361. Prevalence and Molecular Characterization of Staphylococcus aureus from Human Stool Samples at the University of Iowa
Session: Poster Abstract Session: MRSA, MSSA, Enterococci
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Background: Studies have shown Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA) intestinal colonization may be associated with a higher risk of S. aureus infections among hospitalized patients, and contribute to hospital transmission. We aim to determine the prevalence and molecular characteristics of S. aureus and MRSA in human stool samples at the University of Iowa Hospitals and Clinics (UIHC).

Methods: Seven hundred seventy-five stool specimens were retrieved from the UIHC Clinical Microbiology Laboratory. Samples were originally collected for patient clinical care. 50 µL of sample was plated onto Baird-Parker Agar and ChromAgar media and incubated for 48 hours. Presumptive positive colonies were streaked onto Columbia CNA with 5% sheep blood and incubated for 24 hours. S. aureus isolates were confirmed through diagnostic testing. Molecular characteristics were determined using mecA and PVL PCR, and spa typing. Antibiotic susceptibility testing (AST) was performed. 

Results: Sixty-seven isolates (8.6%) were S. aureus with 26 (3.4%) being MRSA. t002 was the most frequent spa type (28/67) and t012 was the second most prevalent spa type (3/67). PCR analysis of mecA and PVL, as well as AST profiles, are complete for 54 of these isolates.  41 of the isolates were positive for the mecA gene and zero were PVL positive. Twenty-five of these isolates were resistant to oxacillin, 5 to tetracycline, 31 to erythromycin, 12 to clindamycin, 19 to levofloxacin, and 5 to rifampin.

Conclusion: S. aureus and MRSA were identified from clinical stool specimens, including hospital-associated isolates (t002/ST5) and international clones (t012/ST30). This indicates the potential for fecal-associated S. aureus to be transmitted via fecal material, or cause gastrointestinal disease.

Ashley Kates, MS1, Margaret Chorazy, Ph.D, M.P.H1 and Tara Smith, PhD2, (1)Epidemiology, College of Public Health, University of Iowa, Iowa City, IA, (2)College of Public Health, University of Iowa, Iowa City, IA


A. Kates, None

M. Chorazy, None

T. Smith, None

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