title: High colonization rates of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in Swiss travellers to South Asia- a prospective observational multicentre cohort study looking at epidemiology, microbiology and risk factors.
abstract: BACKGROUND
  International travel contributes to the worldwide spread of multidrug resistant Gram-negative bacteria. Rates of travel-related faecal colonization with extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae vary for different destinations. Especially travellers returning from the Indian subcontinent show high colonization rates. So far, nothing is known about region-specific risk factors for becoming colonized.
  
  
  METHODS
  An observational prospective multicentre cohort study investigated travellers to South Asia. Before and after travelling, rectal swabs were screened for third-generation cephalosporin- and carbapenem-resistant Enterobacteriaceae. Participants completed questionnaires to identify risk factors for becoming colonized. Covariates were assessed univariately, followed by a multivariate regression.
  
  
  RESULTS
  Hundred and seventy persons were enrolled, the largest data set on travellers to the Indian subcontinent so far. The acquired colonization rate with ESBL-producing Escherichia coli overall was 69.4% (95% CI 62.1-75.9%), being highest in travellers returning from India (86.8%; 95% CI 78.5-95.0%) and lowest in travellers returning from Sri Lanka (34.7%; 95% CI 22.9-48.7%). Associated risk factors were travel destination, length of stay, visiting friends and relatives, and eating ice cream and pastry.
  
  
  CONCLUSIONS
  High colonization rates with ESBL-producing Enterobacteriaceae were found in travellers returning from South Asia. Though risk factors were identified, a more common source, i.e. environmental, appears to better explain the high colonization rates.
authors.affiliation: Division for Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland. esther.kuenzli@usb.ch.
authors.forename: Esther
authors.initials: E
authors.lastname: Kuenzli
authors.forename: Veronika K
authors.initials: VK
authors.lastname: Jaeger
authors.forename: Reno
authors.initials: R
authors.lastname: Frei
authors.forename: Andreas
authors.initials: A
authors.lastname: Neumayr
authors.forename: Susan
authors.initials: S
authors.lastname: DeCrom
authors.forename: Sabine
authors.initials: S
authors.lastname: Haller
authors.forename: Johannes
authors.initials: J
authors.lastname: Blum
authors.forename: Andreas F
authors.initials: AF
authors.lastname: Widmer
authors.forename: Hansjakob
authors.initials: H
authors.lastname: Furrer
authors.forename: Manuel
authors.initials: M
authors.lastname: Battegay
authors.forename: Andrea
authors.initials: A
authors.lastname: Endimiani
authors.forename: Christoph
authors.initials: C
authors.lastname: Hatz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001208:Asia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004755:Enterobacteriaceae / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000453:epidemiology / Q000382:microbiology; D004926:Escherichia coli / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010802:Phylogeny; D011446:Prospective Studies; D012307:Risk Factors; D013557:Switzerland; D014195:Travel; D055815:Young Adult; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D001618:beta-Lactamases