Pet animals and foreign travel are risk factors for colonisation with extended-spectrum β-lactamase-producing Escherichia coli.

OBJECTIVE: The purpose of this study was to determine the prevalence of extended-spectrum β-lactamase (ESBL) and vancomycin-resistant enterococci (VRE) colonisation among healthy infection control personnel and to determine risk factors for ESBL or VRE colonisation within this group.
METHODS: Participants were recruited at an infection control symposium in 2011. Volunteers were asked to perform a rectal swab and to fill in questionnaires on risk factors of ESBL or VRE carriage (report on diet, contact with domestic or production animals, travel, hospital stay and antibiotic use all within the last 12 months). Rectal swabs were inoculated onto ESBL and VRE chromogenic agar; species identification and susceptibility testing was done by using a VITEK 2 system. In the multivariable analysis, a logistic regression with stepwise forward variable selection was performed.
RESULTS: Two hundred and thirty people participated in the study, i.e. 36 % of the symposium attendees (231/639). No VRE faecium or faecalis were isolated, whereas ESBL were isolated from 8 out of 231 individuals, i.e. 3.5 % (95 % confidence interval 1.5-6.7). In the multivariable analysis, travel to Greece or Africa and contact with pets were independently associated with ESBL positivity. The odds ratios were as follows: travel to Greece 15.2, travel to Africa 14.8 and for having a pet animal 6.7.
CONCLUSION: This is the first report showing that contact with pets increases by almost seven-fold the chance to be colonised with ESBL Escherichia coli. A colonisation rate of 3.5 % with ESBL-producing enterobacteriaceae among infection control personnel is of concern and reflects probably less an occupational health risk but the reservoir of and the expansion into the community, especially in persons with pet animals and travel history to high-endemicity countries.