Characterization of Enterobacteriaceae from the Soil and Water of selected Abattoirs in Osun State Nigeria

Abstract

Background: Environmental reservoirs of extended-spectrum β-lactamase (ESBL) producing Enterobacteriaceae are poorly documented in Nigeria despite increasing concerns about antimicrobial resistance.

Objective: To characterize Enterobacteriaceae isolated from soil and water in selected abattoirs in Osun State, Southwestern Nigeria, and determine their antibiotic susceptibility patterns and the presence of β-lactam resistance genes (blaTEM, blaSHV, blaCTXM, and blaOXA48).

Methods: A cross-sectional study was conducted in Osogbo, Ede, and Sekona abattoirs. Soil and water samples were collected during the dry season over a three-month period. Isolation and identification were performed using standard microbiological and biochemical methods. Antibiotic susceptibility was determined using the Kirby Bauer disk diffusion method, while polymerase chain reaction (PCR) was used to detect ESBL genes.

Results: A total of 101 Enterobacteriaceae isolates were recovered (soil: 52; water: 49). Predominant soil isolates were Salmonella spp. (36.5%), Enterobacter spp. (32.7%), Escherichia coli (19.3%), and Klebsiella spp. (11.5%). Water samples were dominated by E. coli (48.9%). Multidrug resistance was observed in 82% of isolates. ESBL genes detected included blaOXA-48 (40%) and blaSHV (35%), while blaTEM and blaCTX-M were detected in single isolates. Molecular confirmation using 16S rRNA sequencing identified representative isolates as E. coli and Enterobacter cloacae.

Conclusion: Improved abattoir waste management, environmental monitoring, and antimicrobial stewardship are essential to limit the spread of resistant bacteria and protect public health within a One Health framework.