Phenotypic Detection of Multi- Drug Resistant Extended Spectrum Beta-Lactamase-Producing Gram-Negative Clinical Bacteria in Health Care Facilities in Akwa Ibom State, Nigeria

Abstract

The prevalence of multi-drug resistant (MDR) extended spectrum β-lactamase (ESBL) Gram-negative bacteria have become a global concern. This constitutes a challenge in the therapeutic management of patients in both hospital and community settings. In order to achieve an effective treatment option, a more robust laboratory technique that combines both routine antimicrobial susceptibility testing and phenotypic confirmatory test for the identification of prevalent species producing ESBL as well as their antibiotic susceptibility pattern is essential.  The aim of this study was to investigate the prevalence of multi-drug resistant ESBL-producing Gram-negative bacteria and assess their antibiotic susceptibility in Akwa Ibom State, Nigeria. A total of 420 clinical samples (urine, n = 310; wound, n = 110) were aseptically collected from consented patients attending University of Uyo Teaching Hospital (UUTH) and General Hospital Iquita (GHI) for laboratory investigation. Isolated Gram-negative bacteria were identified using Microbact 24E (Oxoid, UK), antibiotic susceptibility testing (AST) was done using the modified Kirby-Bauer disc diffusion method while ESBL-producing bacteria were determined by Double Disk Synergy Test (DDST). Gram-negative bacterial growth was detected in 114 (27.1%) cases. The overall prevalence of Gram-negative bacteria was 29% while the most common bacterial strains causing UTI and pyogenic infection were P. aeruginosa (17.2%), followed by Klebsiella spp.(15.6%), Enterobacter spp. (15.6%) and E. coli (12.3%). Antibiotics such as Imipenem, Amoxicillin – clavulanic acid, Gentamicin and Ofloxacin showed 100% sensitivity to the most commonly isolated pathogens in patients with these infections. Overall, 119 (50.4%) were ESBL-producers. The highest ESBL production was observed for K. ozanae(66.7%), P. gergoviae (66.7%), Enterobacter clocae (62.5%), P. agglomerans (60%), E. coli (42.9%), P. mirabilis (50%) and P. aeruginosa (33.3%). ESBL-producing Gram-negative bacteria showed a high level of multidrug resistance (68.9%) compared to non-ESBLs. The high prevalence of MDR in Gram-negative bacteria in community and hospital settings is the probable cause of treatment failures experienced among UTI and pyogenic patients in our study area.