In recent years, the Centers for Disease Control and Prevention (CDC) has observed a notable rise in extensively drug-resistant (XDR) Shigella infections in the United States, with about 5% of reported Shigella cases in 2022 caused by these resistant strains, compared to none in 20151 . This increase poses a serious public health challenge as XDR Shigella strains resist multiple commonly used antibiotics, complicating treatment and control efforts2 . Shigellosis, the illness caused by Shigella bacteria, remains a leading cause of bacterial diarrhea domestically and among travelers, with symptoms ranging from mild to severe inflammatory diarrhea2 .
XDR Shigellosis vs. Other Shigella Infections
Extensively drug-resistant (XDR) Shigella strains differ from typical Shigella infections primarily due to their resistance to multiple antibiotic classes, including first-line treatments such as azithromycin, ciprofloxacin, ceftriaxone, trimethoprim-sulfamethoxazole (TMP-SMX), and ampicillin1 . This resistance limits effective treatment options and complicates clinical management3 . The evolution of XDR Shigella is driven by antibiotic selective pressure, especially in areas with widespread antibiotic use, which promotes the survival and spread of resistant bacterial populations4 5.
Despite resistance differences, the clinical symptoms of shigellosis caused by XDR or non-resistant strains remain consistent. Typical symptoms include fever, abdominal cramps, and bloody or mucoid diarrhea, often accompanied by tenesmus—a persistent urge to defecate6 78. While most infections are self-limiting and resolve without antibiotics, antimicrobial treatment can shorten illness duration by approximately two days and reduce the risk of transmission9 10.
Currently, no formal CDC guidelines exist for the optimal treatment of XDR Shigella infections due to limited clinical data on effective antimicrobial regimens11 1. Researchers and public health officials are actively investigating alternative antibiotic therapies and treatment strategies to address this gap12 .
| Feature | Non-XDR Shigella Infection | XDR Shigella Infection |
|---|---|---|
| Antibiotic susceptibility | Sensitive to first-line antibiotics | Resistant to azithromycin, ciprofloxacin, ceftriaxone, TMP-SMX, ampicillin1 |
| Treatment options | Multiple effective antibiotics | Limited; alternative regimens under study12 |
| Symptoms | Fever, abdominal cramps, bloody diarrhea6 | Same symptoms as non-XDR6 |
| Illness duration with antibiotics | Shortened by ~2 days10 | Antibiotic efficacy uncertain11 |
| Transmission risk | Reduced with treatment | Potentially higher due to prolonged shedding |
“We want to make them more aware of the important role they play in antibiotic stewardship and curbing this concerning increase in XDR shigellosis.”
— Naeemah Logan, Centers for Disease Control and Prevention2
Shigellosis Transmission and Risk Factors
Shigella bacteria are highly contagious due to their low infectious dose; ingestion of as few as 10 to 100 organisms can cause infection13 . Transmission occurs primarily via the fecal-oral route, either through direct person-to-person contact or indirectly through contaminated food, water, or surfaces14 15. The bacteria’s ability to survive stomach acid allows it to colonize the large intestine, causing inflammatory diarrhea16 .
“The thing that really pushed us over the top was receiving these repeated inquiries from our state health partners and clinicians saying 'we don't know what to do with what we're seeing.' It just felt like maybe this is the time to put it on the map.”
— Louise Francois Watkins, Centers for Disease Control and Prevention2
Outbreaks frequently occur in crowded or communal settings such as childcare centers, nursing homes, and assisted-living facilities, where close contact and poor hygiene facilitate spread17 18. Prolonged fecal shedding of Shigella can continue for several weeks after symptoms resolve, contributing to ongoing transmission risk19 .
Certain populations are at increased risk for XDR Shigella infection, including men who have sex with men (MSM), people experiencing homelessness, individuals living with HIV, and international travelers20 2. Sexual contact, especially involving the anus, is a notable transmission route among MSM, with recent outbreaks linked to this group2 . Homelessness increases risk due to crowded living conditions and limited access to sanitation2 .
- Extremely low infectious dose facilitates rapid spread13
- Fecal-oral transmission via direct contact or contaminated food/water14 15
- Outbreaks common in group settings with close contact and poor hygiene17
- Prolonged fecal shedding extends transmission risk after symptoms subside19
- High-risk groups include MSM, homeless individuals, people with HIV, and travelers20 2
“Shigella bacteria are so easily transmitted, and they have such a low infectious dose, that outbreaks are common, and you typically see this among people in close-contact settings or crowded conditions.”
— Naeemah Logan, Centers for Disease Control and Prevention2
Treatment and Prevention of Shigella Infection
Management of shigellosis primarily involves supportive care, focusing on hydration and electrolyte balance to prevent dehydration caused by diarrhea21 . Oral rehydration solutions or over-the-counter fluids like sports drinks can be helpful in maintaining fluid levels22 . Symptom relief may be aided by body positioning (such as lying on the side or fetal position) and use of heating pads for abdominal cramps22 .
Antibiotics are prescribed when necessary, particularly for severe cases, immunocompromised patients, or to reduce transmission during outbreaks in institutional settings22 10. However, the rise of XDR Shigella strains has complicated treatment, as these strains resist commonly recommended empiric and alternative antibiotics1 2. Currently, no official CDC treatment guidelines exist for XDR Shigella infections, highlighting the need for ongoing research and antibiotic stewardship11 1.
Shigellosis is highly contagious and spreads easily in crowded settings and through sexual contact. Good hygiene and careful management of infected individuals are essential to control outbreaks. 232
Prevention relies heavily on hygiene and sanitation measures to interrupt transmission. Frequent handwashing with soap and water, especially after using the bathroom or changing diapers, is the most effective preventive action23 . Safe sexual practices, including avoiding sexual contact during symptoms and for two weeks after diarrhea ends, are critical in high-risk groups such as MSM22 24.
In settings such as childcare, healthcare, and food service, strict exclusion policies apply to infected individuals to prevent spread. Food handlers, healthcare providers, and childcare workers must have two negative stool cultures after diarrhea resolution before returning to work25 . Children with shigellosis should remain home until 48 hours after diarrhea stops or 24 hours after starting antibiotics and diarrhea cessation25 .
- Maintain hydration and electrolyte balance during illness22 21
- Use antibiotics judiciously, guided by susceptibility testing22
- Wash hands thoroughly with soap and water after bathroom use or diaper changes22 23
- Avoid sexual contact during illness and for two weeks after symptoms resolve22 24
- Exclude infected food handlers, healthcare workers, and childcare providers until cleared by stool tests25
