An article by Scientific American says that a particularly resilient strain of Shigella sonnei, a relatively common foodborne illness, has established a firm presence in the United States.
In April, the Centers for Disease Control and Prevention (CDC) released a report announcing that a current outbreak of Shigella sonnei is resistant to ciprofloxacin—one of the last antibiotics in pill form that can kill the bacteria. The CDC confirmed 275 such cases from May 2014 to May 2015. According to the Scientific American investigation, this figure only represents a small fraction of the actual number of such cases, since many go unreported.
Shigella bacteria occur naturally in the United States, but people typically catch the ciprofloxacin-resistant strain while abroad. In the current outbreak, however, many of the victims did not travel internationally, indicating that the ciprofloxacin-resistant strain has taken root domestically.
Symptoms of Shigella include fever, abdominal pain, and diarrhea that is sometimes bloody. Malnourished children and the immunocompromised are at particular risk for developing severe cases.
The CDC and other health agencies recommend that doctors only prescribe antibiotics for severe cases in order to prevent the expansion of multidrug-resistant Shigella. The disease will normally subside with proper hydration and rest.