Antimicrobial drug administration and antimicrobial resistance of Salmonella isolates originating from the broiler production value chain in Nigeria

Abstract

Salmonella is among the pathogens on the high global priority lists for monitoring for studies on the discovery of new antimicrobials and understanding of how antimicrobial resistance (AMR) develops. AMR in connection with antibiotic usage patterns has been considered as a strong factor and contributor to the AMR pool. The purposes of use, pattern of antimicrobial drug administration, as well as the prevalence of AMR in Salmonella originating from the Nigeria broiler production value chain (NBPVC) was explored. A well-structured questionnaire on antimicrobial usage (n = 181) was used for sampling that focused on 21 antimicrobials from 151 locations. Simultaneously, AMR testing for 18 commonly used antimicrobials on Salmonella in humans was also carried out. Antimicrobial resistance Salmonella spp. were isolated in 23% of the samples (261 of 1135 samples from the broiler input, products, and the environment) using modified ISO 6579 and invA PCR protocols. Over 80% of the antimicrobials used in the NBPVC were administered without a veterinarian prescription. Prevalence of antimicrobial administration without prescription were as follows: live-bird-market (100%), hatchery (86.7%), grow-out-farm (75%), and breeder (66.7%). Widespread prophylactic and metaphylactic use of antimicrobials were recorded with the highest use seen for enrofloxacin (63% and 24%), tetracycline (58% and 33%), and erythromycin (50% and 17%). Antimicrobial resistance was highest for flumequine (100%), penicillin (95%), and perfloxacin (89%). High levels of use without laboratory support of a newer generation of a class of antibiotics suspected to confer high resistance on older generations of the same class (quinolones) was observed.