Assessment of airborne bacterial diversity and antibiotic resistance patterns in wastewater treatment plants, hospitals and public transport

Abstract

There is presently insufficient information on the atmospheric microbial level in Botswana, the occurrence and diversity of airborne microbes in Botswana is not well understood. In addition, there is also growing concern in the global spread of antimicrobial resistant bacterial pathogens that continue to emerge and pose a huge challenge to human health. This study, being the first of its kind in the country was aimed at understanding the occurrence, distribution and relative diversity of bacteria in the atmosphere surrounding wastewater treatment plants, in hospitals and public transport. The focus was also to further understand the effects of atmospheric conditions, temperature and humidity on the concentration of airborne bacteria. The highest level of culturable bacteria was detected in aerosols (up to 1.25 x103 CFU/m3) wastewater treatment plant downwind. The atmospheric bacterial population is directly affected by temperature and relative humidity; the highest airborne microbial load was recorded during autumn followed by spring while the lowest was observed during winter season. Pseudomonas species was the most frequently detected (27.1%) bacterium followed by Brucella (15.3 %), Listeria (10.7 %) and Staphylococcus (8.9 %) species. Diversity of genes encoding resistance to various antibiotics was also detected in airborne bacteria captured in various environments. This study remains important to better understand and monitor the atmospheric basal microbial levels in Botswana.