Comparative Genomics of a Population of Human, Animal, and Environmental MRSA Isolates in Ohio
Methods: This is a descriptive study of human, animal, and environmental MRSA isolates sampled in human and animal hospitals from 2007 to 2010 in Ohio. MRSA isolates were genotyped using pulsed-field gel electrophoresis (PFGE) and staphylococcal cassette chromosome mec (SCCmec) typing. Genotypic and phenotypic information was assessed for comparison, and descriptive statistics were compiled.
Results: A total of 1284 human, 41 canine, 7 equine, and 254 environmental MRSA isolates were genotyped. Human MRSA isolates carried the SCCmec II (50.0%) more than other SCCmec elements. The majority of canine MRSA isolates were SCCmec II (≥ 80% for all culture sites), while the majority of equine isolates were SCCmec IV (≥ 75% for most culture sites). For environmental isolates collected from the human hospital, 49.5% (49/99) were SCCmec II and 31.3% (31/99) were SCCmec IV. Environmental MRSA isolates collected from the canine hospital were nearly all SCCmec II (77/82, 93.9%); whereas, the majority of isolates from the equine hospital were SCCmecIV (66/73, 90.4%). PFGE type USA100 and USA300 were the most common among human isolates; alternatively, USA100 and USA500 were the most common among canine and equine isolates, respectively. Multi-drug resistance was highest in environmental isolates collected from the patient hospital (99/99, 100.0%).
Conclusion: Canine and equine MRSA populations had distinct genotypic differences with human strains most common among canine isolates. USA300 (community-associated MRSA) was detected in the healthcare setting. Genotypic environmental MRSA isolate data reflected the distribution of strains circulating in human and animal populations associated with such environments. Future surveillance and infection control research should emphasize understanding of transmission among human, animal, and environmental populations.
J. Van Balen, None
L. Hines, None
S. H. Wang, None
K. Stevenson, None