Antibiotics overuse can may do more harm than good

Antibiotics may kill the body's "good" bacteria that maintain immune cells and keep infections at bay, say scientists including those of Indian origin, warning that the overuse of these medicines can do more harm than good.

The study, published in the journal Frontiers in Microbiology, found that natural defenses were very effective in reducing infection and unwanted inflammation -- and antibiotics can prevent such natural defenses.

Researchers, including Natarajan Bhaskaran and Shivani Butala from Case Western Reserve University in the US, examined "resident" bacteria, their fatty acids and their effect on certain types of white blood cells that combat infections in the mouth.

They looked at the "short-term maintenance" of Tregs and Th-17 cells in fighting fungal infections, such as Candida, in a laboratory setting.

"We set out to find out what happens when you don't have bacteria to fight a fungal infection," said Pushpa Pandiyan, an assistant professor at Case Western.

"What we found was that antibiotics can kill short-chain fatty acids produced by body's own good bacteria," said Pandiyan, who led the study.

Antibiotics are still needed for life threatening infections, researchers said.

"Our bodies have many natural defenses that we shouldn't meddle with. However, needless overuse of antibiotics is not helpful, Pandiyan said.

"Also, we know there is a definite link between oral health and overall health," she added.

Pandiyan said the study could have broader implications on protective effects of "resident microbiota" in other types of infections.