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Researchers Find That Antibiotics Should Not Be Taken for Traveler's Diarrhea

FEB 27, 2017 | KRISTI ROSA
Through overuse and misuse, a number of harmful bacteria have managed to develop resistance to a several currently available antibiotics. Due to the fact that the amount of antibiotic-resistant pathogens continues to increase, it has become a major public health concern. For this reason, healthcare providers across the world are looking into ways to cut down on unnecessary prescriptions and researchers are conducting studies meant to shed additional light on the issue.

One such study took a closer look at millions of travelers who visit high-risk countries each year; countries with notably poor hygiene and “weakly implemented antimicrobial policy.” The researchers, from the University of Helsinki, found that about one third of these aforementioned travelers will come back home with extended-spectrum beta-lactamase-producing Enterobacteriaceae, or ESBL intestinal bacteria. The regions with the highest risk are South Asia, Southeast Asia, Africa, and Latin America. According to study authors, these same regions are “associated with increased risk of travelers’ diarrhea.”

When it comes to traveling to poorer regions of the world, travelers’ diarrhea (TD) “is the most predictable travel-related illness,” according to the Centers for Disease Control and Prevention (CDC), with 30% to 70% of travelers experiencing TD attacks depending on where and when they are traveling. Furthermore, the CDC reports that bacterial pathogens are responsible for a majority of TD cases, namely 80% to 90%. In fact, according to a press release on the Helsinki study, those who contract TD will find themselves at increased risk of acquiring ESBL as well. However, if these individuals choose to treat themselves with antibiotics for TD, their risk of ESBL acquisition “becomes multiplied.” Indeed, a past study conducted by study author Anu Kantele, MD, PhD, professor at the University of Helsinki, found that 80% of individuals who traveled to high-risk areas who contracted TD and took antibiotics as a means to treat their condition, returned carrying ESBL super bacteria.

Dr. Kantele recently spoke with Contagion® about these findings, stating, “In 2015, we published a study in Clinical Infectious Diseases on 430 travelers showing that antibiotic use predisposes the travelers to contract ESBLs. Ninety of our volunteers contracted ESBL during travel. [The properties of ESBL make] the bacterium resistant to two major groups of antibiotics, penicillins and cephalosporins, but they can be sensitive to many other antibiotics as well, such as fluoroquinolones (FQ) and tobramycin. These are the antibiotics we can use for treating ESBL infections, so it is important that the ESBLs are sensitive to these alternative antibiotics.
For this recent study, Dr. Kantele established that taking antibiotics while abroad not only increases the traveler’s risk of acquiring an ESBL infection, but also leads to “the most resistant strains of these bacteria being selected.”

When speaking of the process behind the newest study, Dr. Kantele explained to Contagion®, “We took all the ESBL strains which the 90 persons had contracted and checked what antibiotics they were sensitive to. Then, we divided those persons with the ESBLs into two groups: those who had not taken any antibiotics (but still contracted ESBL, [which] tells about the background risk when you visit such a region) (group FQ-), and those who had taken fluoroquinolone antibiotic (group FQ+). We found that in the FQ- group ([those who] did not take any antibiotics) 37% had an ESBL which was resistant also to FQs.  In the FQ+ group, 95% of the ESBLs were resistant to FQ! [This result is] logical as the FQ they have been taking has killed all the sensitive bacteria which would have liked to enter.”

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