Drug-resistant Shigella outbreak is latest symptom of antibiotic resistance crisis

As of March 8, 29 states had reported infections caused by strains of extensively drug-resistant (XDR) Shigella, a bacterial infection that can cause severe gastrointestinal illness. These XDR strains do not respond to any of the five antibiotics typically used to treat Shigella infections, and, according to The New York Times, the Centers for Disease Control and Prevention “does not currently have a recommended treatment option for the drug-resistant strains.” In just six years (2016-2022), XDR Shigella expanded from one U.S. case to 5% of the 450,000 annual cases across the country, many of which are in children under 5 years old. 

Drug-resistant Shigella is just the latest harbinger of what’s to come for drug-resistant bacteria. Last month, contaminated eye drops were linked to 55 cases of antibiotic-resistant Pseudomonas aeruginosa infections spread across 12 states. A few weeks before, the United States had its first case of a “super strain” of drug-resistant gonorrhea for which “all recommended drugs were less effective or completely ineffective.” All told, drug-resistant infections sicken some 2.8 million Americans annually and kill as many as 162,000. Whenever antibiotics are used, and especially when they’re overused, these and other bacteria can develop the means to thwart the drugs and sicken people with dangerous infections. 

Antibiotic overuse is a primary driver of resistance, so reducing it is key to protecting public health and keeping these drug-resistant “superbugs” from spreading. The Department of Health and Human Services (HHS) has already set national targets to reduce inappropriate antibiotic use in human settings, and hospitals that participate in Medicare or Medicaid must implement antibiotic stewardship programs to ensure these life-saving drugs are used judiciously. That level of accountability doesn’t exist for meat producers, who purchase nearly two-thirds of the medically important antibiotics sold in the United States. Many meat producers feed antibiotics to animals routinely to compensate for unsanitary, stressful and overcrowded industrial farming conditions. This overuse gives drug-resistant bacteria more opportunities to flourish, spread from farms and make people sick. 

The FDA took steps to reduce antibiotic use in meat production that went into effect in 2017, including banning their use for growth promotion and bringing the drugs under veterinary oversight, but the agency did not go far enough. Since a dip in antibiotic sales between 2015 and 2017, sales of medically important antibiotics to meat producers have increased by 8%. 

This year’s reauthorization of the Animal Drug User Fee Act (ADUFA) provides an opportunity for much-needed action. Here’s what Congress should do through ADUFA to improve antibiotic stewardship in meat production:

• Direct the FDA to set a quantifiable target for reducing antibiotic use in meat production, which will spur antibiotic stewardship and promote accountability. The European Union took this approach and nearly cut veterinary antibiotic sales in half from 2011 to 2021.
• Set a deadline for the FDA to release final guidance on duration limits for medically important antibiotics in veterinary settings by the end of 2025. When you get an antibiotic prescription from the doctor, it clearly says “use for X days.” That’s not always the case when antibiotics are used in meat production. Many medically important antibiotics currently have no defined duration limit for veterinary uses, so meat producers can feed antibiotics to groups of animals continuously without signs of infection. That prolonged use is the perfect recipe for breeding drug-resistant bacteria. 
• Direct the FDA to create and implement a new five-year plan to improve veterinary antibiotic stewardship for 2024-2028. The primary goal of the plan should be to reduce the use of medically important antibiotics in meat production to protect public health.

The 2008 ADUFA reauthorization directed the FDA to report on veterinary antibiotic sales, so there is precedent for enhancing antibiotic stewardship through this process. As Congress renews the FDA’s animal drug review program, it should give the agency the direction and resources it needs to reduce antibiotic overuse in meat production. 

In the New York Times article about drug-resistant Shigella, Dr. Louise Francois Watkins, medical officer at the CDC, said it “could be a predictor of what’s to come with other bacterial infections.” We have to act quickly to keep antibiotics effective for the future.