What Is Shigella Infection? Symptoms, Risks, and Treatment Explained as CDC Raises Alarm Over Rising Cases

Cases of extensively drug-resistant Shigella infections are rising in the United States, prompting the Centers for Disease Control and Prevention (CDC) to warn of a growing public health threat. The agency says the proportion of drug-resistant cases has climbed sharply in recent years, with limited treatment options now available for some infections.

In a new report released on April 9, the CDC highlighted that resistance has increased from 0% of tested isolates between 2011 and 2015 to 8.5% in 2023, signalling a significant shift in how the infection is spreading and responding to treatment.

CDC Flags Rise in Drug-Resistant Shigella Cases

The CDC reports that extensively drug-resistant Shigella strains were first identified in 2016 and have steadily increased since then. By 2023, 510 drug-resistant isolates were detected within a 10-month surveillance period. Officials have described the trend as a public health concern due to the lack of effective oral antimicrobial treatments for these strains.

According to the CDC, no Food and Drug Administration-approved oral antibiotics are currently available to treat these extensively drug-resistant infections. The rise in resistance limits clinical options and complicates outbreak control efforts, particularly in community settings where transmission can occur easily.

Shigella Infection Explained

Shigella infection, also known as shigellosis, is a bacterial illness that affects the intestines. It is caused by Shigella bacteria and spreads through contact with contaminated food, water, or surfaces, as well as person-to-person transmission in close-contact environments.

The infection primarily causes inflammation of the digestive tract, leading to gastrointestinal illness that can vary in severity. While many cases are mild, some infections can become more serious, particularly when caused by drug-resistant strains.

Shigella Symptoms to Watch For

The most common symptom of Shigella infection is diarrhoea, which may be bloody or persist for several days. Other symptoms include stomach cramps, fever, nausea, and vomiting.

Some patients may also experience a persistent urge to pass stool even when the bowels are empty. In most cases, symptoms last around five to seven days and resolve without complications. However, severe illness can occur, particularly in vulnerable individuals, and may require medical attention to prevent dehydration or further complications.

Who Is Most at Risk of Infection

Historically, children under the age of five have been the most affected group in Shigella outbreaks. However, recent CDC surveillance data indicates a shift in the affected population.

The majority of recent drug-resistant cases have been identified in adults, particularly men aged over 18. The CDC also noted that more than 80% of cases reported no history of international travel, suggesting that transmission is occurring within domestic settings rather than being imported from abroad.

This change in infection pattern is being closely monitored by health authorities as it may indicate evolving transmission dynamics in community environments.

Treatment and Clinical Guidance

Health guidance indicates that most Shigella infections resolve on their own within five to seven days without the need for antibiotic treatment. The primary approach to managing symptoms involves maintaining adequate fluid intake to prevent dehydration, which is the most common complication.

However, treatment options are more limited in cases involving drug-resistant strains, particularly extensively drug-resistant Shigella, where standard oral antibiotics may not be effective.

Clinical guidance also advises against the use of anti-diarrhoeal medicines such as loperamide (Imodium) or diphenoxylate with atropine (Lomotil) in cases of bloody diarrhoea. These medications may worsen symptoms and are not recommended in more severe gastrointestinal infections.

Public health officials continue to monitor the rise in resistant infections as laboratories track changes in antimicrobial susceptibility patterns across reported cases in the United States.