Near Absence of Vancomycin-Resistant Enterococci but High Carriage Rates of Quinolone-Resistant Ampicillin-Resistant Enterococci among Hospitalized Patients and Nonhospitalized Individuals in Sweden

Abstract

Rates of colonization with enterococci with acquired resistance to vancomycin (vancomycin-resistant enterococci [VRE]) and ampicillin (ampicillin-resistant enterococci [ARE]) were determined by using fecal samples from 670 nonhospitalized individuals and 841 patients in 27 major hospitals. Of the hospitalized patients, 181 (21.5%) were carriers of ARE and 9 (1.1%) were carriers 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 therapy (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), cephalosporins (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 least 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 resistant, whereas 14% of the ampicillin-susceptible Enterococcus faecium isolates 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 according 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, harbored VRE (E. faecium vanA). The absence of VRE colonization in nonhospitalized 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.

Clonality among ampicillin-resistant Enterococcus faecium isolates in Sweden and relationship with ciprofloxacin resistance

“…Collection 1 comprised hospital ARE isolates (n 180) from a 1998 nationwide point prevalence study on fecal ARE and GRE colonization rates [6]. Hospitals in 25 cities representing all counties in Sweden participated in the study.…”

“…Collection 2 comprised outpatient ARE isolates (n 39) from the 1998 nationwide point prevalence study mentioned above [6]. The isolates were obtained from 39 ARE-colonized outpatients in 13 cities.…”

“…Collection 3 comprised hospital ASE isolates (n 169) from ARE-negative hospitalized patients participating in the 1998 point prevalence study [6]. ASE isolates matched with the ARE isolates in collection 1 for hospital, ward and week of isolation were available from 169 patients in 22 cities.…”

Human infections caused by glycopeptide-resistant Enterococcus spp: are they a zoonosis?

“…Fecal VanA‐type GRE colonization among outpatients and healthy community controls has been demonstrated in a number of European studies, varying from 0.1% to 28%[56,71–75]. Table 2 summarizes the data concerning human GRE colonization rates from various studies.…”

“…The rates of GRE colonization in humans are low in Sweden and Norway. Torell et al detected a single VanA‐type E. faecium carrier in a Swedish study of 670 outpatients [73]. Norwegian surveys of human GRE colonization have been performed only in hospitals.…”