Phenotypic Detection of Virulence Markers, Antibiotic and Disinfectant Susceptibility of Bacterial Isolates from Automated Teller Machine Keypads, Computer Keyboards and Mice in Uyo, Nigeria

Abstract

The occurrence and virulence markers of bacterial isolates from Automated Teller Machine Keypads (ATM), Computer Keyboards (CK) and Computer Mice (CM) were determined using standard bacteriological methods. The susceptibilities of the isolates to antibiotics and disinfectants (Savlon, Dettol and hydrogen peroxide) were determined by disc diffusion techniques. The bacterial isolates on the 12 CMs from cyber cafés were Staphylococcus aureus 7 (58.3%), Bacillus spp 5 (41.7%), Staphylococcus epidermidis 4 (33.3%), Streptococcus spp 4 (33.3%), Escherichia coli 2 (16.7%), Enterococcus spp 2 (16.7%) and Pseudomonas aureginosa 1(8.3%). S. aureus was the predominant bacterial isolate from CKs and ATM keypads, while Bacillus spp. had the lowest percentage of occurrence. A total of 23 (47.9%) CK swab samples had single bacterial growth, while 25 (52.1%) had mixed bacterial flora. Of the 12 CM from cybercafés, 3/12 (25.0%) showed growth of single bacterial isolate, while 9 /12 (75.0%) had mixed bacterial growth. More than 52% S. aureus, Streptococcus spp and Enterococcus spp were sensitive to ofloxacin and streptomycin, while ≥ 39.1% E. coli were resistant to ceftriaxone and ampicillin. The results showed that between 46/146 (31.5%) and 61/146 (41.8%) of the isolates produced DNase, TNase and amylase. Of the 73/146 (50.0%) lipase producing bacterial isolates, the widest clear zone was observed on the tributyrin agar plate containing S. aureus SA-C2. More than 21.9% bacterial isolates produced capsules, haemolysins, caseinase and gelatinase. Savlon showed the highest antibacterial activities than Dettol and hydrogen peroxide. The highest and lowest inhibitory zones were observed in the plates containing P. aureginosa PA-B2 and S. aureus SA-A6 having the mean ± SD of 14.0 ± 0.5 mm and 6.4 ± 1.2 mm, respectively. The ATM, computer keyboards and mice harboured multidrug resistant pathogenic bacteria that may be transferred to / among the users and Savlon could be first choice of disinfectant for the cleansing / disinfecting of these fomites.