What is Shigella, the increasingly drug-resistant bacteria the CDC is warning about?

https://www.npr.org/2023/03/03/ [login to see] /shigella-antibiotic-resistant-diarrhea
The Centers for Disease Control and Prevention raising warning doctors and the public about an increase in extensively drug-resistant (XDR) cases of Shigella, a highly transmissible bacteria that causes an infection called shigellosis, an inflammatory diarrhea.

On Tuesday, the CDC held a call to inform clinicians about this emerging public health threat. The Colorado Department of Public Health and Environment and the U.K. Health Security Agency also presented on the call due to their experience dealing with XDR Shigella.

The new forms of the bug are resistant to all five of the antimicrobial treatments that are typically used, which was never seen before 2016 and have been increasing in prevalence ever since, says Dr. Louise Francois Watkins, a medical officer at the CDC. Most Shigella strains are resistant to one or some of the drugs, but not all five, she told NPR.

Because of limited data, the CDC doesn't yet have official alternative recommendations, but there are promising potential treatments.