Prevalence of Beta-lactam Resistance Genes (Bla Genes) in Multidrug-Resistant Strains of Escherichia coli and Klebsiella pneumoniae Isolated from Infections at a University Hospital in Abidjan, Ivory Coast

Abstract

Aim: The overall objective of this study was to characterise the bla genes responsible for beta-lactam resistance in two major strains of Enterobacteriaceae (Escherichia coli and Klebsiella pneumoniae) involved in bacterial infections and producing extended-spectrum beta-lactamases. Study Design:  The resistance of Enterobacteriaceae to various classes of antibiotics in general, and to the beta-lactam class in particular, is showing a worrying trend in Côte d’Ivoire and around the world. This resistance is due to the production of extended-spectrum beta-lactamases (ESBLs) encoded by bla genes. Place and Duration of Study: This study was conducted from August 2022 to February 2024 in Abidjan (Ivory Coast) at the Pasteur Institute of Ivory Coast (IPCI), at the Cocody site, specifically within the Unit for Antibiotics, Natural Substances, and Surveillance of Microorganisms and Anti-Infective Agents (ASSURMI). Methodology: These strains were isolated from biological samples collected from various hospital departments. A total of 40 Enterobacteriaceae strains were identified using MALDI-TOF mass spectrometry (MS), and antibiotic susceptibility testing (antibiogram) was performed using the Mueller-Hinton agar diffusion method. Genes conferring resistance to Beta-lactams were detected using conventional PCR. Results: The strains studied were Escherichia coli (25) and Klebsiella pneumoniae (15). Seventy-five per cent of the strains were multidrug-resistant (Escherichia coli: 19/25; Klebsiella pneumoniae: 11/15). High resistance rates ranging from 52.63% to 100% to amoxicillin-clavulanic acid, aztreonam, and third-generation cephalosporins (cefepime, ceftriaxone, cefotaxime, cefixime) were observed. The Beta-lactam resistance genes detected were blaTEM, blaCTX-M-1, blaCTX-M-8, blaSHV, and blaCTX-M- with prevalence rates of 60%, 50%, 35%, 32.5%, and 7.5%, respectively. The co-expression rate of the resistance genes was 22,5 %, 17,5 %, 15 %, 12,5 %, 7,5 %   et   2,5 %, respectively, for the associations blaTEM /blaCTX-M-8, blaTEM /blaCTX-M-1, blaSHV /blaCTX-M-1, blaSHV /blaCTX-M-8, blaTEM / blaSHV, blaTEM / blaSHV / blaCTX-M-1. Conclusion: This study revealed the presence and persistence of bla genes that have been under surveillance for many years, with an increase in the prevalence of certain genes.