CDC warns of drug-resistant Shigella bacteria, the stomach bug deemed a ‘serious threat to public health’

The Centers for Disease Control and Prevention says it’s tracking a rise in stomach illnesses caused by infections with “extremely drug-resistant” bacteria that leave doctors with few antibiotic options to treat patients. The CDC warns that it now poses a “serious threat to public health.”

In recent years, the CDC says there are signs that the percentage of cases of Shigella bacteria resistant to a wide range of antibiotics has started to climb sharply across the country. These strains can also spread their resistance genes to other stomach bugs.

Analyzes of these bacteria, called XDR Shigella, showed resistance to all the first-line antibiotic treatments generally recommended for the bacteria: azithromycin, ciprofloxacin, ceftriaxone, trimethoprim-sulfamethoxazole and ampicillin.

Outbreaks of Shigella bacteria are often spread through contaminated food and water, surfaces, or through sexual contact. Symptoms of the disease it causes, a form of dysentery called shigellosis, include fever and diarrhea.

Many cases of shigellosis resolve with rest and hydration. But especially without treatment, the most severe cases can lead to hospitalizations and death. The bacteria is estimated to rank among the leading causes of diarrhea-related death worldwide.

The CDC alert comes after a 2015 warning from the agency that multidrug-resistant Shigella had first started to spread in the United States of Americans who had traveled abroad.

The CDC says 5% of all Shigella isolates collected in 2022 were classified as XDR, up from 1% in 2019.

“Given these potentially serious public health concerns, the CDC asks healthcare professionals to be vigilant about suspecting and reporting cases of XDR Shigella infection to their local or state health department and to educate patients and communities at increased risk on prevention and transmission,” the agency said in an alert Friday.

As recently as last month, authorities warned of an outbreak of hundreds of cases of shigellosis in travelers returning from Cabo Verde resorts across the United States and Europe. Last year, the UK also reported “unusually high numbers” of XDR shigellosis across the country.

Some state and local health authorities in the United States also warned of cases in recent months, urging people to wash their hands and take other measures to avoid getting sick.

“We typically see Shigella cases peak in the summer months and decline in the fall and winter. However, Shigella activity increased in the fall of 2022, and we are now seeing antibiotic resistant cases, which are confirmed by antibiotic susceptibility testing,” Brian Spencer, spokesman for the Colorado Department of Public Health and Environment, said in a statement.

This illustration made available by the Centers for Disease Control and Prevention shows the Shigella bacteria.


Spencer said cases have now slowed so far this year. However, authorities expect cases could climb again in the coming months. The Colorado cases have not been linked to the Cabo Verde outbreak.

“The CDPHE has identified multiple outbreaks and clusters of cases that are linked to each other,” Spencer said.

It is unclear what is driving the recent, off-season increases in drug-resistant Shigella infections.

A CDC spokesperson did not respond to a request for comment on recent cases.

The agency’s alert cites studies from 2012 and 2016 observing an increase in drug-resistant infections “particularly among homeless people, international travelers, immunocompromised people and MSM”, using an acronym for men. having sex with men.

More information about the increase is expected to be discussed on Tuesday, when the agency plans to host a webinar for clinicians on the spread of XDR Shigella.

“Clinicians need to understand the nuances of infection testing and management, especially when treating patients from populations at increased risk for drug-resistant shigellosis, including,” the agency says.

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