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Updated: Aug 23, 2026

Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus
Published on: September 5, 2013
Accessory gene regulator group II polymorphism in methicillin-resistant Staphylococcus aureus is predictive of
Pamela A Moise-Broder1, George Sakoulas, George M Eliopoulos
1School of Pharmacy and Pharmaceutical Sciences, State University of New York at Buffalo, Buffalo, NY, USA. pmoise@cplassociates.com
Abstract:
We studied methicillin-resistant Staphylococcus aureus (MRSA) isolates to determine if the group II polymorphism at the accessory gene regulator (agr) locus demonstrated any relationship with the clinical efficacy of vancomycin. One hundred twenty-two MRSA isolates from 87 patients treated with vancomycin were evaluated. Forty-five of 87 patients had no clinical or bacteriological response to vancomycin. Among the 36 clinically evaluable patients with the agr group II polymorphism, 31 had an infection that failed to respond to vancomycin, whereas only 5 had an infection that responded successfully to vancomycin. This finding is of interest in light of our previous findings that glycopeptide-intermediately resistant S. aureus (GISA) and hetero-GISA clinical isolates in the United States and Japan are enriched for the agr group II polymorphism, and it suggests a possible intrinsic survival advantage of some S. aureus clones with this genetic marker under vancomycin selective pressure.
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