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

Environmental monitoring for filamentous fungal pathogens in hematopoietic cell transplant units

The incidence of invasive fungal disease (IFD) is on the rise due to increasing numbers of highly immunocompromized patients. Nosocomial IFD remains common despite our better understanding of its risk factors and pathophysiology. High-efficiency particulate air filtration with or without laminar air flow, frequent air exchanges, a positive pressure care environment, and environmental hygiene, amongst other measures, have been shown to reduce the mould burden in the patient environment. Environmental monitoring for moulds in areas where high-risk patients are cared for, such as hematopoietic cell transplant units, has been considered an adjunct to other routine environmental precautions. As a collaborative effort between authors affiliated to the Infection Prevention and Control Working Group and the Fungal Infection Working Group of the International Society of Antimicrobial Chemotherapy (ISAC), we reviewed the English language literature and international guidance to describe the evidence behind the need for environmental monitoring for filamentous fungi as a quality assurance approach with an emphasis on required additional precautions during periods of construction. Many different clinical sampling approaches have been described for air, water, and surface sampling with significant variation in laboratory methodologies between reports. Importantly, there are no agreed-upon thresholds that correlate with an increase in the clinical risk of mould infections. We highlight important areas for future research to assure a safe environment for highly immunocompromized patients.

Indoor hospital air and the impact of ventilation on bioaerosols: a systematic review

Healthcare-acquired infections (HAIs) continue to persist in hospitals, despite the use of increasingly strict infection-control precautions. Opportunistic airborne transmission of potentially pathogenic bioaerosols may be one possible reason for this persistence. Therefore, this study aimed to systematically review the concentrations and compositions of indoor bioaerosols in different areas within hospitals and the effects of different ventilation systems. Electronic databases (Medline and Web of Science) were searched to identify articles of interest. The search was restricted to articles published from 2000 to 2017 in English. Aggregate data was used to examine the differences in mean colony forming units per cubic metre (cfu/m³) between different hospital areas and ventilation types. A total of 36 journal articles met the eligibility criteria. The mean total bioaerosol concentrations in the different areas of the hospitals were highest in the inpatient facilities (77 cfu/m³, 95% confidence interval (CI): 55-108) compared with the restricted (13cfu/m³, 95% CI: 10-15) and public areas (14 cfu/m³, 95% CI: 10-19). Hospital areas with natural ventilation had the highest total bioaerosol concentrations (201 cfu/m³, 95% CI: 135-300) compared with areas using conventional mechanical ventilation systems (20 cfu/m³, 95% CI: 16-24). Hospital areas using sophisticated mechanical ventilation systems (such as increased air changes per hour, directional flow and filtration systems) had the lowest total bioaerosol concentrations (9 cfu/m³, 95% CI: 7-13). Operating sophisticated mechanical ventilation systems in hospitals contributes to improved indoor air quality within hospitals, which assists in reducing the risk of airborne transmission of HAIs.

The influence of air-dispersed essential oils from lemon (Citrus limon) and silver fir (Abies alba) on airborne bacteria and fungi in hospital rooms

Airborne bacteria and fungi are an ongoing problem in hospitals. Because of the antimicrobial activities of essential oils (EOs) dispersion of EOs into the air may help to reduce this contamination. The aim of this study was to evaluate the efficacy of the dispersion of selected EOs in reducing the microbial contamination in two hospital wards. The study was carried out at two wards of a 1,227-bed acute-care hospital in Austria. The concentration of airborne bacteria and fungi was measured in patient rooms before and after dispersion of a mixture of Citrus limon EO and Abies alba EO. Before dispersion of the EOs in both wards the mean concentration of bacteria was in a typical range (123 colony forming units (CFU) m^-3 and 104 CFU m^-3) while the mean concentration of fungi differed substantially (155 CFU m^-3 and 28 CFU m^-3). After dispersion of the EOs, a reduction in both bacterial and fungal contamination was observed. In the first two hours the mean concentration of airborne bacteria and fungi was reduced by approximately 40% and 30%-60% respectively. The selected EO mixture is effective in reducing the microbial contamination of the indoor air.

A 2-year comparative study of mold and bacterial counts in air samples from neutral and positive pressure rooms in 2 tertiary care hospitals

Immunocompromised patients are at risk of invasive fungal infection. These high-risk patients are nursed in protective isolation to reduce the risk of nosocomial aspergillosis while in hospital-ideally in a positive pressure single room with high-efficiency particulate air filtration. However, neutral pressure rooms are a potential alternative, especially for patients requiring both protective and source isolation. This study examined mold and bacterial concentrations in air samples from positive and neutral pressure rooms to assess whether neutral pressure rooms offer a similar environment to that of positive pressure rooms in terms of mold concentrations in the air. Mold concentrations were found to be similar in the positive and neutral pressure room types examined in this study. These results add to the paucity of literature in this area.

High fungal spore burden with predominance of Aspergillus in hospital air of a tertiary care hospital in Chandigarh

The prevalence of fungal spores in the hospital air is essential to understand the hospital-acquired fungal infections. Air conditioners (ACs) used in hospitals may either reduce spores in air or be colonised by fungi and aid in its dissemination. The present study was conducted to assess the fungal spore burden in AC and non-AC areas. We found a high fungal spore count in air irrespective of whether the area was AC or non-AC. The most predominant species isolated were Aspergillus flavus and Aspergillus fumigatus. Such high concentrations of pathogenic fungi in air may predispose individuals to develop disease.

Hospital environment fungal contamination and aspergillosis risk in acute leukaemia patients in Sousse (Tunisia)

Hospital environment is considered the main source of invasive aspergillosis (IA) in leukemic patients. This study aimed to describe Aspergillus colonisation in leukemic patients and their hospital environment and to test whether Aspergillus environmental contamination was associated with IA. For a 2-year period including 14-month renovation work, 91 acute leukaemia inpatients at the hematology department of University hospital in Sousse (Tunisia) were prospectively included. The incidence of probable IA (EORTC/MSG criteria) was 9.9%. Fifty-six Aspergillus were isolated from 53 (6.5%) of 811 sputa collected from 35 (38.5%) patients. Aspergillus spp. were isolated in 59.7% of 494 air samples and in 52.8% of 1579 surface samples taken in the patients' room. Aspergillus section Nigri (72.7%) was the most frequent. Aspergillus contamination peaked in autumn and winter on surface and in summer and autumn in air samples and was higher (P = 0.03) during the renovation work period. Multivariate analysis showed that for each Aspergillus section Nigri CFU airborne contamination IA risk increased by 1.05 (P = 0.04). In Tunisia, Aspergillus section Nigri and Flavi, but not Fumigati, are chiefly involved in IA. Our findings support swift implementation of airborne fungal contamination control measures in areas where immunocompromised patient are hospitalised.

Effect of Building Construction on Aspergillus Concentrations in a Hospital

Air samples taken in a hospital undergoing construction and analyzed with a quantitative polymerase chain reaction (qPCR) assay for the Aspergillus genus did not show elevated concentrations of Aspergillus or particulate matter with a diameter of 5 μm or less in patient areas. Air samples from the construction zone indicated the containment system, which used polyethylene film barrier and negative pressure, was effective.

Mold contamination in a controlled hospital environment: a 3-year surveillance in southern Italy

Background

Environmental monitoring of airborne filamentous fungi is necessary to reduce fungal concentrations in operating theaters and in controlled environments, and to prevent infections. The present study reports results of a surveillance of filamentous fungi carried out on samples from air and surfaces in operating theaters and controlled environments in an Italian university hospital.

Methods

Sampling was performed between January 2010 and December 2012 in 32 operating theaters and five departments with high-risk patients. Indoor air specimens were sampled using a microbiological air sampler; Rodac contact plates were used for surface sampling. Fungal isolates were identified at the level of genera and species.

Results

Sixty-one samples (61/465; 13.1%) were positive for molds, with 18 from controlled environments (18/81; 22.2%) and 43 (43/384; 11.2%) from operating theaters. The highest air fungal load (AFL, colony-forming units per cubic meter [CFU/m³]) was recorded in the ophthalmology operating theater, while the pediatric onco-hematology ward had the highest AFL among the wards (47 CFU/m³). The most common fungi identified from culture of air specimens were Aspergillus spp. (91.8%), Penicillium spp., (6%) and Paecilomyces spp. (1.5%). During the study period, a statistically significant increase in CFU over time was recorded in air-controlled environments (p = 0.043), while the increase in AFL in operating theaters was not statistically significant (p = 0.145). Molds were found in 29.1% of samples obtained from surfaces. Aspergillus fumigatus was the most commonly isolated (68.5%).

Conclusions

Our findings will form the basis for action aimed at improving the air and surface quality of these special wards. The lack of any genetic analysis prevented any correlation of fungal environmental contamination with onset of fungal infection, an analysis that will be undertaken in a prospective study in patients admitted to the same hospital.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0595-z) contains supplementary material, which is available to authorized users.

Sinonasal risk factors for the development of invasive fungal sinusitis in hematological patients: Are they important?

Invasive fungal sinusitis (IFS) is a highly aggressive infection that can affect hematologic patients. The classically described general risk factors, however, do not fully explain the development of IFS in a small percentage of cases. This study examined the impact of anatomic sinonasal factors and environmental factors on the development of IFS in high-risk patients. Medical records and computed tomography (CT) scans of patients admitted to our institution who were at high risk of developing IFS were retrospectively reviewed. Twenty-seven patients of 797 fulfilled the inclusion criteria. Patients affected by IFS were compared with patients not affected to identify possible sinonasal and environmental risk factors of IFS. Seven patients were excluded because of the lack of adequate radiological images. Six of the 20 eligible patients were assigned to the study group of patients affected by IFS and the remaining 14 patients were assigned to the control group. All but one case developed the infection during the summer with a significantly higher mean environmental temperature (p = 0.002). Anatomic nasal alterations were found in all patients affected by IFS and were significantly more frequent than in the control group (p = 0.014). It would be advisable to have patients with hematologic risk factors of IFS, especially during the summer period, undergo endoscopic nasal assessment. Furthermore, a CT finding of anatomic nasal alterations, such as anterior nasal septum deviation causing nasal obstruction, should increase the suspicion of IFS in case of the occurrence of nasal symptoms.

Dynamics of fungal colonization in a new medical mycology laboratory

OBJECTIVE OF THE STUDY

Study of the spatio-temporal fungal colonization in a new medical mycology laboratory.

METHODS

A 17-month survey of airborne fungal contamination was conducted in a new medical mycology laboratory at a tertiary care university hospital. This survey was implemented at three different periods: before the new premises were occupied (period A), during the move into the new laboratory (period B) and after resumption of the mycological activities in these new premises (period C).

RESULTS

During period A, the airborne fungal load ranged from 2.3 to 6 cfu/m(3). The most frequently recovered airborne fungi were Penicillium spp. (75 to 100%). During period B, a dramatic increase in Penicillium chrysogenum conidia was observed in the air of the new laboratory (40 to 160 cfu/m(3)). During period C, the fungal load ranged from 4.5 to 8.4 cfu/m(3). Penicillium was the most common genus identified in rooms of the laboratory where no filamentous fungi were handled, while Aspergillus was clearly the predominant genus (78%) in the room dedicated to the culture of filamentous fungi.

CONCLUSIONS

We suggest that the specific fungal ecology in air of the room dedicated to the culture of filamentous fungi is due to the handling of a large number of medical strains of A. fumigatus.

Indoor Air Problems in Hospitals

Indoor air problems, caused by moisture damage and limited ventilation, have been detected in Finnish hospital buildings. A recent survey found that hospital personnel experience indoor air-related symptoms more often than office workers. The aim of this study was to assess the role, capabilities, and methods of hospital occupational health professionals in handling indoor air problems. Data were generated through semi-structured interviews. Representatives of occupational health, occupational safety, and infection control were interviewed in seven central hospitals. The data were analyzed using qualitative methods. According to interviewed professionals, indoor air problems are difficult to tackle. The evaluation of health risks and risk communication were considered particularly difficult. A uniform action model for resolving indoor air problems should be created. An interprofessional indoor air group to handle indoor air problems should be created in all hospitals.

Influence of internal and outdoor factors on filamentous fungal flora in hematology wards

BACKGROUND

Nosocomial invasive filamentous fungi infections could result from inhalation of filamentous fungi conidia present in hospital environment.

METHODS

The environmental fungal flora in 3 different hospital wards with similar air conditioning was prospectively studied during 30 months and compared to internal (presence of agranulocytosis patient, behavioral practices, activity, cleaning work) and outdoor factors (meteorologic data, outdoor fungi). The general preventive measures differed from one unit to another.

RESULTS

The hematology wards with filamentous fungi preventive measures were significantly less contaminated than a conventional ward without specific measures. Internal and outdoor factors influenced the level of fungal flora. However, the influence of internal factors was greater in the conventional ward than in hematology wards. The variation of flora in the hospital environment was seasonal, and the level of this contamination in each ward was influenced by the meteorology. However, outdoor factors more readily explain the variations of fungal load in hematology than in the conventional ward.

CONCLUSION

This study highlights that specific preventive measures participate significantly in the control of the filamentous fungal flora intensity due to internal factors but not those due to outdoor factors, stressing the importance of high-efficiency particulate air filtration in high-risk units.

Profiles and seasonal distribution of airborne fungi in indoor and outdoor environments at a French hospital

A one-year prospective survey of fungal air contamination was conducted in outdoor air and inside two haematological units of a French hospital. Air was sampled with a portable Air System Impactor. During this period of survey, the mean viable fungal load was 122.1 cfu/m(3) in outdoor air samples, and 4.1 and 3.9 cfu/m(3) in samples from adult and pediatric haematology units, respectively. In outdoor samples, Cladosporium was the dominant genus (55%) while in the clinical units, Penicillium sp. (23 to 25%), Aspergillus sp. (15 to 23%) and Bjerkandera adusta (11 to 13%) were the most frequently recovered airborne fungi. The outdoor fungal load was far higher in autumn (168 cfu/m(3)), spring (110 cfu/m(3)) and summer (138 cfu/m(3)) than in winter (49 cfu/m(3)). In indoor air, fungal concentrations were significantly lower in winter (2.7 to 3.1 cfu/m(3)) than in summer (4.2 to 5.0 cfu/m(3)) in both haematology units. In the outdoor environment, Penicillium sp. and Aspergillus sp. were more abundant in winter while the levels of Cladosporium were lowest during this season. In the haematological units, the presence of Aspergillus sp. was stable during the year (close to 20%), Bjerkandera sp. was particularly abundant in winter (close to 30%); levels of Penicillium sp. were highest in autumn while levels of Cladosporium sp. were highest in spring and summer.

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.

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.

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.