Antibiotics for Diarrhea Increase Risk of Superbug Colonization

A new study warns that treating travelers' diarrhea (TD) with antibiotics turns them into unknowing carriers of drug-resistant bacteria, and may even contribute to the spreading of these superbugs in their native countries.

Researchers at Helsinki University Hospital (Finland) collected stool samples from 430 Finns before and after traveling outside of Scandinavia. All the specimens were analyzed for Extended-Spectrum Betalactamase-Producing Enterobacteriaceae (ESBL, an enzyme that shields the superbugs against common antibiotics) and carbapenemase-producing Enterobacteriaceae (CPE). Questionnaires were used to survey the participants about use of antimicrobials during their trip, as well as other potential risk factors.

The results revealed that 21% of the travelers had become colonized by ESBL-PE, but none by CPE. Geographic region, occurrence of TD, age, and use of antibiotics were identified as independent risk factors predisposing to contracting ESBL-PE, with nearly 40% of the travelers colonized with ESBL-producing bacteria. However, those who took antibiotics for TD while visiting South-Asian countries, such as India, Bangladesh, and Pakistan, faced the highest risk, with nearly 80% colonized by ESBL-PE. The study was published on January 21, 2015, in Clinical Infectious Diseases.

“The great majority of all cases of travelers’ diarrhea are mild and resolve on their own,” concluded lead author, Professor of Epidemics, Anu Kantele, MD, and colleagues. “In modern pre-travel counseling for those visiting high-risk regions, travelers should be advised against taking antibiotics for mild or moderate travelers' diarrhea.”

TD affects 20%–50% of international travelers (an estimated 10 million persons annually), with the primary source being ingestion of unhygienic, fecally contaminated food or water. The onset of TD usually occurs within the first week of travel but may occur at any time while traveling, and even after returning home. The most important determinant of risk is the traveler's destination; high-risk destinations are the developing countries of Latin America, Africa, the Middle East, and Asia. Persons at particular high-risk include young adults, the immunosuppressed, people with inflammatory-bowel disease or diabetes, and those taking H-2 blockers or antacids.

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