Author(s): Rago JV, Buhs LK, Makarovaite V, Patel E, Pomeroy M,
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Abstract BACKGROUND: Given the frequency with which many different strains of Staphylococcus aureus are found in various prehospital settings, this study sought to characterize S aureus isolates taken from one such environment. The objectives were to determine the frequency of S aureus in front-line, advanced life support (ALS) ambulances throughout the Chicago metropolitan area, and to generate antibiograms (antibiotic resistance profiles) for each S aureus isolate using 8 clinically relevant antibiotics. METHODS: Samples were obtained from 26 sites in 71 ambulances from 34 different Chicago-area municipalities. Selected colonies that demonstrated a growth pattern consistent with that of S aureus were subjected to a latex agglutination test specific for S aureus. Antibiograms and genetic analyses were performed on all latex agglutination test-positive isolates. RESULTS: At least one S aureus isolate was found in approximately 69\% of all ambulances in the study. Of all isolates detected, 77\% showed resistance to at least one antibiotic, and 34\% displayed resistance to 2 or more antibiotics. Some level of oxacillin resistance was found in 21\% of isolates; however, only slightly more than half of these oxacillin-resistant isolates were found to carry the methicillin-resistant S aureus-specific SCCmec cassette. Some 12\% of all isolates were ultimately determined to be methicillin-resistant S aureus, whereas the remaining 88\% were methicillin-sensitive S aureus with varying antibiograms. CONCLUSIONS: Antibiotic resistance appears to be prevalent in S aureus isolates detected in Chicago area ALS ambulances. Given the ease with which S aureus can survive on inanimate surfaces and exchange antibiotic resistance elements, a conscientious approach to the application of existing cleaning techniques, especially in key ambulance sites, is needed. Future work will include further characterizing isolates using multiple techniques, as well as follow-up studies with interested municipalities. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.
This article was published in Am J Infect Control
and referenced in Journal of Microbial & Biochemical Technology