Travelers May Spread Antibiotic Resistance

Anu Kantele, MD PhD Associate Professor, Department of Medicine, University of Helsinki Specialist of Infectious Diseases, Helsinki University Hospital Head of Travel Clinic, Aava Medical Centre "Photo taken by Leena Mattila/YLE/science" Interview with:
Anu Kantele, MD PhD

Associate Professor, Department of Medicine, University of Helsinki Specialist of Infectious Diseases, Helsinki University Hospital Head of Travel Clinic, Aava Medical Centre

Medical Research: What is the background for this study? What are the main findings?

Dr. Kantele: Increasing antimicrobial resistance is considered a serious global threat for modern medicine. Resistance is rapidly surging in regions with poor hygiene and uncontrolled use of antibiotics. Resistant bacteria are gradually spreading from there to countries in which the prevalence has thus far been low.

Our study was conducted among 430 healthy Finnish travelers visiting warm countries (tropical /subtropical regions). The volunteers provided stool samples before and after travel and filled in questionnaires. The stools were analyzed for multidrugresistant bacteria (not only so called ESBL bacteria but also CPE bacteria which are even more resistant).

None of the travelers had CPE strains in their stools before or after their journey. 1% carried ESBL before travel, and 21% acquired a strain while overseas. The risk was greatest in the Indian subcontinent and almost similar in Southeast Asia. In Africa, it proved to be increased but did not reach such a high level. Two factors amplified the risk significantly: travellers’ diarrhea and use of antibiotics. Among the entire study population, ESBL was found in 11% of those staying healthy, 22% of those with diarrhea, and 37% of those who took antibiotics for their diarrhea. In the Indian subcontinent, the respective figures were 23%, 47%, and 80%, and in Southeast Asia 14%, 32%, and 69%.

Medical Research: Why do antibiotics predispose to contracting resistant bacteria from the surroundings?

Dr. Kantele: The effects of antibiotics cannot be restricted to killing merely the bugs we wish them to kill. When doing their job they also wipe out a huge number of our own intestinal bacteria, thereby opening the door for newcomers’ invasion. If antibiotics are taken in an environment exposing people to a multitude of resistant bacteria, part of these newcomers are likely to be resistant ones. Antibiotics may, in fact, kill the sensitive newcomers and favor the resistant ones.

Medical Research: What is the significance of these findings?

Dr. Kantele: Travelers colonized with resistant bacteria mostly remain unaware of the situation, and the bacteria will disappear within months (or years, sometimes). However, if these bacteria manage to cause an infection, many of the antibiotics commonly used will be inefficacious. Infections with multidrugresistant bacteria tend to entail greater costs, longer hospital stay and increased mortality. Furthermore, the bacteria may spread from asymptomatic carriers to their close contacts, such as family members, and, eventually, reach local hospitals. Over the course of time, resistant bacteria are bound to spread to low-prevalence countries, and ultimately, across the globe.

100 million travelers are estimated to contract diarrhea each year. As obvious, with such large numbers of people concerned, whether they take antibiotics for it or not is not at all inconsequential. Treating diarrhea with antibiotics not only forwards the global spread of antimicrobial resistance but also contributes to the local resistance in developing countries, since the antibiotics used by travelers end up in the environment they visit.

Medical Research:
What should clinicians and patients take away from your report?

Dr. Kantele: They should learn to respect antibiotics and reserve them for situations where they are really needed. Travelers’ diarrhea does not count among them: in more than 90% of cases travelers’ diarrhea is mild /moderate and resolves spontaneously. Antibiotics may shorten its duration (1.5 days on the average), yet may cause harm both to the individual and his/her surroundings. The patient should drink enough fluids; if needed, non-antibiotic drugs such as loperamide can be used to relieve symptoms. Antibiotics are warranted only in severe diarrhea (high fever, poor condition etc).

What recommendations do you have for future research as a result of this study?

Dr. Kantele: Antibiotics are like a natural resource: we run the risk of losing them, because we use them too carelessly across the globe. The situation calls for serious action all over: improving hygiene and establishing reasonable antimicrobial policies in high risk regions; surveillance of antimicrobial resistance, infection control at hospitals, development of new antibiotics or other approaches to treating infections; devising vaccines  etc. This study of ours encourages further research into means of preventing the initial colonization, i.e. identifying risk factors and developing approaches that provide protection against contracting the bacteria.


Anu Kantele, Tinja Lääveri, Sointu Mero, Katri Vilkman, Sari H. Pakkanen, Jukka Ollgren, Jenni Antikainen, and Juha Kirveskari

Antimicrobials Increase Travelers’ Risk of Colonization by Extended-Spectrum Betalactamase-Producing Enterobacteriaceae Clin Infect Dis. first published online January 21, 2015 doi:10.1093/cid/ciu957

[wysija_form id=”1″]