Assessment of the Levels of Airborne Bacteria, Gram-Negative Bacteria, and Fungi in Hospital Lobbies

Air is an important part of human life. However, air can be contaminated with microorganisms such as airborne bacteria and fungi. Temperature and relative humidity in a room can have an impact on the quantity of airborne bacteria and fungi. This study aims to figure out the correlation between the number of airborne bacteria and fungi with temperature and relative humidity. In 15 rooms of Microbiology laboratory, NA and SDA Petri plates were placed, after incubation, the number of colonies in each plate was counted. Pearson test was conducted with SPSS to determine the correlation between temperature and relative humidity to the number of airborne bacteria and fungi. The highest number of airborne bacteria was in the reading room (352 CFU/m3), while the lowest number was in the laundry room (13 CFU/m3) and the highest number of airborne fungi was in the Mycology room (156 CFU/m3), while there were no airborne fungi found in the urine and laundry rooms. Based on the results of the Pearson test, it was found that the value of p = 0.668 (p> 0.5) showed that there was no correlation between temperature and the number of airborne bacteria and fungi. Based on the results of the Pearson test, the value of p = 0.745 (p> 0.5) showed that there was no correlation between relative humidity and the number of airborne bacteria and fungi. There is no correlation between temperature and relative humidity with the number of airborne bacteria and fungi.

Indoor airborne bacteria and fungi levels can be selected as indicators of a healthy indoor environment. This study investigated the relationships between the airborne bacteria levels, fungi levels, and thermal environmental parameters, i.e., air temperature and relative humidity, in some offices with a Mechanical Ventilation and Air-Conditioning (MVAC) system operating. A total of 101 samples were collected from two typical Hong Kong air-conditioned office premises. There was evidence that the operation of the MVAC system would have significant influence on both of the indoor airborne bacteria and fungi levels. The results showed that no significant difference in airborne bacteria and fungi levels was observed between offices having similar thermal environments ( p > 0.05). However, significantly higher airborne bacteria and fungi levels were found in the same office during non-office hours when the air-conditioning system was shut down ( p<0.03). It was also reported that the airborne bacteria and fungi levels would be correlated with the thermal environmental parameters in some offices ( p<0.0001).

The concentration of airborne bacteria and fungi in public buildings is regulated by law in Korea. Levels are investigated during the moderate seasons, spring (March—May) and autumn (September—November), using a six-stage cascade impactor. Total concentrations of airborne bacteria and fungi range from 290 to 940 cfu · m-3 and 330 to 540 cfu · m -3, respectively. The levels of airborne bacteria and fungi are significantly highest in a kindergarten building and lowest in an elderly welfare facility ( p<0.05). The ratio of respirable to total concentration range from 30 to 40% for airborne bacteria and from 55 to 70% for airborne fungi but there is no significant difference among the public buildings examined ( p>0.05). The mean ratios of indoor and outdoor concentrations of airborne bacteria and fungi are below 1.0 regardless of the fraction of particle size and building type. The indoor concentration of airborne bacteria and fungi do not correlate significantly with indoor temperature and relative humidity ( p>0.05). However, this does have a significant positive correlation with CO2 and the number of people per area of the sampling site ( p<0.05), which implies that the activity of residents has considerable effect on the levels of both airborne bacteria and fungi.

Thailand border market is where the local Thais, Cambodians, Laotians, and Burmeses exchange their goods and culture at the border checkpoints. It is considered to be the source of aerial disease transmission especially for foreigners because it is always very crowded with people from all walks of life. Unhealthy air quality makes this area high risk of spread of airborne diseases. This study assessed airborne concentrations of bacteria and fungi in a border market to improve exposure estimates and develop efficient control strategies to reduce health risk. The density and distribution of airborne bacteria and fungi were investigated in the Chong Chom border market in Surin Province, Thailand. Eighteen air sampling sites were taken from outdoors and various work environments including indoor footpaths, wooden handicraft shops, electronic shops, the secondhand clothing shops, and fruit market areas. Exposed Petri plate method and liquid impinger sampler were used for sampling at the breathing zone, 1.5 m above the floor level, during weekend and holiday. Meteorological factors such as relative humidity, temperature, and light intensity were collected by portable data logger. The relative humidity was 67–73%, and temperature 29–33°C, and light varied between 18 and 270 Lux m−2. Gram-positive and Gram-negative bacteria were found at a mean value of 104 CFU m−3, and airborne fungi of 103 CFU m−3 were recorded. The highest concentration of culturable airborne microorganisms was found along the indoor footpath (9.62 × 104 CFU m−3 and 750.00 CFU/plate/h for impingement and sedimentation methods, respectively), the fruit market area (7.86 × 104 CFU m−3 and 592.42 CFU/plate/h for impingement and sedimentation methods, respectively), and the secondhand clothing shop (4.59 × 103 CFU m−3 and 335.42 CFU/plate/h for impingement and sedimentation methods, respectively) for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The lowest concentration of Gram-positive bacteria, Gram-negative bacteria, and fungi was found only at the outdoor area at 1.53 × 104 CFU m−3, 0.93 × 104 CFU m−3 and 0.80 × 103 CFU m−3 by means of impingement method and 136.67 CFU/plate/h, 69.25 CFU/plate/h, and 62.00 CFU/plate/h by means of sedimentation methods for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The most frequently present airborne bacteria were identified as Bacillus, Corynebacteria, Diplococcus, Micrococcus, Acinetobacter, Alcaligenes, Enterobacter, and spore former rods. Acremonium, Aspergillus, Cladosporium, Penicillium, and Sporotrichum were the most frequently found aerosol fungi genera. The distribution of airborne microorganisms correlated with relative humidity and light factors based on principal component analysis. In conclusion, the border market is a potential source of aerial disease transmission and a various hazards of bioaerosols for workers, consumers, sellers, and tourists. The bioaerosol concentration exceeded the standard of occupational exposure limit. Many major indicators of allergenic and toxigenic airborne bacteria and fungi, Acinetobacter, Enterobacter, Pseudomonas, Cladosporium, Alternaria, Aspergillus, and Penicillium, were found in the various market environments.

Objectives: This study was undertaken to assess the sanitary conditions in the kitchens of food court/cafeterias and determine seasonal variations. Methods: We measured environmental factors (air temperature, relative humidity, illumination intensity, noise level), and dropping airborne microbes (bacteria and fungi) in the kitchens of eight food court/cafeterias in four seasons (January, April, July, and October). Air temperature and relative humidity were measured with in/out thermo-hygrometers at 1.2-1.5 m above floor level. Illuminance measurement was performed through the multiple point method of Korean Standards (KS). Noise level was measured by the standard methods for the examination of environmental pollution (noise and vibration) of Korea. The estimation of dropping airborne bacteria and fungi was performed through use of Koch`s method. Results: The highest kitchen air temperature was in July, and the lowest in January. The average temperature surpassed throughout the seasons, suggesting a higher temperature than required for the safe handling of food. Humidity in all the kitchens was measured in the range of 50-60%. Half of the kitchens showed illumination intensities below 300 Lux in April. It was found that the sound pressure level of noise in almost all of the kitchens was higher than 85 dB (A). The highest levels of dropping airborne bacteria and fungi were noted in July. The numbers of airborne bacteria were higher than those of fungi. The levels of dropping airborne bacteria and fungi were affected by air temperature, relative humidity, season, and place. Conclusions: This study indicates that the kitchen environments were unqualified to supply safe food. The hygiene level of the kitchens should be improved.

The exposure level and distribution characteristics of airborne bacteria and fungi were assessed in the workers' activity areas (station office, bedroom, ticket office and driver's seat) and passengers' activity areas (station precinct, inside the passenger carriage, and platform) of the Seoul metropolitan subway. Among investigated areas, the levels of airborne bacteria and fungi in the workers' bedroom and station precincts were relatively high. No significant difference was found in the concentration of airborne bacteria and fungi between the underground and above ground activity areas of the subway. The genera identified in all subway activity areas with a 5% or greater detection rate were Staphylococcus, Micrococcus, Bacillus and Corynebacterium for airborne bacteria and Penicillium, Cladosporium, Chrysosporium, Aspergillus for airborne fungi. Staphylococcus and Micrococcus comprised over 50% of the total airborne bacteria and Penicillium and Cladosporium comprised over 60% of the total airborne fungi, thus these four genera are the predominant genera in the subway station.

Municipal workers handling household waste are potentially exposed to a variety of toxic and pathogenic substances, in particular airborne bacteria, gram-negative bacteria (GNB), and fungi. However, relatively little is known about the conditions under which exposure is facilitated. This study assessed levels of airborne bacteria, GNB, and fungi, and examined these in relation to the type of waste-handling activity (collection, transfer, transport, and sorting at the waste preprocessing plant), as well as a variety of other environmental and occupational factors. Airborne microorganisms were sampled using an Andersen single-stage sampler equipped with agar plates containing the appropriate nutritional medium and then cultured to determine airborne levels. Samples were taken during collection, transfer, transport, and sorting of household waste. Multiple regression analysis was used to identify environmental and occupational factors that significantly affect airborne microorganism levels during waste-handling activities. The "type of waste-handling activity" was the only factor that significantly affected airborne levels of bacteria and GNB, accounting for 38% (P = 0.029) and 50% (P = 0.0002) of the variation observed in bacteria and GNB levels, respectively. In terms of fungi, the type of waste-handling activity (R2 = 0.76) and whether collection had also occurred on the day prior to sampling (P < 0.0001, R2 = 0.78) explained most of the observed variation. Given that the type of waste-handling activity was significantly correlated with levels of bacteria, GNB, and fungi, we suggest that various engineering, administrative, and regulatory measures should be considered to reduce the occupational exposure to airborne microorganisms in the waste-handling industry.

Distribution characteristics of airborne bacteria and fungi in the feedstuff-manufacturing factories

Objectives: An objective of this study is to apply a thermal image camera which shows various color according to temperature of indoor surface for estimating concentration of airborne fungi. Materials and Methods: While wall temperature were monitored by applying the thermal image camera, airborne bacteria as well as air temperature and relative humidity have been measured in lecture room and toilet of university for seven months. Results: Based on the results obtained from this study, the ranges of temperature and airborne fungi concentration were <TEX>$20{\sim}24^{\circ}C$</TEX> and <TEX>$20{\sim}400cfu/m^3 $</TEX> for red image, <TEX>$17.5{\sim}20^{\circ}C$</TEX> and <TEX>$35{\sim}150cfu/m^3$</TEX> for orange image, <TEX>$15.5{\sim}17.5^{\circ}C$</TEX> and <TEX>$25{\sim}650cfu/m^3$</TEX> for sky-blue image, and <TEX>$13.5{\sim}15.5^{\circ}C$</TEX> and <TEX>$50{\sim}200cfu/m^3$</TEX> for blue image, respectively. The color of indoor surface taken shot by thermal image camera showed consistent trend with temperature of indoor surface. There is, however, little correlation between color of indoor surface and airborne fungi concentration(p>0.05). Among environmental factors, relative humidity in indoor air showed a significant relationship with airborne fungi concentration(p<0.05). Conclusions: The more measurement data for proving statistically an association between color of indoor surface and airborne fungi concentration should be provided to easily estimate indoor level of airborne fungi.

The aim of this study was to assess the microbiological quality of the air in tie-stall dairy cattle barns and to investigate some factors that influence it. We evaluated 52 dairy cattle barns with tie-stalls, during two years, in the winter period. The number of bacteria and fungi was slightly higher in the evening in comparison to the one in the morning and significantly higher in large barns (P<0.01), with bedding (P<0.01) and dirty (P<0.05). Both in the morning and in the evening positive correlations were observed between temperature and airborne bacteria, relative humidity and fungi. The prevalent species of bacteria were Staphylococcus epidermidis, Staphylococcus xilosus, Aerococcus viridans, Enterococcus faecalis, Enterobacter agglomerans andEscherichia coli. Among fungi, Aspergillus, Penicillium and yeasts predominated. This study’s results showed that the number of bacteria and fungi is variable and high in many cases in the indoors air of dairy cattle tie-stall barns, with the predominance of gram positive bacteria. Many of the identified bacterial and fungal species have pathogenic potential, posing risks for the health of animals and humans. Based on the obtained results, we consider the improvement of barn hygiene to be the most practical recommendation for decreasing concentrations of bacteria. Key words: Airborne bacteria, airborne fungi, indoor air quality, barn hygiene.

We aimed to analyze airborne microorganisms and assess air quality, temperature, and relative humidity at “J” Market, an arcade-type traditional market in Anseong (South Korea). Measurements were taken 16 times, twice per quarter (January, April, July, and October), at both the entrance and intersection of the market in 2020. The concentrations of airborne bacteria and fungi at the entrance and intersection were highest in October and lowest in April; however, they were below the recommended indoor levels (airborne bacteria: <800 CFU/m3, airborne fungi: <500 CFU/m3) in January (second measurement) and April (first and second measurements). The concentrations of microbes during the first measurement in January and both measurements in July and October exceeded the allowed limits. The concentration of microorganisms exceeded the acceptable levels at relative humidity ≥60%. At all time points, except during the eighth survey, when the microorganisms were too numerous to count, microbial concentrations were higher at the intersection than at the entrance. It was confirmed that the microorganisms detected in this experiment were 26 species of bacteria and 21 species of fungi. Three of the four species of bacteria and fungi detected in more than 50% of the 16 experimental results were pathogenic. Our findings suggest that air purification systems must be installed in the market to improve sanitary conditions.

Wholesale traditional markets (WTMs) have established the most comprehensive and advanced auction systems for fresh seafood, meat, and fruits. Understanding the levels of bioaerosols of different sizes in WTMs can help to develop strategies to reduce the spread of infectious diseases. This study was aimed at analyzing and comparing the size distributions of culturable airborne bacteria (AB) and airborne fungi (AF) in a typical wholesale traditional fish market (WTFM). The AB and AF concentrations in the WTFM were relatively both high during and after the operation. The average AB concentration significantly increased from 4.73 × 10 3 during operation to 8.58 × 10 3 CFU/m 3 after operation. The highest concentration of AB was observed at the fourth stage (2.1–3.3 μ m), accounting for 26.22% and 28.15% of the total AB measured during and after operation, respectively. The average AF concentration remained steady from 2.77 × 10 3 during operation to 2.53 × 10 3 CFU/m 3 after operation. The fourth stage also showed the highest AF concentration postoperation, comprising 35.47% of the total AF measured. Particles in this size range can be easily inhaled and deposited in the bronchial tubes, posing significant health risks. This study identified four and two types of possible pathogenicity in dominant AB and dominant AF, respectively. Commonly pathogenic Flavobacterium spp. frequently found in seafood and the highly pathogenic AF species Aspergillus tamarii and Aspergillus ochraceus were also detected. These pathogens and ultrafine biological aerosols (&lt; 1 μ m) can induce respiratory conditions such as aspergillosis. Based on these findings, the WTFM management should implement targeted interventions to reduce the concentration of harmful particles.

Inactivation of airborne microbial contaminants by a heat-pump-driven liquid-desiccant air-conditioning system

Airborne bacteria and fungi in hospital environments are of great concern due to their potential role as a source of nosocomial infections. The aim of this study was to evaluate concentration and diversity of airborne bacteria and fungi in relation to particle mass concentration in sensitive wards of a pediatric hospital. The study was performed in the cardiac care unit (CCU), the neonatal intensive care unit (NICU), the cancer blood ward (BW), the ENT (ear, nose, throat) operation room (OT1) and the eye operation room (OT2). The air samples were collected by impaction using the single-stage Andersen sampler. The flow rate and sampling time of the pump were adjusted to 28.3 l/min for 5 min. The mean concentration of indoor airborne fungi and bacteria ranged from 0–63 to 19–356 CFU/m3, respectively. OT2 and CCU wards were the most contaminated wards for airborne bacteria and fungi, respectively (243 ± 77 vs. 30 ± 7 CFU/m3). The airborne Gram-positive cocci (Staphylococcus and Micrococcus) were the most detected bacterial genera (75%) in all indoor air samples, and the most prevalent genera in indoor environment were Cladosporium spp. (19%) followed by Penicillium spp. (16%), Aspergillus spp. (16%) and Paecilomyces spp. (10%). Results showed that the outdoor airborne bacteria and PM concentration at different sizes were significantly higher than indoors, suggesting that the indoor airborne particle may have originated from the outdoor air. There were significant positive relationships between indoor airborne fungi concentrations with indoor PM2.5 and PM10.

Background: Poor indoor air quality constitutes a significant health problem in schools, mostly in the laboratory sections due to a high number of students per laboratory vis-a-vis space confinement, insufficient outside air supply, poor construction and maintenance of laboratory buildings. Aim: This study was carried out to assess the air quality and identify airborne bacteria and fungi in selected sections of Obong University Laboratory. Materials and Methods: Institutional based study employing passive air sampling, settle plate or gravitational sampling method to collect airborne bacteria and fungi was conducted in 3 selected laboratory sections of the University. Culture, isolation, colony count/air quality assessment and identification of airborne bacteria and fungi were done using standard methods. Results: The mean bacterial load was 111.75 CFU/m3 in the morning and 125.25 CFU/m3 in the afternoon. The highest and lowest bacterial loads were recorded at the Laboratory Animal Room (LAR) to be 165 CFU/m3 and 201 CFU/m3 in the morning and afternoon, respectively. The total fungal load was 100 CFU/m3 in the morning and 170 CFU/m3 in the afternoon with the mean estimate of 25 CFU/m3 in the morning and 42.5 CFU/m3 in the afternoon. The highest fungal load was equally estimated in the LAR at a percentage rate of 55% and 54.12% in the morning and afternoon, respectively. The results of the indoor air quality assessment of the different laboratory sections revealed a very low (&lt;50 CFU/m3) to low (50-100 CFU/m3) degree of both fungal and bacterial air pollution within the sampling time. A total of 3 bacterial and 5 fungal species were isolated as follows: Staphylococcus aureus 16(61.5%), coagulase negative Staphylococcus species (CoNS) 7 (27%) and Bacillus species 3 (11.5%); Aspergillus flavus 7 (25%), Aspergillus niger 8 (28.5%), Penicillium chrysogenum 4 (14.3%), Rhizopus spp. 5 (17.9%) and Fusarium spp. 4 (14.3%). The levels of indoor airborne bacteria and fungi as revealed in this study were found to be within the acceptable and permissible limits of microbial load ≤500 CFU/m3. Conclusion: Attention should be given to control those human, animal and environmental factors which favour the proliferation of bacteria and fungi in the indoor environment of school laboratories to safeguard the health of students, lecturers and laboratory personnel in the University. Keywords: Microbial Quality, Indoor Air, Laboratory, Colony, Pollution