Influence of building construction work on Aspergillus infection in a hospital setting

Risk of invasive fungal infections during hospital construction: how to minimize its impact in immunocompromised patients

PURPOSE OF REVIEW

Fungal outbreaks have been reported in healthcare settings, showing that construction activities are a serious threat to immunocompromised hosts. Preventive measures to control fungal outbreaks (especially Aspergillus spp.) are considered essential during hospital construction. In this article, we update the main advances in each of preventive strategies.

RECENT FINDINGS

Anticipation and multidisciplinary teamwork are the keystone for fungal outbreaks prevention. Strategies focused on environmental control measures of airborne dissemination of fungal spores have proven to be successful. It is important to recommend azole-resistant Aspergillus fumigatus active surveillance from both air (outdoors and indoors) and clinical samples during hospital construction works. Apart from genotyping, studies should be further encouraged to understand the environmental dynamics. Risk assessment and implement preventive measures (environment control strategies, air surveillance, inpatients immunocompromised patients in high-efficiency particulate air filters rooms, patient education, antifungal prophylaxis in high-risk patient groups, etc.) have shown that these accomplish to reduce the incidence of invasive fungal infection (IFI).

SUMMARY

In general, it is not only a strategy that should be implemented to reduce the risk of IFI but is a bundle of preventive measures, which have proven to be successful in control infection and prevention of airborne transmission of fungi.

Experimental induction of mycotic plaques in the guttural pouches of horses

Guttural pouch mycosis (GPM) is a rare but potentially life-threatening condition in horses. GPM is caused by a fungal invasion into the mucosal lining of the guttural pouches and, frequently, the associated neurovascular structures. Although several species of fungi have been associated with this disease, Aspergillus spp. appear to be the most common isolated from the guttural pouches. However, it remains unclear which are the predisposing factors leading to the development of the infection. The objectives of the present study were to experimentally reproduce an infection by Aspergillus fumigatus and to follow the natural evolution of the mycosis. Eight guttural pouches from four horses were experimentally infected by endoscopy-guided intrapouch inoculation of A. fumigatus culture. Horses were monitored for clinical signs and development of fungal plaques through endoscopic examination. Mycotic lesions were observed in all the horses and a spontaneous regression was observed within 15-28 days. No development of clinical signs was noticed. In conclusion, we were able to induce the development of mycotic lesions and to observe a natural regression of these lesions without clinical signs.

En-suite bathrooms in protected haematology wards: a source of filamentous fungal contamination?

BACKGROUND

In spite of 25 recently built high-risk haematology rooms with a protected environment and fitted with en-suite bathrooms in our university hospital centre in 2008, sporadic cases of hospital-acquired invasive aspergillosis remained in these wards.

AIM

This study aimed to identify unsuspected environmental sources of filamentous fungal contamination in these rooms.

METHODS

Over two months, environmental fungal flora in the air (150 samples) as well as air particle counting and physical environmental parameters (airspeed, temperature, humidity, pressure) were prospectively monitored twice on the sampling day in all 25 protected rooms and en-suite bathrooms in use, and on bathroom surfaces (150 samples).

FINDINGS

In rooms under laminar airflow, in the presence of patients during sampling sessions, fungi were isolated in two samples (4%, 2/50) with a maximum value of 2cfu/500L (none was Aspergillus sp.). However, 88% of the air samples (44/50) in the bathroom were contaminated with a median range and maximum value of 2 and 16cfu/500L. Aspergillus spp. were involved in 24% of contaminated samples (12/44) and A. fumigatus in 6% (3/44). Bathroom surfaces were contaminated by filamentous fungi in 5% of samples (8/150).

CONCLUSION

This study highlighted that en-suite bathrooms in protected wards are likely to be a source of fungi. Before considering specific treatment of air in bathrooms, technicians have first corrected the identified deficiencies: replacement of high-efficiency particulate air filters, improvement of air control automation, and restoration of initial technical specifications. Assessment of measure effectiveness is planned.

Refurbishment works in a hospital during normal operation

BACKGROUND

Construction and renovation work in hospitals pose risks of fungal airborne infections for immunosuppressed patients. If possible, reconstruction work will be postponed to periods without patient treatment. However, in many situations urgent damage demands immediate refurbishment works before the transferring of patients to other wards or closure of wards is possible. Reported here are infection control related measures and implemented procedures after two incidents of water damage which occurred on a surgical ward and an intensive care unit at the University hospital of Essen.

METHODS

Between January and April 2009 and between September and October 2009, respectively, concentration of air-borne particles and number of viable fungi were measured at two surgical wards and one ICU. Preventive Infection Control Measures included erection of protective walls and HEPA filtration of air from the renovation area.

RESULTS

During the renovation work on the surgical ward concentrations of moulds and particles ≥5 µm were significantly higher on the left side of the renovation area than on the right side (p=0.036 and p<0.001). Concentrations of particles ≥1 µm and particles ≥5 µm on both sides of the renovation area were significantly increased when compared with the control ward on the same floor but not when compared with the control ward on the other floor. Particles of all size were significantly elevated on the ICU during the renovation work. Aspergillus fumigatus could neither be cultured of the air of cardiac surgery intensive care unit nor of the intermediate care unit (control ward). During renovation works there was no nosocomial mould infection of patients treated on the two wards.

CONCLUSION

Provided that the renovation area is tightly insulated from the areas of patient care on a ward, closure does not seem to be necessary during renovation works because variation of airborne fungi is similar to that of outdoor or control air. However a multidisciplinary team should be established. This team should perform risk assessment and determine necessary protective measures before starting any construction, renovation or maintenance work in health care settings.

Pulmonary injury after combined exposures to low-dose low-LET radiation and fungal spores

Exposure to infectious microbes is a likely confounder after a nuclear terrorism event. In combination with radiation, morbidity and mortality from an infection may increase significantly. Pulmonary damage after low-dose low-LET irradiation is characterized by an initial diffuse alveolar inflammation. By contrast, inhaled fungal spores produce localized damage around pulmonary bronchioles. In the present study, we assessed lung injury in C57BL/6 mice after combined exposures to whole-body X radiation and inhaled fungal spores. Either animals were exposed to Aspergillus spores and immediately irradiated with 2 Gy, or the inoculation and irradiation were separated by 8 weeks. Pulmonary injury was assessed at 24 and 48 h and 1, 2, 4, 8, and 24 weeks later using standard H&E-stained sections and compared with sham-treated age-matched controls. Immunohistochemistry for invasive inflammatory cells (macrophages, neutrophils and B and T lymphocytes) was performed. A semi-quantitative assessment of pulmonary injury was made using three distinct parameters: local infiltration of inflammatory cells, diffuse inflammation, and thickening and distortion of alveolar architecture. Radiation-induced changes in lung architecture were most evident during the first 2 weeks postexposure. Fungal changes were seen over the first 4 weeks. Simultaneous combined exposures significantly increased the duration of acute pulmonary damage up to 24 weeks (P < 0.01). In contrast, administration of the fungus 8 weeks after irradiation did not produce enhanced levels of acute pulmonary damage. These data imply that the inhalation of fungal spores at the time of a radiation exposure alters the susceptibility of the lungs to radiation-induced injury.

Airborne Aspergillus contamination during hospital construction works: efficacy of protective measures

BACKGROUND

The Dijon University Hospital in Dijon, France is involved in a large construction program with heavy truck traffic and a very dusty environment. This study aimed to assess the impact of outdoor hospital construction work on Aspergillus air contamination in the immediate environment of patients at high risk for aspergillosis in the presence of protective measures.

METHODS

Prospective air and surface sampling (n=1301) was performed in 3 hospital units over a 30-month period. Generalized estimating equations were used to test the relationship between Aspergillus air contamination and the different variables (construction period, air treatment system, and surface contamination).

RESULTS

Positivity rates of Aspergillus spp varied from 21.1% before construction work to 16.9% during work for air samples (P=.07), and the associated mean fungal load varied from 1.21 colony-forming units (CFU)/m(3) to 0.64 CFU/m(3) (P=.04). In multivariate analysis, only the use of an air treatment system was associated with decreased airborne Aspergillus contamination (P < .0001). No significant difference was observed between the presence or absence of construction work and the proportion of airborne Aspergillus contamination (P=.91) or the Aspergillus fungal load (P=.10).

CONCLUSIONS

No influence of hospital construction work on airborne Aspergillus contamination was demonstrated when protective measures were taken, including reinforcement of the importance of environmental cleaning.

Flora fúngica no ambiente da Unidade de Terapia Intensiva Pediátrica e Neonatal em hospital terciário

OBJETIVO: As infecções nosocomiais são responsáveis por morbidade e mortalidade significativas no período neonatal. Considerando-se a preocupação com a qualidade do ar de áreas críticas como Unidades de Terapia Intensiva (UTI), foi realizado um levantamento da flora fúngica das UTI Pediátrica e Neonatal do Hospital das Clínicas Samuel Libânio, Pouso Alegre (MG), com a finalidade de identificar a presença de fungos potencialmente patogênicos e oportunistas. MÉTODOS: Foram realizadas 30 coletas, que incluíram leitos, incubadoras, janelas, aparelhos de ar condicionado, telefone, estetoscópios, portas e maçanetas. Placas de Agar Sabouraud Dextrose com o material das coletas foram incubadas em temperatura ambiente por 15 dias. A identificação foi baseada nas características macroscópicas no exame direto e em microcultivos. RESULTADOS: Fungos potencialmente patogênicos e toxigênicos foram isolados. A análise quantitativa das colônias revelou a presença de 11 gêneros. Verificou-se que mais de 40% das colônias correspondem ao gênero Penicillium spp, seguido por Cladosporium spp e Chrysosporium spp. CONCLUSÕES: Os fungos encontrados podem apresentar grande potencial de patogenicidade, principalmente em imunodeprimidos. É importante adotar medidas de controle ambiental, como assepsia dos equipamentos, controle da presença de visitantes, lavagem das mãos pelos funcionários e troca de filtros de ar condicionado.

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.

Laboratory-based management of microbiological alerts: effects of an automated system on the surveillance and treatment of nosocomial infections in an oncology hospital

BACKGROUND

Prevention and surveillance programs are key to contain Nosocomial Infections (Nis). At the European Institute of Oncology, surveillance based on ex-post data collection has been done since the inception of hospital activity; laboratory-based surveillance of microbiological alert was not standardized. This study describes the issues related to the recent introduction into the hospital routine of a laboratory-based automated surveillance system and its clinical impact on monitoring and treatment of Nis.

METHODS

An interdisciplinary team defined the alerts and the actions to be taken in response; recipients of the alert messages were identified and software was programmed. Program features were created so their employment would generate a prompt notification of clinically critical results. After a training period, the program was introduced in the hospital routine.

RESULTS

There were a total of 150 generated alerts; the main alert related to microorganisms requiring prompt patient isolation and/or public notification. Clinical use of the program was relevant in detection and immediate notification of Cytomegalovirus active infection in stem cell recipients and central venous catheter related candidemia: the prompt administration of adequate treatment was possible hours earlier compared to the previous approach.

CONCLUSIONS

A laboratory-based automated surveillance system is effective in facilitating the management of Nis; its clinical employment also leads to important clinical advantages in patient care.

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.

Construction: a model program for infection control compliance

ISSUE

In the 21st century, one of the most challenging tasks for the infection control practitioner (ICP) is establishing collegiality and trust with contractors, architects, maintenance and engineering personnel. We describe how an urban teaching hospital's infection control program cooperated with contractors during a large demolition, construction, and renovation project in order to protect its large population of immunosuppressed patients.

PROJECT

Most contractors are not accustomed to taking special precautions during demolition. Because of a previous Aspergillus outbreak in our heart transplant population, we already had an established infection control (IC) training program for contractors. We expanded and codified it in response to a major hospital renovation. The IC, in-house Design and Construction, and outside contractors meet before the initiation of all major renovation projects to anticipate IC concerns and proactively plan for infection control interventions. Now, all contractors and maintenance staff are required to receive IC training at the time of their employment. A hospital identification badge with attached sticker that indicates the IC training date is required. Infection Control Risk Assessments (ICRA) are initiated by project managers and completed jointly with IC. The ICPs make rounds on all projects at least weekly and large projects are visited daily. We established a team comprised of ICP, project manager, construction manager, and area nurse manager to monitor and make recommendations for improvement continually during the project. Staff are educated about construction so they can help monitor airflow and cleanliness.

RESULTS

Our contractors are more compliant with our IC specifications since they now understand why we insist on them. Through the years of major construction, the workers have jumped on the bandwagon. It is not unusual for construction or maintenance staff to contact IC for advice. There were four years of extensive construction without any hospital acquired Aspergillus infections. In the 5th year, after a neighboring institution started demolition and new construction, we identified two possible nosocomial infections and took immediate steps to make more corrections. There have been no further infections.

LESSONS LEARNED

The IC compliance is based on trust, education, and on-going monitoring. Proactive education and collaboration lead to long-term relationships, trust and patient safety.

OBJECTIVE

This article describes how a large teaching hospital's infection prevention program achieved compliance from contractors during a large renovation.

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.

Factors involved in the aerosol transmission of infection and control of ventilation in healthcare premises

The epidemics of severe acute respiratory syndrome (SARS) in 2003 highlighted both short- and long-range transmission routes, i.e. between infected patients and healthcare workers, and between distant locations. With other infections such as tuberculosis, measles and chickenpox, the concept of aerosol transmission is so well accepted that isolation of such patients is the norm. With current concerns about a possible approaching influenza pandemic, the control of transmission via infectious air has become more important. Therefore, the aim of this review is to describe the factors involved in: (1) the generation of an infectious aerosol, (2) the transmission of infectious droplets or droplet nuclei from this aerosol, and (3) the potential for inhalation of such droplets or droplet nuclei by a susceptible host. On this basis, recommendations are made to improve the control of aerosol-transmitted infections in hospitals as well as in the design and construction of future isolation facilities.

Itraconazole prophylaxis in pediatric cancer patients receiving conventional chemotherapy or autologous stem cell transplants

GOAL OF WORK

During the renovation works at our institution, the incidence density for invasive aspergillosis (IA) increased from <0.5 to 0.99/1,000 inpatient days in 2001. As a direct response to this increased environmental risk, itraconazole (ITC) was administered for primary prophylaxis in pediatric cancer patients for whom a particular high risk of IA was anticipated due to prolonged severe neutropenia (>10 days), autologous stem cell transplantation, acute myeloblastic leukemia or relapsed acute lymphoblastic leukemia, or high-dose steroids >3 weeks.

MATERIALS AND METHODS

In this open-label, prospective observational study, ITC was given in ITC solution or capsule. Trough concentrations were measured in plasma with high-performance liquid chromatography after at least 7 days of treatment. Doses were adjusted to target plasma trough ITC concentrations > or =0.5 mg/l.

RESULTS

From 2001 to 2005, 39 pediatric cancer patients received 44 prophylactic ITC cycles; 102 trough plasma concentrations were measured after oral administration. Plasma target concentrations >0.5 mg/l were achieved with both formulations. A median dose of 8 mg kg(-1) day(-1) (3.5-16.0 mg kg(-1) day(-1)) was necessary in pediatric oncology patients. The bioavailability of the liquid formulation was significantly lower when the solution was given by a feeding tube. Adverse effects (gastrointestinal, elevated transaminases, and one hemolysis) which led to the cessation of the ITC prophylaxis were reported in 11% of all courses. No breakthrough infection was seen in this pediatric population.

CONCLUSION

Oral ITC offers a feasible and inexpensive option for antifungal prophylaxis in selected pediatric cancer patients. Drug monitoring and meticulous consideration of possible interactions and adverse effects are mandatory.

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.

A Systematic Review of Quasi-Experimental Study Designs in the Fields of Infection Control and Antibiotic Resistance

We performed a systematic review of articles published during a 2-year period in 4 journals in the field of infectious diseases to determine the extent to which the quasi-experimental study design is used to evaluate infection control and antibiotic resistance. We evaluated studies on the basis of the following criteria: type of quasi-experimental study design used, justification of the use of the design, use of correct nomenclature to describe the design, and recognition of potential limitations of the design. A total of 73 articles featured a quasi-experimental study design. Twelve (16%) were associated with a quasi-experimental design involving a control group. Three (4%) provided justification for the use of the quasi-experimental study design. Sixteen (22%) used correct nomenclature to describe the study. Seventeen (23%) mentioned at least 1 of the potential limitations of the use of a quasi-experimental study design. The quasi-experimental study is used frequently in studies of infection control and antibiotic resistance. Efforts to improve the conduct and presentation of quasi-experimental studies are urgently needed to more rigorously evaluate interventions.

Infectious complications in patients with hematological malignancies consulted by the Infectious Diseases team: a retrospective cohort study (1997–2001)

In order to identify the characteristics of patients with hematological malignancies (HM) in the presence/suspicion of any accompanying infectious disease, and to find the predictors of mortality in this group, hospital charts of patients with HM consulted by the Infectious Diseases (ID) team for signs/symptoms of any infection between January 1, 1997 and December 31, 2001 were retrospectively reviewed. A total of 1,132 consultations were done for 641 patients: 59.4% of the patients were male and the mean (+/-standard deviation) age of the study participants was 47.9+/-1.4 years. The most common underlying diseases were non-Hodgkin's lymphoma (30.9%), acute myelogenous leukemia (26.2%), and multiple myeloma (10.9%). Clinically and microbiologically documented infections and fever of unknown origin were observed in 43.3%, 38.1%, and 18.5% of the participants, respectively. Bloodstream infections were detected in 134 episodes (20.9%): 56.5% were caused by gram-negative microorganisms. In logistic regression analysis, the presence of pneumonia (OR 7.56, 95% CI 4.84-12.486), invasive fungal infection (OR 4.12, 95% CI 1.78-9.55), relapse or recent diagnosis of the underlying disease (OR 2.82, 95% CI 1.53-5.21) and neutropenia (OR 2.70, 95% CI 1.70-4.31) were identified as statistically significant predictors of mortality.

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.