ANTIBIOTIC SUSCEPTIBILITY PROFILES AND MULTIPLE ANTIBIOTIC RESISTANCE INDEX OF SALMONELLA SPP AND ESCHERICHIA COLI FROM POULTRY DROPPINGS FROM SELECTED FARMS IN SAMARU, ZARIA
The poultry industry represents a critical source of affordable protein globally, yet intensive farming practices involving extensive antibiotic use have created environments favoring the emergence of antibiotic-resistant bacteria, posing significant public health threats. This study aimed to determine the prevalence and antibiotic susceptibility profiles of Salmonella species and Escherichia coli from poultry droppings collected from selected farms in Samaru, Zaria. Poultry droppings were collected from 10 different farms, and bacteria were isolated using culture techniques involving serial dilution and plating on MacConkey agar, followed by subculturing on Eosin Methylene Blue (EMB) and Bismuth Sulfite Agar (BSA). Isolates were identified through Gram staining and biochemical tests which include citrate utilization, urease, sulfide-indole-motility, methyl red, and Voges-Proskauer tests. Antibiotic susceptibility testing was performed using the disc diffusion method against six antibiotics. Multiple antibiotic resistance index (MAR index) and multidrug-resistant was determined. Thirty bacteria were isolated, comprising of 60% E. coli and 40% Salmonella species, identified through distinctive colony morphology and biochemical profiles. All isolates, i.e. 100% of the isolates, showed resistance to amoxicillin and linezolid, while ciprofloxacin showed the highest activity with 36.67% of isolates susceptible, followed by gentamicin at 33.33% susceptibility. All thirty isolates exhibited multidrug resistance and MAR index values exceeding 0.2, suggesting that the isolates originated from high-risk sources with significant antibiotic selective pressure. The study concludes that poultry serves as a significant reservoir for multidrug-resistant Salmonella species and Escherichia coli, with alarming resistance patterns to commonly used antibiotics, though isolates remained highly susceptible to ciprofloxacin and gentamicin, highlighting the urgent need for antimicrobial stewardship interventions in poultry production systems.
Keywords: Antibiotic-resistance, Escherichia coli, poultry, Salmonella species
*Correspondence: tbulus@kasu.edu.ng, +2348051282789
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