at seven positions around the building and weather conditions were monitored at the same time. Concentrations of ultrafine particles, particles > or =0.3, > or =0.5 and > or =1 microm were significantly higher during demolition than before, but only by small factors (ultrafine particles 1.6-fold, particles > or =0.3 microm 1.6-fold, particles > or =0.5 microm 2.9-fold and particles > or =1 microm 3.3-fold). Concentrations of moulds which could be cultured at 37 degrees C did not differ between the two periods (median before demolition: 66 cfu/ m3; median during demolition: 80 cfu/m3). Concentrations of moulds which grew at 22 degrees C correlated significantly with temperature and humidity and were significantly higher before (median: 510 cfu/m3) than during the demolition period (median: 210 cfu/m3). We conclude that the fungal infection risks for patients during demolition work in hospital areas is not increased by demolition if protective measures are in place.

A Review of the Research Literature on Evidence-Based Healthcare Design

Objective:

This report surveys and evaluates the scientific research on evidence-based healthcare design and extracts its implications for designing better and safer hospitals.

Background:

It builds on a literature review conducted by researchers in 2004.

Methods:

Research teams conducted a new and more exhaustive search for rigorous empirical studies that link the design of hospital physical environments with healthcare outcomes. The review followed a two-step process, including an extensive search for existing literature and a screening of each identified study for the relevance and quality of evidence.

Results:

This review found a growing body of rigorous studies to guide healthcare design, especially with respect to reducing the frequency of hospital-acquired infections. Results are organized according to three general types of outcomes: patient safety, other patient outcomes, and staff outcomes. The findings further support the importance of improving outcomes for a range of design characteristics or interventions, including single-bed rooms rather than multibed rooms, effective ventilation systems, a good acoustic environment, nature distractions and daylight, appropriate lighting, better ergonomic design, acuity-adaptable rooms, and improved floor layouts and work settings. Directions for future research are also identified.

Conclusions:

The state of knowledge of evidence-based healthcare design has grown rapidly in recent years. The evidence indicates that well-designed physical settings play an important role in making hospitals safer and more healing for patients, and better places for staff to work.

Invasive pulmonary aspergillosis in neutropenic patients and the influence of hospital renovation

To evaluate the effects of airborne Aspergillus contamination during and after the renovation work of a Florentine haematology unit, we conducted (November 2003-January 2005) a strict programme of environmental fungal surveillance. Air samples were taken from patients' rooms, along the corridors inside the wards, along the corridor between wards and outside the building. The concentration of Aspergillus fumigatus was high along the corridor between the two haematology wards (2.98 CFU m(-3)), lower in the non-neutropenic patients' rooms and outside the hospital building (1.53 and 1.42 CFU m(-3), respectively), very low in the neutropenic patients' rooms (0.09 CFU m(-3)). During this period, three proven cases (A. fumigatus), two probable ones and two possible cases of invasive pulmonary aspergillosis were documented in 97 patients with acute leukaemia (7%). The three cases of proven aspergillosis coincided with the period of renovation work and with the period in which we have found the maximum concentration of A. fumigatus along the corridor. These data suggest a possible relationship between environmental fungal contamination and the incidence of invasive aspergillosis, and underline the importance of environmental surveillance.

Air filtration systems and restrictive access conditions improve indoor air quality in clinical units: Penicillium as a general indicator of hospital indoor fungal levels

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Invasive aspergillosis: epidemiology, diagnosis and management in immunocompromised patients

Morbidity and mortality caused by invasive Aspergillus infections are increasing. This is because of the higher number of patients with malignancies treated with intensive immunosuppressive therapy regimens as well as their improved survival from formerly fatal bacterial infections, and the rising number of patients undergoing allogeneic haematopoietic stem cell or organ transplantation. Early initiation of effective systemic antifungal treatment is essential for a successful clinical outcome in these patients; however, clinical clues for diagnosis are sparse and early microbiological proof of invasive aspergillosis (IA) is rare. Clinical diagnosis is based on pulmonary CT scan findings and non-culture based diagnostic techniques such as galactomannan or DNA detection in blood or bronchoalveolar lavage samples. Most promising outcomes can be expected in patients at high risk for aspergillosis in whom antifungal treatment has been started pre-emptively, backed up by laboratory and imaging findings. The gold standard of systemic antifungal treatment is voriconazole, which has been proven to be significantly superior to conventional amphotericin B and has led to a profound improvement of survival rates in patients with cerebral aspergillosis. Liposomal amphotericin B at standard dosages appears to be a suitable alternative for primary treatment, while caspofungin, amphotericin B lipid complex or posaconazole have shown partial or complete response in patients who had been refractory to or intolerant of primary antifungal therapy. Combination therapy with two antifungal compounds may be a promising future strategy for first-line treatment. Lung resection helps to prevent fatal haemorrhage in single patients with pulmonary lesions located in close proximity to larger blood vessels, but is primarily considered for reducing the risk of relapse during subsequent periods of severe immunosuppression. Strict reverse isolation appears to reduce the incidence of aspergillosis in allogeneic stem cell transplant recipients and patients with acute myeloid leukaemia undergoing aggressive anticancer therapy. Well designed, prospective randomised studies on infection control measures effective to prevent aspergillosis are lacking. Prophylactic systemic antifungal treatment with posaconazole significantly improves survival and reduces IA in acute myeloid leukaemia patients and reduces aspergillosis incidence rates in patients with intermediate-to-severe graft-versus-host reaction emerging after allogeneic haematopoietic stem cell transplantation. Voriconazole prophylaxis may be suitable for prevention of IA as well; however, the results of large clinical trials are still awaited.

Evaluation of a new mobile system for protecting immune-suppressed patients against airborne contamination

BACKGROUND

Invasive aspergillosis is one of the most lethal airborne dangers for immune-suppressed subjects. Providing patient protection from such airborne threats requires costly and high-maintenance facilities. We herein evaluate a new self-contained mobile unit as an alternative for creating a patient protective environment.

METHODS

Airborne contamination levels were monitored for different simulated scenarios and under actual clinical conditions. Functional tests were used to challenge the unit under adverse conditions, and a preliminary clinical study with patients and staff present was performed at 2 different French hospitals.

RESULTS

Functional tests demonstrated that the unit can rapidly decontaminate air in the protected zone created by the unit and in the surrounding room. In addition, the protected zone is not sensitive to large disturbances that occur in the room. The clinical study included 4 patients with 150 accumulated days of testing. The protected zone created by the unit systematically provided an environment with undetectable airborne fungal levels (ie, <1 CFU/m(3)) regardless of the levels in the room or corridor (P < .01).

CONCLUSIONS

These tests show that the unit can be used to create a mobile protective environment for immune-suppressed patients in a standard hospital setting.

Ten-year air sample analysis of Aspergillus prevalence in a university hospital

Airborne fungal samples were collected on a monthly basis for 10 years, from 1995 to 2005, at a tertiary university hospital. Paired samples were cultured at 25 and 37 degrees C. Data were interpreted according to the air filtration systems serving each location. Samples cultured at 37 degrees C from the patient care areas had a mean recovery of 18% of the mean recovery from outdoor air (22 versus 122cfu/m(3)). Recovery of Aspergillus spp. at 37 degrees C in the high-efficiency particulate air (HEPA)-filtered locations was positive for Aspergillus spp. approximately one-third of the time; the rest of the patient care areas were positive half of the time and the outdoor samples were positive 95% of the time. We found 48 sporadic bursts at 37 degrees C which produced counts >3 SD above the mean. Hospital-acquired infection was related to high recovery of Aspergillus fumigatus on at least one occasion. We have found it impossible, without implementing impractical measures, to provide an environment completely devoid of Aspergillus spp. We conclude that routine air sampling is not an effective means of predicting hospital-acquired infections. However, a transient spike, or burst, may be useful in identifying an in-house source of contamination and may be used to consider additional interventional treatments for patients at risk. Emphasis should be placed on maintaining high-efficiency filtration of the outside air and on ensuring that other environmental control methods are used to prevent dissemination of environmental opportunistic fungal spores.

Decreasing airborne contamination levels in high-risk hospital areas using a novel mobile air-treatment unit

OBJECTIVE

To evaluate the performance of a new mobile air-treatment unit that uses nonthermal-plasma reactors for lowering the airborne bioburden in critical hospital environments and reducing the risk of nosocomial infection due to opportunistic airborne pathogens, such as Aspergillus fumigatus.

METHODS

Tests were conducted in 2 different high-risk hospital areas: an operating room under simulated conditions and rooms hosting patients in a pediatric hematology ward. Operating room testing provided performance evaluations of removal rates for airborne contamination (ie, particles larger than 0.5 microm) and overall lowering of the airborne bioburden (ie, colony-forming units of total mesophilic flora and fungal flora per cubic meter of air). In the hematology service, opportunistic and nonpathogenic airborne fungal levels in a patient's room equipped with an air-treatment unit were compared to those in a control room.

RESULTS

In an operating room with a volume of 118 m(3), the time required to lower the concentration of airborne particles larger than 0.5 microm by 90% was decreased from 12 minutes with the existing high-efficiency particulate air filtration system to less than 2 minutes with the units tested, with a 2-log decrease in the steady-state levels of such particles (P<.01). Concurrently, total airborne mesophilic flora concentrations dropped by a factor of 2, and the concentrations of fungal species were reduced to undetectable levels (P<.01). The 12-day test period in the hematology ward revealed a significant reduction in airborne fungus levels (P<.01), with average reductions of 75% for opportunistic species and 82% for nonpathogenic species.

CONCLUSION

Our data indicate that the mobile, nonthermal-plasma air treatment unit tested in this study can rapidly reduce the levels of airborne particles and significantly lower the airborne bioburden in high-risk hospital environments.

Pulmonary dysfunction in pediatric hematopoietic stem cell transplant patients: overview, diagnostic considerations, and infectious complications

Pulmonary complications are among the most common and serious sequelae seen in hematopoietic stem cell transplantation (HSCT) recipients. This two-part review addresses the incidence and impact of pulmonary complications in pediatric HSCT patients. In this first part we review the available data for the use of diagnostic modalities in this population, including flexible bronchoscopy with bronchoalveolar lavage (BAL) and open lung biopsy (OLB). We also review the many infectious pulmonary complications that may occur in pediatric HSCT recipients, utilizing the traditional chronologic divisions of neutropenic phase (0-30 days following HSCT), early phase (30-100 days), and late phase (>100 days).

The utility of intensified environmental surveillance for pathogenic moulds in a stem cell transplantation ward during construction work to monitor the efficacy of HEPA filtration

A 12-week environmental study was performed to ensure that the patient rooms of an SCT ward with high-efficiency particulate air (HEPA) filtration remained uncontaminated by moulds during close-by construction work. The sampling included measuring the ventilation channel pressure, particle count measurements, air sampling, settled dust analysis and fungal cultures from the oral and nasal cavities of the patients. No changes in the air pressure occurred. Median particle counts in patient rooms were 63-420 particles/l. The mean particle count of the outside air was 173,659 particles/l. Patient room air samples were negative for aspergilli in 32 of 33 cases. All samples of the outside air were positive for moulds. Aspergillus fumigatus was isolated at the beginning of excavation works at the construction area and in two of 33 dust samples from patient rooms. All 70 nasal samples were negative. Of 35 mouth samples, one sample was positive for A. niger in a patient with a previously diagnosed aspergillus infection. During a median follow-up of 214 days, no invasive aspergillus infections were diagnosed in the 55 patients treated during the construction period. In conclusion, the HEPA filters seemed to have performed well in preventing an aspergillosis outbreak.

Immune reconstitution following hematopoietic stem-cell transplantation

Hematopoietic stem-cell transplantation is associated with a profound immune deficiency manifested as an increased propensity to develop infections and probably also malignancies. Innate immunity, including epithelial barriers and phagocytes, typically recovers within weeks after grafting, and B-cell counts and CD8 T-cell counts recover within months. CD4 T-cell counts are low for years, and their recovery is particularly slow in older patients with poor thymic function. Therapies to improve immune function include vaccinations, immunoglobulins for recurrent infections, cytokines, and antigen-specific donor lymphocyte infusions.

Reduced fungal contamination of the indoor environment with the Plasmair™ system (Airinspace)

Aspergillus spp. and other moulds cause life-threatening opportunistic infections in immunocompromised patients. Indoor contamination and construction work that liberate fungal spores are a major source of nosocomial aspergillosis. Dijon hospital is a tertiary care institution in northeast France undergoing construction work beside high-risk clinical units. To determine the impact of this activity, a surveillance programme was implemented one year before building work began in order to establish baseline levels of contamination. Air and surface fungal contamination in adult and paediatric haematology units were prospectively examined following use, or not, of a new air-treatment system with mobile Plasmair units (Airinspace). There were significant reductions in overall fungal contamination for the Plasmair treated rooms for air and surface samples in both clinical units. Plasmair treatment also significantly reduced A. fumigatus in the air. These data suggest that Plasmair units may provide an efficient method of reducing indoor fungal contamination in hospitals.

Prevention and monitoring of invasive fungal infections in pediatric patients with cancer and hematologic disorders

BACKGROUND

The occurrence of invasive fungal infection (IFIs) in a pediatric hematology/oncology unit after renovation of the ventilation system, and initiating routine azole antifungal prophylaxis was monitored. In addition, the value of serial screening for Aspergillus galactomannan (GM) for diagnosing invasive aspergillosis was assessed.

PROCEDURE

A total of 98 consecutive high-risk pediatric patients were prospectively surveyed for signs of IFI and weekly monitored for serum GM. The data was not made available to treating physicians.

RESULTS

Only 2 patients had proven and 27 possible IFI based on the European Organization for Research and Treatment of Cancer/Mycoses Study Group definitions. The incidence of proven IFI was 1/31 (3.2%) in the allogeneic stem cell transplant (SCT) (Aspergillus spp), 0/26 in the autologous SCT, and 1/60 (1.6%) in the induction therapy group (C. krusei). GM was detected at least in one tested sample in 12/98 patients (12.2%), in five patients in two or more sequential samples. In the latter group, IFI was proven in one patient and could not be excluded in the others. Four of the five patients belonged to the 31 allogeneic and one to the 26 autologous SCT patients. In patients with only one positive GM test none developed signs of IFI and only one received empirical amphotericin B.

CONCLUSIONS

With the currently used preventative and prophylactic measures, IFI is uncommon in children with high-risk for infection. Regular screening for GM could be useful among allogeneic SCT patients and two positive samples should prompt further investigative procedures and pre-emptive antifungal therapy.

Nosocomial fungal infections: epidemiology, diagnosis, and treatment

Invasive fungal infections are increasingly common in the nosocomial setting. Furthermore, because risk factors for these infections continue to increase in frequency, it is likely that nosocomial fungal infections will continue to increase in frequency in the coming decades. The predominant nosocomial fungal pathogens include Candida spp., Aspergillus spp., Mucorales, Fusarium spp., and other molds, including Scedosporium spp. These infections are difficult to diagnose and cause high morbidity and mortality despite antifungal therapy. Early initiation of effective antifungal therapy and reversal of underlying host defects remain the cornerstones of treatment for nosocomial fungal infections. In recent years, new antifungal agents have become available, resulting in a change in standard of care for many of these infections. Nevertheless, the mortality of nosocomial fungal infections remains high, and new therapeutic and preventative strategies are needed.

Air sampling of Aspergillus fumigatus and other thermotolerant fungi: comparative performance of the Sartorius MD8 airport and the Merck MAS-100 portable bioaerosol sampler

The purpose of our field study was to compare the performance of two portable bioaerosol samplers (Sartorius MD8 airport, and Merck MAS-100) for sampling Aspergillus fumigatus and other airborne thermotolerant fungi. From October 2001 to November 2001, a total of 336 samples were analyzed at 12 sampling days. During the sampling period fungal plate counts ranged from <1 to 300 CFU/m(3) for total thermotolerant fungi and from <1 to 76 CFU/m(3) for A. fumigatus. As compared to the MD8, the relative recovery of the MAS 100 was 0.96 for total thermotolerant fungi and 0.84 for A. fumigatus. We found a good correlation (Pearson's r=0.94 for single, 0.95 for the mean of two, and 0.96 for the mean of three sequential samples) between both portable bioaerosol samplers. The spectrum of thermotolerat fungal genera and Aspergillus species showed only minor differences. We conclude that under the given conditions the results of both samplers are approximately comparable.

Bacterial and fungal counts in hospital air: comparative yields for 4 sieve impactor air samplers with 2 culture media

We compared the yields of 4 recently developed sieve impactor air samplers that meet international standard ISO 14698-1, using 2 growth media (tryptic soy agar and malt extract agar) in real conditions of use. Several hospital sites expected to have different densities of airborne microflora were selected in 2 hospitals. The Samplair MK2, Air Ideal, and Mas-100 samplers yielded higher bacterial counts than did the SAS Super-100 device (P<.05). No significant differences in fungal counts were noted between the 4 devices. The use of malt extract agar in addition to tryptic soy agar significantly improved the fungal yield.

Evolution of the Environmental Contamination by Thermophilic Fungi in a Turkey Confinement House in France

Fungal species constitute a major part of environmental contaminants in facilities where animals are housed. The present investigation was aimed at describing the relative abundances of fungal species and their concentrations in a turkey confinement house in France. Fungal cultures from poultry feed, litter, and air were undertaken every week throughout the 16-wk period of breeding. The incubation temperature of 40 degrees C was selected to isolate thermophilic fungal species (especially Aspergillus spp. and Candida albicans) that are potentially pathogenic for birds. The 2 species Aspergillus fumigatus and Aspergillus flavus were recovered at a mean of 10.5 and 37.0 cfu/m(3) of air sampled, respectively. Individual samplings yielded concentrations of up to 150.0 cfu/m(3) for A. flavus in the first weeks of the investigation. Other fungal species were recovered at a mean of 18.9 cfu/m(3) (maximum 36.3 cfu/m(3)) in the air. The yeast C. albicans was first detected at wk 4 from litter samples and at wk 7 from poultry feed. Densities of C. albicans remained very high in litter samples (63.2 cfu/g) even after new litter was added at wk 10. To analyze the genetic polymorphism of A. fumigatus, the most pathogenic mold in birds, a total number of 198 isolates (134 from air, 34 from litter, and 30 from feed samples) were genotyped using 2 polymorphic microsatellite markers. More than half (42 out of 73, 57.5%) of the genotypes were detected only once. This finding suggests that the contamination of the breeding environment is not due to a single source and confirms the very high genetic diversity of environmental A. fumigatus isolates. As during the study period, no outbreak of fungal infections occurred; the levels of fungal contaminations reported here do not seem sufficient, at least alone, to trigger fungal infections.

Efficacy of environmental measures to decrease the risk of hospital-acquired aspergillosis in patients hospitalised in haematology wards

This study evaluated a multidisciplinary strategy to decrease the rate of invasive pulmonary aspergillosis (IPA) among adult patients hospitalised in two haematology wards in a single 560-bed building at the University Hospital of Saint-Etienne. Upgrading of the air filtration system and construction of an air-lock chamber at the entrance to the unit were completed during 1994. In 1995, specific hygienic measures were introduced during hospital building work, including the use of plastic barriers, watering during demolition work, reduction of pedestrian traffic in construction areas, and the wearing of high-efficiency filtration masks by immunosuppressed patients when outside the protected unit. This strategy was evaluated by a prospective survey of IPA cases between 1993 and 2001, coupled with environmental surveillance. The number and risk-level of hospital renovation projects increased between 1995 and 2001 (p < 0.01). In parallel, the rate of IPA decreased globally in the haematology unit from 0.85% (1.19/1,000 patients) in 1993 to 0.28% (0.21/1,000 patients) in 2001. The incidence of IPA decreased significantly between 1993-1996 and 1997-2001 (p 0.02, Mann-Whitney test). These results show that a multidisciplinary approach involving engineers, infection control practitioners, mycologists and clinicians enables IPA rates among patients hospitalised in haematology wards to be significantly decreased.

A problem of hospital hygiene: the presence of aspergilli in hospital wards with different air-conditioning features

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.

Nosocomial aspergillosis in outbreak settings

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.

Hospital-wide prospective mandatory surveillance of invasive aspergillosis in a French teaching hospital (2000-2002)

A multidisciplinary working group devoted to epidemiological surveillance of invasive aspergillosis (IA) was created in January 2000 in Grenoble University Hospital. This article presents the results of a three-year IA surveillance. The multidisciplinary working group surveyed all hospitalized patients, and the mycology laboratory detected most suspected IA cases. Cases were reviewed monthly by the Aspergillosis Committee, and were classified according to international consensus criteria. Possible nosocomial acquisition was determined. Among the 490 alerts, 74 IA cases were observed: six proven cases (8%), 36 (49%) probable cases and 32 (43%) possible cases. The incidence was 4.4 (95% CI 3.4-5.4) IA/100 000 patient-days. Among the proven and probable IA cases, we observed 10 nosocomial cases and six cases of undetermined origin. No cases were noted in the protected rooms in the haematology unit. Only one cluster of cases (three nosocomial cases) was detected in the haematology unit. Forty-three percent of cases (N=32) were hospitalized in the haematology unit, and all other cases were hospitalized elsewhere. This three-year survey found a high rate of non-nosocomial IA cases and a high frequency of IA cases hospitalized in units other than haematology. Thus, this study shows the importance of IA surveillance in haematology units and all high-risk units.

Clinical implications of environmental sources for Aspergillus

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.

[Monitoring of airborne fungus and yeast species in a hospital unit]

OBJECTIVE

To monitor and characterize airborne filamentous fungi and yeasts from abiotic and biotic sources within a hospital unit.

METHODS

Collections were carried out on a monthly basis, at two different time periods, from the adult and pediatric intensive care units and surgical center of a hospital in Araraquara, Southeastern Brazil. Collection of airborne fungi was carried out using a simple-stage Andersen sample. The presence of yeasts was investigated in samples taken from the hands and oropharynx of staff members as well as from the surface of beds and doorknobs inside the critical areas.

RESULTS

Thirty-two genera of airborne fungi and were recovered from the surgical center and 31 from the intensive care units. Genera most frequently isolated were Cladophialophora spp., Fusarium spp., Penicillium spp., Chrysosporium spp. e Aspergillus spp. During the study period, a new unit was built in the hospital, which coincided with an increase in Cladophialophora spp., Aspergillus spp., and Fusarium spp. colony counts. Yeasts were found in 39.4% of samples obtained from healthcare staff (16.7% from interdigital spaces, 12.1% from nailbeds, and 10.6% from oropharynx) and in 44% of furniture samples, with a predominance of the Candida genus ((C. albicans, C. guilliermondii, C. parapsilosis e C. lusitaniae), followed by Trichosporon spp.

CONCLUSIONS

We found a relatively high number of airborne fungi (potentially pathological) in special areas and expressive levels of yeasts in both biotic and abiotic samples. Microbiological and environmental monitoring should be conducted, especially in special areas which include immunocompromised patients, who are more susceptible to the exposure to environmental and staff-derived pathogens.

Hospital water point-of-use filtration: a complementary strategy to reduce the risk of nosocomial infection

Cholera, hepatitis and typhoid are well-recognized water-borne illnesses that take the lives of many every year in areas of uncontrollable flood, but far less attention is afforded to the allegedly safe potable water in affluent nations and the presumed healthful quality of water in communities and hospitals. Recent literature, however, points to increasing awareness of serious clinical sequelae particularly experienced by immunocompromised patients at high risk for disease and death from exposure to water-borne microbes in hospitals. This review reflects the literature indicting hospital water as an important source for nosocomial infections, examines patient populations at greatest risk, uncovers examples of failures in remedial water treatment methods and the reasons for them, and introduces point-of-use water filtration as a practical alternative or complementary component of an infection control strategy that may reduce the risk of nosocomial infections.

Prevention of systemic mycoses by reducing exposure to fungal pathogens in hospitalized and ambulatory neutropenic patients

PURPOSE/OBJECTIVES

To describe sources of fungal contamination that can incite invasive mycoses in hospitalized and ambulatory neutropenic patients and to discuss approaches to reduce exposure to pathogens.

DATA SOURCES

Published articles, books, and brochures.

DATA SYNTHESIS

Modifications of patient environments and lifestyles include hand hygiene for patients and healthcare workers, air filtration in hospitals, and reduction in exposure to plants, soil, standing water, and dusty environments. The effectiveness of dietary restrictions is controversial, although avoidance of pepper is recommended. These restrictions should be implemented prior to, during, and following neutropenia.

CONCLUSIONS

Mycoses can be hospital or community acquired; however, although guidelines for environmental and lifestyle modifications are well documented for the institutional setting, they are more limited for ambulatory patients.

IMPLICATIONS FOR NURSING

Nurses have a key role in the early identification of outbreaks of fungal infections, evaluation of hospital and home environments for sources of pathogens, education of patients on preventive measures, and research on neutropenic diets and improved technology to reduce exposure to fungal pathogens.

Epidemiological study of invasive pulmonary aspergillosis in a haematology unit by molecular typing of environmental and patient isolates of Aspergillus fumigatus

In order to determine the possible relationship between environmental contamination by Aspergillus fumigatus and occurrence of invasive aspergillosis, a one-year prospective study was carried out in the haematology ward of Hautepierre Hospital, Strasbourg, France. During the study period, 21 environmental isolates and 26 clinical isolates of A. fumigatus were collected. Each was genotyped using a random amplification of polymorphic DNA (RAPD) technique. Thirty-four distinct profiles were identified by RAPD analysis, indicating the great genetic diversity of A. fumigatus isolated from infected patients and from the environment. For two patients, RAPD analysis demonstrated concurrent infection by at least two different strains. In two cases, a genetic similarity was noted between isolates obtained from a patient and from the environment.

Aspergillus surveillance project at a large tertiary-care hospital

A one-year surveillance project was conducted at a large tertiary hospital, which had extensive indoor renovation and extensive demolition/building at several nearby sites. This study collected viable fungi samples in the hospital every six days and analysed 74 duct dust samples for Aspergillus fumigatus mycelial asp f1 protein. Mean total fungi were 257.8 cfu/m3 outdoors, 53.2 cfu/m3 in all indoor samples and 83.5 cfu/m3 in the bone marrow transplant patient rooms. Mean total aspergillus was 6.8 cfu/m3 outdoors, 12.1 cfu/m3 in all indoor samples and 7.3 cfu/m3 in the bone marrow transplant patient rooms. The five most prevalent Aspergillus species collected inside the hospital (mean cfu/m3) were Aspergillus niger 7.57 cfu/m3, Aspergillus candidus 1.72 cfu/m3, Aspergillus flavus 0.97 cfu/m3, A. fumigatus 0.88 cfu/m3 and Aspergillus glaucus 0.45 cfu/m3. In rooms undergoing duct cleaning, mean A. fumigatus concentrations were 11.0 cfu/m3. Forty-eight of 74 (65%) duct dust samples had measurable levels of asp f1 protein, with a mean level of 0.41 ppm and maximum level of 1.94 ppm. Three major incidents involved increased hospital aspergillus concentrations. A. niger levels reached 680 cfu/m3 in an organ transplant room after a water leak from a ceiling pipe. Total aspergillus concentrations rose to 77 cfu/m3 in a bone marrow transplant patient room after improper sealing and water infiltration of the unit's dedicated high-efficiency particulate air filter system. Total aspergillus levels of 160 cfu/m3 were recorded in a renovation area during wood cutting. The higher concentrations of aspergillus seen inside the hospital compared with outdoors and the various moisture/HEPA filter/renovation incidents suggest that numerous small to moderate sources of aspergillus exist in the hospital.

Two years of a fungal aerobiocontamination survey in a Florentine haematology ward

The control of microbial air contamination in hospital wards has assumed great importance particularly for those hospital infections where an airborne infection route is hypothesised, such as aspergillosis. Invasive aspergillosis represents one of the most serious complications in immunocompromised patients. For some authors there is a direct association between this pathology and the concentrations of Aspergillus conidia in the air; in addition, reports of aspergillosis concurring during building construction have been frequent. In this study, two haematology wards were monitored for about 2 years in order to make both a qualitative and quantitative evaluation of fungal burden in the air, also in relation to major construction and demolition work taking place in the same building. Air samples were taken from the hospital rooms of neutropenic patients, in the corridors of their ward and outside the building. Total fungal concentration resulted higher outside (mean 572 Colony Forming Units/m3 of air), lower in the corridors (147 CFU/m3) and even lower in the rooms (50 CFU/m3). In all the samples we found the development of at least one fungal colony. Cladosporium was the most frequently isolated genus (57%), in contrast to Aspergillus spp. (2%). The average concentration of Cladosporium spp. was 24 CFU/m3 in the rooms, 78 CFU/m3 in the corridors and 318 CFU/m3 outside. The average concentration of Aspergillus spp. was 1.2 CFU/m3 in the rooms, 3.5 CFU/m3 in the corridors, 5.6 CFU/m3 outside. Our observations show low concentrations of Aspergillus fumigatus and A. flavus in all the environments examined and particularly in the rooms (0.09 and 0.10 CFU/m3 respectively); this observation could explain the absence of cases of invasive aspergillosis during the period of air monitoring in the two haematology wards.

Environmental investigations and molecular typing of Aspergillus flavus during an outbreak of postoperative infections

After an outbreak of sternal surgical-site infections (SSSI) with Aspergillus flavus following cardiac surgery, a mycological survey of air and surfaces (41 and 149 samples, respectively) was performed throughout the surgical ward (SW) and in other areas of the hospital. Results showed massive contamination by A. flavus: more than 100 cfu per contact plate were frequently observed in some areas of the SW. The distribution of the A. flavus spores in the building, and especially in the SW, enabled the location of a possible source within the non-medical part of the SW, but the true source could not be identified. Four other surveys were made to follow up the decontamination process; the contamination level did not fall rapidly, needing repetitive cleaning operations. Strains from patients and from the hospital environment selected all over the SW were typed by random amplification of polymorphic DNA (RAPD), using two different primers (ERIC-1, BG-2). All these strains showed the same genotype, proving the clonal single-source of the environmental contamination and the intra-operative acquisition of A. flavus in the SSSI outbreak.

Levels of total fungus and Aspergillus on a pediatric hematopoietic stem cell transplant unit

The purpose of this descriptive study was to determine the levels of total fungus (TF) and Aspergillus in a pediatric hematopoietic stem cell transplant (HSCT) unit. One hundred twenty air samples and 120 floor samples were collected from the same locations in 10 patient rooms and bathrooms for 4 consecutive days. The count in colony-forming units of TF and Aspergillus from each of the samples was measured by the institution's mycology laboratory. Means, standard deviations, minimum values, and maximum values were determined for levels of TF and Aspergillus from different locations and on different days in the air and on the floor. Determination of a mean value of TF and Aspergillus for each room allowed for analysis of mean values of TF and Aspergillus for sample category, room side, room type, and room status. After visual examination of the mean values for the air samples collected, it was determined that the TF and Aspergillus in the air were less than the institution's acceptable air baseline standard. t tests and analysis of variance were used to verify the findings.

Positive-pressure isolation and the prevention of invasive aspergillosis. What is the evidence?

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.

How do we assess hospital cleaning? A proposal for microbiological standards for surface hygiene in hospitals

Increasing numbers of hospital-acquired infections have generated much attention over the last decade. The public has linked the so-called 'superbugs' with their experience of dirty hospitals, but the precise role of cleaning in the control of these organisms in unknown. Hence the importance of a clean environment is likely to remain speculative unless it becomes an evidence-based science. This proposal is a call for bacteriological standards with which to assess clinical surface hygiene in hospitals, based on those used by the food industry. The first standard concerns any finding of a specific 'indicator' organism, the presence of which suggests a requirement for increased cleaning. Indicators would include Staphylococcus aureus, including methicillin-resistant S. aureus, Clostridium difficile, vancomycin-resistant enterococci and various Gram-negative bacilli. The second standard concerns a quantitative aerobic colony count of <5 cfu/cm(2) on frequent hand touch surfaces in hospitals. The principle relates to modern risk management systems such as HACCP, and reflects the fact that pathogens of concern are widespread. Further work is required to evaluate and refine these standards and define the infection risk from the hospital environment.

Aspergillosis in a 24-week newborn: a case report

Aspergillosis is an uncommon neonatal infection, diagnosed with an increasing frequency over the last two decades. We report a premature neonate who developed aspergillosis while receiving amphotericin B and fluconazole for candidiasis. Despite early recognition and diagnosis, the infant died. We review the clinical appearance of Aspergillus species, the distinctions between primary cutaneous aspergillosis and invasive aspergillosis, and advances in diagnosis and treatment.

Recent trends in the epidemiology of invasive mycoses

PURPOSE OF REVIEW

Invasive mycoses are emerging as an important public health problem. This development has occurred in large measure due to the increasing numbers of persons at risk. In addition, advances in therapeutic technologies and in particular the development of novel immunosuppressive therapies have prolonged the period of risk for many individuals.

RECENT FINDINGS

Although rates of candida bloodstream infections have been increasing over the past several decades, recent evidence suggests this trend may be reversing. The emergence of non-albicans Candida species, and in particular C. glabrata, has been documented. Invasive aspergillosis and other mold infections have become a significant and increasing problem in hematopoietic stem cell transplant recipients and certain high-risk groups of solid organ transplant recipients. These infections are associated with high mortality rates. Despite marked reductions in the rates of AIDS-associated fungal infections in the USA and other developed countries, the burden of these mycoses in developing countries is large and increasing.

SUMMARY

While gains have been made in the treatment and prevention of invasive mycoses, changes in the epidemiology of these infections and in healthcare practices have resulted in the emergence of new at-risk populations. A better understanding of specific risk factors will be needed if prevention strategies, such as chemoprophylaxis and environmental control measures, are to become more widely applicable and cost-effective.

Demolition of a hospital building by controlled explosion: the impact on filamentous fungal load in internal and external air

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.

Environmental surveillance of filamentous fungi in three tertiary care hospitals in Greece

The environmental fungal load (FL) of three hospitals was studied in representative regions in Greece (Thessalonika, Northern Greece, Athens, Central Greece and Heraklion, Southern Greece). Air, surfaces and tap water from high-risk departments were sampled monthly during one year. Air FL was [median (range)] 10.6 (1.2-37), 5.5 (3-28.8) and 7.7 (3.1-12.1) cfu/m(3) at Thessalonika, Athens and Heraklion, respectively. Air FL was lower in winter and higher in summer and autumn but seldom above acceptable levels. Aspergillus spp. constituted 70.5% of the filamentous fungi isolated. Aspergillus niger was the most prevalent species in the air of all the hospitals followed by Aspergillus flavus and Aspergillus fumigatus. The least contaminated departments were the intensive care units, whilst most contaminated were the solid organ transplantation in Athens and haematology departments in Thessalonika. No correlation between fungal species, season, hospital or departments was observed. Sixty per cent of all surfaces examined yielded filamentous fungi and/or blastomycetes. While no fungi were recovered from water in Thessalonika and Athens, one-third of the samples in Heraklion (apart from those of ICU) yielded multiple fungal species. The higher air FL in Thessalonika and Athens was recorded in departments located close to renovation works. These findings suggest that the air and surface FL fluctuates over the year, is due to varying fungal species, but does not differ greatly among hospitals. The variation among hospitals, as well as the role of hospital water fungal contamination and appropriate measures to eliminate it, need further study.

Hospital-acquired Aspergillus fumigatus infection: can molecular typing methods identify an environmental source?

Aspergillus fumigatus infection in hospitalized immunocompromised patients often raises suspicion regarding the potential for hospital acquisition. Hospital staff have an important responsibility in implementing preventive measures, especially since the advent of current legislation concerning hospital-acquired infections. There have been high expectations that molecular typing methods might determine the source of Aspergillus fumigatus, a ubiquitous mould. The aim of the present epidemiological study, was therefore, to identify the origin(s) of Aspergillus infection in six well-documented patients. All the clinical strains (N=33), and those from hospital (N=14) and home environments (N=34) were isolated according to a standardized protocol and typed by sequence-specific DNA primer analysis. The results confirmed the huge biodiversity of the A. fumigatus population, and consequently the difficulty in ascertaining a hospital source of the infection, as opposed to infections due to other Aspergillus species less frequently encountered.

Epidemiology of invasive aspergillosis in France: a six-year multicentric survey in the Greater Paris area

Invasive aspergillosis is the most prevalent mould infection. An epidemiological surveillance network was set up in 18 teaching hospitals in Paris and the Greater Paris area. Prospective surveillance was conducted between 1994 and 1999. Between 1994 and 1997 cases were categorized as proven or probable aspergillosis and then the European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria were used. The authors analysed 621 cases (115 proven, 506 probable). No seasonal variation was found. Haematological disorders (73%) including stem-cell transplantation (36%), solid-organ transplantations (10%) and AIDS (9%) were the main underlying conditions. The crude mortality was 63%. Incidence of IA was 8% (CI(95): 6.5-9.5) in acute myelocytic leukaemia and 6.3% (CI(95): 4.3-8.3) in acute lymphocytic leukaemia. Incidence was 12.8% (CI(95): 10.8-14.8) following allogeneic stem-cell transplantation and 1.1% (CI(95): 0.7-1.5) following autologous stem-cell transplantation. In solid-organ recipients incidence ranged from 11% following heart-lung transplantation and small bowel to 0.4% following kidney transplantation. Incidence in HIV infected patients ranged from 0.02 to 0.13% per annum. This large series confirmed that patients with haematologic disorders and transplantations are the most at risk for IA.