Diversity and antibiotic susceptibilities of bacterial species from surfaces of publicly used equipment in a medical education setting

Medical and health science colleges have firm links to hospitals and health services centres through clinical training activities. Such colleges are expected to house microorganisms of nosocomial-infection significance that can be transmitted to and from students’ hands and bodies through publicly used equipment, including food and drink vending machines, elevators and computer keyboards. This study aimed to investigate the presence of human body indicator bacterial species on three types of publicly used surfaces in medical and health sciences colleges. Swab samples were collected aseptically from 30 computer keyboards, 10 digital control panels of food vending machines and 10 elevators in the buildings of medicine, dentistry, pharmacy and health sciences colleges over a period of five weeks. Ten surfaces were sampled each week, in the morning and the afternoon (n= 20/week) and cultured in selective and general media. Forty-three percent of surfaces had relatively elevated levels of bacteria, while the rest exhibited no recoverable bacterial growth. Conventional identification methods in addition to 16s rRNA gene sequencing revealed the presence of Bacillus spp., Bhargavaea cecembensis, Brevibacterium casei, Cellulomonas spp., Micrococcus spp., Rothia terrae, Stenotrophomonas maltophilia, Staphylococcus aureus, Staphylococcus epidermidis and other Staphylococcus spp. on the examined surfaces. The antibiotic susceptibilities of the isolates were investigated. Most of the isolates were moderately sensitive to commonly used antibiotics. Resistance to β-lactam antibiotics was detected among most of the Staphylococcus spp. isolates. High bacterial loads were detected in surfaces of publicly used equipment. The majority of the isolates are of human skin sources (Staphylococcus species) and/or soil bacteria (Bacillus species) while no coliform bacteria were recovered.   Key words: Bacillus, staphylococcus, elevators, vending machines, surfaces, antibiotic, sensitivity.