A Cross-Sectional Cohort Study of Extended-Spectrum-Beta-Lactamase-Producing Enterobacterales in Patients with Traveler's Diarrhea

Patients with traveler’s diarrhea (TD) can acquire extended-spectrum-beta-lactamase (ESBL)-producing members of the Enterobacterales (EPE) during travel to areas of endemicity. The aim of the present study was to investigate the prevalence and characteristics of EPE carriage in travelers from southern Sweden who were sampled for bacterial diagnostics of TD compared to those of EPE carriage 10 years ago. Clinical samples sent for culture of common causes of bacterial enterocolitis, if the referral stated foreign travel, were included in the study. Antimicrobial susceptibility testing was done according to the EUCAST disk diffusion test method. EPE strains were subjected to whole-genome sequencing (WGS). Eighty-four of 303 patients carried a total of 92 ESBL-producing members of the Enterobacterales. The overall prevalence of EPE in tested samples was thus 28%, compared to 24% 10 years earlier (P = 0.33). Among 86 strains available for WGS, 47 different sequence types (STs) were identified, and there were only 5 ST131 strains. Of the 79 Escherichia coli isolates, 76% carried at least one fim (type 1 fimbria) gene, 29% carried at least one pap (p-fimbriae) gene, and 43% were extraintestinal pathogenic E. coli (ExPEC) or uropathogenic E. coli (UPEC). Over half of the E. coli strains (57%) were intestinal pathogenic E. coli, most commonly enteroaggregative E. coli (EAEC) (33%), and enteroinvasive E. coli EIEC (22%). A relatively high proportion of patients with traveler’s diarrhea carry EPE, but there was no significant increase compared to 10 years ago. Most E. coli strains were intestinal pathogenic strains. A comparatively high proportion of the strains were ExPEC/UPEC, many expressing the virulence genes pap and/or fim. (This project was assigned ClinicalTrials.gov number NCT03866291.)