Shigellosis Advisory for Healthcare Providers

Shigellosis Outbreak Update and Drug-Resistant and Extensively Drug-Resistant (XDR) Information

Posted Dec. 14, 2023. Past health advisories and alerts are archived for historical purposes and are not maintained or updated.

Be aware that the Centers for Disease Control and Prevention (CDC) has been monitoring an increase in extensively drug-resistant (XDR) Shigella infections (shigellosis) reported through national surveillance systems.

Spokane’s Shigellosis Outbreak Update
  • 71 cases, with over 90% associated with the outbreak among the community of people experiencing homelessness
  • Species type: 44% sonnei; 8% flexneri; 48% species not reported
  • 51% of cases were hospitalized
Susceptibility Results

Spokane susceptibility data suggests that we are not seeing XDR infections, but there is elevated resistance.

Approximately 24 specimens:

Majority of specimens sensitive to:

Majority of specimens resistant to:





Trimethoprim + sulfamethoxazole

Actions Requested
  • Laboratories should consider adding azithromycin to their AST for Shigella specimens using recently established clinical breakpoints for azithromycin for Shigella.
    • Many laboratories currently don’t do Shigella antimicrobial sensitivity testing (AST) for azithromycin, which is a common first-choice antibiotic treatment.
  • Order stool culture and antimicrobial susceptibility testing (AST) for patients suspected of having Shigella. Culture-independent diagnostic testing on its own (e.g., PCR) cannot be used to assess susceptibility.
    • When ciprofloxacin minimum inhibitory concentrations (MICs) are in the 0.12 – 1.0 μg/mL range, even if the laboratory report identifies the isolate as susceptible, be aware there may be one or more resistance mechanisms. It is unclear whether fluoroquinolone treatment in this range is associated with worse clinical outcomes; consultation with a specialist is advised if no alternative antibiotic options are available.
  • Healthcare providers should consult with a specialist knowledgeable in the treatment of antibiotic-resistant bacteria to determine the best treatment option if there are concerns for XDR Shigella infections or in cases of treatment failure without AST results.
    • CDC does not have recommendations for optimal antimicrobial treatment because there are no data from clinical studies of treatment of XDR Shigella infections.
  • Although antibiotic therapy is not routinely recommended for mild infections, consider antibiotic treatment for:
    • Patients with more severe illnesses
    • Patients who are immunocompromised
    • Patients in settings where there is elevated concern for transmission to others (e.g., in congregate living situations)
    • And in outbreak settings
  • Ensure laboratories send all specimens to the Washington State Public Health Lab (PHL) in Shoreline for confirmatory testing.

Please contact the Spokane Regional Health District Communicable Disease at 509.324.1442 or with any questions or concerns.

Fax confirmed cases reports to 509.324.3623 or call our 24/7 Reporting Line at 509.324.1449.