Abstract

There is presently no information on the occurrence, abundance and diversity of airborne bacteria in Botswana hospitals. There is also growing concern in the global spread of antibiotic resistant bacteria that continue to emerge and pose serious challenge to human health. This study was aimed at determining the occurrence, relative abundance and diversity of airborne bacterial species and their antibiotic resistance patterns. Correlation between the meteorological conditions and the bacterial concentrations was also determined. Air impaction method was applied for the collection of airborne bacteria on selective media, antibiotic resistance was determined by screening isolates for resistance phenotypes and polymerase chain reaction (PCR) was applied for detection of resistance genes to clinically relevant antibiotics. The assessment of total airborne bacteria in hospital units revealed high abundance of airborne bacteria in paediatric wards than in the operating theatres. The highest bacterial concentrations were observed at the paediatric wards in Palapye (PPH; 7.9 × 10² CFU/m³), Maun (LMH; 6.4 ×10² CFU/m³) and Francistown (NRH; 5.8 ×10² CFU/m³). Diverse airborne bacterial species were observed with high concentration recorded for Pseudomonas species in all three hospitals’ units. The frequency of antibiotic resistance genes detected in bacterial isolates were; dfr1 (36%), mph(A) (26%), ermC (12%), strB (10%) and intI1 (16%). The study provide evidence suggesting air in hospitals’ units as a hotspot for potentially pathogenic bacteria and antibiotic resistance genes, hence the need to develop surveillance tools for monitoring the movement of airborne bacteria in hospitals in order to mitigate possible spread of nosocomial infections.

Key words: Airborne bacteria, antibiotic resistance genes, operating theatre, paediatric, human health.