India, April 14 -- A recent report shows that Shigella bacteria are becoming harder to treat because they are resisting most common antibiotics. Health officials from across the U.S., including the Centers for Disease Control and Prevention, say this is a growing public health concern.

Since 2011, more cases of Shigella have been found that do not respond to usual medicines. These bacteria are now becoming extensively drug-resistant, meaning they can fight off nearly all antibiotics normally used to treat them, such as azithromycin, ceftriaxone, and ciprofloxacin. At the moment, there is no easy oral medicine to treat these infections.

Shigella causes an illness called shigellosis, which leads to symptoms like diarrhea, fever, and stomach...