title: Accessory gene regulator group II polymorphism in methicillin-resistant Staphylococcus aureus is predictive of failure of vancomycin therapy.
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.
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences, State University of New York at Buffalo, Buffalo, NY, USA. pmoise@cplassociates.com
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Moise-Broder
authors.forename: George
authors.initials: G
authors.lastname: Sakoulas
authors.forename: George M
authors.initials: GM
authors.lastname: Eliopoulos
authors.forename: Jerome J
authors.initials: JJ
authors.lastname: Schentag
authors.forename: Alan
authors.initials: A
authors.lastname: Forrest
authors.forename: Robert C
authors.initials: RC
authors.lastname: Moellering
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001426:Bacterial Proteins / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D016106:Methicillin Resistance / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology; D013211:Staphylococcus aureus / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics*; D014640:Vancomycin / Q000627:therapeutic use; D020713:Vancomycin Resistance / Q000235:genetics*
chemical_list: C095698:Agr protein, Staphylococcus aureus; D001426:Bacterial Proteins; D015534:Trans-Activators; D014640:Vancomycin