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.     

Efficacy of high-efficiency particulate air filtration in preventing aspergillosis in immunocompromised patients with hematologic malignancies.

OBJECTIVES: To describe and investigate the cause of an outbreak of 10 cases of nosocomial invasive infection with Aspergillus flavus in a hematologic oncology patient care unit. DESIGN: A retrospective cohort study. SETTING: The hematologic oncology unit of a comprehensive cancer center. PATIENTS: Ninety-one patients admitted to the hematologic oncology service between January 1 and December 31, 1992, for 4 or more consecutive days were included in the study. RESULTS: Ten (18%) of 55 patients admitted from July to December 1992 were diagnosed as having invasive aspergillosis compared with 0 (0%) of 36 patients admitted from January to June 1992 to the same patient care units. Patient characteristics, mortality rate, autopsy rate, and admitting location did not change significantly during the course of the year to result in a sudden increase in the number of aspergillosis cases. The source of the outbreak was the high counts of Aspergillus conidia determined from air sampling in the non-bone marrow transplant wing during the outbreak. After high-efficiency particulate air (HEPA) filters were installed as an infection control measure, there were only two additional cases of nosocomial aspergillosis in the 2 years following the outbreak. CONCLUSIONS: This outbreak occurred among hematologic oncology patients with prolonged granulocytopenia housed in an environment with neither HEPA filters nor laminar air flow units. Our data demonstrate that in the setting of an outbreak of aspergillosis, HEPA filters are protective for highly immunocompromised patients with hematologic malignancies and are effective at controlling outbreaks due to air contamination with Aspergillus conidia.     

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

BACKGROUND AND OBJECTIVE: Aspergillus fumigatus is a major pathogen causing nosocomial infections. Hospital outbreaks of invasive aspergillosis have been associated with the renovation and construction of buildings. Building construction work for fire safety upgrading was undertaken during a 16-week period in 2001 at Box Hill Hospital. This study was designed to examine the effect of construction on invasive aspergillosis when using standard and additional protective measures. METHODS: Baseline air sampling was conducted in 18 areas. The validity of the air sampling was assessed by comparing the ability of two air samplers to detect Aspergillus conidia. Surveillance of nosocomial Aspergillus infection was conducted by reviewing the records of patients with a sputum culture positive for Aspergillus and those prescribed amphotericin or itraconazole for the period of construction activity and the same period the previous year. RESULTS: Aspergillus was isolated infrequently and there was no statistically significant difference in the levels of viable pathogenic fungi between areas w here construction work was undertaken and areas where it wasnot undertaken. A moderate agreement was observed between the two air samplers (kappa = 0.4; P < .05). There was no difference in the incidence of invasive aspergillosis between 2000 and 2001 (incidence density ratio, 1.2; 95% confidence interval, 0.3 to 4.1). CONCLUSION: The influence of construction work performed with protective measures needs to be examined in an environment with higher levels of airborne fungi to confirm the findings of this study.     

Masking of neutropenic patients on transport from hospital rooms is associated with a decrease in nosocomial aspergillosis during construction.

To prevent nosocomial pulmonary aspergillosis during hospital construction, neutropenic patients with hematologic malignancy were required to wear high-efficiency masks when leaving their rooms. The rate of nosocomial aspergillosis decreased from 0.73 per 1,000 hospital patient-days during fiscal years 1993 to 1996 to 0.24 per 1,000 hospital patient-days during fiscal years 1996 to 1999 (P < .001). High-efficiency masks reduced nosocomial aspergillosis during hospital construction.     

Invasive aspergillus infection: possible non-ward common source within the hospital environment

Six immunocompromised patients housed in widely separated portions of a hospital campus developed invasive aspergillosis during a single month. This represented a significant increase (P less than .001) in the number of cases observed over the 3 years which included this event (19 cases in 36 months). Epidemiological investigation suggested that this cluster of cases was due to a common source outbreak related to construction activity in a central radiology suite serving the hospital. Such non-ward exposures to nosocomial hazards are becoming increasingly important for immunosuppressed hosts.     

Incidence of nosocomial aspergillosis in patients with leukemia over a twenty-year period

The incidence of invasive nosocomial aspergillosis was studied in leukemia patients at an oncology center from 1964 to 1983. A total of 97 cases of aspergillosis occurred in 1,866 patients, yielding an overall case rate of 5.2 cases per 100 patients and an incidence rate of 9.1 per 10,000 patient days. The highest incidence rate was in patients with chronic myelogenous leukemia (13.7 cases per 10,000 patient days), followed by patients with acute myelogeneous leukemia (10.6 cases per 10,000 patient days). Subdividing patients after 1978 into those receiving bone marrow transplantation and those who did not demonstrated the predisposition of transplant recipients to aspergillosis. The rates of aspergillosis among those patients who did not receive a bone marrow transplant were highest for patients with acute myelogeneous leukemia. Increases in the annual rates of aspergillosis over time coincided with the level of internal renovation activity and major construction projects upwind of patient care facilities.     

Successful control of an outbreak of invasive aspergillosis in a regional haematology unit during hospital construction works

We report the successful control of an outbreak of six cases of nosocomial invasive aspergillosis (IA) in our haematology unit coinciding with major hospital construction works. Infection control changes included unit relocation, impermeable barriers at construction site, face-masking and voriconazole prophylaxis of 18 further high-risk patients, none of which developed breakthrough IA. A multi-faceted pre-emptive approach involving clinicians, hospital management, engineering and building departments is essential in preventing nosocomial IA outbreaks.     

Molecular typing of Aspergillus terreus isolates by random amplification of polymorphic DNA

Forty three isolates of Aspergillus terreus of environmental or clinical origin were typed by random amplification of polymorphic DNA (RAPD) with two different primers NS3 and NS7 from the fungal ribosomal 18S subunit gene. For the 31 epidemiologically unrelated isolates tested, the primers NS3 and NS7 gave rise to 23 and 24 different genotypes, respectively, and combining the results obtained with the two primers allowed the differentiation of all these isolates. No clustering was found in relation to pathogenicity, clinical signs, or geographic origin of the isolates. Five groups of related isolates of A. terreus were also typed. Analysis of sequential isolates from patients with cystic fibrosis or with invasive aspergillosis showed the clonality of the colonization or infection by A. terreus. Likewise, this straightforward typing method demonstrated the clonal origin of a massive contamination of the environment in a haematology unit. Therefore this RAPD typing method may constitute a valuable tool for the epidemiological follow-up of airway colonization in patients with cystic fibrosis or investigations of links between nosocomial outbreaks of invasive aspergillosis and environmental contamination.     

NICU患者医院感染的病原学类型与病房环境的关系

目的 研究神经内科重症监护病房(NICU)发生医院感染的病原学与病房环境因素的关系,为有效切断致病菌的传播途径提供依据.方法 选取2010年9月-2011年9月唐山市某三甲医院NICU住院患者为监测对象,监测其医院感染的发生情况,同时监测发生感染患者室内空气及床单位(枕头、被服)等环境.结果 224例住院患者中有65例发生医院感染,感染率为29.02％,感染部位以下呼吸道为主,占90.24％;感染病原菌中革兰阴性杆菌占77.01％,主要为铜绿假单胞菌和肺炎克雷伯菌,革兰阳性球菌占16.67％,主要为金黄色葡萄球菌,真菌占6.32％;感染患者病房环境主要以革兰阳性球菌为主.结论 铜绿假单胞菌、肺炎克雷伯菌、金黄色葡萄球菌等是引发NICU医院感染的主要病原菌,病房空气或床单位等环境因素是这些致病菌的重要传播途径之一,因此应加强病房环境和病床单位的消毒,以防止医院感染的传播.     

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

Invasive aspergillosis (IA) is a major opportunistic infection in haematology patients. Spore inhalation is the usual route of Aspergillus infection, suggesting a determining role of environmental contamination by spores in the epidemiology of IA. We prospectively examined the relationship between environmental contamination by Aspergillus and other fungal species and the incidence of invasive nosocomial aspergillosis (INA) in a bone marrow transplantation unit and two haematology wards. During a four-year period, levels of air and surface fungal contamination were determined bi-monthly in patients' rooms (some equipped with HEPA filters and LAF systems), and various common sites in each ward (corridors, nursing stations, etc.). Results were compared to the incidence of INA. A total of 3100 air and 9800 surface samples were collected, and 79 cases of IA were diagnosed, of which 64 were probably or possibly INA. Patterns of fungal contamination were comparable in the three wards, with a gradient ranging from high levels in common sites to a virtual absence in rooms equipped with HEPA filters and LAF systems. Using a regression model, a significant relationship was found between the incidence of INA and the degree of fungal contamination of air and surfaces in conventional patient rooms (not equipped with HEPA) and common sites. This study shows that in a non-epidemic setting, there is a significant relationship between environmental fungal contamination in haematology wards and the incidence of INA. Our findings underline the importance of environmental surveillance and strict application of preventive measures.     

Efficacy of prevention by high-efficiency particulate air filtration or laminar airflow against Aspergillus airborne contamination during hospital renovation.

OBJECTIVE: To evaluate efficacy of laminar airflow facilities plus high-efficiency particulate air (HEPA) filtration and HEPA filtration alone in preventing environmental Aspergillus contamination during hospital renovation. To show the usefulness of environmental surveillance to facilitate protection of patients at risk for invasive pulmonary aspergillosis. DESIGN: Prospective sampling of air and surfaces for Aspergillus conidia during 2-year period. SETTING: A hematological department adjacent to building renovation at a university hospital. RESULTS: 1,047 air samples and 1,178 surface samples were collected from January 1996 to December 1997. Significantly more air samples were positive for Aspergillus species during the period of building renovation than during the periods before and after renovation in a unit without a protected air supply adjacent to the building work area (51.5% vs 31.7%; odds ratio [OR], 2.3; 95% confidence interval [CI95], 1.4-3.7; P<.001). A major increase in the frequency of positive air samples was also found in another adjacent unit that was protected with HEPA filtration alone (from 1.8% to 47.5%; OR, 48.9; CI95, 12-229; P<10(-7)). In addition, in this unit, the mean count of Aspergillus conidia in positive air samples increased significantly during construction (4 colony-forming units [CFU]/m3 to 24.7 CFU/m3; P=.04) and the proportion of positive surface samples showed a significant increase during renovation (from 0.4% to 9.7%; OR, 28.3; CI95, 3.4-623; P=10(-4)). However, none of 142 air samples collected during renovation in the area protected with laminar airflow plus HEPA filtration showed Aspergillus conidia. In a unit distant from the building renovation site, the results of air and surface samples were not affected by renovation. CONCLUSION: This study showed a strong association between building renovation and an increase in environmental Aspergillus contamination. Results confirmed the high efficacy of laminar airflow plus HEPA filtration and a high air-change rate. Although filtration with HEPA was effective during normal conditions, it alone was unable to prevent the rise of Aspergillus contamination related to building renovation. This study emphasized the necessity of an environmental survey of airborne contamination related to construction, to facilitate prevention of nosocomial aspergillosis outbreaks. A standardized protocol for aerobiological surveillance is needed.     

An outbreak of aspergillosis in a general ITU.

Over a 5-month period, six patients in a general intensive therapy unit became colonized by Aspergillus species including Aspergillus fumigatus, and invasive infection occurred in at least two of them. Broncho-alveolar lavage was unhelpful in discriminating between infection and colonization. The source of infection was presumed to be disturbance of an accumulation of spores in fibrous insulation material above the perforated metal ceiling. Patients in such units without clearly identifiable defects of defence against infection may be at risk from aspergillosis. The risk can be reduced by improved hospital design, satisfactory ventilation and thorough regular cleaning of environmental surfaces.     

The emerging nosocomial pathogens Cryptosporidium, Escherichia coli O157:H7, Helicobacter pylori, and hepatitis C: epidemiology, environmental survival, efficacy of disinfection, and control measures.

New and emerging infectious diseases pose a threat to public health and may be responsible for nosocomial outbreaks. Cryptosporidium parvum and Escherichia coli are gastrointestinal pathogens that have caused nosocomial infections via person-to-person transmission, environmental contamination, or contaminated water or food. Helicobacter pylori has been transmitted via inadequately disinfected endoscopes. Finally, hepatitis C may be acquired by healthcare personnel by percutaneous or mucous membrane exposure to blood or between patients by use of contaminated blood products or via environmental contamination. Rigorous adherence to Standard Precautions, Contact Precautions for patients with infectious diarrhea, disinfection of environmental surfaces, and appropriate disinfection of endoscopes are adequate to prevent nosocomial acquisition of these pathogens.     

The epidemiology of invasive pulmonary aspergillosis at a large teaching hospital.

OBJECTIVE: To characterize the epidemiology of invasive pulmonary aspergillosis (IPA). DESIGN: A retrospective case series. SETTING: An 850-bed, academic, tertiary-care medical center. PARTICIPANTS: Adult inpatients, between January 1, 1990, and December 31, 1998, with either a histopathology report consistent with IPA or a discharge diagnosis of aspergillosis. METHODS: We reviewed medical records and categorized case-patients as definitive or probable and acquisition of IPA as nosocomial, indeterminate, or community using standard definitions. To determine the rate of aspergillus respiratory colonization, we identified all inpatients who had a respiratory culture positive for Aspergillus species without a histopathology report consistent with IPA or a discharge diagnosis of aspergillosis. Three study intervals were defined: interval 1, 1990 to 1992; interval 2, 1993 to 1995; and interval 3, 1996 to 1998. Carpeting in rooms for patients following heart-lung and liver transplant was removed and ceiling tiles were replaced during interval 1; a major earthquake occurred during interval 2. RESULTS: 72 case-patients and 433 patients with respiratory colonization were identified. Acquisition was nosocomial for 18 (25.0%), indeterminate for 9 (12.5%), and community-acquired for 45 (62.5%) case-patients. Seventeen (23.6%) of the 72 case-patients had prior transplants, including 15 solid organ and 2 bone marrow. The IPA rate per 100 solid organ transplants (SOTs) decreased from 2.45 during interval 1 to 0.93 during interval 2 and to 0.52 during interval 3 (chi-square for trend, 5.44; P<.05). The hospitalwide IPA rate remained stable at 0.03 per 1,000 patient days. CONCLUSIONS: The SOT IPA rate decreased after intervals 1 and 2, although the hospitalwide IPA rate remained stable during the study period. Post-earthquake hospital demolition and construction occurring after interval 2 was not associated with an increase in the rate of IPA at our institution.     

Prevention and control of Legionella infection in the hospital environment

An outbreak of nosocomial legionnaires' disease in a hospital of Northern Italy is described, together with the epidemiological survey and the control measures adopted. Two patients developed Legionella pneumophila (serogroup 1) pneumonia, one (immunodepressed) died. The Task Group organised by the Health Service excluded other previous nosocomial infections, and made controls on patients and personnel of at risk units (all negative). An intensive programme of environmental sampling and educational activities on personnel have been carried out. The environmental surveillance revealed that the centralised hot water distribution system of the hospital was colonised with Legionella. Shock heating and hyperchlorination of water were applied, which reduced the number of contaminated sites short term, but recolonisation took place two months later. We underline the difficulties encountered to control Legionella by active surveillance of water quality; once the system is contamined, Legionella eradication may be difficult and expensive, and cases of hospital-acquired legionnaieres' disease are likely to occur.     

Epidemiology, molecular mycology, and environmental sources of Fusarium infection in patients with cancer.

OBJECTIVE: To investigate the epidemiology and environmental sources of Fusarium infections in patients with cancer. DESIGN: Retrospective case-control study conducted following surveillance environmental cultures and DNA analysis of isolated organisms. SETTING: A tertiary-care, university cancer center. METHODS: In 1996 and 1997, environmental cultures were performed on air samples and water systems. A retrospective chart review was performed for 70 patients with cancer identified with fusariosis between 1987 and 1997. Patients with fusariosis were compared with 49 uninfected control patients who occupied hospital rooms with positive environmental cultures for Fusarium. With the use of random amplification of polymorphic DNA, organisms isolated from infected patients were compared with environmental organisms. RESULTS: Most of the patients with Fusarium (40, 57%) were infected on or within 3 days of admission, indicating community rather than nosocomial acquisition. Patients were comparable in terms of underlying immunocompromised status to 49 uninfected control patients. However, the duration from admission to infection in the patients with fusariosis tended to be shorter than the duration from admission to discharge in the exposed control patients (P = .06). Water cultured from the hospital tanks and from sinks and water fountains was negative for Fusarium. With the use of polymerase chain reaction, environmental isolates did not match clinical ones. Quantitative air sampling showed that the quantitative outdoor Fusarium levels were eightfold higher than the indoor levels. During the rainy summer season, outdoor air concentrations of Fusarium were at their highest, coinciding with the peak incidence of fusariosis at our center. CONCLUSION: The most likely source of fusariosis was the external environment rather than nosocomial sources, such as water.     

Antisepsis of mucous membranes--current status and aspects of future development

The mucous membranes colonized by high numbers of microorganisms play a major role as a source of nosocomial infections. According to clinical requirements it seems reasonable to distinguish three modes of application of antiseptics: 1. single prophylactic (prior to mucosa-penetrating interventions), 2. repeated periodical (wound care, treatment of oral cavity in intubated patients, decontamination of granulocytopenic patients), 3. therapeutic (local mucosal infections) including treatment of carriers to prevent transmission and spread of pathogens. Active agents commonly in use are PVP-iodine, cation-active detergents (e.g. chlorhexidine), oxygen-releasing compounds and organic mercury compounds. Presently chlorhexidine and PVP-iodine are the most frequently applied of these antiseptics while the organic mercury compounds are less important because of limited efficacy, toxicological and ecological problems. Preliminary data from investigations using a newly developed antiseptic, octenidine, a bispyridine compound, demonstrate reduction factors comparable to those obtained by PVP-iodine. Yet no standardized test methods for the efficacy of different substances and methods of application have been established.     

Epidemiologic study and containment of a nosocomial outbreak of severe acute respiratory syndrome in a medical center in Kaohsiung, Taiwan.

OBJECTIVE: We conducted an epidemiologic investigation at the beginning of a nosocomial outbreak of severe acute respiratory syndrome (SARS) to clarify the dynamics of SARS transmission, the magnitude of the SARS outbreak, and the impact of the outbreak on the community. METHODS: We identified all potential cases of nosocomially acquired SARS, linked them to the most likely infection source, and described the hospital containment measures. SETTING: A 2,300-bed medical center in Kaohsiung, Taiwan. RESULTS: A total of 55 cases of SARS were identified, and 227 hospital workers were quarantined. The index patient and neighboring patients were isolated. A chest physician team reviewed medical charts and chest radiographs and monitored the development of SARS in patients staying in the ward. The presence of underlying lung disease and immunocompromise in some patients made the diagnosis of SARS difficult. Some cases of SARS were diagnosed after the patients had died. Medical personnel were infected only if they cared for patients with unrecognized SARS, and caretakers played important roles in transmission of SARS to family members. As the number of cases of nosocomial SARS increased, the hospital closed the affected ward and expedited construction of negative-pressure rooms on other vacated floors for patient cohorting, and the last case in the hospital was identified 1 week later. CONCLUSIONS: Timely recognition of SARS is extremely important. However, given the limitations of SARS testing, possible loss of epidemic links, and the nonspecific clinical presentations in hospitalized patients, it is very important to establish cohorts of persons with low, medium, and high likelihoods of SARS acquisition. Rapid closure of affected wards may minimize the impact on hospital operations. Establishment of hospitals dedicated to appropriate treatment of patients with SARS might minimize the impact of the disease in future epidemics.     

Wasser als Infektionsquelle in medizinischen Einrichtungen, Prävention und Kontrolle

New epidemiological and microbiological investigations using molecular typing methods to link patient and environmental strains demonstrate a strong association between water-borne pathogens and nosocomial infections. Avoiding patient exposure to these pathogens results in a decreased incidence of water-borne nosocomial infections. There remains a tremendous potential to reduce hospital acquired infections previously viewed as inevitable and unavoidable through intervention and preventive measures. The characteristics of water application in health care facilities, the vulnerability of patients, the spectrum of relevant pathogens and their ecologic aspects, legal issues and important measures for prevention and control are discussed.