Effect of vancomycin therapy for osteomyelitis on colonization by methicillin-resistant Staphylococcus aureus: lack of emergence of glycopeptide resistance.
BACKGROUND
In treating orthopedic infections, the long-term impact of vancomycin therapy on colonization by methicillin-resistant Staphylococcus aureus (MRSA) and the emergence of vancomycin-intermediate S. aureus is unknown.


METHODS
Prospective surveillance of the effect of long-term vancomycin therapy on colonization by MRSA and the emergence of vancomycin-intermediate S. aureus.


METHODS
Thirty-four patients with MRSA osteomyelitis that was microbiologically documented were longitudinally observed for the emergence of vancomycin-intermediate S. aureus at 3 body sites (wound, anterior nares, and groin) during the initial period of vancomycin therapy and at the 2-month follow-up. Twenty patients received the standard dose (20 mg/kg/d) for 34 +/- 6 days and 14 patients received a high dose (40 mg/kg/d) of vancomycin for 37 +/- 9 days.


RESULTS
During vancomycin treatment, global MRSA carriage (all body sites) fell from 100% to 25% in the group of patients receiving the standard dose of vancomycin, and from 100% to 40% in the group receiving the high dose. During the 2-month follow-up period after vancomycin therapy, global MRSA carriage increased from 25% to 55% in the group receiving the standard dose and decreased from 43% to 36% in the group receiving the high dose.


CONCLUSIONS
Therapy with a high dose of vancomycin contributes to the sustained eradication of MRSA carriage without promoting the emergence of glycopeptide resistance.
D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use*; D002353:Carrier State; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D010019:Osteomyelitis / Q000188:drug therapy*; D011159:Population Surveillance; D011446:Prospective Studies; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000473:pathology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000472:pathogenicity*; D014640:Vancomycin / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*
D000900:Anti-Bacterial Agents; D014640:Vancomycin