CDC warns of Shigella outbreak

The Centers for Disease Control and Prevention has warned of an increase in highly drug-resistant cases of the bacterial infection Shigella, a leading cause of inflammatory diarrhea.

The agency calls the new form of the stomach flu, which causes the diarrheal disease known as shigellosis, a “serious threat to public health.” There is some evidence that the disease is mainly spreading among gay and bisexual men, apparently through sexual contact, both in the US and abroad.

The CDC reached out to the Colorado Department of Public Health and Environment and the UK Health Security Agency on Tuesday to alert doctors to the spread of a form of the bacteria that is resistant to all typically recommended antibiotic treatments.

“We don’t have all the answers today,” says Dr. Louise Francois Watkins, a medical officer with the CDC’s National Center for Emerging and Zoonotic Infectious Diseases, said on the call. The agency, she said, was unable to make official recommendations for alternatives to antibiotics.

A parallel outbreak in the UK, first announced in January 2022, was most likely the result of an initial single infection, UK health officials said on the phone call on Tuesday. That says something about how widely individual resistant strains can spread and about the importance of infection control.

The CDC said in a health alert Friday that the proportion of the roughly 450,000 annual U.S. Shigella infections resistant to all known antibiotic treatments rose from zero in 2015 to 0.4% in 2019 to 5% last year, an indicator of potentially greater spread.

Shigella, which is highly contagious, spreads when infected stool enters the mouth or nose, including through sexual activity or poor hand washing after changing diapers, unsanitary handling of food, or swimming in contaminated water. The infection is usually seen in young children.

The European Center for Disease Prevention and Control issued a warning on Friday about 221 confirmed and 37 possible cases among people who have traveled to Cape Verde off the coast of West Africa since September and returned to about a dozen countries, including the US.

On Tuesday’s CDC call, officers from the UK Health Service reported analyzing all but four of Britain’s 185 cases of the infection as of late 2021. Half needed antibiotics. The Shigella samples retained their sensitivity to four antibiotics: carbapenems, chloramphenicol, fosfomycin and temocillin.

Eighty-seven percent of cases involved men suspected of having sex with men.

Dr. Stephanie Cohen, the division director for HIV and STI prevention at the San Francisco Public Health Department, told NBC News that Shigella is “a very important and serious pathogen.”

“It can cause really bad diarrhea, sometimes bloody diarrhea, cramps and abdominal pain,” she said.

Shigellosis mostly goes away without treatment. But doctors may prescribe antibiotics to speed recovery or otherwise prevent complications in more vulnerable patients.

The infection can cause a long-term and debilitating illness, requiring hospitalization of approximately 6,400 U.S. patients each year.

Death from shigellosis is rare, although it is more likely in people with weakened immune systems, such as from untreated HIV or chemotherapy for cancer.

Shigella is considered highly drug-resistant when it is not sensitive to any of the recommended first-line or alternative antibiotics, including azithromycin, ciprofloxacin, ceftriaxone, trimethoprim-sulfamethoxazole, and ampicillin.

From May 2014 to February 2015, the CDC identified 243 U.S. cases of travel-related Shigella that were resistant to most, but not all, antibiotics.

Now doctors face quite a challenge in caring for patients with this form of Shigella. Reviewing a comprehensive list of possible alternative antibiotics on Tuesday’s call, Watkins noted that the drugs are largely saddled with one or more limitations, such as unavailability in the US, lack of clinical trial data, resistance to the pathogen or the fact that they penetrate the intestinal wall poorly.

The CDC has urged health care providers to be vigilant about possible shigella infections and report suspected cases to state and local health departments, while educating people most at risk about shigellosis.

In addition to gay and bisexual men, antibiotic-resistant Shigella infections are on the rise among people who are homeless, international travelers and people living with HIV.

Of the 232 reported cases as of 2016 on which the CDC has data, 197, or 85%, were men. Only one was with a child. Of the 41 of those people who answered questions about recent sexual activity, 88% were men who reported recent sexual contact with men.

Meanwhile, sexually transmitted gonorrhea, chlamydia, and syphilis have been on the rise in recent years and are particularly common among gay and bisexual men. The CDC has issued increasingly urgent warnings that gonorrhea is at risk of losing sensitivity to the last remaining simple and effective antibiotic to treat the infection.

Enterobacteriaceae include more than a hundred species, including Shigella, Klebsiella, Salmonella, and Escherichia coli.Stephanie Rossow / Science Photo Library via Getty Images

People with shigellosis, advises the GGD, should stay at home if they work in healthcare, catering or childcare. The agency also advises that during the illness and for two weeks afterwards, people should avoid preparing food for others, wash their hands frequently, refrain from swimming and refrain from sexual contact, or at least observe strict hygiene before and after sexual activity.

The World Health Organization lists drug-resistant pathogens, the emergence of which is largely driven by the misuse and overuse of antibiotics in humans and livestock, as one of the top 10 global public health threats facing humanity.

“The clinical pipeline, the drugs being tested in humans, is fragile and there isn’t enough there,” said Kevin Outterson, the executive director of CARB-X, a Boston-based nonprofit that aims to drive innovation in early antibiotic research. and development.

There are encouraging signs with antibiotic development, at least in the early stages, Outterson said.

“If you want a drug that works against this disease or any other bacteria by 2033, we have to work on it today,” he said.

The new Shigella is raising concern in the wake of the global outbreak of mpox (formerly monkeypox), which has spread largely through sex between men. Cases of the virus, first identified in Britain in mid-May, peaked in the US and internationally in early August and have largely disappeared.

As with shigella cases, mpox infections, which can be serious, usually resolve without the need for treatment and are rarely fatal. However, an article published Feb. 21 in The Lancet found an mpox death rate as high as 15% among people who were significantly immunocompromised by HIV.

CORRECTION (March 1, 2023, 1 p.m. ET): An earlier version of this article misrepresented itself when UK health authorities first announced an outbreak of drug-resistant Shigella. The cases were announced in January 2022, not last month.

CDC warns of Shigella outbreak

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