Microbial Air Sampler Research Articles

Influence of indoor microbial aerosol on the welfare of meat ducks

The aim of the study was to evaluate the effects of microbial aerosols on ducks’ welfare and provide information on which to establish microbial aerosol concentration standards for poultry.A total of 1800 1-d-old Cherry Valley ducks were randomly divided into 5 groups (A, B, C, D and E) with 360 ducks in each. To obtain objective data, each group had three replications. Different microbial aerosol concentrations 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, fungi, gram-negative bacteria and an AGI-30 microbial air sampler detected endotoxins. Physiological stress was evaluated in the ducks by adrenocorticotropic hormone (ACTH) values in serum.To assess the effects of bioaerosol factors, welfare indicators including fluctuating asymmetry (FA), appearance and gait as well as the Lactobacillus caecal concentration were evaluated.The data showed group D had already reached the highest limit of concentration of airborne aerobic bacteria, airborne fungi, airborne gram-negative bacteria and airborne endotoxin. The ducks in this group had significantly increased serum ACTH values and significantly decreased caecal lactobacilli concentration. Furthermore, appearance and gait scores, wing length and overall FA and caecal Lactobacillus concentration in this group were significantly increased at 6 and 8 weeks of age.In conclusion, high concentrations of microbial aerosol adversely affected the welfare of meat ducks. The microbial aerosol values in group D suggest a preliminary upper limit concentration of bioaerosols in ambient air for healthy meat ducks.

Effectiveness of UV irradiation for air disinfection in chambers for microbiological tests

The objective of the study was to determine the UV irradiation operation time required to obtain the microbial reduction level specified for the so-called cleanrooms standard in the device for microbiological examination. The samples for examination were collected using an aspiration method and a Sampl`air Lite microbial air sampler (AES Laboratoire Chemunex). Microbial air contamination was established according to the PN, prior to the sterilization and after 3, 4, 5, 6, 14, 16, 18, 20, 22, 24 hours of air sterilization in the chamber. Significant differences were found in the contamination levels at all the sterilization times studied. Depending on exposure time, an over 3-fold and up to 8-fold reduction of the microbial count was noted. The highest microbial load decrease was observed after 16 and then 18 hours of sterilization. As compared to the first period under investigation, a subsequent decline in microbial count reduction was determined after 4, 5 and 6 hours of sterilization operation. Only the 14-h irradiation time resulted in a higher level of microbial contamination reduction as compared to the 3-h exposure time. UV radiation is an effective procedure for air disinfection in a chamber for microbiological examination and the minimum efficient irradiation time is 3 hours.

Microbial Air Contamination in an Intensive Care Unit

Unit layout affects every aspect of intensive care services, including patient safety. A previous study has shown that patients admitted to beds adjacent to the sink and to the door of a large bayroom had the highest number of positive blood cultures and the highest blood culture incidence density, respectively. The present study measures microbial air contamination in a medical intensive care unit of a medical center in central Taiwan. Of the 17 rooms, 8 rooms with distinct physical environmental characteristics were selected. Sampling tests were conducted between December 2013 and February 2014 with a microbial air sampler (MAS-100NT). TSA was used for bacteria collection and DG18 for fungi collection. The overall average bacterial and fungal concentrations were 83CFU/m<sup>3</sup> and 69CFU/m<sup>3</sup>, respectively. The ranges were between 8-354 CFU/m<sup>3</sup> and 0-1468 CFU/m<sup>3</sup>, respectively. A significant difference was found in the bacterial concentration (p=.005) between different room locations. The highest concentration was found in the rooms located at the front end of the circulation (99 CFU/m<sup>3</sup>), while the lowest was found in the rooms located at the rear end of the circulation (55CFU/m<sup>3</sup>). Differences in fungal concentrations for different room locations did not reach statistical significance. In addition, differences in bacterial and fungal concentrations for rooms with different sink locations did not reach statistical significance. Even though the microbial concentrations generally complied with standards, the results may help designers and hospital administrators develop a healthier environment for patients.

Microbial Air Contamination in an Intensive Care Unit

Unit layout affects every aspect of intensive care services, including patient safety. A previous study has shown that patients admitted to beds adjacent to the sink and to the door of a large bayroom had the highest number of positive blood cultures and the highest blood culture incidence density, respectively. The present study measures microbial air contamination in a medical intensive care unit of a medical center in central Taiwan. Of the 17 rooms, 8 rooms with distinct physical environmental characteristics were selected. Sampling tests were conducted between December 2013 and February 2014 with a microbial air sampler (MAS-100NT). TSA was used for bacteria collection and DG18 for fungi collection. The overall average bacterial and fungal concentrations were 83CFU/m<sup>3</sup> and 69CFU/m<sup>3</sup>, respectively. The ranges were between 8-354 CFU/m<sup>3</sup> and 0-1468 CFU/m<sup>3</sup>, respectively. A significant difference was found in the bacterial concentration (p=.005) between different room locations. The highest concentration was found in the rooms located at the front end of the circulation (99 CFU/m<sup>3</sup>), while the lowest was found in the rooms located at the rear end of the circulation (55CFU/m<sup>3</sup>). Differences in fungal concentrations for different room locations did not reach statistical significance. In addition, differences in bacterial and fungal concentrations for rooms with different sink locations did not reach statistical significance. Even though the microbial concentrations generally complied with standards, the results may help designers and hospital administrators develop a healthier environment for patients.

Some aspects on the sampling efficiency of microbial impaction air samplers

Indoor microbial monitoring is an important health issue in many sectors of society. In particular, it is important to monitor microbial concentrations in environments dealing with bio-susceptible products. Many human diseases are related to high, undesired microbial airborne concentrations. However, the lack of a standardized and well-accepted methodology for testing and ranking the performance of microbial air samplers is a source of uncertainty in such measurements. Several works clearly show that results obtained from microbial air sampling depend largely on measuring techniques, especially the air samplers’ physical parameters, such as d50, as well as environmental conditions, sources, and concentrations of microbial organisms in the environment. Furthermore, personnel using cleanroom clothing can reduce the microbial burden within a clean environment. To evaluate this effect, we carried out experimental comparison tests in a cleanroom of class ISO 5 with different air samplers under various microbial concentration levels, generated by a human source dressed in different quality cleanroom clothing. Our results confirm that in addition to the measuring technique, cleanroom clothing does influence microbial contamination, affecting air sampler measurements.

Use of a Real-Time Microbial Air Sampler for Operational Cleanroom Monitoring

A sampler that detects and counts viable particles in the air of cleanrooms in real-time was studied. It was found that when the sampler was used to monitor airborne particles dispersed from a number of materials used in cleanrooms, including garments, gloves, and skin, the number of viable particles dispersed from these materials was greater than anticipated. It was concluded that a substantial proportion of these viables were of a non-microbiological origin. When the sampler was used to monitor a non-unidirectional airflow cleanroom occupied by personnel wearing cleanroom garments, it was found that the airborne viable concentrations were unrealistically high and variable in comparison to microbe-carrying particles simultaneously measured with efficient microbial air samplers. These results confirmed previously reported ones obtained from a different real-time sampler. When the real-time sampler was used in a workstation within the same cleanroom, the recorded viables gave results that suggest that the sampler may provide an effective airborne monitoring method, but more investigations are required. The airborne concentrations measured by a real-time microbial air sampler within an operational, non-unidirectional airflow cleanroom were found to be unrealistically high due to a substantial numbers of particles of non-microbiological origin. These particles, which resulted in false-positive microbial counts, were found to be associated with a number of materials used in cleanrooms. When the sampler was used within a cleanroom workstation, the counts appeared to be more realistic and suggest that this type of real-time airborne microbial counter may provide a useful monitoring method in such workstations, but further investigations are required.

The fungal flora at various historical locations in Izmir, Turkey

In our study, surface and environmental air samples from the historical buildings (houses, kiosks, Turkish bath, khans, train station) in seven different locations were investigated for their fungal flora. Sampling was performed in seven locations in Izmir (Bornova, Buca, Cesme, Foca, Karsiyaka, Konak and Tire) in autumn and summer of 2009. Totally 192 isolates were obtained from the air and surface samples of these places. Air samples were collected using a MAS-100 Microbial Air Sampler (Merck) and fungal load were detected by using Rose Bengal Chloramphenicol Agar (RBCA, Merck). Biofilm samples were obtained from different surfaces (stone, wood, plaster, marble, limestone, brick and paint). As a result of our study, 25 genera related to Zygomycota , anamorph Ascomycota and teleomorph Ascomycota were identified. Besides, Aspergillus sp., Penicillium sp., Phoma sp., Alternaria sp., Chaetomium sp. and Cladosporium sp. were appeared the most frequently fungi genera. However, 6 isolates were not identified. It was observed that Aspergillus sp. was at the first stage with frequency of 21.88% while Penicillium sp. was at the second stage with 17.70%. In our study it was also shown that fungal load was much more in autumn than in summer due to its high moisture content and optimum temperature. Keywords: Airborne fungi, Ascomycota, Biofilm, Biomass, Microfungi. *Corresponding Author: Asli Sahiner (e-mail: asli.sahiner@ege.edu.tr ) (Received: 03.08.2012 Accepted: 03.01.2012)

Variability in airborne bacterial and fungal population in the tertiary health care centre

An investigation of the air quality and the quantity of airborne microbes was conducted in a private and a government tertiary health care centre of Davanagere in the month of November 2011 to assess the level of air borne pathogens. Using a Merck Microbial Air Sampler MAS-100NT, samples were collected in the morning and in the evening from the different environs of the private and government tertiary health care centre. The media used for the study of fungi was sabouraud dextrose agar. Aspergillus spp, Curvularia spp, Alternaria spp, Penicillium spp, Rhizopus spp, Nigrospora spp, and Fusarium spp were found in either of the tertiary health care centre. Aspergillus spp was dominant in the Government tertiary health care centre, and Alternaria spp and Curvularia spp were dominant in the private tertiary health care centre. For the bacteria, quantitative enumeration was done using soyabean casein digest agar and selective media like Escherichia coli and coliform agar and urinary tract infection agar were used in qualitative enumeration. Selected pathogens like E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enteritidis, Staphylococcus aureus, Proteus mirabilis, and Entirococcus faecalis were found in either of the tertiary health care centre. Maximum number of fungi and bacteria were isolated from emergency ward and general ward of government and private health care centre. There was also considerable difference in the morning and in the evening.

OP3-4 Alternative method for airborne virus detection in only few hours/innovative microbial air sampler

OP3-4 Alternative method for airborne virus detection in only few hours/innovative microbial air sampler

Assessment of airborne pathogens in healthcare settings

An investigation of the air quality and quantity of airborne microbes in selected hospitals of Zarqa city, Jordan, was carried out to assess the level of airborne pathogens and to establish standards for further reference. Using a microbial air sampler, air samples were taken from a governmental and a private hospital in Zarqa city. Three factors were investigated to determine how these factors affect the microbial counts, namely the kind of hospital, the type of room and the time of sampling. Nine bacterial species were identified. In a governmental hospital,Staphylococcus aureus (16.2%) was found to be the most common organism, followed by Micrococcus luteus (13.3%) and coagulase-negative Staphylococcus(13%). Coagulase-negative Staphylococcus (17.2%), followed by S. aureus(16.8%) and M. luteus (10.7%) were found to be the most common in a private hospital. Aspergillus spp., Penicillium spp., Rhizopus spp. and Alternaria spp. were isolated in both hospitals. The indoor air of the governmental hospital was more contaminated than that of the private hospital in all units. Maximum bacterial rates were detected in the patient rooms, while minimum bacterial rates were detected in the operating rooms and neonatal wards. The time of visit showed higher microbial rates in governmental hospital, while the private hospital was not affected by this factor. Microbial rates in the patient room, main entrance and intensive care unit (ICU) were found to be influenced by the time of sampling, while the operating room and neonatal ward were not. Several explanations might be involved in these variations, that is, the age of hospital building, the number of beds, the number of visitors, disinfection procedures and ventilation systems. We concluded that the indoor air quality of hospitals in Zarqa city, especially the governmental hospital, needs more care and surveillance and should be given priority in Jordan. Key words: Air sampling, airborne bacteria and fungi, indoor air, hospital, Jordan.

Collection efficiency and design of microbial air samplers

The variables affecting the physical collection efficiency of air samplers of the type that impact microbe-carrying particles onto agar were investigated using a simplified analytical method and computational fluid dynamics. The results from these two techniques were compared, as were the effect of jet velocity, nozzle size, and nozzle distance from the agar surface; also considered was the optimisation of these variables to obtain an efficient design of sampler. A technique is described that calculates the proportion of microbe-carrying particles that a sampler will collect from a typical size distribution of microbe-carrying particles found in an occupied room; the three air samplers studied were found to collect from about 22 % to over 99 % of the micro-organisms in the room air.

Bacterial Shedding and Desquamation from the Hands of Healthcare Workers Correlates with Skin Condition

BACKGROUND/OBJECTIVES: The outer layers of human skin are comprised of corneocytes which are constantly shed (desquamated) into the environment and replaced by fresh layers from underneath. Desquamated skin is laden with the same bacteria populating intact skin and has been documented to pose a significant risk of infection in the surgical setting. The risk of infection from bacteria shed from the hands is controlled in the surgical room through hand hygiene prior to surgery and the use of gloves. Little is known regarding the risk of infection transfer from bacteria shed from the hands in non-surgical settings. It is known that frequent handwashing often damages the skin of healthcare workers and can lead to colonization by pathogenic bacteria. The objectives of this study were to measure viable bacteria shed from the hands of healthcare workers (HCW's) in an acute care setting and determine whether levels of dispersed bacteria correlated with skin condition. METHODS: Data was collected from 3 units of an acute care hospital in Northeast, Ohio. Bacteria shed from the hands of the subjects were collected using a SAS Super 180 Microbial Air Sampler. Approximately 35 minutes after handwashing, HCW's were instructed to rub their hands in a wringing motion 15 cm above the sampler for 30 seconds while 100 L of air was collected. Airborne particles were collected onto RODAC plates containing trypticase soy agar and bacteria were quantified after incubating for 24 hours at 35°C. Skin hydration, transepidermal water loss and desquamation index were measured by standard methods. RESULTS: Bacterial dispersal and quantitative skin measurements were obtained from 86 HCW's over a 3 day period. The levels of bacteria shed from the hands of the HCW's was found to be negatively correlated to corneometer measurements (p CONCLUSIONS: The results of this hospital study demonstrate that the levels of bacteria shed from the hands of healthcare workers are influenced by the health of the individual's skin; i.e. dry skin sheds more bacteria. This increased bacterial dispersal from dry skin may increase the infection transfer risk for HCW's with poor skin condition in the acute care setting. All authors are employees of GOJO. All work was funded by GOJO. Our role in the Skin Care Science group is to understand end users skin condition and the performance / efficacy of our new products / technologies in order to help develop better products &/or position and thereby sell our hand hygiene products to professional markets like Healthcare.

Microbial aerosol generation during laboratory accidents and subsequent risk assessment

To quantify microbial aerosols generated by a series of laboratory accidents and to use these data in risk assessment. A series of laboratory accident scenarios have been devised and the microbial aerosol generated by them has been measured using a range of microbial air samplers. The accident scenarios generating the highest aerosol concentrations were, dropping a fungal plate, dropping a large bottle, centrifuge rotor leaks and a blocked syringe filter. Many of these accidents generated low particle size aerosols, which would be inhaled into the lungs of any exposed laboratory staff. Spray factors (SFs) have been calculated using the results of these experiments as an indicator of the potential for accidents to generate microbial aerosols. Model risk assessments have been described using the SF data. Quantitative risk assessment of laboratory accidents can provide data that can aid the design of containment laboratories and the response to laboratory accidents. A methodology has been described and supporting data provided to allow microbiological safety officers to carry out quantitative risk assessment of laboratory accidents.

Cough-generated aerosols of Mycobacterium tuberculosis: a new method to study infectiousness.

The concentration and size distribution of infectious aerosols produced by patients with pulmonary tuberculosis (TB) has never been directly measured. We aimed to assess the feasibility of a method that we developed to collect and quantify culturable cough-generated aerosols of Mycobacterium tuberculosis. Subjects were recruited from a referral hospital and most had multidrug-resistant TB. They coughed into a chamber containing microbial air samplers while cough frequency was measured during two 5-minute sessions. Cough-generated aerosol cultures were positive in 4 of 16 subjects (25%) with smear-positive pulmonary TB. There was a rapid decrease in the cough-generated aerosol cultures within the first 3 weeks of effective treatment. Culture-positive cough aerosols were associated with lack of treatment during the previous week (p = 0.007), and there was a trend in the association with cough frequency (p = 0.08). The size distributions of these aerosols were variable, but most particle sizes were in the respirable range. Quantification of viable cough-generated aerosols is feasible and offers a new approach to study infectiousness and transmission of M. tuberculosis and other airborne pathogens.

Experimental study of indoor and outdoor airborne bacterial concentrations in Tempe, Arizona, USA

Indoor and outdoor airborne bacterialconcentrations were examined in an occupiedoffice building equipped with an airconditioning (HVAC) system, in Tempe, Arizona,USA. A two-stage microbial air sampler wasused to collect bacteria both inside andoutside the office at fixed locations in space,and at regular time intervals from August toDecember, 2000. Simultaneous measurement ofbacterial concentrations, temperature, relativehumidity, light intensity and wind speed wereperformed to explore the effects ofenvironmental factors on bacteria levels. Tengenera and twenty species of airborne bacteriawere found in our samples. AirborneGram-positive bacteria were most abundant, withmore than 90% of the measured population. Theparticle sizes of most outdoor and indoorairborne bacterial aerosols were larger than8.0 μm. According to the measurements ofeither a typical day or three consecutive days,the concentrations of outdoor airborne bacteriawere highest in the morning, but declined inthe afternoon and reached the lowest point inthe evening. With regard to the effects offour environmental factors – temperature,relative humidity, light intensity, and windspeed, the relative humidity had the mostpronounced influence on the outdoor bacterialconcentration, with the number of bacteriaincreasing sharply on a day of high relativehumidity.

Characterizations and relationships between outdoor and indoor bioaerosols in an office building

Characterizations and relationships between indoor and outdoor bioaerosols were examined in an occupied office building, equipped with an air conditioning (HVAC) system, in Tempe, Arizona, USA. A two-stage microbial air sampler was used to collect bioaerosols both inside and outside the office at fixed locations in space and at regular time intervals from August to December, 2000. Simultaneous measurements of bioaerosol, temperature, relative humidity, light intensity and wind speed were performed to explore the effects of environmental factors on bioaerosol levels. Twenty species of airborne bacteria and four genera of airborne fungi were found in our samples. The particle sizes of most outdoor and indoor bioaerosols were larger than 8.0 μm. According to the measurements of sampling days, the concentrations of outdoor bioaerosols were highest in the morning, but declined in the afternoon and reached the lowest point in the evening. The concentration peak of indoor bioaerosol (especially at the lower level) occurred in the evening, suggesting that the concentration of indoor bioaerosols follows that of outdoors, but with a time delay due to the lag associated with indoor-outdoor air exchange. With regard to the effects of four environmental factors — temperature, relative humidity, light intensity, and wind speed, the relative humidity had the most pronounced influence on the outdoor bioaerosol concentrations with the number of bacteria and fungi increasing sharply on a day of high relative humidity in the desert area.

Residential indoor airborne microbial populations in the United Arab Emirates

An investigation into the types and numbers of airborne microorganisms was carried out in three varying types of residential houses in Al-Ain City, UAE, to establish future reference standards and to determine if they have affected, and to what degree they may affect, human health. Samples were collected using a microbial mechanical air sampler for the enumeration of bacterial and fungal colony forming units (CFU). Nine groups of bacteria and fungi either of human or environmental origin were detected. Environmental agents generally predominated while significantly higher counts were detected as the level of hygiene or standard of housing dropped. Significantly higher human associated microorganisms were detected in bedrooms while environmentally-related microorganisms were more commonly found in living rooms. Only small numbers of potential human pathogens were detected. Five genera of fungi, mainly members of the genus Aspergillus, were isolated from all houses across the board. Microbial occurrence and indoor air quality in the high social strata houses were similar to that reported in clean hospital environment rooms. It was concluded that, although the numbers and types of microbial population in domestic homes were high, they have little adverse effects on human health.

Determination of the collection efficiency of a microbial air sampler

The Biotest RCS Plus air sampler was compared with the well‐established Casella slit sampler for the quantitative analysis of the microbiological content of air. The results of the tests reported here show that the RCS Plus sampling efficiency is similar to that of the Casella sampler over the range of particles likely to be encountered in the environment. For particles less than 4 μm down to the sub‐micronic sizes the efficiency of sampling falls off only gradually so that the efficiency of sampling for 1·0 μm particles is only reduced to about 50%. The ability to pre‐select 10 different volumes (from 1 to 1000 1) enables the samplers to be used for measuring a wide range of concentrations of airborne micro‐organisms in a variety of locations.