In a follow-up to recommendations published in April 2017, the Centers for Disease Control and Prevention (CDC) issued updated recommendations on management and reporting of Shigella infections that have been treated with ciprofloxacin or azithromycin and resulted in possible clinical treatment failure.

The Centers for Disease Control and Prevention (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.

Clinicians should carefully monitor patients with Shigella infections who require fluoroquinolone treatment and report any possible treatment failures. If treatment failure is suspected, clinicians should submit a stool specimen for antimicrobial susceptibility testing, and consider consulting an infectious disease specialist to identify best treatment options.

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).

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


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 [email protected].
  • 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 [email protected] to coordinate additional laboratory testing and/or shipment of the isolate to CDC.

Read more at Update – CDC Recommendations for Managing and Reporting Shigella Infections with Possible Reduced Susceptibility to Ciprofloxacin