Phenotypic detection of multi-drug resistant MBL-producing Gram-negative bacteria isolated from clinical samples of patients in hospitals in Akwa Ibom State, Nigeria

Abstract

Metallo-beta-lactamase (MBL)-producing Gram-negative bacteria (GNB) continue to be a bane in the treatment of clinical infections in both community and hospital settings. Prompt detection of multidrug resistant (MDR) strains using antimicrobial susceptibility testing (AST) and MBL detection are vital for therapeutic options. The aim of this study was to determine the prevalence, distribution and antibiotic susceptibility of MDR and MBL-producing GNB from clinical samples in health facilities in Akwa Ibom State. A total of 480 samples comprising wound, urine and blood were collected aseptically from eligible in- and out-patients for the study and GNB were recovered from the samples using standard bacteriological techniques. The identification of isolated GNB, AST and detection of MBL-producing GNB were done using VITEK®2 COMPACT (Biomerieux) automated system, Modified Kirby Bauer disc diffusion method and IMP+EDTA CDT phenotypic method, respectively. Gram-negative bacterial growth was detected in 135 (77.1%.) cases with Escherichia coli (20.7%), Klebsiella pneumoniae (17.8%) and Burkholderia cepacia (14.1%) being the most preponderant isolates. Urine yielded more GNB, 45.2% than other samples. The isolates were sensitive to gentamicin (63%), imipenem (54.8%), and ofloxacin (46.7%) but showed high resistance to sulfamethoxazole-trimethoprim (78.5%), ceftriaxone (74.1%) and aztreonam (66.7%). The overall prevalence of MDR was 60% with the highest recorded in University of Uyo Teaching Hospital (UUTH), 64.8%. The overall prevalence of MBL producers was 39.3% with H. alvei, M. morgannii, P. mirabilis, R. radiobacter and P. aeruginosa being the majority, mostly from urine samples (47.5%) and UUTH health facility (43.7%). All MBL-producing GNB were MDR strains. Seven strains were pan-drug resistant. A combination of robust antibiotic and MBL screening of drug resistant GNB is essential for effective therapeutic decisions. Also, rational use of antibiotics, review of antibiotic usage policies and increased surveillance of MBL-producing GNB is strongly advocated.