Genome sequences of two Salmonella enterica strains (MEZSAL74 and MEZSAL81) harbouring multiple antimicrobial resistance genes isolated from livestock in South Africa

Abstract

Objectives: Antimicrobial-resistant livestock-associated Salmonella enterica infections pose a significant public-health threat worldwide. Here we report for the first time the draft genome sequences of two multidrug-resistant livestock-associated S. enterica strains isolated from a chicken and a cow in South Africa. Methods: Genomic DNA of S. enterica strains MEZSAL74 and MEZSAL81 was sequenced using an Illumina MiSeq platform. The generated reads were trimmed and de novo assembled. The assembled contigs were analysed for antimicrobial resistance genes, chromosomal mutations and extrachromosomal plasmids. Multilocus sequence typing (MLST) was also performed. In order to compare isolates MEZSAL74 and MEZSAL81 with other previously sequenced S. enterica isolates, raw read sequences were downloaded and all sequence files were treated identically to generate a bootstrapped maximum likelihood phylogenetic tree. Results: Extrachromosomal plasmids and genetic determinants of antimicrobial resistance were detected in both sequenced bacterial isolates to aminoglycosides and fluoroquinolones. By MLST, strain MEZSAL74 belonged to an unknown sequence type (ST) and strain MEZSAL81 belonged to ST33. Conclusion: The genome sequences of strains MEZSAL74 and MEZSAL81 reported here will serve as a reference for molecular epidemiological studies of antimicrobial-resistant livestock-associated S. enterica in Africa.

Keywords

• Salmonella
• Africa
• Zoonosis
• Antimicrobial resistance
• Multidrug
• Genome sequencing