International Travel Increases Antimicrobial-resistant Infection Risk

Researchers reported today in the Journal of Infectious Diseases an increase in non-typhoidal Salmonella (NTS) infections in the United States suggests international travel is a significant risk factor for antibiotic resistance.

Globally, NTS infections are responsible for the highest-burden of all foodborne diseases.

Among 9,301 NTS infections reviewed in this study, 1,159 (12%) occurred after recent international travel.

On May 2, 2023, this Major Article encouraged understanding the risks of resistant infection and could help target prevention efforts when needed.

Providers can help these efforts by obtaining stool or blood samples for patients, requesting isolation of the organism and susceptibility testing, and only prescribing antimicrobials if indicated.

And travelers should consider differences in region-specific risks of a resistant pathogen when prescribing antibiotics, wrote these researchers.

Researchers with the U.S. Centers for Disease Control and Prevention analyzed NTS infections reported to the Foodborne Diseases Active Surveillance Network during 2018-2019 that were screened for resistance genes, including those conferring resistance to first-line agents (ciprofloxacin, ceftriaxone, or azithromycin). 

This study's adjusted odds ratio [aOR] varied by travel region and was highest after traveling to Asia (aOR 7.2, 95% CI 5.5–9.5).

And more travelers than non-travelers receiving ciprofloxacin or other fluoroquinolones had isolates with predicted resistance to fluoroquinolones (29% vs 9%, p<0.01).

Most people with NTS infection experience diarrhea, fever, and stomach cramps, and symptoms usually start 6 hours to 6 days after infection.

An estimated 1.35 million NTS infections occur each year in the U.S., and approximately 16% of these infections are resistant to antimicrobials recommended for treatment.

Although most episodes of NTS infection do not require antimicrobial therapy, antibiotics are critical to treat invasive infections.

Antimicrobial resistance may also be associated with virulence genes, resulting in more severe illness. 

The growing proportion of antimicrobial-resistant NTS limits treatment options and creates opportunities for acquired resistance determinants (resistance genes or mutations) to spread to other pathogens.

Note: The authors have no conflicts of interest to declare. The CDC supported this work.