Antimicrobial Resistance among Enterobacteriaceae Found in Chicken and Cow Droppings and Their Public Health Importance

Abstract

Introduction: The recent surge in the number of antimicrobial resistant cases from hospitals and communities has created a need to study the points and sources of exposure to certain bacteria and determine their susceptibility to commonly used antibiotics. This study aimed at identifying and screening for drug-resistant Enterobacteriaceae isolated from chicken droppings and cow dungs in Onitsha, Anambra state, in the South-Eastern part of Nigeria. Methods: This is a cross-sectional descriptive study which included 50 chickens and 50 cow dung samples collected from five poultry houses and cow ranches respectively using sterile swab sticks. The samples were transported to the laboratory and processed following standard microbiological protocols. Isolates in the samples were recovered using MacConkey Agar, Eosin Methylene Blue Agar and Salmonella-Shigella Agar following standard microbiological procedures and then identified/characterized biochemically using commercial API 20E identification kits following the standard manufacturer’s protocol. Isolates were subjected to antibiotic susceptibility testing on Muller Hinton Agar using Kirby Bauer double-disc diffusion technique. The multiple antibiotics resistance index was determined as well. Isolates with reduced susceptibility to Ceftazidime were screened for extended spectrum beta-lactamase, AmpC- and metallo-beta-lactamase-production using Rosco Diagnostic kit. Results: Sixty-two (100%) Gram-negative bacteria were isolated from a total of 100 samples collected from both sites, out of which 43 (69.4%) are Enterobacteriaceae. A total of 30/43 (69.8%) Enterobacteriaceae including K. pneumoniae, S. enteritica, S. odorifera, E. coli, K. intermediate, P. stuartii, E. aerogenes, P. penneri, P. mirabilis and C. braakii were recovered from chicken droppings, whereas 13/43 (30.2%) Enterobacteriaceae including K. pneumoniae, S. enteritica, S. odorifera, E. coli, K. intermediate, P. stuartii, E. aerogenes, P. penneri, P. mirabilis and C. braakii were recovered from cow dungs. Two (12.5%) different isolates demonstrated metallo-beta-lactamase and cephalosporinase (AmpC) production. The isolates were susceptible to six antibiotics tested except Augmentin and Nitrofurantoin where the resistance is 100% and 85% respectively while Ceftriaxone and Ofloxacin had the best antibacterial activity against the isolates from both sites. Conclusion: The bacteria of public health importance isolated from these sites and their antibiogram profile have shown the need for proper monitoring and management of animal wastes in order to mitigate the threat to human health in the spirit of One Health as well as contribute to the fight against antibiotic resistance.