EFFLUX-PUMP EXPRESSION IN MULTIDRUG-RESISTANT BACTERIA: CASE IN A UNIVERSITY TEACHING HOSPITAL OF CAMEROON (original) (raw)

n line with the high multidrug-resistance rates observed in bacteria and the importance of resistance mechanisms in the management of infectious diseases, the present investigation was conducted to detect with an efflux pump inhibitor (reserpine) efflux pump-expressing bacterial isolates from clinical specimens at the Laboratory of Microbiology of the Université des Montagnes Teaching Hospital. Standard disk diffusion and minimal inhibitory concentration techniques were used as recommended by CASFM, 2016. Susceptibility tests were performed on a total of 51 multidrug-resistant isolates with and without reserpine at the sub-inhibitory concentration. Out of these, 30 eventually selected as potential efflux pump-positive isolates further underwent the micro-dilution at varying concentrations of antibiotic/reserpine combinations. The minimal inhibitory concentration test values recorded with antibiotic/reserpine combination revealed improved effectiveness for Erythromycin, Tetracycline, Gentamicin, Azithromycin, Ciprofloxacin and Ofloxacin. 1024 μg/mL for reserpine was sub-inhibitory, but when it was used at 32μg / mL with Ofloxacin the MIC value recorded dropped by about 1/8 compared to the value recorded when Ofloxacin was used alone on some isolates; and about 1/2 to 1/4 with other antibiotics. Overall, 47% of isolates were positive for efflux pump expression, overwhelmed by Enterobacteriaceae (62.7%) and Micrococaceae (17.6%) and, namely Enterobacter (78%), Escherichia (57%), Staphylococcus (56 %), and Klebsiella (25%). Since organisms from these genera are most frequent etiologies of IDs further work is necessary to detect efflux pump- positive isolates in the routine process.