High carriage rate of ESBL-producing Enterobacteriaceae at presentation and follow-up among travellers with gastrointestinal complaints returning from India and Southeast Asia

Background. International travel contributes to the spread of multidrug-resistant microorganisms including extended spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE). We assessed the proportion of faecal carriers of ESBL-PE among 211 patients with gastrointestinal symptoms who returned to Berlin, Germany, after international travel. Methods. ESBL-PE were screened for on chromogenic agar, antimicrobial susceptibility testing was performed, and ESBL-genes were genotyped. Travel-related data were assessed by questionnaire. Results. Diarrhoea, abdominal pain and nausea were the main symptoms. Half of the travellers carried ESBL-PE (97% Escherichia coli); the proportion was highest for returnees from India (72%) and mainland Southeast Asia (59%), and comparatively lower for Africa (33%) and Central America (20%). Co-resistance to fluoroquinolones (particularly in isolates from India), gentamicin and cotrimoxazole was frequent but all isolates were carbapenem-susceptible. ESBL-PE carriage decreased with increasing timespan from return to presentation, and with age. At revisit of initially ESBL-PE positive patients half a year later, 28% (17/61) of the individuals were still carriers, CTX-M groups being congruent with the initial isolates. CTX-M groups 9 and 1/9, vegetarian diet and cat ownership tended to be associated with ESBL-PE carriage upon revisit. Conclusions. Travellers, particularly those returning from India and Southeast Asia, constitute a relevant source of potential spread of ESBL-PE. Carriage declines over time but ESBL-PE persist for at least 6 months in a substantial proportion of individuals. Both genetic characteristics of the bacteria and lifestyle factors seem to contribute to persistent carriage of ESBL-PE. A recent, extra-European travel history argues for ESBL-PE screening and contact precautions for patients admitted to hospital.