Taking antibiotics for diarrhea could put travelers at a higher risk of contracting and spreading a nasty superbug.

The research calls for greater caution to be used in treating travelers' diarrhea with antibiotics in order to fight drug-resistant bacteria, the Infectious Disease Society of America reported.

"The great majority of all cases of travelers' diarrhea are mild and resolve on their own," said lead study author Anu Kantele, an associate professor in infectious diseases at Helsinki University Hospital in Finland.

To make their findings the researchers collected stool samples from 430 participants from Finland before and after they had travelled outside of Scandinavia. The samples were tested for extended-spectrum beta-lactamase (ESBL), which is an enzyme produced by a resistant type of bacteria from the Enterobacteriaceae family.

They determined 21 percent of the travelers to tropical and subtropical areas in the study had unknowingly contracted ESBL-producing bacteria during their trips, and a significant risk factor for infection included antibiotic use. Among those who took antibiotics for diarrhea, 37 percent were found to be colonized.

The team found those travelling to South Asia had the highest risk of contracting this type of bacteria; in this region 80 percent of travelers who took antibiotics for diarrhea were colonized. Southeast Asia, East Asia and North Africa together with the Middle East, were determined to be the next highest in risk.

"More than 300 million people visit these high-risk regions every year," Kantele said. "If approximately 20 percent of them are colonized with the bugs, these are really huge numbers. This is a serious thing. The only positive thing is that the colonization is usually transient, lasting for around half a year."

The finding suggests there needs to be more focus on educating international travelers to be more cautious with antibiotics.

The study was published in a recent edition of the journal Clinical Infectious Diseases.