Extended-spectrum β-lactamase Enzymes (ESBLs)-Encoding Genes among Some Gram-negative Bacilli from Various Sources in Port Harcourt, Nigeria
S. J. Horsfall *
Faculty of Medical Laboratory Science, Rivers State University, Port Harcourt, Nigeria.
E. G. Nwokah
Faculty of Medical Laboratory Science, Rivers State University, Port Harcourt, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aim: To assess extended-spectrum β-lactamase (ESBL)-encoding genes among selected Gram-negative bacilli from various sources in Port Harcourt, Nigeria.
Study Design: Cross-sectional study.
Place and Duration of Study: University of Port Harcourt Teaching Hospital, Trans-Amadi and Rumuodomaya abattoirs, and Bob-D Ventures Poultry Farms, all in Port Harcourt, Nigeria, between July and December 2019.
Methodology: This study was conducted in the Port Harcourt and Obio/Akpor Local Government Areas of Rivers State, Nigeria, from 2019 to 2020. Hospital wastewater was collected from different sections of two university teaching hospitals: the University of Port Harcourt Teaching Hospital and Rivers State University Teaching Hospital. Abattoir effluent water samples were collected at different sites from the Trans-Amadi and Rumuodomaya abattoirs. Chicken cloacal samples and hand-swab samples from butchers were collected at the two abattoirs. ESBL production was assessed using the double-disc synergy method, together with slime production. Representative isolates with the ESBL phenotype were assessed for selected ESBL-encoding genes and phylogenetic relationships using relevant molecular biology tools.
Results: Of the 19 representative, phenotypically ESBL-positive isolates assessed for ESBL genes, 14 (73.7%) were positive. Five isolates harboured the CTX-M gene, three harboured the SHV gene, two possessed the VEB gene, and four possessed the TEM gene. No target was detected for the NDM gene. The majority of the gene-harbouring isolates were from the wastewater environment.
Conclusion: Multiple-drug resistance to commonly used antibiotics is high in the study area. Contamination of wastewater by antibiotics or other pollutants may contribute to the emergence of resistance through selection pressure. The presence of antibiotic-resistant organisms in these wastewaters should not be overlooked. Proper wastewater treatment and improved sanitary measures are advocated.
Keywords: Extended-spectrum β-lactamase enzymes (ESBLs)-encoding genes, Gram-negative bacilli, Port Harcourt