Distribution characteristics of airborne bacteria and fungi in the general hospitals of Korea

Transmission of human-pet antibiotic resistance via aerosols in pet hospitals of Changchun

In recent years, aerosols have been recognized as a prominent medium for the transmission of antibiotic-resistant bacteria and genes. Among these, particles with a particle size of 2 μm (PM2.5) can directly penetrate the alveoli. However, the presence of antibiotic-resistant genes in aerosols from pet hospitals and the potential risks posed by antibiotic-resistant bacteria in these aerosols to humans and animals need to be investigated. In this study, cefotaxime-resistant bacteria were collected from 5 representative pet hospitals in Changchun using a Six-Stage Andersen Cascade Impactor. The distribution of bacteria in each stage was analyzed, and bacteria from stage 5 and 6 were isolated and identified. Minimal inhibitory concentrations of isolates against 12 antimicrobials were determined using broth microdilution method. Quantitative Polymerase Chain Reaction was employed to detect resistance genes and mobile genetic elements that could facilitate resistance spread. The results indicated that ARBs were enriched in stage 5 (1.1-2.1 μm) and stage 3 (3.3-4.7 μm) of the sampler. A total of 159 isolates were collected from stage 5 and 6. Among these isolates, the genera Enterococcus spp. (51%), Staphylococcus spp. (19%), and Bacillus spp. (14%) were the most prevalent. The isolates exhibited the highest resistance to tetracycline and the lowest resistance to cefquinome. Furthermore, 56 (73%) isolates were multidrug-resistant. Quantitative PCR revealed the expression of 165 genes in these isolates, with mobile genetic elements showing the highest expression levels. In conclusion, PM2.5 from pet hospitals harbor a significant number of antibiotic-resistant bacteria and carry mobile genetic elements, posing a potential risk for alveolar infections and the dissemination of antibiotic resistance genes.

Review of bioaerosols from different sources and their health impacts

The emission of bioaerosols in the ambient atmosphere from different sources is a cause of concern for human health and the environment. Bioaerosols are a combination of biotic matter like microbes and pollens. The present review emphasizes the understanding of various sources of bioaerosols (industries, municipal solid waste, and medical facilities), their components, and their impact on human health. The study of bioaerosols is of great importance as large numbers of people are estimated to be exposed on the global scale. Bioaerosols exposure in different work environments results in health issues such as infectious diseases, allergies, toxic effects, and respiratory problems. Hence, extensive research is urged to establish an effective assessment of bioaerosols exposure in the workplace, risks involved, distribution, and validation. The present review is intended to explore the relationship between bioaerosols exposure to the atmosphere and its impacts on human health. Some of the preliminary findings, based on our analysis of bioaerosols arising from municipal solid waste at a landfill site and a waste transfer station in Hyderabad, India, are also discussed herein.

The Effects of Airflow on the Mechanosensitive Channels of Escherichia coli MG1655 and the Impact of Survival Mechanisms Triggered

Understanding how bacteria respond to ventilated environments is a crucial concept, especially when considering accurate airflow modeling and detection limits. To properly design facilities for aseptic conditions, we must minimize the parameters for pathogenic bacteria to thrive. Identifying how pathogenic bacteria continue to survive, particularly due to their multi-drug resistance characteristics, is necessary for designing sterile environments and minimizing pathogen exposure. A conserved characteristic among bacterial organisms is their ability to maintain intracellular homeostasis for survival and growth in hostile environments. Mechanosensitive (MS) channels are one of the characteristics that guide this phenomenon. Interestingly, during extreme stress, bacteria will forgo favorable homeostasis to execute fast-acting survival strategies. Physiological sensors, such as MS channels, that trigger this survival mechanism are not clearly understood, leaving a gap in how bacteria translate physical stress to an intracellular response. In this paper, we study the role of mechanosensitive ion channels that are potentially triggered by aerosolization. We hypothesize that change in antimicrobial uptake is affected by aerosolization stress. Bacteria regulate their defense mechanisms against antimicrobials, which leads to varying susceptibility. Based on this information we hypothesize that aerosolization stress affects the antimicrobial resistance defense mechanisms of Escherichia coli (E. coli). We analyzed the culturability of knockout E. coli strains with different numbers of mechanosensitive channels and compared antibiotic susceptibility under stressed and unstressed airflow conditions. As a result of this study, we can identify how the defensive mechanisms of resistant bacteria are triggered for their survival in built environments. By changing ventilation airflow velocity and observing the change in antibiotic responses, we show how pathogenic bacteria respond to ventilated environments via mechanosensitive ion channels.

Fungal Catastrophe of a Specimen Room: Just One Week is Enough to Eradicate Traces of Thousands of Animals

Indoor fungi obtain carbon sources from natural sources and even recalcitrant biodegradable materials, such as plastics and synthetic dye. Their vigorous activity may have negative consequences, such as structural damage to building materials or the destruction of precious cultural materials. The animal specimen room of the Seoul National University stocked 36,000 animal resources that had been well-maintained for over 80 years. Due to abandonment without the management of temperature and humidity during the rainy summer season, many stuffed animal specimens had been heavily colonized by fungi. To investigate the fungal species responsible for the destruction of the historical specimens, we isolated fungi from the stuffed animal specimens and identified them at the species level based on morphology and molecular analysis of the β-tubulin (BenA) gene. A total of 365 strains were isolated and identified as 26 species in Aspergillus (10 spp.), Penicillium (14 spp.), and Talaromyces (2 spp.). Penicillium brocae and Aspergillus sydowii were isolated from most sections of the animal specimens and have damaged the feathers and beaks of valuable specimens. Our findings indicate that within a week of mismanagement, it takes only a few fungal species to wipe out the decades of history of animal diversity. The important lesson here is to prevent this catastrophe from occurring again through a continued interest, not to put all previous efforts to waste.

Detection and characterization of bioaerosol emissions from wastewater treatment plants: Challenges and opportunities

Rapid population growth and urbanization process have led to increasing demand for wastewater treatment capacity resulting in a non-negligible increase of wastewater treatment plants (WWTPs) in several cities around the world. Bioaerosol emissions from WWTPs may pose adverse health risks to the sewage workers and nearby residents, which raises increasing public health concerns. However, there are still significant knowledge gaps on the interplay between process-based bioaerosol characteristics and exposures and the quantification of health risk which limit our ability to design effective risk assessment and management strategies. This review provides a critical overview of the existing knowledge of bioaerosol emissions from WWTPs including their nature, magnitude and size distribution, and highlights the shortcoming associated with existing sampling and analysis methods. The recent advancements made for rapid detection of bioaerosols are then discussed, especially the emerging real time detection methods to highlight the directions for future research needs to advance the knowledge on bioaerosol emissions from WWTPs.

Characteristics, non-carcinogenic risk assessment and prediction by HYSPLIT of bioaerosol released from Hospital and Municipal Sewage, China

Bioaerosol is a new type of pollutant, which is related to the spread of many diseases. In particular, the bioaerosol produced in the hospital sewage treatment process contains many pathogenic bacteria, which will impact patients and surrounding residents. In this study, the biochemical tank (BRT) of the hospital sewage treatment station (HSTS) and municipal wastewater treatment plant (MWTP) were used as sampling points. The results showed that the concentration of bacteria (1843 CFU/m³) in bioaerosol produced by BRT of HSTS was higher than that in the air at BRT of MWTP (1278 CFU/m³). The proportion of small-size bacteria (<3.3 µm) in the air of HSTS and MWTP was similar. However, the abundance of small-size pathogenic bacteria in HSTS was higher than that in MWTP, such as Acinetobacter and Arcobacter. The dominant bacteria in HSTS and MWTP were different under different particle sizes. The dominant bacterial genera of bioaerosol in HSTS under different particle sizes were similar (Acinetobacter, Arcobacter, Comamonas); There were significant differences in the dominant bacterial genera of bioaerosol in MWTP under different particle sizes. The dominant strains with particle sizes ranging from 0 ∼ 0.43 µm were Acinetobacter (23.22%). Kocuria (15.13%) accounted for a relatively high proportion in the aerosol of 0.43 µm ∼ 0.65 µm. The dominant strains with particle sizes of 0.65 µm ∼ 1.1 µm and 1.1 µm ∼ 2.1 µm were relatively single, and Exiguobacterium and Paenibacillus accounted for 51.51% and 60.15%, respectively. Source tracker showed that most of the pathogenic bacteria in bioaerosols came from sewage. One hour later, the concentration of particulate matter in the place 200 m away from BRT of HSTS (1 × 10^-10 mg/m³) was higher than that in MWTP (1 × 10^-11 mg/m³). The hazard quotient (HQ) of people around HSTS (HQ_male: 1.70 × 10^-1; HQ_female: 1.36 × 10^-1) was higher than that of MWTP (HQ_male: 1.18 × 10^-1; HQ_female: 9.40 × 10^-2). Pathogenic bacteria (Acinetobacter, Arcobacter) were detected in HSTS and MWTP and the BugBase phenotype prediction results showed potential pathogenicity. More attention should be paid to the protection of the people. It is suggested to strengthen the air sterilization treatment near HSTS according to the diffusion trajectory of bioaerosol, and the surrounding personnel should wear N95 and other protective masks.

Field Survey on Generation Patterns of Airborne Fungi in a Livestock Manure Composting Plant in South Korea

Airborne fungi emitted from livestock manure composting plants are one of the major harmful factors causing respiratory disease for workers and nearby residents. Their generation of emissions is relatively high compared to other workplaces. This study investigated the emission characteristics of airborne fungi generated in livestock manure composting plants and utilized them as basic data to prevent workers’ health. The livestock manure composting plants selected for the survey in this study were according to the fermentation mode, including screw type, rotary type and natural dry type. The field evaluation period was from September 2019 to August 2020 and was surveyed monthly. The equipment for collecting airborne fungi was a six-stage cascade impactor. An analysis of the quantification and qualification of airborne fungi was conducted through a culture method and identification technique, respectively. The mean levels of airborne fungi in livestock manure composting plants were 1143 (±106)CFU m−3 for screw type, 552 (±146)CFU m−3 for rotary type and 434 (±73)CFU m−3 for natural dry type, respectively. Based on the results obtained from this study, the livestock manure composting plant operated by screw type showed the highest concentration of airborne fungi, followed by the rotary type and natural dry type. The monthly concentration of airborne fungi was the highest in June and the lowest in February, regardless of the livestock manure composting plant type. The concentration range of airborne fungi corresponding to the respiratory particle diameter was 40 to 60% relative to the concentration of all airborne fungi. The correlation relationship between airborne fungi and environmental factors (temperature, relative humidity, particulate matter and odor) was not found to be significant in livestock manure composting plants. The predominant genera of airborne fungi identified were Aspergillus spp., Cladosporium spp. and Penicillium spp.

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.

Antibiotic resistance of airborne bacterial populations in a hospital environment

Bacteria in a hospital environment potentially cause hospital-acquired infections (HAIs), particularly in immunocompromised individuals. Treatments of HAIs with antibiotics, however, are ineffective due to the emergence of antibiotic-resistant bacteria (ARB). This study aims to identify airborne bacteria in a tertiary hospital in Malaysia and screen for their resistance to commonly used broad-spectrum antibiotics. Airborne bacteria were sampled using active sampling at the respiratory ward (RW), physician clinic (PC) and emergency department (ED). Physical parameters of the areas were recorded, following the Industry Code of Practice on Indoor Air Quality 2010 (ICOP IAQ 2010). Bacterial identification was based on morphological and biochemical tests. Antibiotic resistance screening was carried out using the Kirby-Bauer disk diffusion method. Results showed that the highest bacterial population was found in the highest density occupancy area, PC (1024 ± 54 CFU/m³), and exceeded the acceptable limit. Micrococcus spp., Staphylococcus aureus, α- and β-Streptococcus spp., Bacillus spp. and Clostridium spp. colonies were identified at the sampling locations. The antibiotic resistance screening showed a vast percentage of resistance amongst the bacterial colonies, with resistance to ampicillin observed as the highest percentage (Micrococcus spp.: 95.2%, S. aureus: 100%, Streptococcus spp.: 75%, Bacillus spp.: 100% and Clostridium spp.: 100%). This study provides awareness to healthcare practitioners and the public on the status of the emergence of ARB in a hospital environment. Early detection of bacterial populations and good management of hospital environments are important prevention measures for HAI.

Airborne bacterial and PM characterization in intensive care units: correlations with physical control parameters

In this study, the spatial variation of airborne bacteria in intensive care units (ICUs) was characterized. Fine particulate matter and several physical parameters were also monitored including temperature and relative humidity. The results showed that the total bacterial load ranged between 20.4 and 134.3 CFU/m³ across the ICUs. Bacterial cultures of the collected samples did not isolate any multi-drug-resistant Gram-negative bacilli indicating the absence of such aerosolized pathogens in the ICUs. Meanwhile, particulate matter levels in several ICUs were found to exceed the international guidelines set for 24-h PM exposure. Moreover, examining bacterial load contribution by size suggested that bacteria with sizes less than 0.65 µm contributed the least to the total bacterial loads, while those with sizes between 0.65 and 1.1 µm contributed the most. A multiple linear regression model was also built to predict the bacterial loads in the ICUs. The regression analysis explained 77% of the variability observed in the measured bacterial concentrations. The model showed that the level of activity in the ICU rooms as well as its occupancy level had strong positive correlations with bacterial loads, while distance away from the patient had a non-linear relationship with measured loads. No statistically significant correlation was found between bacterial load and particulate matter concentrations.

Water as a Source of Indoor Air Contamination with Potentially Pathogenic Aeromonas hydrophila in Aquaculture

Human activities influence the presence of potentially pathogenic bacteria in indoor air. The aim of this study was to determine the effect of the experimental rearing of European grayling and European perch in a recirculating aquaculture system on the contamination of indoor air with potentially pathogenic Aeromonas hydrophila (PPAH) and the resulting health risks to humans. The PPAH counts, their resistance to seven antibiotics, and the multiple antibiotic resistance (MAR) index were determined in samples of indoor air and water from rearing tanks. The PPAH counts were highest in the laboratory bioaerosol where two fish species were reared. The calculated indoor/outdoor ratio (I/O > 1) demonstrated that tank water was the internal source of PPAH emissions. The unconstrained PCA revealed strong positive relationships (p ≤ 0.05) between the PPAH counts in the indoor air and water samples. Most of the PPAH strains isolated from laboratory air were resistant to tetracycline, cefotaxime, and erythromycin, and 26–82% of the isolates exhibited multiple drug resistance. The values of the MAR index were similar in samples of laboratory air and water (0.23–0.34 and 0.24–0.36, respectively). Agglomerative clustering revealed two clusters of strains isolated from laboratory air and tank water. The results of this study indicate that aquaculture can be a source of indoor air contamination with PPAH.

Assessment of fungal bioaerosols and particulate matter characteristics in indoor and outdoor air of veterinary clinics

Veterinary staff are frequently exposed to various occupational hazards. The present study was aimed to investigate the air characteristics of veterinary clinics in terms of fungal bioaerosols and particulate matters. Air samples were taken every six days from the operating room, examination room and outdoor air of three veterinary clinics in Shiraz, southwest Iran. The concentrations of fungal bio-aerosols ranged from 8.05 CFU/m ³ in the outdoor air of clinic B to 47.21 CFU/m ³ in the operating room of clinic A. The predominant fungal genera identified in the studied clinics were Penicillium and Aspergillus niger, respectively. The concentrations of PM_2.5 ranged from 41.88 μg/m ³ in the operating room of clinic C to 60.31 μg/m ³ in the outdoor air of the same clinic. The corresponding values for PM₁₀ ranged from 114.40 μg/m ³ in the operating room of clinic C to 256.70 μg/m ³ in the outdoor air of the same clinic. The results of this study showed a positive correlation between the concentration of fungal bioaerosols and relative humidity (p < 0.05; r = 0.622). Besides, a negative correlation was found between the concentration of fungal bioaerosols and temperature (p < 0.05; r = 0.369). To better assess the individual exposure of veterinarians and staff in veterinary clinics, tests including nasopharyngeal sampling are recommended.

Do closed waste containers lead to less air contamination than opened? A clinical case study at Jena University Hospital, Germany

Nosocomial infections are a growing challenge at hospitals. This clinical study aimed to investigate the influence of waste container construction ((open (O), closed (C), and hands-free opening (HF)) on microbial air contamination in a hospital setting. The results are intended to help develop guidelines for waste containers for the collection of non-infectious waste at hospitals and medical facilities. The clinical experiment was conducted at the University Hospital Jena, Germany. Air Impactor samples were performed and microbiologically evaluated for bacteria and fungi both quantitatively and qualitatively. The results were statistically determined using generalized estimating equations. Quantitatively, the lowest bacterial counts in ambient air were found around closed waste containers (114.74 CFU/m³) in comparison to HF (129.28 CFU/m³) and O (126.28 CFU/m³). For fungi, the surrounding air of C (2.08 CFU/m³) and HF (1.97 CFU/m³) waste containers showed a lower impact of fungal air contamination than for O (2.32 CFU/m³). Overall, it was shown that C are more preferable to HF and O waste containers from the point of view of microbial air contamination at hospitals.

Cytotoxicity of Aspergillus Section Fumigati Isolated from Health Care Environments

This study analyzed 57 Aspergillus section Fumigati (AF) isolates collected by active and passive sampling (N = 450) in several health care facilities and from biological sampling of health care workers (N = 25) and controls (N = 22) in Portugal. All isolates were cultured in different media and screened for azole resistance. Cytotoxicity was assessed for 40 isolates in lung epithelial cells and kidney cells using the MTT assay. Aspergillus section Fumigati was prevalent in the health care facilities and in nasal swabs from health care workers and controls. All AF isolates reduced cell viability and presented medium to high cytotoxicity, with cytotoxicity being significantly higher in A549 lung epithelial cells. The cytotoxicity of isolates from air and nasal swab samples suggested the inhalation route as a risk factor. Notably, 42% of AF isolates exhibited a pattern of reduced susceptibility to some of the most used antifungals available for the treatment of patients infected with these fungi. In sum, the epidemiology and clinical relevance of Aspergillus section Fumigati should continue to be addressed. A deeper understanding of the mechanisms underlying Aspergillus-mediated cytotoxicity is necessary.

Assessment of Bacterial Pathogens and their Antibiotic Resistance in the Air of Different Wards of Selected Teaching Hospitals in Tehran

Context:

Exposure to bio-aerosols in a variety of environments has been of great interest due to the health effects on humans. Hospitals can be the reservoir of these biological agents because of the presence of infectious patients; which can lead to hospital infections and various occupational hazards. In this way, we assessed bacterial contamination in two teaching hospitals in Tehran.

Aims:

Our purpose in this study assessment of bacterial pathogens and their antibiotic resistance in the air of different wards of selected teaching hospitals in Tehran.

Settings and Design:

In this study, sampling was done according to NIOSH 0800.

Methods and Material:

This descriptive study was carried out in the different sections of two hospitals in Tehran. A total of 180 air samples were evaluated according to NIOSH 0800. In each section sampling was performed on the culture media in three stations including primary room, end room, and nursing position then the number of colonies counted. The zone of inhibition was measured in antibiotic disks to determine antibiotic resistance of samples.

Statistical Analysis Used:

Data analysis was performed using SPSS version 21. Initially, the data were normalized using the Kolmogorov–Smirnov test. The difference between the two hospitals was achieved with Mann–Whitney U test for un-normal distribution data.

Results:

Bacterial contamination in hospital 2 was significantly higher than the hospital 1(P < 0.001). The median number of colonies in hospital 1 was 129.87 (87.46–268.97) CFU/m³ and 297.97 (217.66–431.85) CFU/m³ for hospital 2. Bacterial contamination in the all of stations in hospital 2 and 87% of samples in hospital 1 was higher than the acceptable range of ACGIH (75 CFU/m³).

Conclusions:

High bacterial contamination may be related to a lack of hygiene management and poor ventilation system. It seems effective infection control processes, appropriate ventilation systems and supervision systems should be improved.

Simultaneous monitoring of SARS-CoV-2, bacteria, and fungi in indoor air of hospital: a study on Hajar Hospital in Shahrekord, Iran

The novel SARS-CoV-2 outbreak was declared as pandemic by the World Health Organization (WHO) on March 11, 2020. Understanding the airborne route of SARS-CoV-2 transmission is essential for infection prevention and control. In this study, a total of 107 indoor air samples (45 SARS-CoV-2, 62 bacteria, and fungi) were collected from different wards of the Hajar Hospital in Shahrekord, Iran. Simultaneously, bacterial and fungal samples were also collected from the ambient air of hospital yard. Overall, 6 positive air samples were detected in the infectious 1 and infectious 2 wards, intensive care unit (ICU), computed tomography (CT) scan, respiratory patients' clinic, and personal protective equipment (PPE) room. Also, airborne bacteria and fungi were simultaneously detected in the various wards of the hospital with concentrations ranging from 14 to 106 CFU m-3 and 18 to 141 CFU m-3, respectively. The highest mean concentrations of bacteria and fungi were observed in respiratory patients' clinics and ICU wards, respectively. Significant correlation (p < 0.05) was found between airborne bacterial concentration and the presence of SARS-CoV-2, while no significant correlation was found between fungi concentration and the virus presence. This study provided an additional evidence about the presence of SARS-CoV-2 in the indoor air of a hospital that admitted COVID-19 patients. Moreover, it was revealed that the monitoring of microbial quality of indoor air in such hospitals is very important, especially during the COVID-19 pandemic, for controlling the nosocomial infections.

Distribution of airborne respiratory pathogens in pediatric emergency department waiting room

OBJECTIVE

To determine the presence of genetic material from potentially infectious airborne respiratory virus pathogens in a pediatric emergency department (PED) waiting room.

METHODS

A cross-sectional study in the waiting room area of PED at Santo Antonio Children's Hospital, Porto Alegre, in southern Brazil. The room air samples were collected with a portable cyclone sampler (Coriolis®), twice a day (8 a.m. and 8 p.m.), during 5 consecutive weekdays, during two seasons, fall and spring (20 samples), in 2016. Reverse transcription polymerase chain reaction was used to detect influenza A, influenza B, parainfluenza 2, parainfluenza 3, human metapneumovirus, respiratory syncytial virus, human adenovirus, human bocavirus, and Bordetella pertussis. The PED provides care to an average of 6000 patients per month and the age of patients ranges from 1 month to 17 years old. It is waiting area has 645 ft square.

RESULTS

Genetic material from pathogens was detected in 12 out of 20 samples (60%). In 5 samples, more than one pathogen of respiratory virus was identified. Human adenovirus was the most frequent pathogen (n = 9/52%), followed by Bordetella pertussis (n = 4/24%), respiratory syncytial virus (n = 2/12%) and human bocavirus (n = 2/12%). Season and number of people in the waiting room were not associated with the presence of genetic material from pathogens.

CONCLUSIONS

Genetic material from pathogens potentially associated with severe respiratory diseases was found in the room air of a pediatric ED waiting room.

Exposure Assessment of Airborne Bacteria Emitted from Swine Manure Composting Plant

This study was performed to investigate the distribution characteristics of airborne bacteria emitted from swine manure composting plants. The types of swine manure composting plants selected for the survey in this study were as follows: screw type, rotary type, and natural dry type. Mean levels of airborne bacteria in swine manure composting plants were 7428 (±1024) CFU m−3 for the screw type, 3246 (±1407) CFU m−3 for the rotary type, and 5232 (±1217) CFU m−3 for the natural dry type, respectively. Based on the results obtained from this study, the swine manure composting plant operated by screw type showed the highest concentration of airborne bacteria, followed by the natural dry type and rotary type. The monthly concentration of airborne bacteria was the highest in August and the lowest in November, regardless of the type of swine manure composting plant. The respirable size of airborne bacteria accounted for about 50% of the total. The ratio of respirable to the total quantity of airborne bacteria was 50%. The correlation relationships between airborne bacteria and environmental factors (temperature, relative humidity, particulate matters, and odor) were not found to be significant in the swine manure composting plants. The predominant genera of airborne bacteria identified were Micrococcus spp., Staphylococcus spp., Escherichia (E-coli) spp., Enterococcus spp., and Enterobacteriaceae spp.

Fungi in the indoor air of critical hospital areas: a review

Invasive fungal infection is an important cause of mortality and morbidity in neonates, especially in low-birthweight neonates. The contribution of fungi in the indoor air to the incidence of mucocutaneous colonization and to the risk of invasive fungal infection in this population is uncertain. This review aimed to identify and to summarize the best available evidence on the fungal contamination in the indoor air of critical hospital areas with an emphasis on pediatric/neonatal ICUs. Publications from 2005 to 2019 were searched in the databases Scientific Electronic Library Online (SciELO), US National Library of Medicine National Institutes of Health Search (PubMed), and Latin American Caribbean Health Sciences (LILACS). Descriptors in Health Sciences (DeCS) were used. Research papers published in Portuguese, English, and Spanish were included. Twenty-nine papers on all continents except Australia were selected. The results showed that the air mycobiota contained several fungal species, notably Aspergillus, Penicillium, Cladosporium, Fusarium, and yeast (Candida) species. The selected papers point out the risks that fungi pose to neonates, who have immature immune system, and describe simultaneous external factors (air humidity, seasonality, air and people flow, use of particulate filters, and health professionals' hand hygiene) that contribute to indoor air contamination with fungi. Improving communication among health professionals is a great concern because this can prevent major health complications in neonates, especially in low-birthweight neonates. The results reinforced the need to monitor environmental fungi more frequently and efficiently in hospitals, especially in neonatal ICUs.

Assessment of Airborne Bacterial and Fungal Communities in Shahrekord Hospitals

This paper presents information about airborne microorganisms (bacteria and fungi) in the indoor air of two hospitals (Kashani and Hajar) in the city of Shahrekord, Iran. The settle plate technique using open Petri dishes containing different culture media was employed to collect a sample and using Quick Take 30 Sample Pump three days per week for a period of 8 weeks. Standard microbiological methods were employed for the identification of bacterial and fungal isolates. The results showed that the concentration of bacteria in the study area ranged from 0 to 70 cfu/plate/h, while the concentration of fungi was 0 to 280 cfu/plate/h. Also, 12 bacterial and 3 fungal species were isolated and identified with varying frequencies of occurrence, including Staphylococcus spp., Escherichia coli, Salmonella, Enterobacter, Pseudomonas, Serratia Citrobacter, Proteus, and Klebsiella, while the fungal genera isolated included Yeast, Aspergillus flavus, and Penicillium. While the bacterial isolates Staphylococcus aureus (20.50%) and Pseudomonas (9.10%) were the most predominant airborne bacteria, yeast (22.70%) and Penicillium (20.50%) were the most frequently isolated fungal species. The population of microorganisms was the highest during the afternoon. The statistical analysis showed a significant difference between the microbial loads of the two hospitals at P < 0.05. The generated data underline the usefulness of monitoring the air quality of the indoor hospital.

Bacterial Contamination in Health Care Centers: Differences between Urban and Rural Settings

This study aims to assess the airborne bioburden of rural and urban Portuguese Primary Health Care Centers (PHCC) using active and passive sampling methods and identify the potential differences in airborne microbiota between both environments. The highest total aerobic mesophilic bacterial load in indoor air were found in the Vaccination Room (448 CFU.m−3) in the Rural PHCC and in the Waiting Room (420 CFU.m−3) for Urban PHCC. The total coliforms contamination level in indoor air was detected only in the Cleaning Supplies Room (4 CFU.m−3) in the Urban PHCC. The most frequent bacteria genera identified was Micrococcus (21% Rural PHCC; 31% Urban PHCC). The surface samples showed a highest total aerobic mesophilic bacterial contamination in the Treatment Room (86 × 103 CFU.m−2) from the Rural PHCC and in the Front Office (200 × 103 CFU.m−2) from the Urban PHCC. The electrostatic dust cloth (EDC) samples showed a highest bacterial load in the Urban PHCC. Total aerobic mesophilic bacterial load in settled dust and in the Heating, Ventilating and Air Conditioning (HVAC) filter samples in the Urban PHCC (8 CFU.g−1 and 6 × 103 CFU.m−2) presented higher values compared with the Rural PHCC (1 CFU.g−1 and 2.5 × 103 CFU.m−2). Urban PHCC presented higher bacterial airborne contamination compared with the Rural PHCC for the majority of sampling sites, and when compared with the indoor air quality (IAQ) Portuguese legislation it was the Rural PHCC in two sampling places who did not comply with the established criteria.

Study of biochip integrated with microelectrodes modified by poly-dopamine-co-chitosan composite gel for separation, enrichment and detection of microbes in the aerosol

As the urgent need for rapid detection of airborne microbes in a specific environment, a biochip which was integrated with the functions of enrichment and detection was designed and developed. It was composed of cover plate, copper microelectrodes modified with poly-dopamine-co-chitosan (PDA-co-CS) composite gel, sealing washer and substrate containing copper sheet electrode. The microbes were enriched due to the good ventilation efficiency and adhesion of the PDA-co-CS composite gel. The enrichment efficiency of microbes was 99.9%. The electrical impedance spectrum (EIS) test system which was composed of the copper electrodes and the copper sheet electrode were used to detect the concentrated microbes and establish the quantitative detection method of single microbe (S. aureus ATCC 6538) and mixed microbes (S. aureus ATCC 6538, E. coli JM109, and Candida albicans). It was shown that the biochip could respond to the aerosol with 1.26 × 10³ cfu/m³S. aureus ATCC 6538, which was 25 times as high as the detection limit of natural deposition method. Meanwhile, the Surface-enhanced Raman Spectrum (SERS) of different microbes were detected in-situ with the help of the silver sol. The SERS data of S. aureus, E. coli and Candida albicans had been analyzed to establish recognition model by the principal component analysis (PCA) method and the three microbes were successfully identified. It was demonstrated that the designed biochip could be applied for separation, enrichment and detection of microbes in the aerosol.

Factors affecting the exposure to physicochemical and microbiological pollutants in vehicle cabins while commuting in Lisbon

Commuters are exposed to a variety of physicochemical and microbiological pollutants that can lead to adverse health effects. This study aims to evaluate the indoor air quality (IAQ) in cars, buses and trains in Lisbon, to estimate inhaled doses while commuting and to evaluate the impacts of cleaning and ventilation on the IAQ. Particulate matter with diameter lower than 1, 2.5 and 10 μm (PM₁, PM_2.5 and PM₁₀), black carbon (BC), carbon monoxide (CO), carbon dioxide (CO₂) volatile organic compounds (VOCs), formaldehyde (CH₂O) and total airborne bacteria and fungi were measured and bacterial isolates were identified. Results showed that the type of ventilation is the main factor affecting the IAQ in vehicle cabins. Under the fan off condition, the concentration of BC was lower, but the concentration of gases such as CO₂, CO and VOC tended to accumulate rapidly. When the ventilation was used, the coarse particles were filtered originating the decrease of indoor concentrations. Commuters travelling in trains received the lowest dose for all chemical pollutants, except VOC, mainly because railways are further away from the direct vehicular emissions. Commuters travelling in cars without ventilation received the highest inhaled dose for almost all pollutants despite having the lowest travel duration. Airborne microbiota was highly affected by the occupancy of the vehicles and therefore, the fungi and bacterial loads were higher in trains and buses. Most of the isolated species were human associated bacteria and some of the most abundant species have been linked to respiratory tract infections.

Size distribution of microbial aerosols in overground and subterranean treatment chambers at health resorts

PURPOSE

to perform comparative analyzes of the size distributions of bacteria and fungi in the air of overground therapy chambers in Szczawnica sanatorium and subterranean inhalation chambers in Bochnia Salt Mine health resort taking into account influence of the season and presence of pathogenic species.

METHODS

bioaerosol samples were collected using 6-stage Andersen impactor. Bacterial and fungal aerosol concentrations and size distributions were calculated and isolated microorganisms were taxonomically identified based on their morphological, biochemical, and molecular features. Results: in both treatment rooms and atmospheric (outdoor) air, the acceptable microbial pollution levels were periodically exceeded. The size distribution analyzes revealed that in the case of bacteria - emission from the patients and in the case of fungi - transport with atmospheric (outdoor) air were the major processes responsible for microbiological contamination of indoor premises. The majority of microbial particulates were present in the air of studied premises as single bacterial vegetative cells, spores and fungal conidia or (most commonly) formed small microbial or microbial-dust aggregates. This phenomenon may have a significant effect on patients' actual exposure (especially on those treated for respiratory diseases) in terms of the dose of inhaled particles.

CONCLUSIONS

the microbiological quality of the air in sanatoriums and health resorts is a key factor for their therapeutic and prophylactic functions. When microbial pollution crossed the acceptable level, the measures that enable reducing undesirable contamination should be introduced, especially if large groups of patients undergo such therapy.

Particle size distribution of the major Alternaria alternata allergen, Alt a 1, derived from airborne spores and subspore fragments

Fungal fragments are abundant immunoreactive bioaerosols that may outnumber the concentrations of intact spores in the air. To investigate the importance of Alternaria fragments as sources of allergens compared to Alternaria spores, we determined the levels of Alternaria spores and Alt a 1 (the major allergen in Alternaria alternata spores) collected on filters within three fractions of particulate matter (PM) of different aerodynamic diameter: (1) PM_>10, (diameter>10 μm); (2) PM_2.5-10 (2.5-10μm); (3) PM_2.5 (0.12-2.5 μm). The airborne particles were collected using a three stage high-volume ChemVol cascade impactor during the Alternaria sporulation season in Poznań, Poland (30 d between 6 July and 22 September 2016). The quantification of Alt a 1 was performed using the enzyme-linked immunosorbent assay. High concentrations of Alt a 1 were recorded during warm and dry d characterized by high sunshine duration, lack of clouds and high dew point values. Atmospheric concentrations of Alternaria spores correlated significantly (r = 0.930, p < 0.001) with Alt a 1 levels. The highest Alt a 1 was recorded in PM_2.5-10 (66.8 % of total Alt a 1), while the lowest in PM_2.5 (<1.0 %). Significantly more Alt a 1 per spore (>30 %) was observed in PM_2.5-10 than in PM_>10. This Alt a 1 excess may be derived from sources other than spores, e.g. hyphal fragments. Overall, in outdoor air the major source of Alt a 1 are intact Alternaria spores, but the impact of other fungal fragments (hyphal parts, broken spores, conidiophores) cannot be neglected, as they may increase the total atmospheric Alt a 1 concentration.

Assessment of air purifier on efficient removal of airborne bacteria, Staphylococcus epidermidis, using single-chamber method

We evaluated the efficiency of an air purifier using the single-chamber method for the effective removal of airborne Staphylococcus epidermidis, a nosocomial infection-causing bacterium. In this experiment, the bacterial strain S. epidermidis was injected using a nebulizer into the test chamber, which was similar to a consumer living space (60 m3). The microbial sampling was conducted via the air sampler method, and the reduction in S. epidermidis growth was monitored by performing three consecutive tests. Initially, a blank test was conducted to determine the natural decay rate and calibrate the experimental setup. After injecting the bacterial strain from 1240 to 11180 CFU per unit volume (m3), the natural decay rate showed a maximum deviation of 3.1% with a sampling error of 1.1% p at a confidence level of 95%. In addition, the particle size distribution in the test chamber was found to range from 0.3 to 5.0 μm, and a subsequent decrease in large-sized particles was observed with the operation of the air purifier, which is the size similar to that of suspended airborne bacteria. This can be used to assess the performance of the air purifier by calibrating the natural reduction value to the reduced operation value. Thus, the single-chamber technique is a promising approach for analyzing the removal efficacy of airborne bacteria from indoor air.

Antibiotic Resistance of Airborne Viable Bacteria and Size Distribution in Neonatal Intensive Care Units

Despite their significant impact on public health, antibiotic resistance and size distributions of airborne viable bacteria in indoor environments in neonatal intensive care units (NICU) remain understudied. Therefore, the objective of this study was to assess the antibiotic resistance of airborne viable bacteria for different sizes (0.65–7 µm) in private-style and public-style neonatal intensive care units (NICU). Airborne bacteria concentrations were assessed by a six-stage Andersen impactor, operating at 28.3 L/min. Public-style NICU revealed higher concentrations of airborne viable bacteria (53.00 to 214.37 CFU/m³) than private-style NICU (151.94–466.43), indicating a possible threat to health. In the public-style NICU, Staphylococcus was the highest bacterial genera identified in the present study, were Staphylococcus saprophyticus and Staphylococcus epidermidis predominated, especially in the second bronchi and alveoli size ranges. Alloiococcus otitidis, Bacillus subtiles, Bacillus thuringiensis, Kocuria rosea, and Pseudomonas pseudoalcaligene, were identified in the alveoli size range. In NICU#2, eight species were identified in the alveoli size range: Bacillus cereus, Bacillus subtilis, Bacillus thuringiensis, Eikenella corrodens, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus gordoni. Multi-drug-resistant organisms (MDROs) were found in both of the NICUs. Bacillus cereus strains were resistant to Ampicillin, Cefoxitin, Ceftaroline, and Penicillin G. Staphylococcus cohnii ssp. cohnii was resistant in parallel to ampicillin and G penicillin. Staphylococcus saprophyticus strains were resistant to Ampicillin, Penicillin G, Oxaxilin, and Erythromycin. Results may indicate a potential threat to human health due to the airborne bacteria concentration and their antibiotic resistance ability. The results may provide evidence for the need of interventions to reduce indoor airborne particle concentrations and their transfer to premature infants with underdeveloped immune systems, even though protocols for visitors and cleaning are well-established.

Indoor hospital air and the impact of ventilation on bioaerosols: a systematic review

Healthcare-acquired infections (HAIs) continue to persist in hospitals, despite the use of increasingly strict infection-control precautions. Opportunistic airborne transmission of potentially pathogenic bioaerosols may be one possible reason for this persistence. Therefore, this study aimed to systematically review the concentrations and compositions of indoor bioaerosols in different areas within hospitals and the effects of different ventilation systems. Electronic databases (Medline and Web of Science) were searched to identify articles of interest. The search was restricted to articles published from 2000 to 2017 in English. Aggregate data was used to examine the differences in mean colony forming units per cubic metre (cfu/m³) between different hospital areas and ventilation types. A total of 36 journal articles met the eligibility criteria. The mean total bioaerosol concentrations in the different areas of the hospitals were highest in the inpatient facilities (77 cfu/m³, 95% confidence interval (CI): 55-108) compared with the restricted (13cfu/m³, 95% CI: 10-15) and public areas (14 cfu/m³, 95% CI: 10-19). Hospital areas with natural ventilation had the highest total bioaerosol concentrations (201 cfu/m³, 95% CI: 135-300) compared with areas using conventional mechanical ventilation systems (20 cfu/m³, 95% CI: 16-24). Hospital areas using sophisticated mechanical ventilation systems (such as increased air changes per hour, directional flow and filtration systems) had the lowest total bioaerosol concentrations (9 cfu/m³, 95% CI: 7-13). Operating sophisticated mechanical ventilation systems in hospitals contributes to improved indoor air quality within hospitals, which assists in reducing the risk of airborne transmission of HAIs.

Bioaerosols in the waterpipe cafés: genera, levels, and factors influencing their concentrations

This study was conducted in order to assess the exposure to bacterial and fungal bioaerosols in the air of waterpipe cafés (AWPCs), in the hose of waterpipe (HWP), and in the water bowl of the waterpipe (WBWP) and to investigate the factors influence increasing the contamination levels in waterpipe cafés in Ardabil. From all the 50 cafés studied, the samples were taken from air and from water contained in water bowl and hose for bacterial and fungal analyses. The results demonstrated that the mean numbers of bacteria and fungi in the indoor air of café, hose, and water bowl were 33.90 ± 14.86 and 25.24 ± 1.99 CFU/m³, 72.16 ± 29.55 and 72.78 ± 42.45 CFU/plate, 53.7 ± 25.46 and 25.26 ± 13.94 CFU/ml, respectively. The predominant bacterial genera in waterpipe cafés were Pseudomonas and Bacillus in air, Staphylococcus and Pseudomonas in the hose, and Staphylococcus and Pseudomonas in the water bowl, respectively. The predominant fungal species in waterpipe cafés were Penicillium and Cladosporium in air, yeast and Fusarium in the hose, and Paecilomyces and yeast in the water bowl, respectively. The results of statistical analysis showed that there was a significant relationship between the mean concentrations of bacterial aerosol and qualitative variables such as type of heating system, materials of wall and ceiling, traditional restaurants, interior supermarkets, moisturized walls, the number of people, area of cafés, and temperature. But there was no significant relationship between these variables and the mean concentration of fungal aerosols. The results also showed that the levels of bioaerosols were high in the air, hose, and water bowl of the waterpipe. Therefore, cafés can be a potential source for the transmission of pathogenic agents and increase the risk of respiratory diseases among waterpipe smoking individuals.

The effect of temperature on airborne filamentous fungi in the indoor and outdoor space of a hospital

Fungi are one of the bioaerosols in indoor air of hospitals. They have adverse effects on staff and patients. The aim of this study was to investigate the effects of three incubation temperature on the density and composition of airborne fungi in an indoor and outdoor space of hospital. Sabouraud dextrose agar was used for culture the fungi. For improvement of aseptic properties, chloramphenicol was added to this medium. The density of airborne fungi was less than 282 CFU/m³. The highest density was detected in emergency room and the lowest of them was in neonatal intensive care unit (NICU) and operation room (OR). Results showed that fungi levels at 25 °C were higher than 37 and 15 °C (p = 0.006). In addition, ten different genera of fungi were identified in all departments. The predominant fungi were Fusarium spp., Penicillium spp., Paecilomyces spp., and Aspergillus niger. Moreover, the density and trend of distribution of Fusaruim spp. in the indoor space was directivity to outdoor space by ventilation system. The present study has provided that incubation temperature had effect on airborne fungi remarkably. We are suggested that more studies would be conducted on incubation temperature and other ambient factors on airborne fungi.

Concentration and type of bioaerosols before and after conventional disinfection and sterilization procedures inside hospital operating rooms

Operating rooms (ORs) in hospitals are sensitive wards because patients can get infections. This work aimed to characterize the type and concentration of bioaerosols in nine ORs of an educational hospital before and after sterilization and disinfection. During 2017, fungal samples were incubated at 25-28 °C for 3-7 days and bacterial samples at 37 °C for 24-48 h. The study results showed that the concentrations of fungi before cleaning procedures (for both of disinfection and sterilization) were limited from 4.83 to 18.40 CFU/m3 and after cleaning procedures ranged from 1.90 to 8.90 CFU/m3. In addition, the concentrations of bacteria before cleaning procedures were limited 14.65-167.40 CFU/m3 and after cleaning procedures ranged from 9.50 to 38.40 CFU/m3. The difference between the mean concentrations of airborne bioaerosols before and after sterilization was significantly different than the suggested value of 30 CFU/m3 (p ≤ 0.05). The bacterial concentration was higher than the recommended value (30 CFU/m3) in 41% of the ORs. The main fungal species identified in the indoor air of ORs (before vs. after sterilization) were A. fumigatus (25.6 vs. 18.3%), A. Niger (11.6 vs. 5.8%), Penicillium spp. (5.5 vs. 3.3%), Alternaria spp. (2.8 vs. 0.7%), Fusarium spp. (9.7 vs. 3.7%), Mucor spp. (15 vs. 12.7%), Cephalotrichum spp. (1.7 vs. 0.8%), A. Flavus (24.6 vs. 18.5%), Cladosporium spp. (2.6 vs. 0.8%), and Trichoderma spp. (0 vs. 0.9%). The growth of biological species even after sterilization and disinfection likely resulted from factors including poor ventilation, sweeping of OR floors, inadequate HVAC filtration, high humidity, and also lack of optimum management of infectious waste after surgery. Designing well-constructed ventilation and air-conditioning systems, replacing HEPA filters, implementing more stringent, frequent, and comprehensive disinfection procedures, and controlling temperature and humidity can help decrease bioaerosols in ORs.

A review on airborne microorganisms in particulate matters: Composition, characteristics and influence factors

Airborne microorganisms (AM), vital components of particulate matters (PM), are widespread in the atmosphere. Since some AM have pathogenicity, they can lead to a wide range of diseases in human and other organisms, meanwhile, some AM act as cloud condensation nuclei and ice nuclei which let them can affect the climate. The inherent characteristics of AM play critical roles in many aspects which, in turn, can decide microbial traits. The uncertain factors bring various influences on AM, which make it difficult to elaborate effect trends as whole. Because of the potential roles of AM in environment and potent effects of factors on AM, detailed knowledge of them is of primary significance. This review highlights the issues of composition and characteristics of AM with size-distribution, species diversity, variation and so on, and summarizes the main factors which affect airborne microbial features. This general information is a knowledge base for further thorough researches of AM and relevant aspects. Besides, current knowledge gaps and new perspectives are offered to roundly understand the impacts and application of AM in nature and human health.

Microbial Stability of Pharmaceutical and Cosmetic Products

This review gives a brief overview about microbial contamination in pharmaceutical products. We discuss the distribution and potential sources of microorganisms in different areas, ranging from manufacturing sites, pharmacy stores, hospitals, to the post-market phase. We also discuss the factors that affect microbial contamination in popular dosage forms (e.g., tablets, sterile products, cosmetics). When these products are contaminated, the microorganisms can cause changes. The effects range from mild changes (e.g., discoloration, texture alteration) to severe effects (e.g., changes in activities, toxicity). The most common method for countering microbial contamination is the use of preservatives. We review some frequently used preservatives, and we describe the mechanisms by which microorganisms develop resistance to these preservatives. Finally, because preservatives are inherently toxic, we review the efforts of researchers to utilize water activity and other non-preservative approaches to combat microbial contamination.

Assessment of airborne bacteria in selected occupational environments in Quezon City, Philippines

Exposure to bioaerosols has been associated with health deterioration among workers in several occupational environments. This highlights the need to study the microbiological quality of air of workplaces as no such study has been conducted yet in the Philippines. To detect and characterize the culturable mesophilic airborne bacteria in selected occupational environments we used passive sedimentation technique. It was observed that the number of colony-forming units was highest in junk shop, followed by the light railway transit station and last the office. By contrast, the bacterial composition was similar in all sites: Gram-positive cocci > Gram-positive bacilli > Gram-negative bacteria. Staphylococcus aureus and Bacillus spp. were also detected in all sites. These findings suggest that the presence of airborne bacteria may be a potential health hazard in urban occupational environments in the Philippines.

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

•

Bacterial concentrations during bronchoscopies are higher than during backgrounds.

•

Opportunistic bacteria were identified in the ambient air during bronchoscopies.

•

Pathogens are to be expected depending on the patient pathology.

•

Main problem comes from patients with unsuspected or undiagnosed infections.

Background

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.

Methods

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.

Results

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.

Conclusions

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.

Hospital air: A potential route for transmission of infections caused by β-lactam-resistant bacteria

BACKGROUND

The emergence of bacterial resistance to β-lactam antibiotics seriously challenges the treatment of various nosocomial infections. This study was designed to investigate the presence of β-lactam-resistant bacteria (BLRB) in hospital air.

METHODS

A total of 64 air samples were collected in 4 hospital wards. Detection of airborne bacteria was carried out using culture plates with and without β-lactams. BLRB isolates were screened for the presence of 5 common β-lactamase-encoding genes. Sequence analysis of predominant BLRB was also performed.

RESULTS

The prevalence of BLRB ranged between 3% and 34%. Oxacillin-resistant bacteria had the highest prevalence, followed by ceftazidime- and cefazolin-resistant bacteria. The frequency of β-lactamase-encoding genes in isolated BLRB ranged between 0% and 47%, with the highest and lowest detection for OXA-23 and CTX-m-32, respectively. MecA had a relatively high frequency in surgery wards and operating theaters, whereas the frequency of blaTEM was higher in intensive care units and internal medicine wards. OXA-51 was detected in 4 wards. Acinetobacter spp, Acinetobacter baumannii, and Staphylococcus spp were the most predominant BLRB.

CONCLUSIONS

The results revealed that hospital air is a potential route of transmission of BLRB, such as Acinetobacter and Staphylococcus, 2 important causative agents of nosocomial infections. Therefore, improvement of control measures against the spreading of airborne bacteria in hospital environments is warranted.

Characteristics of airborne micro-organisms in a neurological intensive care unit: Results from China

OBJECTIVE

To describe the characteristics of airborne micro-organisms in the environment in a Chinese neurological intensive care unit (NICU).

METHODS

This prospective study monitored the air environment in two wards (large and small) of an NICU in a tertiary hospital in China for 12 months, using an LWC-1 centrifugal air sampler. Airborne micro-organisms were identified using standard microbiology techniques.

RESULTS

The mean ± SD number of airborne bacteria was significantly higher in the large ward than in the small ward (200 ± 51 colony-forming units [CFU]/m(3) versus 110 ± 40 CFU/m(3), respectively). In the large ward only, the mean number of airborne bacteria in the autumn was significantly higher than in any of the other three seasons. A total of 279 airborne micro-organisms were identified (large ward: 195; small ward: 84). There was no significant difference in the type and distribution of airborne micro-organisms between the large and small wards. The majority of airborne micro-organisms were Gram-positive cocci in both wards.

CONCLUSION

These findings suggest that the number of airborne micro-organisms was related to the number of patients on the NICU ward.

Characteristics of airborne Staphylococcus aureus (including MRSA) in Chinese public buildings

The aim of this study was to evaluate the concentration and size distribution of airborne culturable Staphylococcus aureus (S. aureus) (including MRSA) in Chinese public buildings. Air samples were collected, using six-stage Andersen sampler from five different public buildings in one large Chinese community. The mean indoor concentrations of the total and respirable airborne S. aureus were 72 and 50 CFU/m3 in the general hospital, 72 and 49 CFU/m3 in the kindergarten, 76 and 52 CFU/m3 in the hotel, 84 and 57 CFU/m3 in the movie theater, and 55 and 40 CFU/m3 in the university classroom. Respirable S. aureus amounted to approximately 57-73 % of the total S. aureus concentrations. Mean total and respirable concentrations of airborne MRSA were 32 and 20 CFU/m3 in the general hospital, 20 and 13 CFU/m3 in the kindergarten, 23 and 16 CFU/m3 in the hotel, 33 and 20 CFU/m3 in the movie theater, and 24 and 17 CFU/m3 in the university classroom. Respirable MRSA amounted to approximately 61-72 % of the total MRSA concentrations. The ratios of indoor and outdoor concentration for airborne S. aureus and MRSA were more than 1.0 in all the investigated public buildings. The size distribution results showed relatively high collection rates on stage 4 (2.1-3.3 μm) for both airborne culturable S. aureus and MRSA regardless of the type of public buildings.

Efficacy of the Precise Climate Controller on the reduction of indoor microorganisms

BACKGROUND

Nowadays, there are many methods to reduce microorganisms in the air, such as dehumidifier, air purifier or humidity and temperature controller. The Precise Climate Controller is an instrument for controlling humidity and temperature, a concept that is demonstrated.

OBJECTIVE

To determine the efficacy of this device, in order to reduce the quantity of the fungi and bacteria in the closed system.

METHODS

This study is a perspective experimental study and is conducted as follows - the air sample in the closed system, a 42-cubic-meter room, is collected before the installation of the Precise Climate Controller. Next, the room is fumed with Aspergillus flavus and closed for 2 days. Then the instrument is in use in order to keep the relative humidity (RH) and the temperature constant at 55% RH and 25 degrees Celsius (℃). The air samples are collected every 3 days for 5 times during the period of 15 days to identify the type and calculate the quantity of the microorganisms.

RESULTS

Before the Precise Climate Controller has been installed. Three species of bacteria are found in the air samples, but none of the fungus exists in the testing room. Once the room has been fumed with a large amount of A. flavus and the instrument is in use for 3 days, nine colonies of A. flavus are identified, but later on when the instrument is in use for 6, 9, 12, and 15 days, the air samples contain neither fungus nor bacteria.

CONCLUSION

After keeping the RH and temperature of the closed system constant at 55% RH and 25℃ by using the Precise Climate Controller, it is found that the efficaciousness in controlling the quantity and species of fungi and bacteria is clinically significant.

Seasonal evaluation of bioaerosols from indoor air of residential apartments within the metropolitan area in South Korea

The aims of the present study were to determine the levels of bioaerosols including airborne culturable bacteria (total suspended bacteria, Gram-positive bacteria, Staphylococcus, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and Gram-negative bacteria), fungi, endotoxin, and viruses (influenza A, influenza B, respiratory syncytial virus types A/B, parainfluenza virus types 1/2/3, metapnemovirus, and adenovirus) and their seasonal variations in indoor air of residential apartments. Of the total suspended bacteria cultured in an indoor environment, Staphylococcus was dominant and occupied 49.0 to 61.3% of indoor air. Among Staphylococcus, S. aureus were detected in 100% of households' indoor air ranging from 4 to 140 CFU/m(3), and 66% of households were positive for MRSA ranging from 2 to 80 CFU/m(3). Staphylococcus and S. aureus concentrations correlated with indoor temperature (adjusted β: 0.4440 and 0.403, p < 0.0001). Among respiratory viruses, adenovirus was detected in 14 (14%) samples and influenza A virus was detected in 3 (3%) samples regarding the indoor air of apartments. Adenovirus concentrations were generally higher in winter (mean concentration was 2,106 copies/m(3)) than in spring (mean concentration was 173 copies/m(3)), with concentrations ranging between 12 and 560 copies/m(3). Also, a strong negative correlation between adenovirus concentrations and relative humidity in indoor air was observed (r = -0.808, p < 0.01). Furthermore, temperature also negatively correlated with adenovirus concentrations (r = -0.559, p < 0.05).

Investigation on distribution of airborne fungi in outdoor environment in Tehran, Iran

BACKGROUND

Airborne fungi are responsible for the majority of fungal infections in humans and animals. Outdoor air markedly influences the prevalence of fungal spore levels in indoor air and thus, it is the major source of fungal infections in indoor environments especially in hospitalized individuals.

METHODS

Using a settle plate method, air sampling (1092 air samples from 93 sampling sites in 22 geographic regions of Tehran) was performed by exposing 90 mm settle plates containing Malt extract agar and Potato dextrose agar to the air for 30 min. The plates were incubated at 28°C for 2-3 weeks and examined daily for visible fungal growth. Purified fungal colonies were identified at the genus level based on morphological criteria according to standard methods.

RESULTS

A total of 6455 colonies belonging to 24 different fungal genera were isolated. Area V situated in the city center was the most contaminated region with 2523 fungal colonies (39.1%), while area IV in the West showed the least contamination rate (636 colonies; 9.8%). Airborne fungi isolated were classified into 4 classes including hyaline Hyphomycetes (53.5%), dematiaceous Hyphomycetes (41.6%), Zygomycetes (2.8%) and Coelomycetes (0.2%). Aspergillus (31.3%) was the most prominent isolated fungus followed by Cladosporium (22.1%), Penicillium (13.8%) and Alternaria (12.2%).

CONCLUSION

Our results indicate that outdoor air is a potential threat to public health because of harboring a wide array of pathogenic and allergenic airborne fungal spores which can serve as the main source of contamination of indoor environments such as homes, offices and hospitals.

Assessment of the levels of airborne bacteria, Gram-negative bacteria, and fungi in hospital lobbies

Aims: We assessed the levels of airborne bacteria, Gram-negative bacteria (GNB), and fungi in six hospital lobbies, and investigated the environmental and hospital characteristics that affected the airborne microorganism levels. Methods: An Andersen single-stage sampler equipped with appropriate nutrition plate agar was used to collect the samples. The three types of microorganisms were repeatedly collected at a fixed location in each hospital (assumed to be representative of the entire hospital lobby) from 08:00 through 24:00, with a sampling time of less than 5 min. Temperature and relative humidity were simultaneously monitored. Results: Multiple regression analysis was used to identify the major factors affecting microorganism levels. The average levels of bacteria (7.2 × 10² CFU/m³), GNB (1.7 × 10 CFU/m³), and fungi (7.7 × 10 CFU/m³) indicated that all hospital lobbies were generally contaminated. Season was the only factor that significantly affected the levels of all microorganisms (p < 0.0001), where contamination was the highest during the summer, significantly higher than during the winter. Other significant factors varied by microorganism, as follows: airborne bacteria (number of people in the lobby, sampling time), GNB (scale of hospital), and fungi (humidity and air temperature). Conclusions: Hospital lobby air was generally contaminated with microorganisms, including bacteria, GNB, and fungi. Environmental factors that may significantly influence the airborne concentrations of these agents should be managed to minimize airborne levels.