AUTHOR=Neyaz Leena , Rajagopal Nisha , Wells Harrington , Fakhr Mohamed K. 

TITLE=Molecular Characterization of Staphylococcus aureus Plasmids Associated With Strains Isolated From Various Retail Meats

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00223

DOI=10.3389/fmicb.2020.00223

ISSN=1664-302X

ABSTRACT=<p><italic>Staphylococcus aureus</italic> is considered one of the most important foodborne bacterial pathogens causing food poisoning and related illnesses. <italic>S. aureus</italic> strains harbor plasmids encoding genes for virulence and antimicrobial resistance, but few studies have investigated <italic>S. aureus</italic> plasmids, especially megaplasmids, in isolates from retail meats. Furthermore, knowledge about the distribution of genes encoding replication (<italic>rep</italic>) initiation proteins in food isolates is lacking. In this study, the prevalence of plasmids in <italic>S. aureus</italic> strains isolated from retail meats purchased in Oklahoma was investigated; furthermore, we evaluated associations between <italic>rep</italic> families, selected virulence and antimicrobial resistance genes, and food source origin. Two hundred and twenty-two <italic>S. aureus</italic> isolates from chicken (<italic>n</italic> = 55), beef liver (<italic>n</italic> = 43), pork (<italic>n</italic> = 42), chicken liver (<italic>n</italic> = 29), beef (<italic>n</italic> = 24), turkey (<italic>n</italic> = 22), and chicken gizzards (<italic>n</italic> = 7) were subjected to plasmid screening with alkaline lysis and PFGE to detect small-to-medium sized and large plasmids, respectively. The <italic>S. aureus</italic> isolates contained variable sizes of plasmids, and PFGE was superior to alkaline lysis in detecting large megaplasmids. A total of 26 <italic>rep</italic> families were identified by PCR, and the most dominant <italic>rep</italic> families were <italic>rep</italic><sub>10</sub> and <italic>rep</italic><sub>7</sub> in 164 isolates (89%), <italic>rep</italic><sub>21</sub> in 124 isolates (56%), and <italic>rep</italic><sub>12</sub> in 99 isolates (45%). Relationships between selected <italic>rep</italic> genes, antimicrobial resistance and virulence genes, and meat sources were detected. In conclusion, <italic>S. aureus</italic> strains isolated from retail meats harbor plasmids with various sizes and there is an association between <italic>rep</italic> genes on these plasmids and the meat source or the antimicrobial resistance of the strains harboring them.</p>