MONDAY, Jan. 5, 2026 (HealthDay News) -- There is marked variability of nonsusceptibility to two major classes of antibiotics commonly used for treating travelers' diarrhea, according to a study published online Dec. 22 in JAMA Network Open.Bhawana Amatya, M.D., from CIWEC Hospital and Travel Medicine Center in Kathmandu, Nepal, and colleagues examined antibiotic nonsusceptibility patterns for 859 cases of travelers' diarrhea presenting at 58 international GeoSentinel sites (April 14, 2015, to Dec. 19, 2022).The researchers found that among Campylobacter isolates, nonsusceptibility to fluoroquinolones was seen for 206 of 274 isolates (75 percent) and nonsusceptibility to macrolides was seen for 30 of 255 isolates (12 percent). Nonsusceptibility was highest in travelers to South Central Asia (45 of 51 isolates; 88 percent). Among nontyphoidal Salmonella species, 96 of 302 isolates (32 percent) were nonsusceptible to fluoroquinolones, 18 of 111 isolates (16 percent) were nonsusceptible to macrolides, and 15 of 273 isolates (5 percent) were nonsusceptible to third-generation cephalosporins. For Shigella species, 44 of 196 isolates (22 percent) were nonsusceptible to fluoroquinolones, while 36 of 103 isolates (35 percent) were nonsusceptible to macrolides. For E. coli, 12 of 66 isolates (18 percent) had fluoroquinolone nonsusceptibility. For nonsusceptibility to fluoroquinolones, 19 of 24 isolates (79 percent) were among travelers to South Central Asia, and for nonsusceptibility to macrolides, and 29 of 37 isolates (78 percent) were among travelers to South America."Antimicrobial susceptibility from culture should be obtained when possible, including after pathogen detection by culture-independent methods," the authors write. "These findings may help inform strategies for self-treatment and clinician management of travelers' diarrhea."Several authors disclosed financial ties to the pharmaceutical industry.Abstract/Full Text.Sign up for our weekly HealthDay newsletter