RESISTANT ENTEROCOCCI - A PROSPECTIVE-STUDY OF PREVALENCE, INCIDENCE,AND FACTORS ASSOCIATED WITH COLONIZATION IN A UNIVERSITY HOSPITAL

OBJECTIVE: To determine the prevalence of gastrointestinal tract colon ization with antibiotic-resistant enterococci at ward entry and to stu dy the incidence and risk factors for nosocomial acquisition of coloni zation with resistant enterococci. DESIGN: A prospective cohort study conducted between February 1 and March 15, 1993. METHODS: Rectal cultu res were obtained within 24 hours of admission or transfer onto the st udy wards and repeated at weekly intervals and at the time of discharg e. Patients harboring antibiotic-resistant enterococci at the time of admission or after admission were compared to patients who were not co lonized with these organisms. Clinical and epidemiologic risk factors for colonization were abstracted prospectively by daily chart review. Following a univariate analysis of risk factors associated with coloni zation, a multivariate statistical analysis using three separate model s was done. SETTING: A 1,125-bed, tertiary-care teaching hospital in N orth Carolina. PATIENTS: A total of 350 patients admitted to two gener al medical wards and the medical intensive we unit during the study pe riod. RESULTS: Antibiotic-resistant enterococci were isolated from 52 patients: 19 were colonized at admission to the study, and 33 later ac quired resistant-strains. At the time of admission, 5.4% of the patien ts were colonized with ampicillin-resistant enterococci (ARE), includi ng 1.1% that were colonized with vancomycin-resistant enterococci. Pri or hospitalization was associated with colonization with ARE at admiss ion (P=.01). Independent risk factors for nosocomial acquisition of AR E included treatment with more than three antibiotics, empiric use of antibiotics, use of third-generation cephalosporins, and the use of en teral tube feedings. Antibiotics used prophylactically were not associ ated with resistant enterococcal colonization. CONCLUSIONS: Our data h elp to elucidate the epidemiology of gastrointestinal tract colonizati on with resistant enterococci. We hypothesize that surveillance and co ntrol programs will be more likely to succeed if targeted at patients receiving more than three antibiotics, empiric antibiotics, and entera l tube feedings.