Meningococcal disease is a potentially life-threatening bacterial infection caused by Neisseria meningitidis. The Centers for Disease Control and Prevention (CDC) has recently issued new guidelines on the use of alternative antibiotics for prophylaxis in close contacts of individuals with meningococcal disease. This article will explore the recommendations provided by the CDC and the rationale behind them.
The CDC recommends the use of rifampin, ceftriaxone, or azithromycin as first-line alternatives to ciprofloxacin prophylaxis in areas where meningococcal disease is highly resistant to ciprofloxacin. These recommendations are based on several criteria:
Ciprofloxacin Resistance
Health departments should consider using alternative antibiotics when there have been two or more cases of invasive meningococcal disease caused by ciprofloxacin-resistant strains in the local catchment area over the past 12 months. This criterion indicates a high prevalence of ciprofloxacin resistance.
Prevalence of Ciprofloxacin-Resistant Strains
In addition to the number of cases, the CDC advises considering alternative antibiotics when 20% or more of all reported invasive meningococcal disease cases in the area are caused by ciprofloxacin-resistant strains. This threshold further emphasizes the significance of ciprofloxacin resistance in the local population.
Duration of Monitoring
The CDC recommends maintaining the use of alternative antibiotics for prophylaxis until a full 24 months have passed without any reported cases of invasive meningococcal disease caused by ciprofloxacin-resistant strains in the catchment area. This extended period ensures the effectiveness of the new prophylaxis approach.
Ciprofloxacin has historically been effective in treating meningococcal disease in the United States. However, the prevalence of ciprofloxacin-resistant strains has been increasing in recent years. From 2011 to 2018, there was an annual average of 1.25 cases of invasive meningococcal disease caused by ciprofloxacin-resistant strains. However, from 2019 to 2021, that number rose to an annual average of 9.7 cases, despite a decline in the overall incidence of the disease during the same period.
Emergence of Resistant Strains
Most of the recent cases of ciprofloxacin-resistant meningococcal disease were caused by NmY strains that are also resistant to penicillin. These cases were geographically dispersed throughout the United States, with notable clusters in New Mexico and California. The emergence and spread of these resistant strains warrant the use of alternative antibiotics for prophylaxis.
While the CDC is responsible for monitoring and reporting on antimicrobial susceptibility testing for N. meningitidis, local health departments and healthcare providers typically do not conduct susceptibility testing. Consequently, the results of such testing usually do not guide the choice of antimicrobial prophylaxis for close contacts of affected patients. However, if local testing provides information on susceptibility, prophylaxis can be adjusted accordingly, irrespective of the CDC thresholds.
The CDC’s recommendations for alternative antibiotics are based on a comprehensive systematic review and meta-analysis conducted in 2013. This analysis compared the efficacies and safety profiles of various antibiotics for the prevention of meningococcal infections. The findings of the meta-analysis are as follows:
Rifampin
Rifampin was found to be effective at eradicating N. meningitidis a week after prophylaxis, with a relative risk (RR) of 0.17 (95% CI 0.13-0.24) compared to no treatment.
Ceftriaxone
Two studies included in the review compared rifampin with ceftriaxone and found no statistically significant difference in eradication (RR 3.71, 95% CI 0.73-18.86). This indicates that ceftriaxone can be an effective alternative to rifampin.
Azithromycin
A study comparing azithromycin to rifampin reported no statistically significant difference in eradication (RR 0.30, 95% CI 0.30-5.54). This suggests that azithromycin can also be considered as an alternative antibiotic for prophylaxis.
Ongoing monitoring for antibiotic resistance of meningococcal isolates, as well as reporting of prophylaxis failures by healthcare providers, will guide future updates to prophylaxis considerations and recommendations. It is crucial to stay vigilant and adapt the prophylaxis approach as the landscape of antibiotic resistance evolves.
The CDC’s new guidance on alternative antibiotics for meningococcal disease prophylaxis in areas with high ciprofloxacin resistance provides a vital framework for preventing and managing infections. Rifampin, ceftriaxone, and azithromycin are recommended as first-line alternatives to ciprofloxacin prophylaxis based on their efficacy and safety profiles. It is essential for health departments and healthcare providers to stay informed and adapt their practices to effectively combat the rise of ciprofloxacin-resistant strains and protect the public’s health.