Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2019

Multidrug-resistant Salmonella isolated in Australia harbour a conjugative plasmid similar to that from a Salmonella strain isolated in Canada (#232)

Amreeta Sarjit 1 2 , Joshua T Ravensdale 1 , Ranil Coorey 3 , Narelle Fegan 2 , Gary A Dykes 1
  1. School of Public Health, Curtin University, Bentley, Western Australia, Australia
  2. CSIRO, Agriculture and Food, Brisbane, Queensland, Australia
  3. School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia

Red meat has been implicated as a source of foodborne bacterial pathogens such as Salmonella enterica. Antimicrobial resistance to antibiotics is a major concern to both human and red meat species. The aim of this study was to determine the presence of antibiotic resistance genes and occurrence of conjugative plasmids in antibiotic resistant Salmonella strains isolated from different red meat species in Australia. Whole genome sequencing of S. Heidelberg (n = 3) and S. Typhimurium (n = 1) was performed using the Illumina Miseq Sequencer (V3 2 x 300 bp reads). Genomes were assembled using SPAdes and annotated using Rapid Annotation using Subsystems Technology (RAST). Bioinformatic tools were used to determine antimicrobial resistance genes, plasmid replicons and orthologous average nucleotide identity. Aminoglycoside, beta lactam, macrolide, sulphonamide, tetracycline and trimethoprim resistance genes were detected in S. Heidelberg 329 and S. Typhimurium 2470. Three plasmids were detected in S. Heidelberg 329 and two plasmids in S. Typhimurium 2470. S. Heidelberg 329 and S. Typhimurium 2470 harboured a similar plasmid to a multidrug resistant S. Heidelberg strain N13-01290 plasmid pN13-01290_23 isolated in Canada. S. Heidelberg 329 and S. Typhimurium 2470 have plasmids belonging to the IncHI2 group similar to plasmid pN13-01290_23. S. Heidelberg 632 and S. Heidelberg 2581 had only aminoglycoside and fosfomycin resistance genes. S. Heidelberg 632 has two plasmids belonging to the InclI group while no plasmids were detected in S. Heidelberg 2581. This study suggests the IncH12 group plasmid is present in strains from different countries and may infer that these plasmids are involved in the transmission of multiple antibiotic resistance genes on a conjugative plasmid. This may confer an advantage towards the persistence and survival of Salmonella.