Importance: Diarrheal disease causes substantial morbidity in international travelers. Knowledge of antibiotic resistance of causative pathogens helps guide empiric treatment decisions.
Objective: To characterize antimicrobial nonsusceptibility patterns of culture-confirmed Campylobacter species, nontyphoidal Salmonella (NTS) species, Shigella species, and diarrheagenic Escherichia coli isolated from international travelers with diarrhea identified by the GeoSentinel Surveillance Network.
Design, setting, and participants: This is a retrospective cross-sectional analysis of antimicrobial susceptibility data for 4 major pathogens causing travel-associated diarrhea, reported from April 14, 2015, to December 19, 2022, at 58 of 71 international GeoSentinel sites. Participants included a convenience sample of international travelers with acute diarrhea seen during or after travel presenting at the GeoSentinel sites.
Main outcomes and measures: The main outcomes were demographics, clinical characteristics, and antimicrobial susceptibility profiles of patients with culture-confirmed Campylobacter species, NTS species, Shigella species, and diarrheagenic E coli species. Routinely collected antimicrobial susceptibility data with intermediate susceptibility and resistant were defined as nonsusceptible. The antimicrobial susceptibility test results were described as numbers and percentages, and binomial 95% CIs were calculated for the proportions.
Results: Of 859 total cases, the median (IQR) age was 30 (23-43) years, and 440 travelers (51%) were male. Among Campylobacter isolates, nonsusceptibility to fluoroquinolones was found in 206 of 274 isolates (75%; 95% CI, 70%-80%), and nonsusceptibility to macrolides was found in 30 of 255 isolates (12%; 95% CI, 8%-16%) and was highest in travelers to South Central Asia (45 of 51 isolates; 88%; 95% CI, 76%-96%). Among NTS species, 96 of 302 isolates (32%; 95% CI, 27%-37%) were nonsusceptible to fluoroquinolones, 18 of 111 isolates (16%; 95% CI, 10%-24%) were nonsusceptible to macrolides, and 15 of 273 isolates (5%; 95% CI, 3%-9%) were nonsusceptible to third-generation cephalosporins. For Shigella species, 44 of 196 isolates (22%; 95% CI, 17%-29%) were nonsusceptible to fluoroquinolones, and 36 of 103 isolates (35%; 95% CI, 26%-45%) were nonsusceptible to macrolides. For E coli, fluoroquinolone nonsusceptibility was 18% (12 of 66 isolates; 95% CI, 10%-30%). Of note, 19 of 24 Shigella isolates (79%; 95% CI, 58%-93%) were nonsusceptible to fluoroquinolones among travelers to South Central Asia, and 29 of 37 Shigella isolates (78%; 95% CI, 62%-90%) were nonsusceptible to macrolides among travelers to South America.
Conclusions and relevance: In this cross-sectional study of travelers' diarrhea antimicrobial resistance patterns, there was marked variability of nonsusceptibility to 2 major classes of antibiotics commonly used for treating travelers' diarrhea among global regions. Antimicrobial susceptibility from culture should be obtained when possible, including after pathogen detection by culture-independent methods. These findings may help inform strategies for self-treatment and clinician management of travelers' diarrhea.