Centers for Disease Control and Prevention

Antimicrobial Resistance Threats Report

Drug-resistantnontyphoidal Salmonella

Threat Level: SERIOUS

In the United States in 2023:

CDC changed methodologies and data sources to produce the most comprehensive AR Threats Report to date. Direct comparison of this threat's data to previous reports is not recommended.

What you need to know

Nontyphoidal Salmonella bacteria can cause diarrhea (which may be bloody), fever, and stomach cramps. Nontyphoidal Salmonella spread commonly through contaminated food or water, contact with animals or their feces (poop), or contact with places animals live and roam. Some people are more likely to get an infection or become seriously ill, including young children, older adults, people with weakened immune systems, and international travelers.

Nontyphoidal Salmonella are a leading cause of foodborne illness, hospitalizations, and deaths linked to foodborne illness. Although most people with nontyphoidal Salmonella infection recover within four to seven days without antibiotics, healthcare providers sometimes use antibiotics to treat severe infections. Nontyphoidal Salmonella are becoming increasingly resistant to antibiotics, which can limit treatment options. If treatment with antibiotics is needed, healthcare providers can order laboratory tests to determine which antibiotics might be effective.

Drug-resistant nontyphoidal Salmonella data

As resistance to certain antibiotics increased since 2016, drug-resistant nontyphoidal Salmonella caused more infections and hospitalizations.

Estimated number of drug-resistant nontyphoidal Salmonella infections and hospitalizations by year in the U.S.

Drug-resistant nontyphoidal Salmonella caused an estimated 400,000 infections in 2022 and 520,000 infections in 2023. These bacteria caused an estimated 3,800 hospitalizations in 2022 and 5,200 hospitalizations in 2023.

Ampicillin, azithromycin, ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole are antibiotics recommended for treatment of nontyphoidal Salmonella infections. Resistance to these antibiotics limits treatment options.

Percent resistant or nonsusceptible to antibiotics by year among nontyphoidal Salmonella isolates tested in the U.S.

The percentage of nontyphoidal Salmonella isolates (pure samples of nontyphoidal Salmonella) with resistance to at least one of the recommended antibiotics including ampicillin, ceftriaxone, trimethoprim-sulfamethoxazole, and nonsusceptible (resistant or not completely susceptible) to ciprofloxacin increased from 14.7% to 20.8% between 2016 and 2023. Similarly, the percent of isolates nonsusceptible to ciprofloxacin increased from 5.2% to 17.1% between 2016 and 2023, largely driven by the emergence of a nonsusceptible strain of Salmonella Enteritidis [1]. In contrast, resistance to ceftriaxone decreased from 2.7% to 1.9% between 2016 and 2023.

As resistance to recommended antibiotics increases, selecting an effective treatment when antibiotics are needed may become more challenging. Continued monitoring of drug resistance helps identify emerging resistance trends, inform treatment recommendations, and guide public health efforts to prevent and control drug-resistant nontyphoidal Salmonella infections.

Supercharging surveillance with advanced testing technology

A laboratorian uses a pipette to place a sample in lab equipment.

CDC works to increase laboratory testing capacity nationwide by supporting the implementation of whole genome sequencing (WGS), which is a faster and more accurate way to identify and track concerning drug-resistant bacteria.

Our understanding of drug resistance doesn't appear out of the blue—part of it comes from extensive laboratory testing. To better track and respond to drug resistance threats, such as drug-resistant nontyphoidal Salmonella, CDC is increasing laboratory testing capacity nationwide. Since 2012, CDC has provided funds and training for public health laboratories to establish and sustain the infrastructure needed to implement whole genome sequencing (WGS) technology. WGS is a faster and more efficient way to get genetic data that can be used to accurately identify concerning drug-resistant enteric bacteria. Partnering with public health laboratories on WGS provides CDC with quicker results and data on a larger subset of samples than conventional testing methods, which require significantly more time, resources, and effort.
During a nontyphoidal Salmonella outbreak linked to diced onions in 23 states, CDC quickly analyzed WGS data for 98% of patient samples to determine that none of the Salmonella causing infections were resistant to antibiotics. Without WGS technology, this information may not have been available to quickly inform the outbreak investigation.
WGS enhances our ability to track and understand drug resistance in nontyphoidal Salmonella and other enteric pathogens by providing more data in less time and with greater efficiency.
Other WGS benefits include:
  • Providing resistance results for antibiotics not typically included in other tests.
  • Revealing the genes causing the resistance.
  • Determining how easily resistance genes can transfer to other bacteria.
This information helps us provide timely treatment guidance to healthcare providers, identify concerning or emerging strains, and develop practical strategies to prevent the spread of drug resistance.

How CDC combats drug-resistant nontyphoidal Salmonella

  • Detecting new and emerging resistance

    CDC, federal partners, and public health departments work together to track emerging resistance among nontyphoidal Salmonella. A newly established collaborative network is monitoring data from 10,000 bacterial isolates (pure samples of bacteria) every month to track and respond to emerging resistance.

  • Tracking concerning strains

    Despite prevention efforts, some nontyphoidal Salmonella strains continue to make people sick. CDC works with state and federal partners to identify, track, and investigate these strains.

  • Understanding sources of infections

    CDC collects detailed information from patients with nontyphoidal Salmonella infections, including international travel history, animal contact, and other possible exposures. This informs our understanding of Salmonella infections and helps guide prevention efforts, including alerting the public about outbreaks.

  • Sharing timely updates

    CDC, the U.S. Food and Drug Administration, and the U.S. Department of Agriculture publish interim updates to share unusual or concerning drug resistance findings in enteric bacteria monitored by the National Antimicrobial Resistance Monitoring System (NARMS) . CDC also shares information on reoccurring, emerging, or persisting (REP) strains with partners to promote collaboration, stimulate research, and support infection prevention efforts.

  • Informing healthcare providers

    CDC notifies healthcare professionals about concerning or emerging strains of nontyphoidal Salmonella and provides treatment recommendations, including guidance for multidrug-resistant Salmonella Newport, which have caused an increase in infections among travelers to or from Mexico.

Drug-resistant nontyphoidal Salmonella resources

Illustration of Drug-resistant nontyphoidal Salmonella