Mapping Antimicrobial Resistance in Commensal Bacteria from Food Animals Across Six Geopolitical Zones in Nigeria

Baseline antimicrobial resistance data from commensal bacteria in food animals across Nigeria's geopolitical zones are essential for national surveillance program design and international reporting obligations. This study mapped antimicrobial resistance profiles in commensal Escherichia coli and Enterococcus isolates from food animals across all six geopolitical zones of Nigeria. A stratified multi-stage sampling design was employed, targeting cattle, poultry, and pigs from selected abattoirs and farms in 12 states representing all zones. Commensal E. coli and Enterococcus faecalis were isolated from fecal samples and subjected to minimum inhibitory concentration determination for 14 antimicrobial agents. Zone-level resistance prevalence was calculated, and a resistance index was generated for comparative analysis. High resistance to tetracycline, ampicillin, and sulfonamides was found across all zones in E. coli, exceeding 60%. Fluoroquinolone resistance was highest in the South West at 44.3% and lowest in the North East at 28.7%. Vancomycin-resistant Enterococcus isolates were identified in all zones, with the South South showing the highest proportion at 19.4%. Multi-drug resistance exceeded 50% in E. coli from all zones. The study provides the first geopolitically stratified commensal resistance baseline for Nigeria, concluding that antimicrobial resistance is widespread across all zones and food animal species. A national food animal antimicrobial resistance surveillance program with standardized methodologies is urgently needed. Keywords: antimicrobial resistance, commensal bacteria, food animals, Nigeria geopolitical zones, surveillance