Abstract

A major contributing factor to Gram Negative Bacteria (GNB) resistance to third and fourth generation cephalosporin is the formation of Extended Spectrum Beta-Lactamases (ESBLs). Antibiotic resistance, particularly mediated by ESBL enzymes, poses a major global public health challenge. This study investigated the distribution of GNB, ESBL resistance genes, and their occurrence in clinical and environmental samples from two healthcare facilities. A total of 566 bacterial were isolated from clinical and environmental samples at the hospitals using MacConkey agar. The GNB were identified using standard microbiological methods and subjected to antibiotic susceptibility testing using the Kirby Bauer disk diffusion method. Isolates (137) that showed resistance to at least eight antibiotics were selected for ESBLs resistance genes (bla-_TEM, bla-_CTX-M, bla-_SHV) detection using primer specific PCR. Isolates that haboured resistance genes were identified using 16S rRNA sequencing. Data were analysed using descriptive statistics. Out of a total of 566 bacteria isolated, 409(72.3%) were GNB and were tested for Multidrug Resistance (MDR). Molecular characterization revealed that 66 (16.1%) of the isolates harbored ESBL genes. The distribution of ESBL genes showed that bla-_TEM (53.0%) was the most prevalent, followed by bla-_CTX-M (37.9%) and bla-_SHV (9.1%). Clinical isolates accounted for the majority of ESBL genes (77.3%), compared to environmental isolates (22.7%). Escherichia coli was the predominant ESBL-producing organism, accounting for 74.5% of clinical isolates and 40.0% of environmental isolates. Molecular identities of the isolates were Enterobacter hormaechei, Escherichia coli, Klebsiella pneumoniae, Klebsiella quasipneumoniae, Proteus mirabilis and Pseudomonas sp. The presence of ESBL genes in environmental samples underscores the role of hospital environments as reservoirs for antibiotic resistance and supports the potential for horizontal gene transfer among bacterial populations.