LAUSR

BACKGROUND One third of travellers to the poor regions of the (sub)tropics become colonized by extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE). Co-resistance to non-beta-lactam antibiotics complicates the treatment of potential ESBL-PE infections. METHODS We analysed co-resistance to non-beta-lactams among travel-acquired ESBL-PE isolates of 90 visitors to the (sub)tropics with respect to major risk factors of colonization: destination, age, travellers' diarrhoea (TD) and antibiotic (AB) use. RESULTS Of the ESBL-PE isolates, 53%, 52%, 73%, and 2% proved co-resistant to ciprofloxacin, tobramycin, co-trimoxazole, and nitrofurantoin, respectively. The rates were similar among those with (TD+) or without (TD-) travellers' diarrhoea. Among fluoroquinolone-users vs. AB non-users, the co-resistance rates for ciprofloxacin were 95% versus 37% (p = 0.001), for tobramycin 85% versus 43% (p = 0.005), co-trimoxazole 85% versus 68% (p = 0.146), and nitrofurantoin 5% versus 2% (p = 0.147). In multivariable analysis co-resistance to ciprofloxacin was associated with increasing age, fluoroquinolone use, and tobramycin resistance. CONLUSIONS While TD predisposes to ESBL-PE non-selectively, antimicrobial use favours strains resistant to drug taken and, simultaneously, any drug with resistance genetically linked to the drug used. Antibiotics taken during travel predispose to ESBL-PE with a high co-resistance rate.