The Centers for Disease Control and Prevention (CDC) announced the last week in February an increase in extensively drug-resistant (XDR) Shigella infections (shigellosis) reported through national surveillance systems and appearing at a significantly high rate in men who have sex with other men (MSM).

 In 2022, about five percent of Shigella infections reported to the CDC were caused by XDR strains, compared with zero percent in 2015. Clinicians treating patients infected with XDR strains have limited antimicrobial treatment options. Shigella bacteria are easily transmissible. XDR Shigella strains can spread antimicrobial resistance genes to other enteric bacteria. Given these potentially serious public health concerns, the CDC has asked healthcare professionals to be vigilant about suspecting and reporting cases of XDR Shigella infections to their local or state health department and educating patients and communities at increased risk about prevention and transmission.

Shigellosis is an acute enteric infection that is an important cause of domestically acquired and travel-associated bacterial diarrhea in the United States. Shigellosis usually causes inflammatory diarrhea that can be bloody and may also lead to fever, abdominal cramping, and tenesmus, a consistent feeling that you need to pass stools, even though your bowels are already empty. It may involve straining, pain, and cramping.. 

Infections are generally self-limiting; however, antimicrobial treatment may be indicated to prevent complications or shorten the duration of illness. 

The CDC defines XDR Shigella bacteria as strains that are resistant to all commonly recommended empiric and alternative antibiotics — azithromycin, ciprofloxacin, ceftriaxone, trimethoprim-sulfamethoxazole (TMP-SMX), and ampicillin. Currently, there is no data from clinical studies of treatment of XDR Shigella to inform recommendations for the optimal antimicrobial treatment of these infections. As such, CDC does not have recommendations for optimal antimicrobial treatment of XDR Shigella infections.

The Shigella bacteria is transmitted by the fecal-oral route, directly through person-to-person contact including sexual contact, and indirectly through contaminated food, water, and other routes. Shigella bacteria are easily transmitted because of the low infectious dose (as few as 10–100 organisms), and outbreaks tend to occur among people in close-contact settings.

Historically, shigellosis has predominantly affected young children (age 1–4 years) in the United States. More recently, CDC has observed an increase in antimicrobial-resistant Shigella infections among adult populations, especially gay, bisexual, and other men who have sex with men (MSM), people experiencing homelessness, international travelers and people living with HIV

Most people with diarrheal illness require only supportive care and fluid replacement. Antimicrobial agents are not always needed for mild shigellosis, but they may be indicated to shorten the duration of illness (by about 2 days) and reduce the likelihood of transmission, during outbreaks, in institutional settings, from food handlers, to immune compromised individuals or those being treated with immunosuppressive drugs, and to people living with HIV.In the United States, recommended empiric antimicrobial agents include azithromycin, ciprofloxacin, or ceftriaxone. ampicillin or TMP-SMX are recommended as alternative treatments for susceptible strains .

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