Microbiological analysis of bacterial and fungal bioaerosols from burn hospital of Yazd (Iran) in 2019.

Abstract

Bioaerosols play an important role in incidence of infections in indoor and outdoor air of hospitals. Microorganisms play a critical role in the health of human beings and they are found everywhere in the environment, including different wards of a hospital. So, quantitative and qualitative analysis of microorganisms is highly important in hospital air. The aim of this study was to evaluate the diversity and density of bacteria and fungi in the air of Shohadaye Mehrab Hospital in Yazd City, Iran. Sampling was performed using a single-stage pump (Quick Take30) at a flow rate of 28.3l per minute for five minutes. As a result, 288 indoor and outdoor hospital air samples were collected. Numbers and types of bacterial and fungal colonies were identified using colony morphology, gram staining, and standard microbial tests. Chi-square test, PCA and linear mixed model were run by SPSS version 24.0 for data analysis. The highest bacterial contaminations were found in the burns ward (294CFU/m3), operating theater (147CFU/m3), and emergency department (124CFU/m3), respectively. Fungal contamination was higher in the derm ward (110CFU/m3) than other sampling sites. The dominant genus of gram-positive bacteria was Staphylococcus epidermidis (n = 60, 62.5%) and the dominant genus of gram-negative bacteria was Citrobacter freundi (n = 11, 11.5%). The most fungal gens isolated from the hospital air samples were Penicillium (n = 73, 76%), Alternaria (n = 51, 53.1%), Aspergillus niger (n = 40, 41.7%), and Aspergillus flavus (n = 34, 35.4%), respectively. Considering that the burn wounds represent a susceptible site for opportunistic microorganisms, even low concentration of fungi/bacteria in air can be considered as a risk factor that facilitates transmission of the infectious agents in the hospital. Therefore, control measures should be taken to reduce the infection hazard in health staff and patients. These measures include ensuring effective ventilation, cleaning and decontaminating surfaces and equipment, restricting the personnel and patient companions' movement across the wards.