Airborne Bacterial Counts Research Articles

Dust and Bacterial Air Contamination in a Broiler House in Summer and Winter

This study aimed to investigate dust and bacterial air contamination in a broiler house during different seasons. The study was carried out in commercial housing conditions during five weeks of the rearing cycle in summer and winter. The total dust concentration ranged from 1.90 to 4.50 mg/m3 in summer and from 2.80 to 5.10 mg/m3 in winter. The total bacterial count ranged from 2.85 × 104 to 1.03 × 105 CFU/m3 in summer and from 2.12 × 104 to 2.28 × 105 CFU/m3 in winter. The study results showed the dust concentration to be increased in winter as compared to summer, yielding a significant correlation (r = 0.602, p < 0.05) with a significantly higher airborne bacterial count in winter (p < 0.001). Furthermore, dust concentration showed significant correlations (p < 0.05) with air temperature (r = −0.418), relative humidity (r = 0.673), and broiler activity (r = 0.709), while bacterial count yielded significant correlations (p < 0.05) with air temperature (r = −0.756), relative humidity (r = 0.831), and airflow rate (r = 0.511). The results obtained in the study can prove useful in the field. Seasonal variability in dust and bacterial air contamination should be considered in the development of guidelines or standards of air quality in broiler housing and evaluation of the effectiveness of remedial strategies.

Study of The Feasibility of Minimarkets in Pontianak Cities Based on the Microbiological Quality of Air In Relation to the Physical Condition of the Room

Indoor air quality affects human health and productivity. The presence of microorganisms in indoor air is influenced by physical parameters of the space, activities within the space, building factors, ventilation systems, and human maintenance and care. This study aims to assess air quality and analyze the difference in the number of bacteria between minimarkets and the relationship test with their influencing factors. The study used a cross sectional method with 4 minimarket samples, 2 AC and 2 non-AC. Airborne bacterial colony counts were measured using a passive method with blood agar media, a contact time of 15 minutes, and 3 days of repetition. The average value of airborne bacterial colony counts in non-air-conditioned minimarkets (294.3 CFU/) was lower than in air-conditioned minimarkets (531.8 CFU/). The Rank Spearman correlation test results indicated that there was no significant relationship between airborne bacterial colony counts and temperature (p=0.498), humidity (p=0.089), light intensity (p=0.948), and visitor count (p=0.481). All studied minimarkets met the microbiological air quality, population density, and air circulation standards, but not all met the standards for room temperature, humidity, and light intensity based on the quality standards of the Indonesian Ministry of Health Number 1405/MENKES/SK/XI/2002.

Bacteriological assessments of indoor air in the staff quarters of a tertiary institution in Benin City, Nigeria

Indoor air contains large number of airborne microorganisms such as bacteria and fungi and their estimation is important for use as index of cleanliness for any particular environment and to determine the relation they bear on human health. This study was aimed at determining the bacteriological air quality of the living rooms in some selected Staff Quarters in University of Benin and University of Benin Teaching Hospital. The airborne bacterial loads of indoor air in the living rooms of Twelve (12) Staff Quarters in University of Benin and University of Benin Teaching Hospital both in Benin City were determined using the Settle Plate methods. The houses were categorized as Apartment 1 which represents University of Benin Junior Staff Quarters (JSQ), Apartment 2 which represents University of Benin Teaching Hospital Quarters, and Apartment 3 which represents University of Benin Senior Staff Quarters (SSQ). The living rooms were sampled twice a month between April, 2017 and September, 2017. The airborne samples were studied using standard microbiological methods and Polymerase Chain Reaction and 16S rRNA techniques were used for the gene sequencing. The antibiotic susceptibility pattern and plasmid profile of the characterized airborne bacterial isolates were evaluated using spread plate and agarose gel electrophoresis methods. The temperature and relative humidity of the indoor air environment in the sampled areas in the living rooms were determined using the thermometer and hygrometer respectively. The mean indoor temperature and relative humidity for Apartments 1, 2 and 3 ranged from 26.10 ± 1.190C to 31.20 ± 0.870C and 81 ± 2.70% to 87 ± 1.89% respectively. The mean indoor airborne bacterial counts in Apartment 1 and Apartment 3 ranged between 1.00 x 103 ± 0cfu/m3 to 4.42 x 103 ± 1.42cfu/m3 and 1.09 x 103 ± 0.09cfu/m3 to 5.17 x 103 ± 3.17cfu/m3 respectively. In Apartment 2, the counts ranged from 1.00 x 103 ± 0.00cfu/m3 to 6.99 x 103 ± 4.69cfu/m3. The difference in the airborne bacterial counts obtained in the morning and afternoon period of study in Apartment 1 was statistically significant (P<0.05) while Apartments 2 and 3 showed no significant differences respectively (P>0.05). Ten airborne bacterial isolates were characterized, further characterization by molecular techniques, confirmed them to be identified as Staphylococcus aureus strain S33 R, Bacillus subtilis subsp. strain 168, Oceanobacillus manasiensis strain YD3-56, Streptomyces vietnamensis strain GIM4.0001, Actinosynnema pretiosum strain C-15003, Micrococcus caseolyticus strain 235, Ornithinibacillus composti strain GSS05 and Bacillus ectoiniformans strain NE-14. General and personal hygienic practices are important for healthy living, and living rooms used for close contact interactions and good ventilation.

Assessment of Indoor Air Quality of Four Primary Health Care Centers in Qatar.

Airborne bacteria pose a potential risk to human health upon inhalation in the indoor environments of health care facilities. Airborne bacteria may originate from various sources, including patients, workers, and daily visitors. Hence, this study investigates the quantity, size, and identification of airborne bacteria indoors and outdoors of four Primary Health Care Centers (PHCC) in Doha, Qatar. Air samples were collected from the lobby, triage room, and outside environment of the centers, including, Qatar University (QU-HC), Al-Rayyan (AR-HC), Umm-Ghuwailina (UG-HC), and Old Airport (OA-HC) between August 2020 and March 2021, throughout both the hot and the cold seasons. Samples were collected using an Anderson six-stage cascade impactor. The mean of the total colony-forming units was calculated per cubic meter of air (CFU/m3). QU-HC had the lowest mean of total bacterial count compared with other centers in the indoor and outdoor areas with 100.4 and 99.6 CFU/m3, respectively. In contrast, AR-HC had the highest level, with 459 CFU/m3 indoors, while OA-HC recorded the highest bacterial concentration of the outdoor areas with a total mean 377 CFU/m3. In addition, 16S rRNA sequencing was performed for genera identification. Staphylococcus, Acinetobacter, Bacillus, and Pseudomonas were the four most frequently identified bacterial genera in this study. The abundance of airborne bacteria in the four health centers was higher in the cold season. About 46% of the total airborne bacterial count for three PHCC centers exceeded 300 CFU/m3, making them uncompliant with the World Health Organization’s (WHO) recommendation for indoor settings. Consequently, an IAQ standards should be shaped to establish a baseline for measuring air pollution in Qatar. Additionally, it is crucial to understand seasonal fluctuations better so that hospitals can avoid rising and spreading infection peaks.

Microbiological contamination of indoor and outdoor environments in a desert climate

Microbiological air contamination in the desert environment is becoming an essential subject for the health of office building occupants and public health. In this study, the concentrations and compositions of airborne microorganisms (bacteria and fungi) were assessed in indoor and outdoor environments using a multistory building complex in Kuwait as a case study. Airborne microorganism samples were collected from 12 sites within the building complex containing nineteen stories over four seasons. Culturable airborne bacteria and fungi were impacted on selected media to determine their concentrations and compositions with a Biolog Omnilog GEN III system and Biolog MicroStation. The indoor mean airborne bacterial count concentrations ranged from 35 to 18,463 CFU/m3, concentrations that are higher than 2,000 CFU/m3, demonstrating high–very high contamination levels in all seasons. Fungal contamination was high in winter and summer, with detected concentrations > 2,000 CFU/m3. Indoor-to-outdoor (I/O) ratios showed that airborne microbial contamination inside building floors originated from indoor air contamination. All the building floors showed bacterial and fungal concentrations ranging from less than 2,000 to more than 2,000 CFU/m3, indicative of a high to very high air contamination level. Statistical analysis showed no correlation between bacterial and fungal concentrations, demonstrating that they originated from unrelated sources. In the indoor building air, the most prevalent bacterial isolate was Bacillus pseudomycoides/cereus, whereas the most dominant fungal isolate was Aspergillus spp. The low count for indoor air bacterial species suggested no particular health risk for the occupants. In contrast, the high count of indoor air fungal species in the winter samples and the presence of potentially allergenic genera detected may suggest possible health risks for the occupants. The results obtained are the basis for the recommendation that the maintenance activities of the HVAC system and the periodical cleaning operation program be revised and preplanned as protective measures.

BACTERIOLOGICAL QUALITY OF INDOOR AIR ENVIRONMENT IN PRIVATE AND GOVERNMENT OWNED ABATTOIRS IN BENIN CITY, NIGERIA

The airborne bacterial load of two abattoirs, private and government abattoirs in Benin City was studied using the settled plate methods. The air samples were collected during and after slaughtering operations in the two abattoirs monthly for a period of six months, between October, 2011 and March, 2012. The temperature and relative humidity of the two abattoirs were determined during each sampling time. The plasmid DNA profile of the isolated airborne bacterial was determined using the alkaline lysis method. The temperature reading ranged between 25 0C and 34 0C in the private abattoir and between 26 0C and 35 0C in the government abattoir. The relative humidity reading ranged between 46 % and 67 % in the private abattoir and between 34 % and 65 % in the government abattoir. The mean airborne bacterial counts on nutrient agar and blood agar in the private abattoir ranged from 17.55 x 102 ± 3.77cfu/m3 to 108.0 x 102 ± 10.35cfu/m3 during slaughtering and 12.84 x 102 ± 1.51 cfu/m3 to 49.71 x 102 ± 3.61 cfu/m3 after slaughtering. The mean airborne bacterial counts on nutrient agar and blood agar in the government abattoir ranged from 24.63 x 102 ± 3.75cfu/m3 to 58.30 x 102 ± 6.49 cfu/m3 during slaughtering and 15.62 x 102 ± 2.97 cfu/m3 to 114.13 x 102 ± 19.75 cfu/m3 after slaughtering. The mean airborne bacterial counts grown on eosine methylene blue agar in the private abattoir ranged from 1.057 x 102 ± 2.58 cfu/m3 to 22.54 x 102 ± 5.70 cfu/m3 during slaughtering and 2.44 x 102 ± 1.41 cfu/m3 to 9.87 x 102 ± 1.41 cfu/m3 after slaughtering. The mean airborne bacterial counts grown on eosine methylene blue agar in the government abattoir ranged from 1.05 x 102 ± 5.62 cfu/m3 to 24.40 x 102 ± 4.66 cfu/m3 during slaughtering and 1.06 x 102 ± 4.24 cfu/m3 to 21.08 x 102 ± 3.94 cfu/m3 after slaughtering. The result revealed the isolation of seven airborne bacterial isolates which include Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus sp., Bacillus sp., Pseudomonas sp., Klebsiella sp., and Escherichia coli. The frequency of occurrence and distribution of the airborne bacterial isolates revealed Staphylococcus. aureus (48.75%) and Bacillus sp. (28.68%) as the most frequently isolated airborne bacterial isolates in the private abattoir, while S. aureus (31.95%) and Bacillus sp. (41.93%) were also recorded as the most frequently isolated airborne bacterial isolates in the government abattoir. The statistical analysis showed no significant difference between the airborne bacterial counts recorded during and after slaughtering in the two abattoirs. The result of the plasmid determination revealed that the airborne bacterial isolates harboured plasmid sizes which ranged between 1.5 kbs to 25.2 kbs. The result revealed that, the quality of air in the abattoirs was greatly influenced by the population and type of airborne bacterial isolates, which play significant role in the level of hygiene in meat processing plants. The type and population of airborne bacterial isolates in the indoor air of the two abattoirs are of great concern, which serves as index of quality of air in the environment. Hence, great measures are taken to checkmate this menace caused by the poor hygienic systems in the abattoirs

Performance of Calcium Chloride and Silica Gel as Solid Desiccant Dehumidifiers for Indoor Air Quality

Desiccant materials are recently discovered as a viable alternative in dehumidification technology due to their naturally hygroscopic qualities and minimal energy requirement. This paper discusses the performance of four brand samples of selected desiccants used for dehumidification. In this study, dehumidification ability and indoor air quality (IAQ) tests were carried out. The dehumidification ability test was conducted in a controlled environmental chamber at a temperature of 25°C, relative humidity of 70%, and air velocity of 2 m/s for 45-minute session. Meanwhile, the IAQ test was carried out in a naturally ventilated test room, and six IAQ parameters (relative humidity, air velocity, air temperature, particulate matter (PM10), airborne bacteria and carbon dioxide (CO2) were studied. The IAQ test was performed for five different conditions: control, application of brand samples A, B, C and D in the test room. From this study, it was found, brand A (0.6823 g/kg) and brand B (0.6849 g/kg) had a relatively good dehumidification ability during the 45-minute dehumidification ability test compared to brand C (0.3108 g/kg) and brand D (0.3982 g/kg). The IAQ test revealed that brand A had the biggest variation in indoor-outdoor relative humidity of 13.12%, while brand D had the smallest difference of 11.83%. Brand B had the highest average PM10 concentration of 0.037 μg/m3. The airborne bacterial count for all conditions had no statistical significance, indicating the application of desiccants were not effective in reducing airborne bacteria. From this study, it can be concluded that calcium chloride (brand A and B) samples performed better than silica gel (brand C and D) samples in terms of dehumidification ability and IAQ profile.

Bacteria and Their Antibiotic Resistance Profiles in Ambient Air in Accra, Ghana, February 2020: A Cross-Sectional Study.

Inappropriate use of antibiotics has led to the presence of antibiotic-resistant bacteria in ambient air. There is no published information about the presence and resistance profiles of bacteria in ambient air in Ghana. We evaluated the presence and antibiotic resistance profiles of selected bacterial, environmental and meteorological characteristics and airborne bacterial counts in 12 active air quality monitoring sites (seven roadside, two industrial and three residential) in Accra in February 2020. Roadside sites had the highest median temperature, relative humidity, wind speed and PM10 concentrations, and median airborne bacterial counts in roadside sites (115,000 CFU/m3) were higher compared with industrial (35,150 CFU/m3) and residential sites (1210 CFU/m3). Bacillus species were isolated in all samples and none were antibiotic resistant. There were, however, Pseudomonas aeruginosa, Escherichia coli, Pseudomonas species, non-hemolytic Streptococci, Coliforms and Staphylococci species, of which six (50%) showed mono-resistance or multidrug resistance to four antibiotics (penicillin, ampicillin, ciprofloxacin and ceftriaxone). There was a positive correlation between PM10 concentrations and airborne bacterial counts (rs = 0.72), but no correlations were found between PM10 concentrations and the pathogenic bacteria nor their antibiotic resistance. We call for the expansion of surveillance of ambient air to other cities of Ghana to obtain nationally representative information.

Decreasing Foot Traffic in the Orthopedic Operating Room: A Narrative Review of the Literature.

Surgical site infections (SSIs) are implicated in poor outcomes in orthopedic surgical patients. Decreasing foot traffic in orthopedic surgical suites is correlated with the reduction of SSI risk. This review aims to understand the background and significance of the problem, isolate factors contributing to the movement in and out of operating rooms, and identify interventions that decrease traffic in procedure areas. A comprehensive search was completed using the databases Embase and Medline (Ovid). A PICOT question was used in the literature search to evaluate the efficacy of a standardized guideline on operating room door opening frequency. The Mixed Methods Appraisal Tool was used to appraise the literature critically, and conventional content analysis methodology identified themes within the publications. The literature search yielded 18 articles providing 3 different themes of evidence: airborne bacterial counts and their association with foot traffic; specific personnel, namely, nurses demonstrating the greatest amount of foot traffic; and interventions aimed at minimizing this foot traffic. Implementing multiple evidence-based interventions can decrease foot traffic and reduce the risk of SSIs in orthopedic patients. Further studies are needed to directly link airborne bacterial counts to SSIs, increase the level of evidence, and isolate interventions.

Assessment of indoor air bacterial load and antibiotic susceptibility profile of bacteria from some hospitals in Dutse, Jigawa State

Indoor air microbial communities play significant roles on the increase in hospitals acquired infections globally. In view of the importance of indoor air bacterial quality in the transmission of nosocomial infections, a study was conducted to assess the air bacterial load and antibiotic susceptibility profile of bacteria from some hospitals in Dutse, Jigawa State. A total of 114 air samples were collected and analyzed using standard procedures from wards and units of Rasheed Shekoni Teaching Hospital Dutse, General Hospital Dutse and Primary Health Care Centre Shuwarin. Settling platetechnique was employed and sampling was done twice daily (Morning and Afternoon). Aerobic mesophilic bacterial counts were conducted. Isolates were identified according to standard methods. The Medical Surgical Ward (MSW) revealed the highest airborne bacterial count (2.770x103 CFU/m3). General Hospital Dutse was found to have a higher indoor bacterial load than Rasheed Shekoni Teaching Hospital and Primary Healthcare Centre Shuwarin. Airborne Gram positive cocci were the most frequently detected (100%) in all the indoor environments. Staphylococcus aureus, Klebsiella pneumoniae, Proteus mirabilis and Escherichia coli were the bacterial species identified in the study. It was observed that the bacterial isolates were more susceptible to gentimicin. The findings revealed the presence of five (5) methicillin resistant staphylococcus aureus isolates (MRSA) 60% in Male Medical Ward (MMW), 20% in Female Medical Ward (FMW), and 20% in Post-natal Ward (PNW). In conclusion, 84.2% of the hospitals’ units were having aerobic mesophilic bacterial counts within the acceptable limits. It is recommended that disinfection of male, female and post-natal wards should be intensified.

Efficacy of infection control pathway in reducing postoperative infections in patients undergoing neurosurgery.

The environment of the operating room (OR) is closely related to the postoperative complications of patients, and it is necessary to study, to what extent, the stringent management of the OR can reduce postoperative complications. 426 patients who underwent surgery between January 2016 and December 2017 were selected from two class-100 laminar flow ORs of equivalent area, and were divided into an experimental group and a control group. The experimental group had significantly lower total air-borne bacterial count in the OR than the control group 10 minutes before surgery (6.21 ± 4.14 vs. 11.58 ± 5.36 CFU/cm3), 10 minutes (15.67 ± 6.21 vs. 20.83 ± 5.78 CFU/cm3), 30 minutes (27.34 ± 8.18 vs. 39.56 ± 7.86 CFU/cm3) and 60 minutes (43.62 ± 7.66 vs. 51.63 ± 8.43 CFU/cm3) into surgery, and at the end of surgery (57.34 ± 7.67 vs. 69.33 ± 9.41 CFU/cm3) (all p < 0.05). The incidence rates of increased body temperature and leukocyte count 3 days post-surgery, and the duration of antibiotic therapy and hospital stay were significantly reduced in the experimental group compared to the control group (all p < 0.05). Furthermore, the total number of pathogens in the incision at 2 hours into surgery was also significantly lower in the experimental group than in the control group (p < 0.05). Stringent application of the infection control pathway is an efficacious measure for improving the air cleanliness of the neurosurgery OR, decreasing the incidence rates of postoperative complications and infection, as well as controlling pathogen transmission.

CORRELATION BETWEEN CLASSROOM POPULATION, VENTILATION BACTERIAL LOADS AND THIER ANTIMICROBIAL PATTERNS IN SCHOOLS WITHIN IKOT EKPENE, NIGERIA

Indoor air of classroom in eight schools (4 nursery; NS1, NS2, NS3 and NS4, and 4 secondaries; SS1, SS2, SS3 and SS4) within Ikot Ekpene, Akwa Ibom State, Nigeria, were analyzed at ambient and populated sampling conditions using natural sedimentation on nutrient agar medium. The results revealed varying ventilation patterns in each of the classrooms, and the following airborne bacterial counts; NS1 (16.6 cfu/m3), NS2 (13.3 cfu/m3), NS3 (23.3 cfu/m3), NS4 (33.3 cfu/m3), SS1 (6.6 cfu/m3), SS2 (6.6 cfu/m3), SS3(28.3 cfu/m3) and SS4 (15 cfu/m3) at ambient sampling and 40 cfu/m3, 41.6 cfu/m3, 58.3 cfu/m3, 68.3 cfu/m3, 6.6 cfu/m3, 31.6 cfu/m3, 56.6 cfu/m3 and 25 cfu/m3 respectively at populated sampling. Bacterial isolates identified were Lactobacillus, Staphylococcus, Bacillus, Rothia, Kurthia, Corynebacterium, Pseudomonas, Brevibacterium, and Flavobacterium. Statistical analysis of the results revealed negative relationships between class area and aerobic plate counts (p&gt;0.05), class population and aerobic plate count (p&gt;0.805), and significant increase in aerobic plate counts at populated conditions over that at ambient conditions (p&lt;0.05). The results therefore point to the dimensions of classrooms, ventilation and population of the classrooms as important factors in determining the bacterial air quality, and invariably affecting the health condition of students.

Distribution and Influencing Factors of Airborne Bacteria in Public Facilities Used by Pollution-Sensitive Population: A Meta-Analysis.

The aim of this study was to support management of airborne bacteria in facilities used by pollution-sensitive individuals (in daycares, medical facilities, elder care facilities, and postnatal care centers). A field survey was conducted on 11 facilities from October 2017 to April 2018. Elder care facilities in industrial, urban, and forested areas were excluded. Two indoor, and one outdoor, measuring points were selected per facility. These points were located in areas most often used by the residents. Measurements were taken at random time-points before February 2018 and at specific times in the morning and afternoon thereafter. The relationships among bacterial counts, carbon dioxide concentrations, dust levels, temperature, relative humidity, and ventilation were examined. The pooled average bacterial counts at the daycares, medical facilities, elder care facilities, and postnatal care centers were 540.25 CFU m−3, 245.49 CFU m−3, 149.63 CFU m−3, and 169.65 CFU m−3, respectively. Considering the upper 95% confidence interval, the bacterial counts in many daycares may in fact be >800 CFU m−3, which is the threshold set by the Korean Ministry of the Environment. The pooled average indoor: outdoor bacterial count ratio was 1.13. Indoor airborne bacterial counts were influenced mainly by their sources. This study found no significant correlations among indoor temperature, relative humidity, carbon dioxide concentration, dust levels, and airborne bacterial counts, unlike previous studies. Airborne bacteria management at daycares should be a top priority. The sources of airborne bacteria must also be identified, and a management plan must be developed to control them.

Physical Condition and Air-Borne Bacterial Count in Air-Conditioned and Non-Air-Conditioned Work Rooms in Faculty of Tarbiyah and Teacher Training Science, IAIN Samarinda

Physical Condition and Air-Borne Bacterial Count in Air-Conditioned and Non-Air-Conditioned Work Rooms in Faculty of Tarbiyah and Teacher Training Science, IAIN Samarinda

0106 Evaluating preweaned calf housing and its impact on calf respiratory parameters on New York dairy farms

The objectives of this project were to (1) evaluate environmental and air quality parameters across different types of calf housing facilities; (2) evaluate rates of respiratory illness in preweaned calves; and (3) determine the impact of environmental factors, air quality, and housing type on calf health. This was an observational study in which calf facilities were evaluated on a single visit during June 2015. Housing included hutches (n = 9), individual pens in a barn (n = 11), and group pens in a barn (n = 9). Facility and calf pen evaluations included wind speed, temperature, relative humidity, heat stress index, bedding type, bedding composite sample for bacteria counts, nesting score of calf pens, calf health scoring, and airborne bacteria. Data were analyzed using SAS 9.3 to determine the impact of housing type, environmental, and air quality variables on calf respiratory score. A total of 29 facilities and 437 preweaned calves were evaluated. Calf facility temperature averaged 24.2°C (range 15.5 to 30.6°C) with a relative humidity of 21.5% (range 10 to 78%) and a heat index of 21.5°C (range 6 to 30.9°C). Temperature and airborne bacterial counts were greater in hutches as compared with individual and group pens (P < 0.01). Humidity was similar for hutches and group pens, but greater than individual pens. Gram negative airborne bacterial counts were lowest in individual pens. No difference in heat index was observed across housing type. Mean calf respiratory scores was 2.5 (range of 0 to 9) on a 12 point scale; 13.33% of calves evaluated scored greater than 5, indicating a respiratory challenge. Prevalence of respiratory illness in preweaned calves ranged from 0 to 50% of calves on a per farm basis (mean = 11.05% of calves/farm), with 44.82% of farms having no respiratory illness and 10.32% of farms having 30 to 50% of evaluated calves exhibiting signs of respiratory illness. There was a negative correlation between respiratory score and pen temperature (R2 = 0.90). There was no influence on respiratory score by housing system, bedding type, ventilation system, relative humidity, airflow, or airborne bacterial counts. Data collected from this study suggests that respiratory illness continues to be a challenge, even when weather is temperate. Additional research is needed to evaluate rates of respiratory illness during cold stress and transitional weather, as well as to evaluate management factors that increase the risk of infection.

Air and hygiene quality in crowded housing environments – a case study of subdivided units in Hong Kong

The purpose of this study is to explore the environmental quality and hygiene in crowded living environments, subdivided units in Hong Kong. Subdivided units are an emerging form of housing environment for the urban poor. It is hypothesised that subdivided unit residents have a higher risk of exposure to poor hygiene conditions but no measurement has ever been taken to test this hypothesis. Twenty questionnaires and environmental assessments were conducted. Dominant bacterial species were identified as Micrococcus luteus and Staphylococcus spp., and the microbial counts were correlated with building, occupants and environmental parameters. Driven by the high bacterial counts and poor hygiene observation, eight subdivided units were selected for endotoxin, glucan and allergen analysis in bed and floor dust. Total airborne bacterial counts and endotoxin and glucan in dust were found at very high levels in some subdivided units, while unexpectedly, the allergen and mould levels were low. In crowded environments the skin bacteria may mislead the environmental and atmospheric bacterial contamination. Outdoor microbial pollution and deteriorated building conditions can be the main source of indoor contamination. ‘Good’ or ‘Excellent’ class of bacterial counts satisfying the Indoor Air Quality Objective does not guarantee a low endotoxin and glucan level.

Determination of dust and microorganism accumulation in different designs of AHU system in Shaanxi History Museum

Serial environmental measurements were conducted in the Shaanxi History Museum with two different air handling unit (AHU) designs to obtain a distribution of airborne and dust-borne microorganisms, and to determine the effects of occupant density, temperature and relative humidity (RH) on airborne or dust-borne microbial counts. Samples were collected from five segments of three AHU systems during 9:00–10:00 and 15:00–16:00. The results indicated that a high density of occupants caused a serious accumulation of airborne bacteria and fungi regardless of whether the system was a constant air volume (CAV) or variable air volume (VAV) system. In both of the aforementioned systems, the same downward trend in airborne bacterial counts was observed, where the highest counts were found at the return air segment, followed by the filter and supply air segments. Nevertheless, airborne fungal counts showed opposing trends in CAV and VAV systems. Our results also demonstrated that dust loading in the VAV system was in the range of 1.1–13.3 g/m2 which meets the Chinese standard, while dust-borne bacterial counts (4.6 × 104–36.9 × 104 CFU/gdust) and fungal counts (5.3 × 104–1129 × 104 CFU/gdust) far exceeded relevant threshold value. Furthermore, dust loading was more closely correlated with dust-borne bacteria levels than dust-borne fungi levels. In addition, airborne or dust-borne fungal counts were higher than the bacterial counts in the same sampling locations in the two systems. The predominant fungal genera that were consistently identified in different segments of both CAV and VAV systems were Penicillium, Aspergillus and Cladosporium. Moreover, RH exerted a greater influence on microbial growth than temperature.

Operating theatre ventilation systems and microbial air contamination in total joint replacement surgery: results of the GISIO-ISChIA study

Recent studies have shown a higher rate of surgical site infections in hip prosthesis implantation using unidirectional airflow ventilation compared with turbulent ventilation. However, these studies did not measure the air microbial quality of operating theatres (OTs), and assumed it to be compliant with the recommended standards for this ventilation technique. To evaluate airborne microbial contamination in OTs during hip and knee replacement surgery, and compare the findings with values recommended for joint replacement surgery. Air samplings were performed in 28 OTs supplied with unidirectional, turbulent and mixed airflow ventilation. Samples were collected using passive sampling to determine the index of microbial air contamination (IMA). Active sampling was also performed in some of the OTs. The average number of people in the OT and the number of door openings during the sampling period were recorded. In total, 1228 elective prosthesis procedures (60.1% hip and 39.9% knee) were included in this study. Of passive samplings performed during surgical activity in unidirectional airflow ventilation OTs (U-OTs) and mixed airflow OTs (M-OTs), 58.9% and 87.6% had IMA values >2, respectively. Of samplings performed during surgical activity in turbulent airflow OTs (T-OTs) and in turbulent airflow OTs with the surgical team wearing Steri-Shield Turbo Helmets (TH-OTs), 8.6% and 60% had IMA values ≤ 2, respectively. Positive correlation was found between IMA values and the number of people in the OT and the number of door openings (P < 0.001). In addition, correlation was found between active and passive sampling (P < 0.001). These findings challenge the belief that unidirectional systems always provide acceptable airborne bacterial counts.

Real-time measurements of airborne biologic particles using fluorescent particle counter to evaluate microbial contamination: Results of a comparative study in an operating theater

Airborne bacterial contamination poses a risk for surgical site infection, and routine surveillance of airborne bacteria is important. Traditional methods for detecting airborne bacteria are time consuming and strenuous. Measurement of biologic particle concentrations using a fluorescent particle counter is a novel method for evaluating air quality. The current study was to determine whether the number of biologic particles detected by the fluorescent particle counter can be used to indicate airborne bacterial counts in operating rooms. The study was performed in an operating theater at a university hospital in Hefei, China. The number of airborne biologic particles every minute was quantified using a fluorescent particle counter. Microbiologic air sampling was performed every 30minutes using an Andersen air sampler (Pusong Electronic Instruments, Changzhou, China). Correlations between the 2 different methods were analyzed by Pearson correlation coefficients. A significant correlation was observed between biologic particle and bacterial counts (Pearson correlation coefficient=0.76), and the counting results from 2 methods both increased substantially between operations, corresponding with human movements in the operating room. Fluorescent particle counters show potential as important tools for monitoring bacterial contamination in operating theatres.

A novel method of personnel cooling in an operating theatre environment

An optimized theatre environment, including personal temperature regulation, can help maintain concentration, extend work times and may improve surgical outcomes. However, devices, such as cooling vests, are bulky and may impair the surgeon's mobility. We describe the use of a low-cost, low-energy 'bladeless fan' as a personal cooling device. The safety profile of this device was investigated by testing air quality using 0.5- and 5-µm particle counts as well as airborne bacterial counts on an operating table simulating a wound in a thoracic operation in a busy theatre environment. Particle and bacterial counts were obtained with both an empty and full theatre, with and without the 'bladeless fan'. The use of the 'bladeless fan' within the operating theatre during the simulated operation led to a minor, not statistically significant, lowering of both the particle and bacterial counts. In conclusion, the 'bladeless fan' is a safe, effective, low-cost and low-energy consumption solution for personnel cooling in a theatre environment that maintains the clean room conditions of the operating theatre.