Prolonged carriage of resistant E. coli by returned travellers: Clonality, risk factors and bacterial characteristics

B. A. Rogers*, K. Kennedy, H. E. Sidjabat, M. Jones, P. Collignon, D. L. Paterson

*Corresponding author for this work

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43 Citations (Scopus)


The aim of this study was to delineate the potential risks and dynamics of the prolonged carriage of resistant E. coli in returned travellers. A sample of 274 previously collected E. coli resistant to ceftriaxone (CRO), ciprofloxacin, gentamicin and/or nalidixic acid recovered from 102 travellers was studied. Travellers were assessed pre-travel then longitudinally (maximum 6 months) with peri-rectal/rectal swabs. Clonality was determined by REP-PCR and the presence of O25b-ST131 was assessed. Comparison was made longitudinally for individuals and between identified co-travellers. The risk of prolonged carriage was lower for CRO than for ciprofloxacin or gentamicin resistance. Repeated isolation of the same phenotype at different time points occurred in 19% of initial CRO-resistant carriers compared with 50% of ciprofloxacin- or gentamicinresistant carriers. The duration of carriage was also longer for the latter resistance phenotypes (75th quartile 8 vs 62 and 63 days respectively). In multivariate analysis, risks of prolonged carriage included antimicrobial use whilst travelling (3.3, 1.3-8.4) and phylogenetic group B2 (9.3, 3.4-25.6) and D (3.8, 1.6-8.8). Clonality amongst longitudinal isolates from the same participant was demonstrated in 92% of participants who were assessable and most marked amongst CRO-resistant isolates. ST-131 was surprisingly infrequent (3% of participants). Prolonged carriage of ciprofloxacin- and gentamicin-resistant isolates is more frequent and prolonged than CRO resistance after travel. Risks of prolonged carriage indicate a contribution of host and bacterial factors to this carriage. These require further elucidation. The strong clonality identified suggests that carriage of a "phenotype" was mediated by persistence of bacteria/plasmid combinations rather than persistence of the plasmid after horizontal transfer to other bacteria.

Original languageEnglish
Pages (from-to)2413-2420
Number of pages8
JournalEuropean Journal of Clinical Microbiology and Infectious Diseases
Issue number9
Publication statusPublished - Sept 2012
Externally publishedYes


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