• The CDC is warning about new cases of drug-resistant Shigella bacterial infections.
  • The bacteria can also spread antimicrobial resistance genes to other bacteria that infect the intestines, the agency said.
  • A Shigella infection, also known as shigellosis, can cause symptoms such as diarrhea (sometimes bloody), fever, stomach pain, and feeling the need to pass stool even when the bowels are empty.

The Centers for Disease Control and Prevention (CDC) says it is monitoring an increase in intestinal infections caused by “extensively drug-resistant” Shigella bacteria.

Limited antibiotics are available to treat patients infected with these particular drug-resistant strains of Shigella, the agency said Feb. 24 in a health advisory.

These bacteria can also spread antimicrobial resistance genes to other bacteria that infect the intestines, the agency said.

Here are the top things to know about infections caused by this antibiotic-resistant bacteria.

A Shigella infection, also known as shigellosis, can cause symptoms such as diarrhea (sometimes bloody), fever, stomach pain, and feeling the need to pass stool even when the bowels are empty.

Shigella spread easily — just a few bacteria can make someone sick. People infected with Shigella can also spread the bacteria for several weeks after their diarrhea ends.

People can become infected when they get Shigella on their hand and then touch their mouth. This can occur after touching surfaces contaminated with the bacteria or while taking care of an infected person.

The bacteria can also spread directly through person-to-person contact, and indirectly through contaminated food and water.

Historically, shigellosis has mainly affected young children.

But the CDC said in its advisory that it has seen an increase in antimicrobial-resistant Shigella infections among adult populations, including men who have sex with men, people experiencing homelessness, international travelers and people with weakened immune systems.

Overall, the percentage of Shigella infections caused by extensively drug-resistant bacteria increased from 0% in 2015 to 5% in 2022, according to the advisory.

Dr. Mahdee Sobhanie, an infectious diseases physician at The Ohio State University Wexner Medical Center in Columbus, told Healthline that the majority of Shigella infections clear up on their own.

Patients will generally recover from shigellosis in 5 to 7 days without the need for antibiotics, the CDC said on its website. In mild cases, people may need only fluids and rest.

In more severe cases, antibiotics may be recommended to prevent complications or shorten the duration of illness.

However, all commonly used antibiotics will not work against extensively drug-resistant Shigella bacteria — including azithromycin, ciprofloxacin, ceftriaxone, trimethoprim-sulfamethoxazole and ampicillin.

The CDC said in its advisory that it does not have recommendations for how to treat infections caused by these drug-resistant strains.

Of particular concern are antibiotic-resistant Shigella infections in people with weakened immune systems, said Sobhanie, because these people are unable to clear the infection on their own.

Although antibiotic-resistant Shigella infections are on the rise, the risk to the general public is “relatively low,” Dr. John Sellick, Jr., an infectious diseases professor in the Jacobs School of Medicine & Biomedical Sciences at the University at Buffalo, told Healthline.

Overall, Shigella causes an estimated 450,000 infections in the United States each year, according to the CDC. In contrast, Salmonella causes an estimated 1.35 million illnesses.

In addition, an estimated 77,000 drug-resistant Shigella infections occur in the United States each year, the agency said, resulting in fewer than 5 deaths annually.

“So generally, this is not a very fatal kind of infection,” Dr. Ahmed Babiker, an assistant professor and infectious diseases and medical microbiology physician at Emory University School of Medicine in Atlanta, told Healthline.

Still, antibiotic-resistant Shigella pose an even broader public health concern, said Babiker, because “resistance can be passed from bacteria to bacteria.”

This is of special concern with bacteria that live in the intestines.

“The gut is a massive ecosystem full of different types of bacteria,” he said. “So when antibiotic-resistant Shigella gets in there, it can pass on genes that allow other bacteria to become resistant to antibiotics.”

Shigella is not alone in having strains that are resistant to antibiotics.

“Antibiotic resistance is something all of us should be concerned about, not just with Shigella, but with other bacteria which can cause illnesses such as pneumonia, urinary tract and skin infections,” said Sobhanie.

Each year, more than 2.8 million antimicrobial-resistant infections occur in the United States, resulting in more than 35,000 deaths, according to the CDC.

In 2019, an estimated 5 million deaths worldwide were associated with bacterial antimicrobial resistance, according to a report by the United Nations.

This is expected to increase by 10 million annually by 2050, unless steps are taken to reduce the emergence, transmission and spread of these “superbugs,” the UN said.

“Undoubtedly, the increase in antibiotic resistance is related to the considerable amount of antibiotic use,” said Sellick, “some of which may be inappropriate.”

This includes misuse in people, such as use of antibiotics when they are not recommended and sharing leftover antibiotics with another person.

Widespread use of antibiotics in the agricultural sector can also contribute to the spread of antibiotic resistance.

In its advisory, the CDC said, “given these potentially serious public health concerns … healthcare professionals [should] be vigilant about suspecting and reporting cases of [extensively drug-resistant] Shigella infection to their local or state health department.”

Sellick said doctors need to be aware of the presence of antibiotic-resistant Shigella and other bacteria in the community, because if a patient does not get better on their own, they may be carrying a drug-resistant bacteria.

Of course, “we don’t want all patients coming in and asking for the most potent antibiotics,” he said, “because that’s going to contribute to the problem of antibiotic resistance.”

Sobhanie said doctors have a responsibility to prescribe and use antibiotics responsibly — what’s known as “antibiotic stewardship.”

This includes asking questions such as: “Do we need antibiotics to treat an infection?” and “If so, how long do we need to give the antibiotics for?”

Stewardship also means not using antibiotics to treat viral infections, because these drugs do not work against viruses.

By misusing antibiotics in this way, “you are exposing bacteria in your body to an antibiotic that you don’t need,” said Sobhanie. In turn, some of these bacteria could develop resistance to the drugs.

“This is why we need to be very careful with prescribing antibiotics,” he said.

Babiker pointed out that there are simple steps you can take to protect yourself against Shigella, such as:

  • Wash your hands with soap and water after using the bathroom, changing a diaper, or helping clean someone who has used the bathroom. Also, wash your hands before preparing food, both at home and in a professional setting.
  • When traveling internationally, wash your hands frequently with soap and water, and follow safe food and water habits.
  • For those who engage in sexual activity that involves the anus, avoid these activities if you have diarrhea or other symptoms of shigellosis.
  • If you have diarrhea or generally feel unwell, stay at home and be extra vigilant about washing your hands. If concerned about your symptoms, reach out to a doctor.


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