Shigella, an antibiotic-resistant bacteria, is on the rise. Now, the Atlanta-based Centers for Disease Control and Prevention has issued a warning on the matter.

“Shigella bacteria cause an infection called shigellosis,” the CDC explained. “Shigella cause an estimated 450,000 infections in the United States each year and an estimated $93 million in direct medical costs.”

The CDC said that shigella spreads easily, taking “just a small number of bacteria to make someone ill.” Those infected by the bacteria can remain infectious to others for several weeks, often spreading the bacteria through prepared food, on surfaces (such as bathroom fixtures), and even in swimming pool water.

Symptoms of shigella include bloody diarrhea lasting more than three days, fever, stomach pain and feeling the need to pass stool. Symptoms usually begin one to two days after infection and can last for up to a week. In some cases, bowel habits do not return to normal for several months.

Children under five years old are the most likely to be infected by shigella, though people of all ages can be infected.

“Many outbreaks occur in early care and education settings and schools,” the CDC reported. “Infection commonly spreads from young children to their family members and other people in their communities because these bacteria spread easily.”

Due to shigella’s antibiotic resistance, doctors must think outside the box when it comes to treatment.

“If Shigella bacteria are resistant, first-choice antibiotics recommended to treat these infections may not work,” the CDC warned. “Healthcare providers might need to prescribe second- or third-choice drugs for treatment. However, these drugs might be less effective, may need to be taken through a vein (IV) instead of by mouth, may be more toxic, and may be more expensive. Recommended antibiotics for severe infections include fluoroquinolones, azithromycin, and ceftriaxone.”