What is the recommended treatment for Shigella infection?

From the Guidelines

The recommended treatment for Shigella infection is azithromycin or ciprofloxacin for 3-5 days, depending on local resistance patterns and susceptibility testing, as indicated by the most recent guidelines 1. When considering treatment for Shigella infection, it's essential to weigh the severity of the case and the patient's risk factors. For mild cases, supportive care, including rest and adequate fluid intake, may be sufficient to manage symptoms and prevent dehydration. However, for more severe cases or high-risk patients, such as those with compromised immune systems, antibiotic therapy is crucial to reduce symptom duration, prevent complications, and limit disease spread.

Key Considerations for Treatment

• Azithromycin and ciprofloxacin are recommended as first-line treatments for Shigella infection, with the choice between them depending on local resistance patterns and the patient's specific situation 1.
• Trimethoprim-sulfamethoxazole (TMP-SMX) can be considered as an alternative, but its use may be limited by resistance patterns, especially in cases acquired internationally or in HIV-infected individuals 1.
• The duration of treatment typically ranges from 3 to 5 days, but in cases of Shigella bacteremia, extending treatment to 14 days may be reasonable, depending on the severity of the infection 1.
• It's critical to avoid prescribing fluoroquinolones if the ciprofloxacin MIC is 0.12 μg/mL or higher, even if the laboratory report identifies the isolate as susceptible, as indicated by recent guidelines 1.

Additional Recommendations

• Patients should practice strict handwashing and hygiene measures to prevent the transmission of Shigella to others, as the bacteria are highly contagious.
• Anti-diarrheal medications like loperamide should be avoided, as they can worsen the infection by delaying bacterial clearance.
• Treatment aims to reduce symptom duration, prevent complications such as dehydration and electrolyte imbalances, and limit disease spread, considering the bacteria invade the intestinal lining, causing inflammation and the characteristic bloody diarrhea.

From the FDA Drug Label

Infectious Diarrhea caused by Escherichia coli (enterotoxigenic strains), Campylobacter jejuni, Shigella boydii†, Shigella dysenteriae, Shigella flexneri or Shigella sonnei† when antibacterial therapy is indicated.

The recommended treatment for Shigella infection is ciprofloxacin (PO), as it has been shown to be active against most strains of Shigella boydii, Shigella dysenteriae, Shigella flexneri, and Shigella sonnei 2.

• Key points:
  • Ciprofloxacin is indicated for the treatment of infectious diarrhea caused by Shigella species.
  • The drug has been shown to be active against most strains of Shigella boydii, Shigella dysenteriae, Shigella flexneri, and Shigella sonnei.
  • Antibacterial therapy with ciprofloxacin should only be initiated when it is indicated, and the patient's condition should be closely monitored 2.

From the Research

Treatment Options for Shigella Infection

The treatment for Shigella infection typically involves the use of antimicrobial agents to shorten the duration of symptoms and reduce the excretion of pathogens.

• Azithromycin has been shown to be effective in the treatment of moderate to severe shigellosis caused by multidrug-resistant Shigella strains 3.
• Ciprofloxacin is also effective, with a single 1-gram dose being sufficient for patients infected with species of Shigella other than S. dysenteriae type 1 4.
• However, resistance to commonly used antibiotics such as azithromycin, ceftriaxone, and ciprofloxacin is increasing, with studies showing high rates of resistance among Shigella spp. isolates 5.

Antibiotic Resistance

• The resistance rate of Shigella spp. to azithromycin, ceftriaxone, and ciprofloxacin has been reported to be 25.5%, 43.6%, and 3.8%, respectively 5.
• Pharmacodynamic analyses suggest that all tested fluoroquinolones would achieve a favorable area under the concentration-time curve (AUC)/MPC ratio for wild-type strains, but mutant selection in strains with existing resistance is likely if ciprofloxacin is used 6.
• Azithromycin and ceftriaxone are predicted to promote mutant selection in both wild-type and resistant strains 6.

Considerations for Treatment

• The choice of antibiotic should be based on the results of antimicrobial susceptibility testing, if possible.
• Newer agents such as the orally administered second- and third-generation cephalosporins may be effective alternatives, but more data are needed on their safety and efficacy 7.
• The increasing resistance to commonly used antibiotics highlights the need for continued monitoring and evaluation of treatment options for Shigella infection 3, 4, 5, 7.