Journal Article

Assessing the mechanisms of multi-drug resistant non-typhoidal Salmonella (NTS) serovars isolated from layer chicken farms in Nigeria

Lettini, Antonia A., Antonello, Keti, Kabir, Junaidu A., Umoh, Jarleth U., Ramon, Elena, Ricci, Antonia, Abdu, Paul A., Aworh, Mabel K., Fagbamila, Idowu Oluwabunmi, Kwaga, Jacob K. P., Muhammad, Maryam, Barco, Lisa, Longo, Alessandra

2023

Overview

In Nigeria, there have been reports of widespread multiple antimicrobial resistance (AMR) amongst Salmonella isolated from poultry. To mitigate the impact of mortality associated with Salmonella on their farms, farmers resort to the use of antimicrobials without sound diagnostic advice. We conducted this study to describe the AMR patterns, mechanisms and genetic similarities within some Salmonella serovars isolated from different layer farms. We determine the AMR profiles of two hundred Salmonella isolates, selected based on frequency, serovar, and geographical and sample type distribution. We also assessed the mechanisms of multi-drug resistance for specific genetic determinants by using PCR protocols and gene sequence analysis. Pulsed-field gel electrophoresis (PFGE) was conducted on seven selected serovars to determine their genetic relatedness. Of 200 isolates, 97 (48.5%) revealed various AMR profiles, with the multiple antibiotic resistance (MAR) index ranging from 0.07-0.5. Resistance to ciprofloxacin was common in all the multi-drug resistant isolates, while all the isolates were susceptible to cefotaxime, ceftazidime, and meropenem. Genotypic characterization showed the presence of resistance genes as well as mutations in the nucleotide genes with subsequent amino acid substitutions. Fifteen isolates (43%) of S. Kentucky were indistinguishable, but were isolated from four different states in Nigeria (Ogun, n = 9; Kaduna, n = 6; Plateau, n = 3, and: Bauchi, n = 2). PFGE revealed 40 pulsotype patterns (Kentucky, n = 12; Larochelle, n = 9; Virchow, n = 5; Saintpaul, n = 4; Poona, n = 3; Isangi, n = 2, and; Nigeria, n = 2). This study recorded strictly related but diversely distributed Salmonella serovars with high AMR rates in poultry. We recommend strict regulation on antimicrobial use and regular monitoring of AMR trends among bacteria isolated from animals and humans to inform public policy.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Agriculture / Amino acids / Analysis / Animals / Antibiotic resistance / Antibiotics / Antimicrobial agents / Antimicrobial resistance / Bacterial infections / Biology and Life Sciences / Care and treatment / Cefotaxime / Ceftazidime / Chickens / Ciprofloxacin / Contamination / Diagnosis / Dihydrofolate reductase / Drug resistance / Drug resistance in microorganisms / Electrophoresis / Enzymes / Farmers / Farms / Genes / Health aspects / Humans / Infections / Livestock farms / Medicine and Health Sciences / Meropenem / Multidrug resistance / Mutation / Nigeria / Nucleotides / Poultry / Poultry farming / Poultry industry / Public health / Public policy / Pulsed-field gel electrophoresis / Research and Analysis Methods / Salmonella / Salmonellosis / Sequence analysis / Serogroup / Tetracycline / Tetracyclines / Veterinary medicine