Travelers Are Importing Intestinal Antibiotic-Resistant Superbugs Interview with:

Herr A. Endimiani, MD, PhD, Prof (Hab. ITA/EU) Institute for Infectious Diseases University of Bern

Herr Dr. Endimiani

Prof. Andrea Endimiani, MD, PhD
Institute for Infectious Diseases
University of Bern What is the background for this study?

Response: The spread of multidrug-resistant Gram-negative bacteria represents a serious issue for the healthcare system worldwide because our antibiotic armamentarium is becoming too limited. These «superbugs» may cause serious infections with high morbidity and mortality rates – there are already 700,000 estimated deaths per year worldwide because common antimicrobial therapies have become ineffective. In this scenario, colistin has represented the last active antibiotic option able to cure many infected people.

Unfortunately, in November 2015 a new mechanism of resistance against colistin was found with a high prevalence in Escherichia coli and Klebsiella pneumoniae strains detected in China among humans, food animals, and chicken meat; more recently, it has also been found in other countries.

This mechanism is encoded by a gene (named mcr-1) that is plasmid-mediated, thus assuring its great ability to mobilize and spread between different enterobacteria, including those normally present in the human and animal intestinal tracts. What are the main findings?

Response: We analyzed for the first time the bacterial population of the intestinal tract of travelers from Switzerland to India and found out that 76% of the tourists returning from India were colonized with superbugs. More importantly, 11% of the travelers had in their stools colistin-resistant E. coli strains, including those possessing the new plasmid-mediated mcr-1 gene.

Molecular analyses also indicated that these life-threatening bacteria were acquired from the environment and/or food chain in India. Notably, healthy people carrying superbugs in the intestinal tract can have a high risk to further develop infections such as urinary tract infections or bacteremia due to these difficult to treat bacteria. What should readers take away from your report?

Response: Travelers should be aware that during their trip they can acquire superbugs. These bacterial can colonize their intestinal tract and in future might cause difficult to treat infections. In addition, being colonized can favor transmission among people leaving in contact (e.g., in the same household).

To try preventing the acquisition of superbugs, travelers should try to drink only tap water, do not eat fresh vegetables, dairy products and uncooked meat. Moreover, they should wash very well and frequently their hands. What recommendations do you have for future research as a result of this study?

Response: The acquisition of colistin-resistant bacteria during trips is a phenomenon that needs to be carefully monitored to prevent the spread of such untreatable bacteria in countries (e.g., Switzerland) that still have a low prevalence of superbugs.

We strongly recommend a rapid implementation of specific and sensitive surveillance programs to prevent unexpected outbreaks due to enterobacteria possessing the mcr-1 gene. New rapid and cost effective diagnostic tests are also welcome. Thank you for your contribution to the community.


Odette J. Bernasconi, Esther Kuenzli, João Pires, Regula Tinguely, Alessandra Carattoli, Christoph Hatz, Vincent Perreten, Andrea Endimiani. Travelers Can Import Colistin-ResistantEnterobacteriaceaeIncluding Those Possessing the Plasmid-Mediatedmcr-1Gene. Antimicrobial Agents and Chemotherapy, 2016; AAC.00731-16 DOI: 10.1128/AAC.00731-16

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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