There were no significant differences between rifaximin and placebo in the incidence of diarrhea or MD after treatment was stopped. Enterotoxigenic E. coli was the major cause of diarrhea and MD in this study. All the trials reported no differences in the rate of adverse events between the two groups. Statistical analysis using fixed-effects model and random-effects model demonstrated similarly significant results. There are some limitations in the present meta-analysis. Owing to limited numbers of studies available,

use of funnel plots to evaluate publication bias was not possible. The research data were obtained from participants’ diaries, so the outcome measurement has a degree of subjectivity. Owing to the lack of relevant information on the original works, such as microbiological findings, an adequate statistical analysis could not be performed. Finally, identifying the most effective dose or frequency of SCH772984 mw rifaximin was also not possible in this review. Nearly all studies of TD were carried out in healthy adult subjects. The application of these findings to less healthy populations or different travel environments requires further validation.

Up to 40% of TD cases are of unknown etiology, even after the comprehensive microbiological evaluation.[19-21] Rifaximin can prevent illness caused by diarrheagenic E. coli including ETEC and enteroaggregative E. coli, but not against invasive bacterial strains. The use of rifaximin in geographic areas with different pathogenic bacteria requires further evaluation. AZD6244 in vitro In a volunteer study, it was found that shigellosis was prevented by prophylactic oral rifaximin.[22] Its efficacy in preventing diarrhea caused by other invasive organisms found in Asia, including Salmonella

and Campylobacter, is not known.[21, 23] The risk of acquiring TD in any geographic region is influenced by the season. Rainy seasons are associated with a higher risk than dry seasons. Local weather conditions and type of travel (ie, in camping and backpacking) Tobramycin can also affect the risk of acquiring TD.[24] Also, the incidence of diarrheal episodes caused by noroviruses increases during the winter months.[25] The most common organisms developing resistance to rifaximin are aerobic Gram-positive cocci. Gram-negative organisms, such as E. coli, do not develop resistance to rifaximin after 3 to 5 days of therapy.[26-28] In spite of these advantages, owing to rifaximin’s structural relationship to other rifamycins, the resistance rates to rifaximin in Enterococcus, Bacteroides, Clostridium, and Enterobacteriaceae range from 30% to 90% after 5 days of treatment. When rifaximin treatment is stopped, the resistant strains tend to disappear within 1 to 12 weeks.[29] Current recommendations advise treating diarrhea with azithromycin during rifaximin prophylaxis,[30] because of the increased risk of an invasive enteropathogen.