Nasal Carriage of Epidemic Methicillin-Resistant Staphylococcus aureus 15 (EMRSA-15) Clone Observed in Three Chicago-Area Long-Term Care Facilities

Abstract

The spread of pandemic methicillin-resistant Staphylococcus aureus (MRSA) clones such as USA300 and EMRSA-15 is a global health concern. As a part of a surveillance study of three long-term care facilities in the Greater Chicago area, phenotypic and molecular characterization of nasal MRSA isolates was performed. We report a cluster of pandemic EMRSA-15, an MRSA clone rarely reported from the United States, detected during this study.

Copyright © 2013, American Society for Microbiology. All Rights Reserved.

Figures

Fig 1

Molecular characterization and antibiogram of isolates showing EMRSA-15 pulsotype. The PFGE dendrogram compares fingerprint patterns of the related isolates from 14 patients. Columns marked “MUP” and “PVL” indicate the results for genetic tests performed to detect the mupA and PVL genes, respectively. CIP, ciprofloxacin; TMSZ, trimethoprim-sulfamethoxazole; GENT, gentamicin; MINO, minocycline; CLIND, clindamycin; N, negative; P, positive; S, susceptible; R, resistant; I, intermediate; †, all isolates belong to spa types included in the cluster ST22, a recognized cluster for EMRSA-15; **, this isolate has a unique pulsotype, although it is closely related to pulsotype A; the spa sequence was unique and not listed in the Ridom SpaServer database; *, this isolate had a distinct PFGE profile and belongs to spa type t005; it is also the only isolate positive for the PVL gene; of note, spa type t005 has been reported to be PVL positive (29).