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

Abstract

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

Staphylococcus aureus in Intensive Pig Production in South Africa: Antibiotic Resistance, Virulence Determinants, and Clonality

“…Therefore, studies involving a larger number of isolates could provide a better picture of the clonality along the farm-to-fork continuum. A similar trend was observed in a study by Neyaz et al on the characterisation of S. aureus from various meat products where a high prevalence of tetracycline resistance was reported in two different clones [ 65 ]. A 2019 study in Italy using other typing methods, including WGS, reported 94.1% of human MRSA isolates belonging to the same epidemiological group as swine MRSA isolates [ 26 ].…”

“…PVL is also considered a genetic marker for CA-MRSA due to its prominence in this epidemiological class [ 64 ]. A substantial number of isolates carried the PVL gene, corroborating a study conducted on S. aureus isolated from backyard-raised pigs and pig workers in Nigeria, with 27% of isolates harbouring PVL [ 65 ]. However, although PVL has been associated with necrotising pneumonia and joint infection in humans, its role in pigs is not thoroughly investigated; hence, the current findings should be interpreted with caution [ 66 ], as its presence does not necessarily imply diseased animals.…”

Antimicrobial activity of Wickerhamomyces anomalus mycocins against strains of Staphylococcus aureus isolated from meats

“…About 45% of the worldwide food poisoning are caused by bacteria of the genus Staphylococcus. Contamination occurs mainly during food production and storage periods, as it is during this period that temperatures are proper for the proliferation of this microorganism (Cunha et al, 2002;Neyaz et al, 2020).…”

Chemical proteomics tracks virus entry and uncovers NCAM1 as Zika virus receptor

“…In addition, we examined temporally ZIKV-crosslinked proteins against protein components involved in major endocytic mechanisms for ZIKV internalization. Prior studies showed ZIKV infection could be prevented by lysosomotropic agents which neutralize the normally acidic pH of endosomal compartments and was also blocked by chlorpromazine 34 , 35 , indicating the requirement of clathrin-mediated endocytosis and low pH for ZIKV infection. In our study, ITGB1, HSPA8, RAB5C, RACK1, and RAB11A were crosslinked, suggesting the clathrin-mediated pathway employed by the virus to infect Vero cells.…”