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Travel Medicine and Infectious Disease (2015) xx, 1e1

Available online at www.sciencedirect.com

ScienceDirect journal homepage: www.elsevierhealth.com/journals/tmid

EDITORIAL

Protecting elderly travelers from travelers’ diarrhea. Do probiotics work? Shifts in global population demographics have resulted in a higher proportion of people who are elderly and are healthy enough to travel. International travel is rapidly increasing, with more than one billion trips reported globally in 2013 [1]. As more of our population enters into the retirement age and wish to travel, more and more of these elderly are emerging as a unique, high-risk population of travelers. Many of the elderly have chronic disease conditions, may be immunocompromised, or less able to combat the infections associated with travel. As many as 24-40 million tourists worldwide are affected by travelers’ diarrhea (TD) with rates varying from 8% to 40% depending upon the destination of the journey [2]. Although travelers’ diarrhea typically lasts 1e5 days, it can have dire consequences besides disrupting travel plans. Losses of $290-490 million dollars are lost per day globally due to travelers’ diarrhea and one in five travelers return home with persistent gastrointestinal complaints, postinfectious irritable bowel syndrome or other problems. As changes in food and beverage consumption have typically not been effective in preventing TD, traveler’s often selftreat with antibiotics with limited benefit and may result in as high as 80% carriage of antibiotic-resistant organisms for those travelers [3]. In addition, many travelers use antibiotics to prevent TD from occurring, but this behavior may actually increase the risk of developing diarrhea due to the disruption of the normally protective intestinal microbiome due to the antibiotic exposure. Thus, diarrhea experienced by travelers may due to exposure to pathogenic organisms in food or beverages, or be a consequence of perceived preventive measures (antibiotics). One strategy to prevent diarrhea associated with either antibiotic use or to travel exposures is to use probiotics to assist in the recovery of the intestinal microbiome after it has been disrupted. In this issue, Xie et al. reviewed studies that focused on the elderly and the use of probiotics to prevent antibiotic-associated diarrhea [4]. The elderly are at higher risk for the development of antibiotic-associated diarrhea and may also be at higher risk for other types of travelrelated diseases, yet there are few studies aimed at this

high-risk population. Xie et al. found one probiotic appeared effective, but could not determine if the other five investigated probiotic species were effective for diarrhea due to the limited number of clinical trials in this population. A previous meta-analysis of probiotics for the prevention of traveler’s diarrhea examined 12 randomized trials and found some probiotic strains were effective, but the enrolled traveler population was typically 30e50 years old and the elderly population was not included in these studies [5]. Unfortunately, we have no clear recommendations for this emerging population of travelers, who might be at higher risk for travel-related illness. The study by Xie et al. highlights the importance of finding effective methods to prevent travel-related diarrhea associated with antibiotic use in the elderly population.

References [1] Patel RR, Liang SY, Koolwal P, Kuhlmann FM. Travel advice for the immunocompromised traveler: prophylaxis, vaccination, and other preventive measures. Ther Clin Risk Manag 2015;11: 217e28. [2] Paredes-Paredes M, Flores-Figueroa J, DuPont HL. Advances in the treatment of travelers’ diarrhea. Curr Gastroenterol Rep 2011;13:402e7. [3] Kantele A, Laaveri T, Mero S, Vilkman K, Pakkanene SH, Ollgren J, et al. Antimicrobials increase travelers’ risk of colonization by extended-spectrum betalactamase-producing Enterobacteriaceae. Clin Infect Dis 2015;60(6):837e46. [4] Xie C, Li J, Wang K, Li Q, Chen D. Probiotics for the prevention of antibiotic-associated diarrhea in older patients: a systematic review. Travel Med Infect Dis 2015 [in press]. [5] McFarland LV. Meta-analysis of probiotics for the prevention of traveler’s diarrhea. Travel Med Infect Dis 2007;5(2):97e105.

Lynne V. McFarland, Infectious Disease Epidemiologist University of Washington Seattle, WA 98195, USA E-mail address: [email protected] 5 March 2015

http://dx.doi.org/10.1016/j.tmaid.2015.03.008 1477-8939/Published by Elsevier Ltd.

Please cite this article in press as: McFarland LV, Protecting elderly travelers from travelers’ diarrhea. Do probiotics work?, Travel Medicine and Infectious Disease (2015), http://dx.doi.org/10.1016/j.tmaid.2015.03.008