Clinical Overview of Multidrug-resistant Salmonella Newport infections

What to know

  • CDC has observed an increase in certain Salmonella infections among travelers to or from Mexico.
  • The Salmonella causing these infections are a strain of multidrug-resistant Salmonella serotype Newport (MDR Salmonella Newport).
  • Information on this page is intended for the management of patients with known or suspected MDR Salmonella Newport infection after travel to or from Mexico.
Map of Mexico. This particular strain of Salmonella has been found among travelers who have visited Mexico.

Diagnosis

  • Obtain appropriate cultures (e.g., stool, urine, blood).
    • If Salmonella is identified by a culture-independent diagnostic test (CIDT), a follow-up (reflex) culture is recommended to obtain an isolate for antimicrobial susceptibility testing.
    • Serologic testing is unreliable and not advised.
  • Order antimicrobial susceptibility testing of the Salmonella isolate to guide the choice of antibiotic if antibiotic treatment is needed.
  • Laboratory-confirmed salmonellosis infections are reportable in the United States. Follow guidance from your local or state health department.

Patient management

  • Limit use of antibiotics for patients with an acute diarrheal illness to those with clinical indications.
  • Consider the resistance profile of this strain of MDR Salmonella Newport when selecting empiric treatment for patients who traveled to Mexico in the 7 days before illness began.
  • Ceftriaxone or an alternative agent should be considered for empiric treatment.
    • Most isolates are susceptible to ceftriaxone.
    • Most isolates are resistant to ampicillin, ciprofloxacin, and trimethoprim-sulfamethoxazole.
    • Azithromycin may not be effective for treating this strain and should be used with caution. Clinical breakpoints to determine resistance have not been established for azithromycin, but most isolates carry a macrolide resistance gene and show an elevated minimum inhibitory concentration (>32 µg/ml) on laboratory testing.
  • Tailor antibiotic treatment to the results of antimicrobial susceptibility testing when possible.
  • Consider consulting an infectious disease specialist for management of patients with MDR or complicated Salmonella infection.
  • Advise patients about returning to work based on local and state health department recommendations. Some health departments require a negative stool test before a person can return to work in a high-risk setting (such as food preparation, childcare, or healthcare) after a Salmonella infection.

Managing other Salmonella infections
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Get in-depth information on managing infections caused by all other Salmonella.
Clinical Overview

Resources

Antimicrobial-resistant Salmonella

Learn about antimicrobial-resistant Salmonella and ways to access CDC data, including on antibiograms.

Travel guidance

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Content Source:
National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)