Molecular epidemiological characteristics and genetic evolutionary relationships of methicillin-resistant <i>Staphylococcus aureus</i> of different avian origins in Qingdao, China, using whole-genome sequencing

Abstract Introduction To understand the prevalence of avian methicillin-resistant Staphylococcus aureus (MRSA) and current status drug resistance in Qingdao, a comprehensive molecular epidemiological investigation analysis evolutionary relationships MRSA isolates from broiler layer chickens waterfowl was conducted. Material Methods One hundred two strains were identified by multi-locus sequence typing, staphylococcal protein A ( spa ) cassette chromosome mec (SCCmec) whole-genome sequencing. Results The type (ST) 9-t899-SCC IVb represented highest proportion avian-derived (71.57%), with ST398 occasionally observed broilers waterfowl. poultry-derived all resistant to eight or more antimicrobials. Avian-derived carried 20 genes, 109 virulence genes 10 plasmids. Strains carrying cfr oxazolidinone gene seen broiler- layer-derived MRSA. Single nucleotide polymorphism (SNP) core genome evolution locus difference showed that closest ST9-t899 (to which also affiliated number strains) this occurred on three kinds poultry farm, but SNP loci between same ranged 0 1472. Conclusion dominant different sources Qingdao is ST9-t899-SCC IVb, commonly variety antimicrobial drugs carries large genes. Sequence 9-t899 widely spread among investigated, there are differences affiliations.