World travellers often import multidrug-resistant intestinal bacteria
People who travel to distant destinations often import multidrug-resistant intestinal bacteria known as ESBL-producing bacteria, which are resistant to common antibiotics. These were the results of the COMBAT study conducted by Maastricht University/Maastricht UMC+, Ease Travel Clinic & Health Support, Erasmus MC and Travel Clinic Havenziekenhuis in Rotterdam, and the AMC and Tropencentrum AMC in Amsterdam. As part of this study, the researchers also collaborated with Utrecht University. The results were recently published in the leading scientific journal The Lancet Infectious Diseases.
Travellers import multidrug-resistant bacteria
The participants in this large-scale study were recruited by the Travel Clinics, which offer vaccinations for travellers headed to tropical destinations. More than 10,000 faecal samples and questionnaires have been collected since November 2012 from 2,001 travellers and 215 non-travelling household members. More than 34% of participants had acquired multidrug-resistant bacteria during their travels and imported it back into the Netherlands. Significant differences were detected per destination. Of the participants who travelled to South Asia, 75% returned with multidrug-resistant bacteria in their gastrointestinal systems. Of the participants who travelled to Central Asia, East Asia, the Middle East and North Africa, 40-50% returned with multidrug-resistant bacteria. Travellers to India had the highest risk of contracting
ESBL-producing bacteria. In addition to the travel destination, the researchers also took other risk factors into account. Factors such as antibiotic use during travel, traveller's diarrhoea and chronic bowel disease increased the risk of acquiring multidrug-resistant bacteria. However, the highest risk factor was the destination itself.
Multidrug-resistant bacteria: a growing health problem
The participants were tested several times after their return for multidrug-resistant bacteria. The median duration of colonisation after travel was 30 days. One in nine cases remained colonised at twelve months. The study also found that the probability of transmitting the multidrug-resistant bacteria to a non-travelling household member was 12%. 'Multidrug-resistant bacteria will soon become one of the biggest threats to public health,' says researcher John Penders, who is affiliated with the Department of Medical Microbiology at Maastricht University/Maastricht UMC+. 'Estimates suggest that by 2050 more people will die from infections caused by multidrug-resistant microorganisms than the number of deaths currently caused by cardiovascular disease or cancer. In the Netherlands, the risk of infection is relatively small; however, it's important to consider resistance if someone develops an infection, such as a bladder infection, shortly after returning home from a remote destination. This is particularly true for high-risk areas.'
What is ESBL?
The study focused on ESBL-producing bacteria. ESBL stands for extended spectrum beta-lactamase, an enzyme that can break down common antibiotics like penicillin, allowing the bacteria to build up resistance to these types of antibiotics. Simple intestinal bacteria are capable of producing ESBL. These bacteria are perfectly harmless in healthy people, as long as they stay in the intestinal tract. Once outside, however, they can cause infections. Infections caused by ESBL bacteria are particularly dangerous in hospitals. When intestinal bacteria begin producing ESBL, the infection becomes harder to treat and the treatment itself becomes more expensive. As a result, the cheaper antibiotics used to treat similar infections are no longer effective.