Vancomycin-resistant Staphylococcus aureus in the absence of vancomycin exposure.
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.
Whitener
Cynthia J
CJ
The Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA. cwhitener@psu.edu
Park
Sarah Y
SY
Browne
Fred A
FA
Parent
Leslie J
LJ
Julian
Kathleen
K
Bozdogan
Bulent
B
Appelbaum
Peter C
PC
Chaitram
Jasmine
J
Weigel
Linda M
LM
Jernigan
John
J
McDougal
Linda K
LK
Tenover
Fred C
FC
Fridkin
Scott K
SK
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
D000900:Anti-Bacterial Agents; D014640:Vancomycin; D008712:Methicillin