Drug-resistant Shigella infections are increasing in the United States, complicating treatment. Health officials are urging greater awareness, testing and prevention.
A highly contagious bacterial infection that causes diarrhea and can spread through sexual contact is becoming increasingly resistant to antibiotics in the United States, raising concerns among public health officials. Shigella bacteria cause an illness known as shigellosis, which can produce severe gastrointestinal symptoms and, in some cases, life-threatening complications. The U.S. Centers for Disease Control and Prevention estimates that approximately 450,000 Shigella infections occur annually in the country.
A CDC analysis published in April 2026 found that extensively drug-resistant Shigella strains accounted for 8.5% of tested bacterial samples in 2023, compared with none recorded in the surveillance data from 2011 to 2015. Researchers examined nearly 17,000 samples collected between 2011 and 2023, identifying 510 extensively drug-resistant infections. About one-third of patients with these infections were hospitalized, underscoring the potential severity of the illness.
Shigella typically spreads when microscopic amounts of infected fecal matter enter another person’s mouth. Transmission can occur through contaminated food or water, inadequate hand hygiene and close personal contact, including sexual activity. Although the infection can affect anyone, health authorities have identified a disproportionate burden of drug-resistant infections among adult men, including gay and bisexual men and other men who have sex with men. Researchers caution that incomplete sexual-history information makes it difficult to establish precisely how many infections result from sexual transmission.
Symptoms can include diarrhea, sometimes containing blood or mucus, abdominal cramps, fever and vomiting. Severe illness can lead to dehydration and other complications, particularly among people with weakened immune systems. While many infections resolve without antibiotics, some patients require medical treatment. The CDC has reported that no U.S. Food and Drug Administration-approved oral antibiotic treatment is available specifically for extensively drug-resistant Shigella infections, making appropriate diagnosis and treatment decisions increasingly important.
Scientists are also investigating how antibiotic resistance develops and spreads. One possible factor is known as bystander selection, in which antibiotic use intended to treat another infection creates conditions that favor resistant bacteria. Research in the United Kingdom has documented similar concerns involving Shigella strains associated with sexual transmission. However, the precise contribution of different factors to the growing resistance remains under investigation, and the findings do not mean that every Shigella infection is resistant to treatment.
Health authorities recommend that people with symptoms seek medical advice and consider testing, particularly if diarrhea is severe, persistent or bloody. Clinicians may use stool testing to identify the bacteria and, when appropriate, determine which antibiotics are likely to work. Patients should avoid taking leftover antibiotics or using medication without medical guidance, as inappropriate treatment can contribute to resistance and may not address the infection.
Prevention depends on careful hygiene and reducing opportunities for fecal-oral transmission. The CDC advises sexually active people to avoid sex while experiencing diarrhea and to wait at least two weeks after diarrhea has ended before resuming sexual activity. Washing hands and genital and anal areas with soap and water before and after sex, cleaning shared sex toys and using barriers during oral and anal sex can also reduce risk. Public health specialists say greater awareness of sexual transmission, timely testing and responsible antibiotic use are important to limiting the spread of resistant strains.
Information from the U.S. Centers for Disease Control and Prevention, ScienceAlert, the New York Post and the Toronto Sun.