Antimicrobial resistance profiles of Salmonella gallinarum isolates from free-range chickens in Nasarawa state, Nigeria

Abstract

The development of antimicrobial resistance in bacteria represents a global challenge to the control of
bacterial diseases. The aim of this study was to investigate antimicrobial resistance in S. gallinarum
isolated from free-range chickens in Nasarawa State, Nigeria. The isolates (n=49) were screened for
antimicrobial resistance profiles against 13 antibiotics using the disc diffusion method. Overall, 81.7%
resistance was recorded against ciprofloxacin, followed by gentamicin, (76.1%); ampicillin, (65.8%);
chloramphenicol and cotrimoxazole, (66.2%); tetracycline, (58.1%), while neomycin, nalidixic acid, colistin,
oxytetracycline, norfloxacin, kanamycin and amoxycillin had 43.9%, 42.2%, 35.5%, 33.4%, 30.1%, 24.4% and
12.9% resistances respectively. These resistances were found to be statistically significant (p<0.05), with
the exception of nalidixic and tetracycline which were insignificant (p>0.05). Nasarawa West Senatorial
Zone had an overall percentage drug resistance of 55.1%, followed by Nasarawa North, 44.2% and
Nasarawa South, 40.6%. There was no significant difference (p>0.05) in antimicrobial resistance in the three
senatorial zones. S. gallinarum resistance against the various tested antibiotics was generally low in
Assakio and Andaha when compared with the drug resistance of the isolates in other study areas. Since
free range chickens hardly receive any antibiotic medication, it is probable that the drug resistance
observed may be a reflection of the consequence of drug use among human and animal populations in the
study areas. This is a threat to the control of fowl typhoid in Nasarawa State.