Near absence of vancomycin-resistant enterococci but high carriage rates of quinolone-resistant ampicillin-resistant enterococci among hospitalized patients and nonhospitalized individuals in Sweden

Rates of colonization with enterococci with acquired resistance to vancomyc in (vancomycin-resistant enterococci [VRE]) and ampicillin (ampicillin-resi stant enterococci [ARE]) were determined by using fecal samples from 670 no nhospitalized individuals and 841 patients in 27 major hospitals. Of the ho spitalized patients, 181 (21.5%) were carriers of ARE and 9 (1.1%) were car riers of VRE. In univariate analyses, length of hospital stay (odds ratio [ OR], 4.6; 95% confidence interval [CI], 2.5 to 8.9) and antimicrobial thera py (OR, 4.7; 95% CI, 3.3 to 6.7) were associated with ARE colonization, as were prior treatment with penicillins (OR, 3.1; 95% CI, 1.8 to 5.5), cephal osporins (OR, 2.9; 95% CI, 1.7 to 5.0), or quinolones (OR, 2.7; 95% CI, 1.5 to 4.7). In logistic regression analysis, antimicrobial therapy for at lea st 5 days was independently associated with ARE carriage (adjusted OR, 3.8; 95% CI, 2.6 to 5.4). Over 90% of the ARE isolates were fluoroquinolone res istant, whereas 14% of the ampicillin-susceptible Enterococcus faecium isol ates were fluoroquinolone resistant. ARE carriage rates correlated with the use of fluoroquinolones (P = 0.04) but not with the use of ampicillin (P = 0.68) or cephalosporins (P = 0.40). All nine VRE isolates were E. faecium vanB and were found in one hospital. Seven of these isolates were related a ccording to their types as determined by pulsed-field gel electrophoresis. Among the nonhospitalized individuals, the ARE carriage rate was lower (6%; P < 0.05), and only one person, who had recently returned from Africa, har bored VRE (E. faecium vanA). The absence of VRE colonization in nonhospital ized individuals reflects an epidemiological situation in Sweden radically different from that in countries in continental Europe where glycopeptides have been widely used for nonmedical purposes.