Microbial Air Sampler Research Articles

Effect of Agar Weight Loss with Passive Continuous Air Monitoring According GMP Annex 1 2023

The GMP Annex 1 2023 requests that microbial environmental monitoring by active and passive microbial air samplers is actuated by continuous air monitoring. A prolonged sampling produces a loss of moisture in the agar of the Petri dish and therefore it is necessary that during the “continuous time” the dryness of the nutrient media is under control to guarantee a regular growing of the cfu. The purpose of this paper is to evaluate if the agar of settle plate (which volume was reduced with a treatment under sterile laminar flow before aspiration) has still the correct nutrient characteristics during the incubation. The results of the study are summarised in Table 1 and 2. The average loss of humidity after 4 hours in the first part of test under laminar flow was 14,7%. In the second part of test, the Petri dishes aspirated the air in a normal open environment and the average growth after incubation (indicated in cfu/ plate), in comparation with control plates with the original volume of agar, was 87%. The acceptance criteria using the US Pharmacopeia Validation Recommendation for microbiological examination (chapter ) is that the test plates had to recover < 70% of the challenge.

293. Risk factors for COVID-19 associated pulmonary aspergillosis (CAPA) in severe COVID-19 and impact of airborne fungal contamination within negative pressure isolation room

Abstract Background COVID-19 increase the risk of invasive pulmonary aspergillosis. However, the risk factors and fungal origin of COVID-19 associated pulmonary aspergillosis (CAPA) is not fully defined yet. We aim to identify the risk factors for CAPA in severe COVID-19 and evaluate association between fungal contamination within the air of negative pressure rooms and diagnosis of CAPAs. Methods We performed a retrospective case-control study to identify risk factors for CAPA with 420 severe COVID-19 patients from March 2020 to January 2022 who admitted to a tertiary care hospital in South Korea. CAPA was defined with modified AspICU criteria. Control, matched by admission date and severity of COVID-19 at admission, was selected for each case. Air sampling and fungal culture was done on Jan 2022 with a microbial air sampler (MAS-100NT) at 11 spaces in the COVID-19 designated isolation ward including 9 negative pressure isolation rooms (IRs). A cross-sectional comparison between rooms with and without airborne fungal contamination was performed. Results A total of 420 COVID-19 patients were hospitalized during the study period, and 51 patients were diagnosed with CAPA (prevalence 12.14%, incidence 6.26 per 1000 patient•day). Multivariate analysis showed that older age (odds ratio [OR] 1.051, 95% confidence intervals [CI] 1.006-1.009, p=0.025), mechanical ventilator use (OR 2.692, 95% CI 1.049-6.911, p=0.04), and lymphopenia (OR 4.353, 95% CI 1.727-10.975, p=0.02) were independent risk factors for CAPA. (Table 1, 2) Aspergillus spp. was identified within the air from 7 out of 11 spaces including 6 IRs and 1 doctors’ room. (Figure 1). All 6 IRs with positive aspergillus culture were being occupied by patients at least 8 days. Among 6 patients, 3 had already been diagnosed with CAPA whereas the other 3 were not diagnosed with CAPA through the observation period. Among 4 patients in isolation rooms without airborne aspergillus contamination, one patient had been diagnosed as CAPA before air sampling. (Table 3). Conclusion Association between CAPA and airborne aspergillus contamination within the negative pressure room could not be demonstrated in this study. Rather than environmental factors, patient factors such as older age, ventilator care, and lymphopenia were found to be associated with CAPA diagnosis. Disclosures All Authors: No reported disclosures.

Efficacy of the PlasmaShield®, a Non-Thermal, Plasma-Based Air Purification Device, in Removing Airborne Microorganisms

Airborne microorganisms play a significant role in the transmission of infectious diseases. As such, improving indoor microbial air quality can enhance infection control in numerous settings. This study examined the efficacy of the PlasmaShield® air purification device to remove airborne microorganisms under laboratory conditions. Pure cultures of model microorganisms at varying concentrations were aerosolized using a 1-jet Collison nebulizer through stainless-steel removable piping prior to reaching the PlasmaShield® device. The surviving microorganisms were captured using the Staplex® MBS-6 Six Stage Microbial Air Sampler and enumerated via culture on agar plates. The positive-hole-corrected colony/plaque-forming units were compared with the negative control (microorganisms aerosolized through an empty PlasmaShield® casing). The PlasmaShield® statistically significantly (p < 0.05) reduced airborne Escherichia coli, Staphylococcus epidermidis, Bacteriophage MS2 and Cladosporium sp. compared with the negative control. The maximum removal achieved was estimated to be 4 × log10E. coli (99.99% removal), 4 × log10S. epidermidis (99.97% removal), 7 × log10 MS2 (99.99998% removal) and 5 × log10Cladosporium sp. (99.999% removal). Scanning electron microscope images of the surviving microorganisms showed that the PlasmaShield® damaged the cell membrane of these model microorganisms. This study provides proof-of-concept evidence to support the use of this technology to improve indoor microbial air quality.

Detection of SARS-CoV-2 in the Indoor and Outdoor Areas of Urban Public Transport Systems of Three Major Cities of Portugal in 2021.

Airborne transmission is mainly associated with poorly ventilated and crowded indoor environments where people stay for long periods of time. As such, public transport is often perceived as having a high risk for the transmission of SARS-CoV-2. Considering that data on the detection of SARS-CoV-2 in public transport systems are scarce, we performed air sampling for SARS-CoV-2 in indoor and outdoor spaces of public transport systems in Portugal. Air (n = 31) and surface (n = 70) samples were collected using a Coriolis® Compact microbial air sampler and sterile flocked plastic swabs, respectively. Samples were extracted and analyzed through RT-qPCR. Only two air samples from an outdoor and a partially open space were found to be positive for SARS-CoV-2 RNA. No positive surface samples were detected. These results indicate that the viral concentration in ambient air in public transport systems is linked to the number of people present in that environment and whether they are wearing properly fitting masks. Considering the current lifting of COVID-19 restrictions around the world, it is essential that people continue to wear masks in both indoor and outdoor environments, especially in crowded spaces. More studies on this topic are needed to fully elucidate the real risk of infection in outdoor spaces.

ASSESSMENT OF AIRBORNE FUNGAL SPORES IN INDOOR ENVIRONMENT OF LIBRARIES IN NNAMDI AZIKIWE UNIVERSITY

Background: Polluted indoor environments pose health challenges such as allergy, infections, and toxicity. Most indoor air pollution comes from hazardous non-biological and biological agents. Due to the nature of the indoor environment of libraries, it is prone to colonization by fungal species. Method: Three sampling sites were used for the study and they include Festus Aghagbo Nwako Library, Main campus Awka, Medical Library, Nnewi Campus and Library Complex, Agulu campus. A total of 100 air samples were analyzed Using the Zefon A6 Single-stage microbial air sampler and Malt Extract Agar supplemented with 0.05mg/ml of chloramphenicol while 16 nasal swabs were collected from the staff present using sterile swab sticks. The mould isolates were identified using the slide culture technique while the yeast isolates were subjected to candida chrom agar and integral yeast plus identification. Antifungal susceptibility was performed using the integral yeast plus system and the agar well diffusion technique. Results: Out of the 100 air samples, a total of 625 fungal isolates were identified of which C.lunata 201 (32.16%) was the most predominant, while P. marneffi, P. expansum, A. restrictus, A. infectoria and R. rubra 1(0.16%) occurred the least. All significant at (p≤0.01). A total of 7 fungal spores were isolated from the 16 nasal swabs and appeared thus in descending order of frequency: P. notatum, 3 (42.85%), A. niger, C. lunata, C. albicans and F. aqueductum, 1(14.3%). Antifungal Susceptibility of the 28 yeast isolates indicated that C. famata, C. laurentii and C. luteolus, were all susceptible to commonly used antifungals in the integral yeast plus system with a 100% susceptibility value, while the mould isolates showed relatively moderate susceptibility to selected antifungals. Conclusion: The organisms isolated are well known to be pathogenic especially to immunocompromised individuals. Their presence in the indoor environment of libraries serves as a risk factor to both the library staff and visitors. Adequate precautionary measures and occasional environmental surveillance need to be inculcated in order to reduce the number of fungi in the indoor environment of these libraries.

Assessment of Fungal Concentrations Associated with Relative Humidity and Temperature Variations in the Indoor Environment

Background: Indoor environmental factors and human activities influence the presence and concentration of fungal propagules which may lead to the risk of developing respiratory infections and allergic reactions.
 Aim/Objectives: This study aimed to identify the factors that influence indoor fungal composition and determine its association with the development of respiratory and allergic reactions.
 Methodology: A total of 549 air samples and 226 nasal swabs of occupants were examined using health base questionnaire, malt extract agar and A6 single stage microbial air sampler. House dampness, mould growth on indoor materials, temperature, relative humidity, type of ventilation, type of human activity, and location of building were found to affect the prevalence and diversity of indoor fungi.
 Results: A total of 55, 46 and 50 species of fungi were isolated from homes, offices and hospitals respectively. High fungal count, were recorded in homes with moisture problems, low temperature and high relative humidity and homes located in high density areas. High cases of respiratory health problems were reported by occupants of these homes.
 Conclusion: Improvement in housing and establishment of awareness programmes can be used to lower fungal load and health problems associated with dampness in homes.It is necessary to maintain and prevent the housekeeping activities that can predispose fungal concentration in indoor environment.

Microbial Air Samplers for Meaningful Cleanroom Environmental Monitoring

Airborne microbiological concentrations within pharmaceutical cleanrooms are determined by sampling and to maximise the detection of any airborne microbes, it is essential that the sampling is undertaken in locations where there is greatest contamination risk using air samplers that have a verified and appropriate performance. Sampler performance can be assessed by review of both the physical and biological collection efficiencies that are determined by testing. The physical collection efficiency is the ability to collect particles of various sizes and the biological collection efficiency assesses the collection of viable microbes that includes the losses caused by the physical collection efficiency and the detrimental effect that the sampling has on the viability of the captured microbes. Due to the limitations of the established biological collection efficiency test method, this efficiency is only determined for microbes of sub-micron size which are not representative of the larger microbe-carrying particles typically present with cleanrooms. Samplers with a low physical collection efficiency for sub-micron particles are likely to have a poor performance when this test method is utilised and in an attempt to remove this bias from the testing the ‘biological efficiency’, is often reported. This is a measure of the likelihood that any captured microbes would survive, but is often mistaken for the biological collection efficiency and samplers may be utilised in the false belief that they have an appropriate performance. This article provides information regarding air sampler performance testing and reviews the test results reported by the same independent specialist testing company, therefore negating issues resulting from different testing methods, for three different air samplers. The results that are used to determine the ‘biological efficiency’ are examined to provide information relating to the biological collection efficiency of each sampler and to also provide additional information relating to the physical collection efficiency. Improvements to enhance the air sampler testing procedures, to enable a better direct comparison of the performance of different samplers, are suggested.

Effects of different air change rates on cleanroom ‘in operation’ status

The objective of this experimental study is to analyze non-viable and viable particle loads in a pharmaceutical cleanroom under ‘in operation’ conditions using different air change rates (ACRs). Regulatory guidelines give limit values for particles/m3 and colony forming units (CFUs)/m3. A widely used ACR is 20 h−1 as this value is recommended by the Food and Drug Administration (FDA) in its guidance for industry on sterile drug products. However, this value may be too high, resulting in increased costs for energy. A typical pharmaceutical cleanroom was used for this study, and operations were simulated with a process unit and two operators in the room. The experiments were conducted twice with four different ACRs and four different types of operator garments, resulting in 32 trials in total. Particle load and CFUs were measured by calibrated particle counters and microbial air samplers. The results give evidence that an ACR of 20 h−1 is not required. ACR 10 h−1 is sufficient without compromising the demanded air quality. Furthermore, it was found that regulatory agencies should reevaluate the expected limits as these currently give a high buffer between the required and actual values, which potentially cover up problems in aseptic manufacturing.

Microbial Aerosol Investigation and Health Risk Assessment of Residential Area in Wuhan City

In order to investigate the distribution and risk of microbial aerosols in residential areas after the COVID-19 in Wuhan Ctiy, Changqing Garden residential area, a mature community was selected as a case in this study. From October to December 2020, the Andersen-sixstage microbial air sampler was used to collect samples in six typical places in this residential area, and the microbial aerosol concentration was determined by the plate count method. In addition, the health risk assessment was evaluated according to the Chinese Population Exposure Parameters Manual (Adult Volume). The results showed that: (1) The concentration of microbial aerosol can be ranked in this order: fresh food market >underground parking lot >food street >central basketball court >central square >green pavilion. (2) The concentration of bacteria and fungus aerosol was different in different places, and the maximum aerosol concentration occurred in the fresh food market ((1525.32±1311.31) CFU/m3) and the food street ((1296.82±113.84) CFU/m3), respectively. (3) Take the air microbial concentration in typical places as the evaluation standard: the central basketball court, green pavilion and central square were clean, the fresh food market and underground parking lot were slightly polluted, and the food court was lightly pollution. (4) The median diameter of microbial aerosols was less than 4.7 μm, which can easily cause lower respiratory tract infections in residents. (5) The Hazard Quotient (HQ) of the typical places from October to December 2020 was less than 1, indicating that the health risk of microbial aerosol exposure in Changqing Garden residential area was relatively small. This research shows that the air quality of the Changqing Garden residential area is good under the epidemic prevention and control normalized measures, which meets the requirements for sanitary conditions in the post-COVID-19 era. © 2021, Editorial Board, Research of Environmental Sciences. All right reserved.

Indoor air quality monitoring and human perception survey on air quality in public buildings in Timisoara

The paper presents a study aimed at investigating the indoor air quality (IAQ) and people’s perception regarding the indoor environment of schools and public buildings in Timisoara. The indoor air quality monitoring was performed during the cold season, in the period January 2020 – February 2021. Six public buildings – schools and administrative edifices belonging to the municipality were subject of monitoring. An Andersen microbial air sampler was used to enumerate the numbers and different kinds of respirable bacteria and fungi inside of the selected classrooms and offices. The results of the specialized laboratory analyses indicate that the microbiological contaminant counts, expressed in colonyforming unit (CFU/m3), fall within the permissible limits for all monitored rooms. No beta-hemolytic streptococci or Staphylococcus aureus were identified, conditionally pathogenic bacteria for the upper respiratory tract. Most moulds were of the genus Penicillium, without having a pathogenic significance for humans. Occupants’ perception on indoor air quality, thermal comfort, health complaints and symptoms such allergies or respiratory illnesses with possible connection to the Sick building syndrome were surveyed by questionnaire. The findings were analysed and a plan to improve IAQ in the public buildings was proposed, with specific measures to increase the comfort and health of the learning and working environment.

Assessment of the indoor air quality based on airborne bacteria and fungi measurements in a public school of Istanbul

This study aimed at determining culturable airborne bacteria (CAB) and fungi (CAF) concentrations in different sections of a primary school located in Istanbul. Occupancy variables were determinants of exposure and the environmental, ventilation, and comfort parameters within the study. Air samples were collected twice in the summer and spring seasons using a microbial air sampler (Sampl’air™) and were analyzed in terms of CAB and CAF concentrations. Obtained results were visualized using geographic information system (GIS) technology for presenting the spatial variations of CAB and CAF concentrations with respect to environmental determinants and changing weather conditions as temperature and humidity. The study introduced that the CAB and CAF concentrations vary indoors based on the sampling location and human occupancy. As an interesting finding of the study, CAB (3300 CFU/m3) and CAF (3100 CFU/m3) concentrations in the 5th classroom, where relative humidity and temperature values were recorded as 62% and 25.3 °C, respectively, were observed, confirming higher values than those of communal areas. This result proved the importance of indoor characteristics like location, ventilation, occupation time, and hygiene as the substantial determinants of CAB and CAF exposure besides the indoor population. This study emphasized the importance of regular and systematic monitoring of airborne microorganisms in different sections of schools using objective and quantitative methodologies in terms of providing healthy educational environments for students.

Investigation of fungal contamination in indoor air and on surfaces of traditional public baths in a historical city.

It has been proven that exposure to bioaerosols is associated with several health effects, such as pulmonary diseases and allergies. The present cross-sectional study was aimed to investigate fungal contamination in indoor air and on the surfaces of four traditional baths in Shiraz, Iran, one of the most historical cities in the world. Samples were taken from indoor air, using a microbial air sampler, as well as the surfaces of the shower, hallway, and dressing rooms of studied baths for 3months. Totally 180 samples, including 45 air and 135 surfaces samples, were collected from studied baths. The concentrations of fungi collected from the air of studied baths were ranged from 22.6 to 34.6CFU/m3. Besides, the levels of fungi collected from the surface samples of studied baths were ranged from 21.2 to 60CFU/m2. The highest and lowest fungi species detected both in air and surfaces samples of the studied baths were Penicillium spp. and Mucor spp. respectively. Although the levels of fungi in the studied baths were lower than the levels recommended by the World Health Organization, some environmental health measures such as washing and disinfecting surfaces and tools after each working shift and periodic inspections are recommended ensuring the safety of costumers who are visiting such places.

Aerosol and environmental surface monitoring for SARS-CoV-2 RNA in a designated hospital for severe COVID-19 patients.

There is limited information concerning the viral load of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in aerosols deposited on environmental surfaces and the effectiveness of infection prevention and control procedures on eliminating SARS-CoV-2 contamination in hospital settings. We examined the concentration of SARS-CoV-2 in aerosol samples and on environmental surfaces in a hospital designated for treating severe COVID-19 patients. Aerosol samples were collected by a microbial air sampler, and environmental surfaces were sampled using sterile premoistened swabs at multiple sites. Ninety surface swabs and 135 aerosol samples were collected. Only two swabs, sampled from the inside of a patient's mask, were positive for SARS-CoV-2 RNA. All other swabs and aerosol samples were negative for the virus. Our study indicated that strict implementation of infection prevention and control procedures was highly effective in eliminating aerosol and environmental borne SARS-CoV-2 RNA thereby reducing the risk of cross-infection in hospitals.

Quantification of Airborne Resistant Organisms With Temporal and Spatial Diversity in Bangladesh: Protocol for a Cross-Sectional Study.

BackgroundAntimicrobial resistance is a widespread, alarming issue in global health and a significant contributor to human death and illness, especially in low and middle-income countries like Bangladesh. Despite extensive work conducted in environmental settings, there is a scarcity of knowledge about the presence of resistant organisms in the air.ObjectiveThe objective of this protocol is to quantify and characterize the airborne resistomes in Bangladesh, which will be a guide to identify high-risk environments for multidrug-resistant pathogens with their spatiotemporal diversity.MethodsThis is a cross-sectional study with an environmental, systematic, and grid sampling strategy focused on collecting air samples from different outdoor environments during the dry and wet seasons. The four environmental compartments are the frequent human exposure sites in both urban and rural settings: urban residential areas (n=20), live bird markets (n=20), rural households (n=20), and poultry farms (n=20). We obtained air samples from 80 locations in two seasons by using an active microbial air sampler. From each location, five air samples were collected in different media to yield the total bacterial count of 3rd generation cephalosporin (3GC) resistant Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae, vancomycin-resistant Enterococci and methicillin-resistant Staphylococcus aureus.ResultsThe study started in January 2018, and the collection of air samples was completed in November 2018. We have received 800 air samples from 80 study locations in both dry and wet seasons. Currently, the laboratory analysis is ongoing, and we expect to receive the preliminary results by October 2019. We will publish the complete result as soon as we clean and analyze the data and draft the manuscript.ConclusionsThe existence of resistant bacteria in the air like those producing extended-spectrum beta-lactamases, carbapenem-resistant Enterobacteriaceae, vancomycin-resistant Enterococci, and methicillin-resistant Staphylococcus aureus will justify our hypothesis that the outdoor environment (air) in Bangladesh acts as a reservoir for bacteria that carry genes conferring resistance to antibiotics. To our knowledge, this is the first study to explore the presence of superbugs in the air in commonly exposed areas in Bangladesh.International Registered Report Identifier (IRRID)DERR1-10.2196/14574

ANALISIS KUALITAS FISIK RUMAH DENGAN KEBERADAAN MYCOBACTERIUM TUBERCULOSIS DI UDARA

Tuberculosis (TB) cases in Indonesia are most prevalent in West Java, East Java, and Central Java Provinces. TB cases in those provinces accounted for 38% of all incident TB cases in Indonesia. Transmission of the disease is influenced by environmental factors and unhealthy behavior. Environmental factors that affect the incidence of TB such as temperature, humidity, and natural lighting. This was an observational research, using case-control study design. Data then compared with the Regulation of Health Minister Republic Indonesia No. 1077 in 2011 about Guideline for Air Sanitation in the Home Space and Decision of Health Minister Republic Indonesia No. 829 in 1999 about Housing Health Requirement. Samples were taken by pusposive sampling with a sample size of 10 houses of pulmonary TB patients and 10 home instead of pulmonary TB patiens. Data collection using observation sheet and measurement. Air sampling using Microbial Air Sampler (MAS), then samplees sent to the laboratory for examination of Mycobacterium tuberculosis bacteria. The result showed that most of the temperature, humidity, natural lighting, wide ventilation, and light intensity in the home of tuberculosis patiens not eligible. Mycobacterium tuberculosis was found in all TB home patients. People should maintain the cleanliness of the house by cleaning the floor with disinfectant and adding ventilation to improve air circulation and the sunlight can enter the room.

Prevalence of and environmental factors associated with aerosolised Aspergillus spores at a zoological park

Aspergillus is a significant pathogen in zoological species, although information on environmental variables influencing fungal prevalence in zoological settings are lacking. The objective of the study was to estimate the...

Indoor Airborne Microbial Load of Selected Offices in a Tertiary Institution in South-Western Nigeria

Indoor air quality (IAQ) has been identified by the Environmental Protection Agency (EPA) as one of the most urgent top five environmental risks to public health. Numerous studies have documented that sick building syndrome (SBS) is surprisingly common even in buildings without widespread complaints and its relationship with hypersensitivity disease are often associated with exposure to high concentration of airborne microbial organisms. To contribute to knowledge on IAQ, this study evaluates the levels and composition of bacterial and fungal contamination of different offices in a tertiary institution in South-western Nigeria. A cross sectional design was used to compare the indoor airborne microbial load of three categories of offices within the institution premises: the central administrative (CA), academic (AC) and work and maintenance (W&M) offices. Indoor temperature (oC) and relative humidity (%) of the respective offices were measured using a 5-in-1 multi-tester N21FR made in China and categorized into comfort and high levels. Air samples were collected using a TE-10-890 Andersen single stage microbial air sampler and the total counts per cubic metre were compared with the American Industrial Hygiene Association guideline (AIHA). Data were analyzed using descriptive statistics, t-test, Spearman’s rank correlation and regression analysis. Offices in CA recorded the highest mean indoor Total Bacteria Count (TBC) of 22.6 ± 12.2cfu/m3 as compared to W&M (18.3 ± 10.4cfu/m3) and AC (15.6 ± 8.4cfu/m3) p 0.05. The indoor TBC and TFC of the categories of offices were found to be lower than the AIHA guideline limit. The number of persons at the point of sampling was found to significantly predict the level of indoor TBC, p<0.01. The most isolated bacteria were Staphylococcus spp., Streptococcus spp. and Micrococcus spp., whereas Cladosporium spp., Aspergillus spp. were the most abundant fungi isolates. The present study implicated population as a major source of microbial contamination in the office environment. Adequate knowledge about indoor air quality in terms of microbial contamination and its implication on health should be provided to staff of the institution in the hierarchy of control measures to mitigate the levels of indoor airborne microorganisms.

Occurrence of fungi and cytotoxicity of the species: Aspergillus ochraceus, Aspergillus niger and Aspergillus flavus isolated from the air of hospital wards.

The basic care requirement for patients with weakened immune systems is to create the environment where the risk of mycosis is reduced to a minimum. Between 2007 and 2013 air samples were collected from various wards of a number of hospitals in Kraków, Poland, by means of the collision method using MAS-100 Iso MH Microbial Air Sampler (Merck Millipore, Germany). The air mycobiota contained several species of fungi, and almost 1/3 of it was made up of the species of the Aspergillus genus. Sixty-one strains of species other than A. fumigatus were selected for the research purposes, namely: 28 strains of A. ochraceus, 22 strains of A. niger and 11 strains of A. flavus species. Selected fungi underwent a cytotoxicity evaluation with the application of the MTT colorimetric assay (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide). The assay assesses cell viability by means of reducing the yellow tetrazolium salt to insoluble formazan. A semi-quantitative scale for cytotoxicity grading was adopted: low cytotoxic effect (+) with half maximal inhibitory concentration (IC50) for values ranging from 31.251 cm2/ml to 7.813 cm2/ml, medium cytotoxic effect (++) for values ranging from 3.906 cm2/ml to 0.977 cm2/ml and the high one (+++) for values ranging from 0.488 cm2/ml to 0.061 cm2/ml. The absence of cytotoxicity was determined when the IC50 values was at ≥ 50. For 48 samples the analyzed fungi displayed the cytotoxic effect with A. ochraceus in 26 out of 28 cases, with 11 strains displaying the high cytotoxic effect. The lowest cytotoxicity was displayed by fungi of A. niger in 13 out of 22 cases, and the major fungi of A. flavus species were toxic (9 out of 11 cases). A half of the fungi displayed the low cytotoxic effect. On the basis of the comparison of average cytotoxicity levels it was determined that there were significant differences in the levels of cytotoxicity of the analyzed fungi. However, such statement may not provide grounds for a definite conclusion about the compared species of fungi that display a more cytotoxic effect than others. Int J Occup Med Environ Health 2017;30(2):231-239.

Effects of Microbial Aerosol in Poultry House on Meat Ducks' Immune Function.

The aim of this study was to evaluate effects of microbial aerosols on immune function of ducks and shed light on the establishment of microbial aerosol concentration standards for poultry. A total of 1800 1-d-old cherry valley ducks were randomly divided into five groups (A, B, C, D, and E) with 360 ducks in each. To obtain objective data, each group had three replications. Concentrations of airborne bacteria, fungi, endotoxin in different groups were created by controlling ventilation and bedding cleaning frequency. Group A was the control group and hygienic conditions deteriorated progressively from group B to E. A 6-stage Andersen impactor was used to detect the aerosol concentration of aerobes, gram-negative bacteria, fungi, and AGI-30 microbial air sampler detect the endotoxin, and Composite Gas Detector detect the noxious gas. In order to assess the immune function of meat ducks, immune indicators including H5 AIV antibody titer, IgG, IL-2, T-lymphocyte transformation rate, lysozyme and immune organ indexes were evaluated. Correlation coefficients were also calculated to evaluate the relationships among airborne bacteria, fungi, endotoxin, and immune indicators. The results showed that the concentration of airborne aerobe, gram-negative bacteria, fungi, endotoxin have a strong correlation to H5 AIV antibody titer, IgG, IL-2, T-lymphocyte transformation rate, lysozyme, and immune organ indexes, respectively. In addition, when the concentration of microbial aerosol reach the level of group D, serum IgG (6–8 weeks), lysozyme (4 week) were significantly higher than in group A (P < 0.05); serum IL-2 (7 and 8 weeks), T-lymphocyte transformation rate, lysozyme (7 and 8 weeks), spleen index (6 and 8 weeks), and bursa index (8 week) were significantly lower than in group A (P < 0.05 or P < 0.01). The results indicated that a high level of microbial aerosol adversely affected the immune level of meat ducks. The microbial aerosol values in group D provide a basis for recommending upper limit concentrations of microbial aerosols for healthy meat ducks.

Bacteria emitted in ambient air during bronchoscopy-a risk to health care workers?

Health care workers are at risk of occupational infections, and some procedures are known to increase this risk. The aim of this study was to qualify and quantify bioaerosol concentrations during bronchoscopy to estimate the occupational risk. Full-day sampling was conducted in 2 rooms while bronchoscopies were performed on patients. Two microbial air samplers were used, a wet wall cyclonic sampler and an impactor, on culture media. Identification of the culturable bacterial flora was performed with chromatographic analysis of cellular fatty acid of the isolated strain and additional biochemical tests if needed. Specific polymerase chain reaction analysis was completed on wet wall cyclonic samples for the detection of influenza A and B and Mycobacterium spp. A wide variety of bacteria were collected from the ambient air. All samples yielded at least 1 Staphylococcus species. Although most of the culturable bacteria identified were normal nonpathogenic flora, such as Streptococcus spp, Neisseria spp, and Corynebacterium spp, some opportunistic pathogens, such as Streptococcus pneumoniae, were found. Neither Mycobacterium spp nor influenza virus was detected with the polymerase chain reaction method during this study. Culturable bacteria from oral, nasal, and pulmonary flora are aerosolized during bronchoscopy and could be inhaled by medical staff. The potential presence of pathogens in those aerosols could represent an occupational infection risk.