title: Vancomycin-resistant Staphylococcus aureus in the absence of vancomycin exposure.
abstract: We report findings from our investigation of the world's second clinical isolate of vancomycin-resistant Staphylococcus aureus (VRSA). An elderly man was hospitalized with an infected chronic heel ulcer and osteomyelitis. Before hospital admission, he received multiple courses of antibiotic therapy but, notably, no vancomycin. Numerous cultures of ulcer specimens (performed on an outpatient basis) grew methicillin-resistant, vancomycin-susceptible S. aureus and vancomycin-resistant Enterococcus species. At admission, an additional culture of a specimen from the heel ulcer grew S. aureus that was identified as VRSA (minimal inhibitory concentration for vancomycin [by broth-microdilution], 32 microg/mL). Further evaluation confirmed the presence of the vanA gene mediating vancomycin resistance. To assess VRSA transmission, we performed a carriage study of 283 identified contacts and an environmental survey of the patient's home; no VRSA isolates were recovered. This case illustrates that recent exposure by patients to vancomycin is not necessary for development of vanA-containing VRSA. For clinical and public health reasons, it is essential that microbiology laboratories adequately test for vancomycin-resistance in S. aureus.
authors.affiliation: The Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA. cwhitener@psu.edu
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Whitener
authors.forename: Sarah Y
authors.initials: SY
authors.lastname: Park
authors.forename: Fred A
authors.initials: FA
authors.lastname: Browne
authors.forename: Leslie J
authors.initials: LJ
authors.lastname: Parent
authors.forename: Kathleen
authors.initials: K
authors.lastname: Julian
authors.forename: Bulent
authors.initials: B
authors.lastname: Bozdogan
authors.forename: Peter C
authors.initials: PC
authors.lastname: Appelbaum
authors.forename: Jasmine
authors.initials: J
authors.lastname: Chaitram
authors.forename: Linda M
authors.initials: LM
authors.lastname: Weigel
authors.forename: John
authors.initials: J
authors.lastname: Jernigan
authors.forename: Linda K
authors.initials: LK
authors.lastname: McDougal
authors.forename: Fred C
authors.initials: FC
authors.lastname: Tenover
authors.forename: Scott K
authors.initials: SK
authors.lastname: Fridkin
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005500:Follow-Up Studies; D006801:Humans; D017053:Infection Control / Q000331:legislation & jurisprudence; D008297:Male; D008712:Methicillin / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D017063:Outcome Assessment, Health Care; D013211:Staphylococcus aureus / Q000187:drug effects*; D014640:Vancomycin / Q000494:pharmacology*; D020713:Vancomycin Resistance
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin; D008712:Methicillin