CDC Updates Recommendations for Managing and Reporting Shigella Infections with Possible Reduced Susceptibility to Ciprofloxacin

PUBLISHED: Jun 7, 2018
Relevant to: Ambulatory Care, Clinical Lab, Critical Access Hospitals, Home Health, Hospitals, Long Term Care, Medical Office, Pharmacy, Rural Health Clinics

The U.S. Centers for Disease Control and Prevention (CDC) has issued an update via its Health Alert Network that provides current recommendations on management and reporting of Shigella infections that have been treated with ciprofloxacin or azithromycin and resulted in possible clinical treatment failure.

The CDC continues to identify an increasing number of Shigella isolates that test within the susceptible range for the fluoroquinolone antibiotic ciprofloxacin (minimum inhibitory concentration [MIC] values of 0.12-1 μg/mL), but harbor one or more resistance mechanisms. CDC remains concerned about potential clinical failures with fluoroquinolone treatment.

The CDC has also identified an increasing number of Shigella isolates with azithromycin MICs that exceed the epidemiological cutoff value (ECV) and is requesting reports of any possible treatment failures occurring among patients with Shigella infections treated with azithromycin (see below).

Recommendations for Clinicians

  1. If antibiotic treatment is necessary, monitor patients carefully.
  2. If you identify or receive a report of a patient with Shigella infection and possible fluoroquinolone or azithromycin treatment failure:
    • Consider consulting an infectious disease specialist to identify other treatment options, because some Shigella isolates with susceptible ciprofloxacin MICs may harbor one or more quinolone resistance mechanisms.
    • Contact your local health department to coordinate reporting treatment failure information. This information should be reported to CDC at
    • Collect a stool specimen for culture, and work with your clinical microbiology laboratory to submit for additional antimicrobial susceptibility testing.
    • Request that your laboratory expedite submission of the Shigella isolate to your state public health laboratory. Your state laboratory should notify CDC at to coordinate additional laboratory testing and/or shipment of the isolate to CDC.

Shigellosis is a nationally notifiable condition; all cases should be reported to local health departments.

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