Antimicrobial resistance of enterobacteriaceae isolated from shell eggs in owerri west, imo state, nigeria

Abstract

Poultry eggs represent one of the most widely consumed sources of animal protein across the globe, yet eggshell surfaces can serve as reservoirs for pathogenic bacteria that pose serious public health risks when contaminated with antibiotic resistant organisms. This study examined the presence and antimicrobial susceptibility patterns of Enterobacteriaceae isolated from shell eggs obtained from two commercial chicken farms in Owerri West Local Government Area, Imo State, Nigeria. A total of 100 fresh eggs (50 per farm) were subjected to standard bacteriological analysis. Bacterial isolates were identified through colony morphology, Gram staining, and biochemical characterization using IMViC, catalase, oxidase, urease, and motility tests. Antimicrobial susceptibility was assessed using the Kirby Bauer disk diffusion method against ten commonly used antibiotics. Two Gram negative Enterobacteriaceae were provisionally identified as Enterobacter spp. and Klebsiella pneumoniae. Total bacterial counts varied between sampling locations, with eggs from Location A recording substantially higher counts (7.0 × 104 CFU/mL) than those from Location B (1.0 × 104 CFU/mL). Ciprofloxacin demonstrated the strongest inhibitory activity among all tested antibiotics, while resistance was observed towards augmentin, gentamicin, and nalidixic acid in K. pneumoniae. The findings underscore the potential role of eggshells as reservoirs of antimicrobial resistant bacteria and highlight the necessity for improved hygiene practices, regular surveillance, and strengthened biosecurity measures in poultry production systems within the One Health framework.