Occurrence, Antimicrobial Resistance Profiles, and One Health Implications of Klebsiella Species in Commercial Layer Chickens and Poultry Farm Environments in Maiduguri, Northeastern Nigeria

Abstract

Antimicrobial-resistant Klebsiella species in poultry pose a One Health threat, yet surveillance data from Northeastern Nigeria are scarce. This cross-sectional study (July 2025–May 2026) investigated the occurrence, species distribution, and antimicrobial resistance (AMR) profiles of Klebsiella species in commercial layer chickens and farm environments in Maiduguri, Borno State, Nigeria, and assessed associated farmer practices. A total of 125 samples (75 cloacal swabs, 25 surface swabs, 13 feed, and 12 water) were collected from five poultry farms and processed using standard microbiological and biochemical methods. Antimicrobial susceptibility was determined using Kirby–Bauer disk diffusion method, and a structured questionnaire assessed antimicrobial use and biosecurity practices among 75 respondents from 15 purposively selected commercial poultry farms. The overall prevalence of Klebsiella species was 21.6% (27/125), comprising K. pneumoniae (70.4%), K. oxytoca (22.2%), and K. variicola (7.4%). Deep litter management was significantly associated with higher colonization (42.9% against 7.5% in battery cages; p = 0.0003). High resistance rates were observed against ampicillin (70.4%), tetracycline (66.7%), and trimethoprim-sulfamethoxazole (59.3%); 44.4% of isolates were multidrug-resistant (MDR), including one extensively drug-resistant isolate. The mean multiple antibiotic resistance index was 0.38 ± 0.22, with 44.4% of isolates exceeding the 0.21 high-risk threshold. Non-adherence to dosage and absence of veterinary consultation were significantly associated with MDR (p = 0.0433 each), while tertiary education was associated with better biosecurity and stewardship practices (p < 0.05). These findings demonstrate substantial environmental and avian reservoirs of antimicrobial-resistant Klebsiella in Maiduguri, underscoring the urgent need for integrated One Health surveillance, antimicrobial stewardship, and improved biosecurity in poultry production.