Antimicrobial Resistance and Virulence Gene Profiles of Methicillin-Resistant and -Susceptible Staphylococcus aureus From Food Products in Denmark

Abstract

Foods may potentially serve as vehicles for the transmission of antimicrobial-resistant variants of Staphylococcus aureus that are important in a human clinical context. Further, retail food products can be a cause of staphylococcal food poisoning. For these reasons and to account for source attribution and risk assessment, detailed information on the population structure, resistance, and virulence profiles of S. aureus originating from retail food products is necessary. In the current study, whole-genome sequences from 88 S. aureus isolates were subjected to bioinformatics analyses in relation to sequence types, antimicrobial resistance, and virulence profiles.The sequence types (ST) identified belonged to 13 clonal complexes (CC) with CC5 and CC398 being the most common. CC398 was identified as the dominant clone (n = 31). CC5 was identified as of avian origin, with the presence of ϕAVβ prophage genes (n = 13). In total, 39.8% of the isolates contained multiple resistance genes, and methicillinresistant Staphylococcus aureus (MRSA) isolates were found in CC8, CC9, and CC398. Genes conferring resistance to the antimicrobial classes of β-lactams, tetracycline, and erythromycin were detected in this study, all of which are commonly used in Danish livestock production. The tst gene encoding the toxic shock syndrome toxin was for the first time identified in ST398 isolates, probably as a result of a single acquisition of a SaPI-like element. The sushi-CC398 isolates carrying the scn gene likely originated from a human reservoir, while the other isolates originated from livestock. Taken together, our results show that both human and animal reservoirs contribute to contamination in food products and that retail foods may serve as a vehicle of S. aureus between livestock and humans.

Profiles of coagulase-positive and -negative staphylococci in retail pork: prevalence, antimicrobial resistance, enterotoxigenicity, and virulence factors

“…Although coagulase-positive S. aureus is the most common cause of SFP among staphylococcal species [ 1 ], recent studies have indicated that CoNS can produce SEs and become a potential cause of food poisoning. Staphylococci are normally present in the human and animal microbiota and are frequently found on the skin and in the upper respiratory tract of the host [ 18 ].…”

“…These five isolates were all positive for mecA and displayed an OXA-resistant CoPS, Coagulase-positive staphylococci; CoNS, Coagulase-negative staphylococci. 1) SCCmec, staphylococcal cassette chromosome mec.…”

“…Based on their ability to coagulate rabbit plasma, staphylococci have traditionally been grouped into coagulase-positive staphylococci (CoPS) or coagulase-negative staphylococci (CoNS). As a major human and animal pathogen CoPS, S. aureus can cause a variety of infections including superficial skin and soft tissue infections, osteomyelitis, and septicemia [ 1 ]. Although not usually life-threatening, staphylococcal food poisoning (SFP) is one of the most frequent food-borne diseases, and results from the ingestion of staphylococcal enterotoxins (SEs) that are secreted mainly by CoPS, especially S. aureus [ 1 ].…”

“…As a major human and animal pathogen CoPS, S. aureus can cause a variety of infections including superficial skin and soft tissue infections, osteomyelitis, and septicemia [ 1 ]. Although not usually life-threatening, staphylococcal food poisoning (SFP) is one of the most frequent food-borne diseases, and results from the ingestion of staphylococcal enterotoxins (SEs) that are secreted mainly by CoPS, especially S. aureus [ 1 ]. SFP is a noncontagious acute gastrointestinal disease caused shortly after ingestion of food contaminated with enterotoxin-producing staphylococci.…”

Molecular typing, phenotypic and genotypic assessment of antibiotic resistance and virulence factors amongst the Staphylococcus aureus bacteria isolated from raw chicken meat

“…Thus, the high distributions of etA and etB genes in examined chicken meat samples could be due to the transmission of S. aureus strains from the skin of workers and staffs of slaughterhouses [55]. H Li, P Andersen, M Stegger, R Sieber, H ngmer, N Staubrand, A Dalsgaard and J Leisner [56] reported that the S. aureus strains isolated from poultry meat samples didn't harbor etA and etB virulence factors, while the distribution of the tsst-1 gene was 3.40%. The tsst-1 gene is a super-antigen that can cause a diversity of clinical complications.…”