Indoor exposure to airborne bacteria and fungi in sensitive wards of an academic pediatric hospital

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