Antimicrobials increase travelers' risk of colonization by extended-spectrum betalactamase-producing Enterobacteriaceae

Abstract

Background: More than 300 million travelers visit regions with poor hygiene annually. A significant percentage of them become colonized by resistant intestinal bacteria such as extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) and may transmit the strains to others and to medical care settings when they return home. Despite the threats to global healthcare caused by an upsurge in antimicrobial resistance, no effort has been centered on prevention of colonization while traveling.

Methods: Stool samples were collected from 430 Finns before and after traveling outside Scandinavia. All specimens were analyzed for ESBL- and carbapenemase-producing Enterobacteriaceae (CPE). Questionnaires were used to survey volunteers about use of antimicrobials as well as other potential risk factors. The results were subjected to multivariable analysis.

Results: Twenty-one percent (90/430) of the travelers became colonized by ESBL-PE and none by CPE. Geographic region, occurrence of travelers' diarrhea (TD), age, and use of antimicrobial (AB) for TD were identified as independent risk factors predisposing to contracting ESBL-PE. Eleven percent of those in subgroup TD-AB-, 21% in TD+AB-, and 37% in TD+AB+ acquired ESBL-PE. The risk proved to be highest in South Asia (46%); 23% became colonized in subgroup TD-AB-, 47% in TD+AB-, and 80% in TD+AB+. In Southeast Asia, the rates were 14%, 37%, and 69%, respectively.

Conclusions: TD and antimicrobials for TD proved to be independent risk factors, with up to 80% of TD+AB+ travelers contracting ESBL-PE. In modern pre-travel counseling for those visiting high-risk regions, travelers should be advised against taking antibiotics for mild or moderate TD.

Keywords: ESBL; antimicrobials; colonization; travel; travelers’ diarrhea.

Figure 1.

Study protocol for investigating risk factors associated with extended-spectrum beta-lactamase (ESBL)–producing Enterobacteriaceae colonization of Finnish travelers.

Figure 2.

World map indicating the risk levels of contracting extended-spectrum beta-lactamase–producing Enterobacteriaceae (ESBL-PE) in different geographic regions as established in the present investigation. In the entire study population, 21% of the travelers contracted ESBL-PE; 11% in subgroup TD−AB− (travelers' diarrhea/antimicrobials), 21% in TD+AB−, and 37% in TD+AB+ contracted ESBL-PE. The respective subgroup analyses for the regions with highest risk (Africa, South Asia, and Southeast Asia) are given in the boxes with arrows. The ESBL-PE strains contracted were all Escherichia coli, except for 2 Klebsiella oxytoca and 1 Escherichia hermannii.