CDC Warns: Drug-Resistant ‘Superbug’ That Causes Diarrhea Is Spreading in the U.S.

The Centers for Disease Control and Prevention (CDC) has raised a red flag about a drug-resistant “superbug” that causes diarrhea and is becoming more common in the United States.

A new report from the CDC, published April 9 in its Morbidity and Mortality Weekly Report (MMWR), shows that infections linked to a type of bacteria called Shigella are on the rise. These bacteria cause an illness known as shigellosis.

Shigella is responsible for about 450,000 infections in the U.S. every year, according to the CDC.

“Antibiotic resistance is a global issue because antibiotics are overused and used inappropriately around the world,” said Dr. William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt University School of Medicine. “In the U.S., clinicians and public health have worked hard to become good stewards of antibiotics, using them carefully,” he told Healthline.

XDR Shigella Cases Jumped to 8.5%

The CDC looked at 16,788 samples of Shigella bacteria collected through a system called PulseNet between 2011 and 2023. About 3% of those samples—510 in total—were identified as extensively drug-resistant, or XDR.

The share of XDR samples went from 0% between 2011 and 2015 to 8.5% in 2023.

XDR Shigella is resistant to five common antibiotics: ampicillin, azithromycin, ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole.

The CDC also noted that there are currently no oral antibiotics approved by the Food and Drug Administration (FDA) to treat XDR Shigella infections.

Most Cases Happen in the U.S., Not Abroad

The CDC report shows that the pattern of XDR Shigella infections has changed. In the past, Shigella outbreaks in the U.S. were caused by strains that responded to antibiotics, and they mostly affected children. Now, XDR Shigella cases are mostly seen in adult males with an average age of 41.

Travel data also shows that most cases are caught in the U.S. Among people with available information, 76.2% said they had not traveled recently within the country, and 82.4% reported no recent international travel.

How Does Shigella Spread?

Shigella bacteria are easy to pass along. They are found in stool, and swallowing even a tiny amount can make you sick. Anything that gets contaminated with fecal matter can spread the bacteria.

Common ways Shigella spreads include:

– Contaminated food or water

– Contact with someone who is sick or has recently been sick with Shigella

– Sexual activity with someone who is infected

Because XDR strains are becoming more common, the CDC says stronger monitoring, routine testing for antibiotic resistance, and faster reporting of shigellosis cases are needed. Shigellosis is already a disease that must be reported to public health officials. The CDC also called for targeted prevention efforts to stop the spread of XDR Shigella.

How to Prevent Shigella Infection

– Wash your hands often, especially after using the bathroom

– Be careful when changing diapers

– Don’t swallow water while swimming

– If your partner has had shigellosis, avoid sexual activity for at least 2 weeks after diarrhea stops

What Are the Treatment Options?

“Treatment options for XDR Shigella are extremely limited,” said Dr. Robert Glatter, an emergency medicine physician at Lenox Hill Hospital in New York City and an assistant professor at Zucker School of Medicine at Hofstra/Northwell.

Schaffner agreed. “Antibiotic-resistant Shigella bacteria are a concern because they leave us with no antibiotics to treat the more serious infections, requiring us to rely on supportive therapy to help patients get over their illness,” he said.

Glatter explained that most cases get better with supportive care, such as drinking fluids to prevent dehydration, replacing electrolytes, eating a normal diet after rehydration, and taking zinc supplements, especially for people who are malnourished.

“For severe infections that need antibiotics, doctors may use carbapenems given through an IV, which are the most reliable option for severe XDR infections but require hospital care,” Glatter said. “Treatment decisions should be guided by antibiotic sensitivity testing when possible, and doctors must carefully weigh the risks and benefits of using antibiotics given the limited options.”

What Are the Symptoms of Shigellosis?

The CDC says certain groups are at higher risk for shigellosis, including:

– Children under 5 years old

– People traveling to places with poor sanitation

– People who engage in sexual activity that involves stool exposure

– People experiencing homelessness

Symptoms usually appear 1 to 2 days after contact with Shigella bacteria and may include:

– Diarrhea that may be bloody or lasts more than 3 days

– Stomach pain

– Fever

– Feeling like you need to have a bowel movement even when your bowels are empty

Some people may not have any symptoms. Symptoms usually last 5 to 7 days, but in some cases, they can last up to 4 weeks.