Acute travelers’ diarrhea (TD) is one of the most common diseases that affects international travelers, caused by bacterial pathogens like Campylobacter species, Shigella species, nontyphoidal Salmonella (NTS), and diarrheagenic Escherichia coli, causing mild to severe cases. Increasing global antimicrobial resistance specifically to fluoroquinolones and macrolides, which are the basis of empiric therapy, presents a significant challenge to effective management. Resistance patterns differ by geographic area, but the information describing antimicrobial susceptibility in isolates from international travelers is limited and regionally restricted. Understanding these patterns is important to guide empirical treatment suggestions, optimize patient care, and support public health surveillance efforts in the context of increasing use of culture-independent diagnostic methods.
The aim of this study was to characterize regional antimicrobial nonsusceptibility patterns of common bacterial causes of acute TD in international travelers. The study used data from the GeoSentinel global surveillance network to describe resistance to key antibiotics in many regions of exposure and inform evidence-based empiric treatment strategies for travelers with mild to severe diarrhea.
This cross-sectional retrospective study analyzed deidentified surveillance data collected by the GeoSentinel network, which involved 71 specialized travel and tropical medicine sites on six continents. Cases from April 2015 to December 2022 were involved if travelers had acute diarrhea lasting less than 2 weeks, culture-confirmed infection with Campylobacter species, NTS, Shigella species, or diarrheagenic E. coli, and at least one antimicrobial susceptibility test (AST) result with known region of exposure. Demographic, travel-related, clinical, and laboratory data were extracted from the GeoSentinel database. Intermediate and resistant AST results were combined and categorized as nonsusceptible. Definitions for multidrug-resistant and extensively drug-resistant organisms were applied where appropriate. Statistical analyses were descriptive by using medians, interquartile range, proportion, and 95% confidence intervals (CI) and were conducted using R software. The study was classified as public health surveillance and followed STROBE reporting guidelines.
A total of 859 travelers with acute bacterial diarrhea and available AST data from 58 GeoSentinel sites were included. The median age was 30 years, with an approximately equal distribution of male and female travelers. The most frequently identified pathogens were NTS (305 cases), Campylobacter species (286 cases), Shigella species (215 cases), and diarrheagenic E. coli (75 cases). The most common regions of exposure were sub-Saharan Africa, Southeast Asia, South America, and South-Central Asia. Most travelers presented for care after travel, and nearly one-quarter required hospitalization.
Marked regional variation in antimicrobial nonsusceptibility was observed. Campylobacter species showed very high fluoroquinolone nonsusceptibility overall (75%), particularly among travelers to South Central Asia (88%) and Southeast Asia (80%), while macrolide nonsusceptibility was lower but still notable (12% overall). NTS isolates demonstrated moderate fluoroquinolone nonsusceptibility (32%), with higher rates in South Central Asia and the Caribbean and relatively low nonsusceptibility to macrolides and third-generation cephalosporins. Shigella species exhibited substantial resistance, including high fluoroquinolone nonsusceptibility in South Central Asia (79%) and high macrolide nonsusceptibility in South America (78%). One extensively drug-resistant Shigella case was identified. Diarrheagenic E. coli showed lower overall resistance, though data were limited and largely derived from a single site in Peru. Across pathogens, resistance patterns often differed from standard empiric treatment recommendations used in travelers’ countries of origin.
This multicontinent study shows significant geographic differences in antimicrobial resistance in bacterial causes of travelers’ diarrhea, with specifically high fluoroquinolone resistance and emerging macrolide resistance in key areas. These results underscore the limitations of uniform empiric informed by surveillance data. Continued use of stool culture and susceptibility testing in travelers alongside global resistance monitoring is important to guide effective empiric therapy, update clinical guidelines, and mitigate the spread of resistant enteric pathogens.
Reference: Amatya B, Pandey P, McGuinness SL, et al. GeoSentinel Analysis of Travelers’ Diarrhea Antimicrobial Resistance Patterns. JAMA Netw Open. 2025;8(12):e2551089. doi:10.1001/jamanetworkopen.2025.51089
