London, Jan 22 (IANS): A study has revealed that taking antibiotics for diarrhea may put travellers visiting developing parts of the world at higher risk for contracting superbugs and spreading these drug-resistant bacteria to their home countries.

Those travelling to South Asia faced the highest risk of contracting the resistant bacteria.

Nearly 80 percent of travellers who took antibiotics for diarrhea while visiting the region were colonised with ESBL-producing Enterobacteriaceae, a concerning type of drug-resistant superbug that is a serious threat to public health.

Southeast Asia, East Asia, and North Africa together with the Middle East, in order, were next highest in risk.

Researchers found that taking antibiotics for travellers' diarrhea increased the risk of becoming colonised by ESBL bacteria.

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

Kantele calls for greater caution in using antibiotics for travellers' diarrhea, except in severe cases. The US Centers for Disease Control (CDC) and Prevention has called ESBL-producing bacteria a serious concern and a significant threat to public health.

The bacteria can cause severe infections that are harder and more expensive to treat and more likely to be fatal.

In the study, researchers collected stool samples for testing from 430 Finns before and after they travelled outside of Scandinavia.

Overall, 21 percent of the travellers to tropical and subtropical areas had unknowingly contracted ESBL-producing bacteria during their trips.

Among those who took antibiotics for diarrhea, 37 percent were colonised.

Even if colonised travellers do not develop infections themselves, they may, after returning home, unknowingly spread the superbugs to their own countries where today these bacteria are less prevalent.

"More than 300 million people visit these high-risk regions every year. If approximately 20 percent of them are colonised with the bugs, these are really huge numbers. This is a serious thing," Kantele said.

Greater attention should be aimed at educating international travellers to take a more cautious attitude toward antibiotics, the authors wrote.

The study is available online in the journal Clinical Infectious Diseases.