Outpatient vancomycin use and vancomycin-resistant enterococcal colonization in maintenance dialysis patients

Background Although outpatient vancomycin is widely used as empiric therapy for dialysis-associated infections, its relationship with vancomycin-resis tant enterococcal (VRE) colonization is not established. Methods. During a two-year prospective: cohort study, rectal swabs obtained from patients at the start and finish of the study period and during inter im hospitalizations were cultured for VRE. Results. Ten of 124 patients initially grew VRE. Twenty-four of the remaini ng patients had no follow-up cultures because of patient death (62%). trans fer to another dialysis facility (17%), patient's refusal (7%), and transpl antation (4%). and were thus excluded. The remaining patients (N = 90) had a median age of 54.3 years and were 92% African American and 50% male. Fift y-eight percent were treated by hemodialysis. They received 403 g of intrav enous vancomycin over 157.2 patient-years of follow-up, 73% as outpatients. Sixteen of 90 patients (17.8%) became colonized with VRE, an incidence rat e of one case per 9.8 patient-years of follow-up. None of the 29 patients w ho did not receive vancomycin developed VRE compared with 26% of those trea ted with vancomycin (P = 0.001). The odds ratio (95%, CI) fur the associati on of outpatient vancomycin (g per year) with VRE colonization was 1.23 (1. 05, 1.44, P = 0.008). The association remained significant following adjust ment in separate logistic regression analyses for relevant demographic, cli nical, antimicrobial (inpatient vancomycin, oral or intravenous cephalospri ns. aminoglycosides. quinalones. or antianaerobics), and hospitalization ex posures. The unadjusted relative risk of death in patients growing VRE was significantly higher than in those not colonized with VRE (P = 0.005). Conclusions. VRE colonization is a relatively common and underrecognized pr oblem among chronic dialysis patients. It is strongly and independently ass ociated with the outpatient use of vancomycin, which should be avoided when ever possible.