Failure to develop vancomycin-resistant Enterococcus with oral vancomycin treatment of Clostridium difficile.

Objective: Oral vancomycin therapy has been a risk factor for turning culture positive for vancomycin-resistant Enterococcus (VRE). VRE colonization status was reviewed for all patients who received oral vancomycin and underwent prospective cultures.

Methods: Data were extracted from the medical records of all patients receiving oral vancomycin between August 1995 and February 2001 regarding history, hospital course, and perirectal VRE cultures. Hospital policy required contact isolation for patients receiving oral vancomycin until colonization with VRE was excluded.

Results: Twenty-six courses of oral vancomycin were given to 22 patients. VRE colonization status after completion of therapy was evaluated for 23 courses in 20 (91%) of these patients. None of these patients became VRE culture positive during a median follow-up of 18 days (range, 9 to 39 days), with a median duration of treatment of 10 days (range, 3 to 58 days), and with a median total dose of 6,500 mg (range, 1,250 to 29,000 mg). All patients received other antibiotics within 30 days prior to therapy with oral vancomycin, during therapy with oral vancomycin, or both; 95% had received anti-anaerobic therapy and 35% had received parenteral vancomycin.

Conclusions: Even when other risk factors were present, no patient receiving oral vancomycin at our facility subsequently became culture positive for VRE. This suggests that oral vancomycin therapy or other antibiotic use, including anti-anaerobic therapy, may not be a significant independent risk factor for turning culture positive for VRE among patients not previously exposed to the microbe.