MRSA in Conventional and Alternative Retail Pork Products

Abstract

In order to examine the prevalence of Staphylococcus aureus on retail pork, three hundred ninety-five pork samples were collected from a total of 36 stores in Iowa, Minnesota, and New Jersey. S. aureus was isolated from 256 samples (64.8%, 95% confidence interval [CI] 59.9%–69.5%). S. aureus was isolated from 67.3% (202/300) of conventional pork samples and from 56.8% (54/95) of alternative pork samples (labeled “raised without antibiotics” or “raised without antibiotic growth promotants”). Two hundred and thirty samples (58.2%, 95% CI 53.2%–63.1%) were found to carry methicillin-sensitive S. aureus (MSSA). MSSA was isolated from 61.0% (183/300) of conventional samples and from 49.5% (47/95) of alternative samples. Twenty-six pork samples (6.6%, 95% CI 4.3%–9.5%) carried methicillin-resistant S. aureus (MRSA). No statistically significant differences were observed for the prevalence of S. aureus in general, or MSSA or MRSA specifically, when comparing pork products from conventionally raised swine and swine raised without antibiotics, a finding that contrasts with a prior study from the Netherlands examining both conventional and “biologic” meat products. In our study spa types associated with “livestock-associated” ST398 (t034, t011) were found in 26.9% of the MRSA isolates, while 46.2% were spa types t002 and t008—common human types of MRSA that also have been found in live swine. The study represents the largest sampling of raw meat products for MRSA contamination to date in the U.S. MRSA prevalence on pork products was higher than in previous U.S.-conducted studies, although similar to that in Canadian studies.

Prevalence and Characterization of Methicillin-Resistant Staphylococcus aureus Isolates from Retail Meat and Humans in Georgia

“…These samples included pork ears, pork feet, pork tails, and pork hocks, which included intact parts of the skin of the pig, as well as some internal organs, such as pork liver and beef tongue. A recent study included a number of cuts of pork different from those normally reported (pork riblet, pork ribs, pork sausage, pork steak, pork loin, and pork roast), which may or may not be the same as or similar to some of the products sampled in this study (20). However, although the cuts may be similar in name, comparisons between the individual items are not made in this study in order to avoid error between the samples.…”

“…In the United States, regional studies of retail meat for the presence of MRSA have found very few samples containing MRSA, and only one MRSA ST398 isolate was identified (14)(15)(16)(17)(18)(19). Recently, a study of conventional and retail pork products found higher prevalence levels; almost 27% of the samples were contaminated with an ST398-associated MRSA type (20). A more recent study examined MRSA from swine herds through processing and to retail distribution (21).…”

Distinct Roles of Phenol-Soluble Modulins in Spreading of Staphylococcus aureus on Wet Surfaces

“…One of these other habitats might be animal meat intended for human consumption. There are many reports on the contamination of meat products with S. aureus, including MRSA (50)(51)(52). This is highly unwanted, first, because S. aureus is renowned as a causative agent of food poisoning (53).…”

Methicillin Resistant Staphylococcus aureus (MRSA): A Review

“…MRSA strains have been discovered from foods such as bovine milk and cheese, pork and beef as well as raw chicken meat (Kwon et al, 2006;Normanno et al, 2007;Van Loo et al, 2007;O'Brien et al, 2012). The strains of MRSA isolated in most food samples include ST398, ST125 and ST217 (Faccioli-Martins and de Souza da Cunha, 2012) while the recent mecC homologue of mecA gene has been isolated in bovine milk in England (Paterson et al, 2014b).…”