Resistant pathogens as causes of traveller's diarrhea globally and impact(s) on treatment failure and recommendations

Background: Diarrhea is a frequent clinical syndrome affecting international travellers. Bacterial etiologic agents have a long history of emergent antimicrobial resistance against commonly used antibiotics. Current approaches applying first-line antimicrobial therapy are being challenged by increasingly resistant organisms. This review summarizes recent epidemiological and clinical evidence of antibiotic resistance among enteropathogens causing traveller's diarrhea and the subsequent impact on current treatment recommendations. Methods: The PubMed database was systemically searched for articles related to antibiotic susceptibility and diarrheal pathogens. Results: Antibiotic resistance related to travellers' diarrhea has increased in recent years. Most notably, fluoroquinolone resistance has expanded from the Campylobacter-associated cases well documented in Southeast Asia in the 1990s to widespread occurrence, as well as increases among other common bacterial enteropathogens including, enterotoxigenic and enteroaggregative Escherichia coli, Shigella and non-typhoidal Salmonella. Multidrug resistance among enteropathogenic Enterobacteriacae and Campylobacter species create further challenges with the selection of empiric therapy. Treatment failures requiring early use of alternative agents, as well as delayed recovery comparable to placebo rates emphasize the impact of antimicrobial resistance on effective treatment. Conclusions: Although there are limitations in the available data, the increasing antibiotic resistance and adverse impact on clinical outcome require continued surveillance and reconsideration of practice guidelines.