Drug-Resistant Shigella Infections Surge in U.S., CDC Reports

A concerning increase in drug-resistant bacterial infections has prompted an alert from the Centers for Disease Control and Prevention (CDC), as cases of antibiotic-resistant Shigella bacteria have risen dramatically across the United States over the past decade.

According to findings published in the CDC’s Morbidity and Mortality Weekly Report on April 9, researchers analyzed more than 16,000 Shigella samples between 2011 and 2023, testing them for resistance to commonly prescribed antibiotics. The results revealed a troubling trend: while no cases of highly drug-resistant Shigella infections were recorded in 2011, approximately 8.5% of infections met that criteria by 2023.

“The data shows a substantial increase in drug-resistant infections over this period,” said CDC researchers, who defined drug resistance as bacteria not responding to standard treatments including ampicillin, azithromycin, ceftriaxone, ciprofloxacin or trimethoprim-sulfamethoxazole.

Particularly concerning is the lack of FDA-approved oral antimicrobial treatments for these resistant strains, limiting treatment options for infected patients.

The demographic analysis of patients revealed that the majority (86%) were adult men with a median age of 41. Nearly half of those who provided their HIV status were HIV-positive, suggesting an increased vulnerability among immunocompromised individuals. Approximately one-third of infected patients required hospitalization, indicating the serious nature of these infections.

Public health officials were particularly alarmed to discover that over 80% of patients who reported their travel history had not recently left the country, suggesting domestic transmission rather than imported cases. This pattern differs from historical trends where many bacterial infections were primarily associated with international travel.

Shigellosis typically manifests as diarrhea (often bloody), fever, and stomach pain beginning one to two days after exposure. While symptoms typically last five to seven days, some individuals may experience prolonged illness lasting several weeks. In rare cases, serious complications can develop, including reactive arthritis, bloodstream infections, seizures, or hemolytic-uremic syndrome, which involves damage to blood vessels in the kidneys.

The bacteria spreads easily through an infected person’s stool. Transmission occurs when people get Shigella germs on their hands and then touch food or their mouth. Common transmission routes include changing the diaper of an infected child, caring for someone with the illness, touching contaminated surfaces, consuming raw or contaminated produce, or swallowing recreational water containing the bacteria.

Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, who was not involved in the study, explained why this trend is concerning. “The rise in antibiotic resistance represents one of our greatest public health challenges. When common infections no longer respond to available treatments, we face potential increases in hospitalization rates, treatment costs, and mortality.”

The CDC identified several populations at higher risk, including young children, international travelers, gay or bisexual men, and individuals with weakened immune systems.

While the research offers valuable insights, the CDC acknowledged some limitations. Their surveillance data may not capture all U.S. cases, and there were missing data points for key variables like travel history and HIV status. Additionally, the findings may not be generalizable to all populations or settings.

To reduce infection risk, health experts recommend thorough handwashing with soap and water after activities that could cause exposure. They also advise against swallowing water from lakes, ponds, or pools, and recommend following safe food and water practices while traveling. Anyone experiencing symptoms should consult a healthcare provider and stay home while ill.

The CDC emphasized the need for ongoing surveillance and a robust public health response to combat the rise of these resistant infections, which represent part of the broader global challenge of increasing antimicrobial resistance.