title: Prevalence and molecular characterization of Staphylococcus aureus in commercially available meat over a one-year period in Iowa, USA.
abstract: Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of infectious disease morbidity and mortality. Previous studies have confirmed the presence of S. aureus, including MRSA, on raw meat products. We investigated the prevalence and molecular epidemiology of S. aureus and MRSA in commercially-distributed antibiotic-free and conventional raw meat products (n = 3290) purchased in 8 Iowa retail stores weekly for a period of one year. Isolates were characterized using spa typing, and PCR was used to detect the presence of the Panton-Valentine leukocidin (PVL) and mecA genes. Quantitation of S. aureus on meat products was carried out one week per month. The prevalence of S. aureus on meat samples was 27.8% (913/3290). Compared to antibiotic-free meat samples, higher prevalence of both MRSA and methicillin-susceptible S. aureus (MSSA) were found in conventional meat samples. Among the S. aureus isolates, 18 were PVL-positive (1.9%) and 41 (4.5%) carried mecA. Phenotypic oxacillin resistance was observed for 17.1% (41/239) of the isolates tested, while 23% (55/239) were multi-drug resistant. A total of 132 spa types were detected from 913 contaminated meat samples. Overall, t002 was the most common spa type identified (137; 15.0%). The number of colony-forming units (CFU) per 10 g meat ranged from 2 to 517 (median: 8 CFU per 10 g of meat; mean: 28) with the highest bacterial load observed on turkey samples. These data reinforce the need to consider meat products as potential vehicles of S. aureus transmission from farm into human households, and the potential need for public health intervention programs pre and post-slaughter in meat processing facilities.
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145N. Riverside Drive, Iowa City, IA, 52242, United States; Center for Emerging Infectious Diseases, University of Iowa College of Public Health, 2501 Crosspark Rd, Coralville, IA, 52241, United States.
authors.forename: Dipendra
authors.initials: D
authors.lastname: Thapaliya
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145N. Riverside Drive, Iowa City, IA, 52242, United States; Center for Emerging Infectious Diseases, University of Iowa College of Public Health, 2501 Crosspark Rd, Coralville, IA, 52241, United States.
authors.forename: Brett M
authors.initials: BM
authors.lastname: Forshey
authors.affiliation: Kent State University, College of Public Health, Department of Biostatistics, Environmental Health Sciences and Epidemiology, 750Hilltop Drive, Kent, OH, 44242, United States.
authors.forename: Jhalka
authors.initials: J
authors.lastname: Kadariya
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145N. Riverside Drive, Iowa City, IA, 52242, United States; Center for Emerging Infectious Diseases, University of Iowa College of Public Health, 2501 Crosspark Rd, Coralville, IA, 52241, United States.
authors.forename: Megan K
authors.initials: MK
authors.lastname: Quick
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145N. Riverside Drive, Iowa City, IA, 52242, United States; Center for Emerging Infectious Diseases, University of Iowa College of Public Health, 2501 Crosspark Rd, Coralville, IA, 52241, United States.
authors.forename: Sarah
authors.initials: S
authors.lastname: Farina
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145N. Riverside Drive, Iowa City, IA, 52242, United States; Center for Emerging Infectious Diseases, University of Iowa College of Public Health, 2501 Crosspark Rd, Coralville, IA, 52241, United States.
authors.forename: Ashley
authors.initials: A
authors.lastname: O' Brien
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145N. Riverside Drive, Iowa City, IA, 52242, United States; Center for Emerging Infectious Diseases, University of Iowa College of Public Health, 2501 Crosspark Rd, Coralville, IA, 52241, United States.
authors.forename: Rajeshwari
authors.initials: R
authors.lastname: Nair
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145N. Riverside Drive, Iowa City, IA, 52242, United States; Center for Emerging Infectious Diseases, University of Iowa College of Public Health, 2501 Crosspark Rd, Coralville, IA, 52241, United States.
authors.forename: Amos
authors.initials: A
authors.lastname: Nworie
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145N. Riverside Drive, Iowa City, IA, 52242, United States; Center for Emerging Infectious Diseases, University of Iowa College of Public Health, 2501 Crosspark Rd, Coralville, IA, 52241, United States.
authors.forename: Blake
authors.initials: B
authors.lastname: Hanson
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145N. Riverside Drive, Iowa City, IA, 52242, United States; Center for Emerging Infectious Diseases, University of Iowa College of Public Health, 2501 Crosspark Rd, Coralville, IA, 52241, United States.
authors.forename: Ashley
authors.initials: A
authors.lastname: Kates
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145N. Riverside Drive, Iowa City, IA, 52242, United States; Center for Emerging Infectious Diseases, University of Iowa College of Public Health, 2501 Crosspark Rd, Coralville, IA, 52241, United States.
authors.forename: Shylo
authors.initials: S
authors.lastname: Wardyn
authors.affiliation: Department of Epidemiology, University of Iowa College of Public Health, 145N. Riverside Drive, Iowa City, IA, 52242, United States; Center for Emerging Infectious Diseases, University of Iowa College of Public Health, 2501 Crosspark Rd, Coralville, IA, 52241, United States; Kent State University, College of Public Health, Department of Biostatistics, Environmental Health Sciences and Epidemiology, 750Hilltop Drive, Kent, OH, 44242, United States. Electronic address: tsmit176@kent.edu.
authors.forename: Tara C
authors.initials: TC
authors.lastname: Smith
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001427:Bacterial Toxins / Q000235:genetics; D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D005098:Exotoxins / Q000235:genetics; D005516:Food Microbiology; D005838:Genotype; D006801:Humans; D007484:Iowa / Q000453:epidemiology; D007956:Leukocidins / Q000235:genetics; D008460:Meat / Q000382:microbiology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D011200:Poultry / Q000382:microbiology; D066256:Raw Foods / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification*; D013752:Tetracycline / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D013752:Tetracycline
keywords: Antibiotic resistance; Genotype; MRSA; Meat; Staphylococcus aureus