Travelers to areas like Latin America, Africa and South and Southeast Asia often carry antibiotics in case of infection, but treating diarrhea with those antibiotics can leave travelers at great risk of contracting extended spectrum beta-lactamases, or ESBL bacteria.
Such bacteria are resistant to penicillins and cephalosporins, so an infection is treated with antibiotics from other groups, like fluoroquinolones.
Researchers recruited Finnish travelers for a study and collected stool samples before and after travel. Ninety of the travelers contracted an intestinal strain of ESBL bacteria on their trip and participated in a follow-up study.
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Among those who did not use an antibiotic, 37 percent had an ESBL strain resistant to fluoroquinolone. Nearly all (95 percent) of those who did use fluoroquinolone to treat their infection had a strain of ESBL bacteria resistant to that and other antibiotics.
Usually, ESBL infections do not have symptoms. However, symptomless carriers can still spread the bacteria, which can cause life-threatening diseases in other people.
"In practice this means that travelers pick up the most resistant strains of ESBL, and we are left with dwindling treatment options for ESBL infections," said Anu Kantele, MD, PhD, the study's lead author.
"The spread of resistant strains of bacteria makes the situation worse. Therefore, unnecessary use of antibiotics should be avoided also while traveling," Dr. Kantele said.