Investigation of type and density of bacterial bioaerosols in the air of Imam Hossein hospital in Tehran in 2018

Introduction: Hospital microorganisms are the potential sources of infection for patients and staff. Exposure to bioaerosols is relevant to a wide range of health effects, including infectious diseases, acute toxic effects, and allergies. Materials and methods: In this study, ZTHV02 sampling device was used to evaluate and determine the density of bacterial airborne bioaerosols. The culture medium used in this study was tryptophan agar for bacterial agents to which the antibiotic cyclohexamide was added to prevent fungal growth. Sampling time was 10 min on average. The collected samples were immediately taken to the laboratory and incubated for 48 h. Then the number of colonies was counted and the bacteria were identified. Finally, bacterial density was expressed in CFU/m3. Results: The results showed that the mean total density of bacteria measured in Imam Hossein hospital were 16.07 CFU/m3. The ICU unit of Imam Hossein hospital has the highest bacterial contamination. The most abundant bacteria observed in the air of Imam Hossein hospital were enterococci, Pseudomonas species, coagulase negative staphylococci, Klebsilla species and group D non-enterococcal streptococci, respectively. Conclusion: Pseudomonas, Klebsiella and Enterococcus species were obtained. The number of bacteria was not significantly related to ambient temperature and humidity, but their number in the evening shift (appointment time) was significantly higher than the morning shift (p<0.05). High density of airborne bacteria in the studied hospitals can be considered as an important risk factor for the health of employees and patients.