Drug-Resistant ‘Superbug,’ Shigella on the Rise in U.S., CDC Says

• The Centers for Disease Control and Prevention (CDC) recently released a report that showed that drug-resistant Shigella is on the rise in the United States.
• Shigella bacteria cause the infection shigellosis.
• Extensively drug-resistant (XDR) Shigella strains are typically resistant to five commonly used antibiotics.
• Shigella can be easily transmitted, including through person-to-person contact and contaminated food.
• There are ways to prevent the spread of Shigella, including regular handwashing.

The Centers for Disease Control and Prevention (CDC) has issued a warning about a drug-resistant, diarrhea-causing “superbug” on the rise in the United States.

According to the CDC, Shigella causes around 450,000 infections in the United States each year.

“Antibiotic resistance is a global issue because antibiotics are overused and used inappropriately around the world,” said William Schaffner, MD, a professor of preventive medicine and professor of medicine in the Division of Infectious Diseases at the 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.

The CDC analyzed 16,788 Shigella isolates that were collected through PulseNet between 2011 and 2023.

Around 3% (510) of these isolates were identified as XDR. The proportion of XDR isolates changed from 0% during 2011 to 2015 to 8.5% in 2023.

XDR Shigella is defined by its resistance to five commonly used antibiotics:

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

The CDC report indicates that the epidemiology of XDR Shigella has shifted.

Epidemiology refers to the patterns and distributions of health-related events, such as diseases.

Previously, outbreaks of Shigella in the U.S. were drug-susceptible strains and primarily affected children. In contrast, XDR Shigella cases have mostly occurred in adult males with an average age of 41.

The travel history data also showed that the majority of Shigella cases were acquired domestically.

Among individuals with available data, 76.2% reported no recent domestic travel, and 82.4% reported no recent international travel.

Shigella bacteria are easily spread. These bacteria appear in feces and fecal matter. Swallowing just a small amount of Shigella can make you sick.

Anything that may become contaminated with fecal matter can potentially spread Shigella.

• contaminated food or water
• contact with a person who is sick or has recently been sick with a Shigella infection
• sexual activity with someone who is sick

With the rising prevalence of XDR Shigella strains, the CDC noted in its report that stronger surveillance, routine antimicrobial susceptibility testing, and timely reporting of shigellosis are needed. Shigellosis is a nationally notifiable disease.

The CDC also called for targeted prevention methods to limit further spread of XDR Shigella infections.

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

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 said that most cases resolve with supportive treatments, such as oral rehydration and electrolyte replacement, continued feeding or resumption of a usual diet after rehydration, and zinc supplementation, especially for malnourished individuals.

“For severe infections requiring antibiotics, physicians may use carbapenems given intravenously, which are the most reliable option for severe XDR infections but require hospitalization,” Glatter said.

“Treatment decisions should be guided by antimicrobial susceptibility testing when available, and physicians must carefully weigh the risks and benefits of antibiotic therapy given the limited options,” he added.