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

Risk of fungal exposure in the homes of patients with hematologic malignancies

BACKGROUND

Patients with hematological malignancies are at a high risk of developing invasive fungal infections (IFI) because they undergo several cycles of treatment leading to episodes of neutropenia. In addition, they alternate between hospital stays and periods spent at home. Thus, when an IFI is diagnosed during their hospital stays, it is highly challenging to identify the origin of the fungal contamination. The objective of this study was to analyze at home fungal exposure of 20 patients with leukemia by taking air and water samples in their living residence.

METHODS

Air was sampled in 3 rooms of each home with a portable air system impactor. Tap water was collected at 3 water distribution points of each home. For positive samples, fungi were identified by mass spectrometry or on the basis of their morphological features.

RESULTS

85 % of homes revealed the presence in air of Aspergillus spp. and those belonging to the section Fumigati presented the highest concentrations and the greatest frequency of isolation. Concerning mucorales, Rhizopus spp. and Mucor spp. were isolated in air of 20 % and 5 % of dwellings, respectively. In 4 homes, more than 70 % of the fungal species identified in air were potential opportunists; these were mainly Aspergillus spp. with concentrations greater than 20 cfu/m3. The water samples revealed the presence of Fusarium in 3 dwellings, with concentrations up to 80 cfu/L. Finally, for one patient, fungal species isolated during a period of hospitalization were phenotypically similar to those isolated in samples taken at home. For a second patient, a PCR Mucorale was positive on a sample of bronchoalveolar fluid while air samples taken at his home also revealed also the presence of mucorales.

CONCLUSION

The presence of opportunistic fungal species in the air of all the explored homes suggests the need for strengthened preventive measures in the home of immunocompromised patients. It would be interesting to compare the fungi isolated (from patients and from their environment) by genotyping studies aimed at specifying the correspondence existing between fungal species present in the patients' homes and those responsible for IFI in the same patients.

Fungal Contamination of Building Materials and the Aerosolization of Particles and Toxins in Indoor Air and Their Associated Risks to Health: A Review

It is now well established that biological pollution is a major cause of the degradation of indoor air quality. It has been shown that microbial communities from the outdoors may significantly impact the communities detected indoors. One can reasonably assume that the fungal contamination of the surfaces of building materials and their release into indoor air may also significantly impact indoor air quality. Fungi are well known as common contaminants of the indoor environment with the ability to grow on many types of building materials and to subsequently release biological particles into the indoor air. The aerosolization of allergenic compounds or mycotoxins borne by fungal particles or vehiculated by dust may have a direct impact on the occupant’s health. However, to date, very few studies have investigated such an impact. The present paper reviewed the available data on indoor fungal contamination in different types of buildings with the aim of highlighting the direct connections between the growth on indoor building materials and the degradation of indoor air quality through the aerosolization of mycotoxins. Some studies showed that average airborne fungal spore concentrations were higher in buildings where mould was a contaminant than in normal buildings and that there was a strong association between fungal contamination and health problems for occupants. In addition, the most frequent fungal species on surfaces are also those most commonly identified in indoor air, regardless the geographical location in Europe or the USA. Some fungal species contaminating the indoors may be dangerous for human health as they produce mycotoxins. These contaminants, when aerosolized with fungal particles, can be inhaled and may endanger human health. However, it appears that more work is needed to characterize the direct impact of surface contamination on the airborne fungal particle concentration. In addition, fungal species growing in buildings and their known mycotoxins are different from those contaminating foods. This is why further in situ studies to identify fungal contaminants at the species level and to quantify their average concentration on both surfaces and in the air are needed to be better predict health risks due to mycotoxin aerosolization.

Effectiveness of a novel, non-intrusive, continuous-use air decontamination technology to reduce microbial contamination in clinical settings: A multi-centric study

BACKGROUND

Despite rigorous disinfection and fumigation, healthcare associated infection (HAI) remains a significant concern in health care settings. We have developed a novel airborne-microbicidal technology "ZeBox" which clears over 99.999% of airborne microbial load under controlled lab conditions [1].

AIM

To evaluate the clinical performance of ZeBox in reducing airborne and surface microbial load.

METHODS

The study was conducted in single bed and multi bed ICU of two hospitals. Airborne and surface microbial loads were sampled pre- and post-deployment of ZeBox at pre-determined sites. Statistical significance of the reduction was determined using Mann-Whitney's U test.

RESULTS

ZeBox brought statistically significant reduction of both airborne and surface bacterial and fungal load. In both hospital ICUs, airborne and surface bacterial load decreased by 90% and 75% on average respectively, providing a low bioburden zone of ∼10-15 feet diameter around the unit. The reduced microbial level was maintained during ZeBox's operation over several weeks. Most clinical bacterial isolates recovered from one of the hospitals were antibiotic resistant, highlighting ZeBox's ability to eliminate antimicrobial-resistant bacteria among others.

CONCLUSIONS

ZeBox significantly reduces airborne and surface microbial burden in clinical settings. It thereby serves an unmet need for reducing the incidence of HAI.

A systematic review and meta-analysis of indoor bioaerosols in hospitals: The influence of heating, ventilation, and air conditioning

OBJECTIVES

To evaluate (1) the relationship between heating, ventilation, and air conditioning (HVAC) systems and bioaerosol concentrations in hospital rooms, and (2) the effectiveness of laminar air flow (LAF) and high efficiency particulate air (HEPA) according to the indoor bioaerosol concentrations.

METHODS

Databases of Embase, PubMed, Cochrane Library, MEDLINE, and Web of Science were searched from 1st January 2000 to 31st December 2020. Two reviewers independently extracted data and assessed the quality of the studies. The samples obtained from different areas of hospitals were grouped and described statistically. Furthermore, the meta-analysis of LAF and HEPA were performed using random-effects models. The methodological quality of the studies included in the meta-analysis was assessed using the checklist recommended by the Agency for Healthcare Research and Quality.

RESULTS

The mean CFU/m3 of the conventional HVAC rooms and enhanced HVAC rooms was lower than that of rooms without HVAC systems. Furthermore, the use of the HEPA filter reduced bacteria by 113.13 (95% CI: -197.89, -28.38) CFU/m3 and fungi by 6.53 (95% CI: -10.50, -2.55) CFU/m3. Meanwhile, the indoor bacterial concentration of LAF systems decreased by 40.05 (95% CI: -55.52, -24.58) CFU/m3 compared to that of conventional HVAC systems.

CONCLUSIONS

The HVAC systems in hospitals can effectively remove bioaerosols. Further, the use of HEPA filters is an effective option for areas that are under-ventilated and require additional protection. However, other components of the LAF system other than the HEPA filter are not conducive to removing airborne bacteria and fungi.

LIMITATION OF STUDY

Although our study analysed the overall trend of indoor bioaerosols, the conclusions cannot be extrapolated to rare, hard-to-culture, and highly pathogenic species, as well as species complexes. These species require specific culture conditions or different sampling requirements. Investigating the effects of HVAC systems on these species via conventional culture counting methods is challenging and further analysis that includes combining molecular identification methods is necessary.

STRENGTH OF THE STUDY

Our study was the first meta-analysis to evaluate the effect of HVAC systems on indoor bioaerosols through microbial incubation count. Our study demonstrated that HVAC systems could effectively reduce overall bioaerosol concentrations to maintain better indoor air quality. Moreover, our study provided further evidence that other components of the LAF system other than the HEPA filter are not conducive to removing airborne bacteria and fungi.

PRACTICAL IMPLICATION

Our research showed that HEPA filters are more effective at removing bioaerosols in HVAC systems than the current LAF system. Therefore, instead of opting for the more costly LAF system, a filter with a higher filtration rate would be a better choice for indoor environments that require higher air quality; this is valuable for operating room construction and maintenance budget allocation.

Nosocomial Fungal Infections: Epidemiology, Infection Control, and Prevention

Invasive fungal infections are an important cause of morbidity and mortality in hospitalized patients and in the immunocompromised population. This article reviews the current epidemiology of nosocomial fungal infections in adult patients, with an emphasis on invasive candidiasis (IC) and invasive aspergillosis (IA). Included are descriptions of nosocomial infections caused by Candida auris, an emerging pathogen, and IC- and IA-associated with coronavirus disease 2019. The characteristics and availability of newer nonculture-based tests for identification of nosocomial fungal pathogens are discussed. Recently published recommendations and guidelines for the control and prevention of these nosocomial fungal infections are summarized.

Assessing microbial decontamination of indoor air with particular focus on human pathogenic viruses

Transmission of bacterial, fungal, and viral pathogens is of primary importance in public and occupational health and infection control. Although several standardized protocols have been proposed to target microbes on fomites through surface decontamination, use of microbicidal agents, and cleaning processes, only limited guidance is available on microbial decontamination of indoor air to reduce the risk of pathogen transmission between individuals. This article reviews the salient aspects of airborne transmission of infectious agents, exposure assessment, in vitro assessment of microbicidal agents, and processes for air decontamination for infection prevention and control. Laboratory-scale testing (eg, rotating chambers, wind tunnels) and promising field-scale methodologies to decontaminate indoor air are also presented. The potential of bacteriophages as potential surrogates for the study of airborne human pathogenic viruses is also discussed.

The Plasmair Decontamination System Is Protective Against Invasive Aspergillosis in Neutropenic Patients

OBJECTIVE Invasive aspergillosis (IA) is a rare but severe infection caused by Aspergillus spp. that often develops in immunocompromised patients. Lethality remains high in this population. Therefore, preventive strategies are of key importance. The impact of a mobile air decontamination system (Plasmair, AirInSpace, Montigny-le-Bretonneux, France) on the incidence of IA in neutropenic patients was evaluated in this study. DESIGN Retrospective cohort study METHODS Patients with chemotherapy-induced neutropenia lasting 7 days or more were included over a 2-year period. Cases of IA were confirmed using the revised European Organization for Research and Treatment of Cancer (EORTC) criteria. We took advantage of a partial installation of Plasmair systems in the hematology intensive care unit during this period to compare patients treated in Plasmair-equipped versus non-equipped rooms. Patients were assigned to Plasmair-equipped or non-equipped rooms depending only on bed availability. Differences in IA incidence in both groups were compared using Fisher's exact test, and a multivariate analysis was performed to take into account potential confounding factors. RESULTS Data from 156 evaluable patients were available. Both groups were homogenous in terms of age, gender, hematological diagnosis, duration of neutropenia, and prophylaxis. A total of 11 cases of probable IA were diagnosed: 10 in patients in non-equipped rooms and only 1 patient in a Plasmair-equipped room. The odds of developing IA were much lower for patients hospitalized in Plasmair-equipped rooms than for patients in non-equipped rooms (P=.02; odds ratio [OR] =0.11; 95% confidence interval [CI], 0.00-0.84). CONCLUSION In this study, Plasmair demonstrated a major impact in reducing the incidence of IA in neutropenic patients with hematologic malignancies. Infect Control Hosp Epidemiol 2016;37:845-851.

Indoor fungal contamination: health risks and measurement methods in hospitals, homes and workplaces

Indoor fungal contamination has been associated with a wide range of adverse health effects, including infectious diseases, toxic effects and allergies. The diversity of fungi contributes to the complex role that they play in indoor environments and human diseases. Molds have a major impact on public health, and can cause different consequences in hospitals, homes and workplaces. This review presents the methods used to assess fungal contamination in these various environments, and discusses advantages and disadvantages for each method in consideration with different health risks. Air, dust and surface sampling strategies are compared, as well as the limits of various methods are used to detect and quantify fungal particles and fungal compounds. In addition to conventional microscopic and culture approaches, more recent chemical, immunoassay and polymerase chain reaction (PCR)-based methods are described. This article also identifies common needs for future multidisciplinary research and development projects in this field, with specific interests on viable fungi and fungal fragment detections. The determination of fungal load and the detection of species in environmental samples greatly depend on the strategy of sampling and analysis. Quantitative PCR was found useful to identify associations between specific fungi and common diseases. The next-generation sequencing methods may afford new perspectives in this area.

[Epidemiology and prevention of nosocomial invasive infections by filamentous fungi and yeasts]

Knowledge of the epidemiology of invasive fungal diseases in health care settings helps to establish the action levels necessary for its prevention. A first step is to identify groups of patients at high risk of invasive fungal diseases, establish accurate risk factors, observing the periods of greatest risk, and analyze the epidemiological profile in genera and species, as well as the patterns of antifungal resistance. Secondly, mechanisms to avoid persistent exposure to potential fungal pathogens must be established, protecting areas and recommending measures, such as the control of the quality of the air and water inside and outside the hospital, and determining and promoting appropriate architectural designs of health institutions. Finally, apart from the correct implementation of these measures, the use of antifungal prophylaxis should be considered in selected patients at very high risk, following the guidelines published.

Supplemental treatment of air in airborne infection isolation rooms using high-throughput in-room air decontamination units

BACKGROUND

Evidence has recently emerged indicating that in addition to large airborne droplets, fine aerosol particles can be an important mode of influenza transmission that may have been hitherto underestimated. Furthermore, recent performance studies evaluating airborne infection isolation (AII) rooms designed to house infectious patients have revealed major discrepancies between what is prescribed and what is actually measured.

METHODS

We conducted an experimental study to investigate the use of high-throughput in-room air decontamination units for supplemental protection against airborne contamination in areas that host infectious patients. The study included both intrinsic performance tests of the air-decontamination unit against biological aerosols of particular epidemiologic interest and field tests in a hospital AII room under different ventilation scenarios.

RESULTS

The unit tested efficiently eradicated airborne H5N2 influenza and Mycobacterium bovis (a 4- to 5-log single-pass reduction) and, when implemented with a room extractor, reduced the peak contamination levels by a factor of 5, with decontamination rates at least 33% faster than those achieved with the extractor alone.

CONCLUSION

High-throughput in-room air treatment units can provide supplemental control of airborne pathogen levels in patient isolation rooms.

Fungal aero-decontamination efficacy of mobile air-treatment systems

Immunosuppressed patients are at high risk of acquiring airborne fungal infections, mainly caused by Aspergillus species. Although HEPA filters are recommended to prevent environmental exposure, mobile air-treatment units can be an alternative. However, many different models of mobile units are available but there are few data on their fungal aero-decontamination efficacy and usefulness in the prevention of Aspergillus infections. Thus, we developed a challenge test, based on the aerosolization of 10(6) Aspergillus niger conidia, in order to compare the particle and fungal decontamination efficacy of the following four mobile air-treatment systems; Plasmair T2006, Mobil'Air 1200 (MA1200), Mobil'Air 600 (MA600) combined with Compact AirPur Mobile C250 (C250), and the prototype unit Compact AirPur Mobile 1800 (C1800). The use of all these air-treatment systems was able to significantly decrease the concentration of particles or fungal viable conidia. ISO7 was the maximum particle class reached within 20 min with the Plasmair T2006 and MA1200, 1 h by the combined MA600/C250, and 1 h and 30 min with the C1800. After 2 h, fungal counts were significantly lower with Plasmair T2006, MA1200 and the combined MA600/C250 (2.2 ± 1.9 to 5.0 ± 3.7 CFU/m(3)) than achieved with the C1800 (23.8 ± 12.8 CFU/m(3); P ≤ 6.0E-3). All the air-treatment systems were able to decrease aerial particle and fungal counts, but their efficacy was variable, depending on the units' air-treatment modalities and rates of air volume that was processed. This comparative study could be helpful in making an informed choice of mobile units, and in improving the prevention of air-transmitted fungal infections in non-protected areas.

Nosocomial fungal infections: epidemiology, infection control, and prevention

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

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.

Mobile air-decontamination unit and filamentous fungal load in the hematology ward: how efficient at the low-activity mode?

Air treatment with a mobile Plasmair air-decontamination unit significantly reduces the fungal spore load in hematology wards. We report that this system used at a low aspiration flow does not perform total biodecontamination against filamentous fungi. Moreover, the filamentous fungus load remaining in rooms equipped with this mobile air-decontamination unit is lowest in wards in which other preventive measures against nosocomial filamentous fungal infections are implemented.

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 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.