Colonisation with Escherichia coli resistant to critically important antibiotics: a high risk for international travellers

Antimicrobial resistance among community-acquired isolates of Escherichia coli is increasing globally, with international travel emerging as a risk for colonisation and infection. The aim was to determine the rate and duration of colonisation with resistant E. coli following international travel. One hundred and two adult hospital staff and contacts from Canberra, Australia, submitted perianal/rectal swabs before and following international travel. Swabs were cultured selectively to identify E. coli resistant to gentamicin, ciprofloxacin and/or third-generation cephalosporins. Those with resistant E. coli post-travel were tested monthly for persistent colonisation. Colonisation with antibiotic-resistant E. coli increased significantly from 7.8% (95% confidence interval [CI] 3.8-14.9) pre-travel to 49% (95% CI 39.5-58.6) post-travel. Those colonised were more likely to have taken antibiotics whilst travelling; however, travel remained a risk independent of antibiotic use. Colonisation with resistant E. coli occurred most frequently following travel to Asia. While over half of those carrying resistant E. coli post-travel had no detectable resistant strains two months after their return, at least 18% remained colonised at six months. Colonisation with antibiotic-resistant E. coli occurs commonly after international travel, and can be persistent. Medical practitioners should be aware of this risk, particularly when managing patients with suspected Gram-negative sepsis.