Evaluation of spiramycin in meningococcal carriage

Area of Science:

• Microbiology
• Pharmacology
• Infectious Diseases

Background:

• Neisseria meningitidis (meningococci) are common nasopharyngeal colonizers.
• Carriage of meningococci poses a public health concern for potential transmission.
• Antibiotic therapy is explored for meningococcal carrier state eradication.

Purpose of the Study:

• To evaluate the efficacy of spiramycin in eliminating meningococci from healthy carriers.
• To determine optimal dosing regimens for meningococcal eradication.
• To assess the relationship between salivary drug concentrations and eradication rates.

Main Methods:

• Healthy carriers received spiramycin at various doses (1.5g BID, 2.5g QD for 3 days, or 1.5g QD for 10 days).
• Nasopharyngeal and throat swabs were analyzed for meningococci presence.
• Saliva concentrations of spiramycin were measured and correlated with eradication.
• Carrier contacts were monitored for evidence of reinfection.

Main Results:

• Spiramycin achieved elimination in approximately 50% of carriers across all tested regimens.
• Temporary suppression, not eradication, occurred in the remaining 50% of carriers.
• Successful elimination correlated with salivary spiramycin concentrations exceeding the Minimum Inhibitory Concentration (MIC) for at least 42 hours.
• No evidence of reinfection from close contacts was found.
• Dose escalation was prevented by dose-limiting side effects.

Conclusions:

• Spiramycin demonstrates limited efficacy in eradicating meningococci from healthy carriers.
• Achieving sustained salivary drug concentrations above the MIC is crucial for potential eradication.
• Side effects restrict the use of higher spiramycin doses.
• Further investigation of spiramycin as a monotherapy for meningococcal carrier eradication is not recommended.