Predictors and Molecular Epidemiology of Community-Onset Extended-Spectrum β-Lactamase–Producing Escherichia coli Infection in a Midwestern Community

Abstract

OBJECTIVE To identify predictors of community-onset extended-spectrum β-lactamase (ESBL)–producing Escherichia coli infection. DESIGN Prospective case-control study. SETTING Acute care hospitals and ambulatory clinics in the Chicago, Illinois, region. PATIENTS Adults with E. coli clinical isolates cultured in ambulatory settings or within 48 hours of hospital admission. METHODS Cases were patients with ESBL-producing E. coli clinical isolates cultured in ambulatory settings or within 48 hours of admission, and controls were patients with non-ESBL-producing E. coli isolates, matched to cases by specimen, location, and date. Clinical variables were ascertained through interviews and medical record review. Molecular methods were used to identify ESBL types, sequence type ST131, and aac(6′)-Ib-cr. RESULTS We enrolled 94 cases and 158 controls. Multivariate risk factors for ESBL-producing E. coli infection included travel to India in the past year (odds ratio [OR], 14.40 [95% confidence interval (CI), 2.92–70.95]), ciprofloxacin use (OR, 3.92 [95% CI, 1.90–8.1]), and age (OR, 1.04 [95% CI, 1.02–1.06]). Case isolates exhibited high prevalence of CTX-M-15 (78%), ST131 (50%), and aac(6′)-Ib-cr (66% of isolates with CTX-M-15). CONCLUSIONS Providers should be aware of the increased risk of ESBL-producing E. coli infection among returned travelers, especially those from India.

Escherichia coli ST131, an Intriguing Clonal Group

“…ESBL-producing isolates and 72% among the ESBL producers (42). However, if all the E. coli isolates causing bacteremia collected in San Francisco were taken into account, the prevalence of E. coli ST131 was 26%, similar to the 27% reported for the United States general population in 2011 (110). This raises questions about the suitability of the prevalence of E. coli ST131 among bacteremia E. coli isolates as an indicator of the actual prevalence of E. coli ST131 infection in in-and outpatients infected with E. coli.…”

“…In the United Kingdom, an analysis of 300 consecutive UTI E. coli isolates showed the prevalence of E. coli ST131 to be 9% among the non-ESBL-producing isolates and 54% among those producing ESBL (109). The lower of these two figures (9%) is similar to that reported in France for all non-ESBL-producing isolates (10%), whereas the higher figure (54%) is closer to that reported in the United States among all ESBL-producing isolates (49 to 50%) than to that reported in France (36%) (16,110). A study by Croxall et al focused on elderly patients in the United Kingdom, in whom E. coli ST131 accounted for 22% of the E. coli isolates causing community-and hospital-acquired UTI (17).…”

“…Two narrow-spectrum ␤-lactamases, OXA-1 and TEM-1, have frequently been found in ST131 isolates, generally in association with CTX-M-15 enzymes, following plasmid transfer (see "Characterization of plasmids harbored by clinical isolates of E. coli ST131" above) (9,55,58,62,94,106). Another resistance gene, aac(6=)-Ibcr, which confers resistance to both aminoglycosides (amikacin and tobramycin) and ciprofloxacin, has frequently been detected in association with CTX-M-15 enzymes (9,19,(107)(108)(109)(110). Only a few studies in Spain and Portugal have reported the detection of qnr determinants, another plasmid-mediated mechanism of quinolone resistance in ST131 isolates (111)(112)(113).…”

“…Among UTI E. coli isolates, the prevalence of clone ST131 varied with age: Ͻ10% in children, 13% in women of reproductive age, and Ͼ20% in elderly patients. Banerjee et al showed, with unselected isolates, that E. coli ST131 predominated in adults over the age of 50 years and that the prevalence of infections with this clonal group increased with age (110). If only ESBL-producing or fluoroquinolone-resistant E. coli isolates were considered, the prevalence of clone ST131 was generally much higher, varying from 20 to 66% among ESBL producers and from 10 to 72% among fluoroquinolone-resistant iso- Tables 5 and 6 (36).…”

“…In addition, antibiotic prescribers should be aware of the risk factors for infection with ESBL-producing E. coli isolates, including E. coli ST131, and should adapt their prescriptions accordingly (110,156,208,(211)(212)(213).…”