Susceptibility of Neisseria meningitidis to Doxycycline
Yes, Neisseria meningitidis is generally susceptible to doxycycline, which can be used as an effective antibiotic for prophylaxis in close contacts of meningococcal disease patients. 1, 2
Evidence of Susceptibility
- Doxycycline has demonstrated effectiveness against N. meningitidis and is included in treatment regimens for close contacts of meningococcal disease patients 3
- Studies examining the susceptibility of N. meningitidis to various antimicrobial agents have shown that tetracyclines, including doxycycline, are effective against most meningococcal strains 2
- Historical data indicates that tetracycline has shown 100% effectiveness against N. meningitidis isolates in susceptibility testing 4
Clinical Applications
Prophylaxis for Close Contacts
- Doxycycline is one of several antibiotics that can be used in combination regimens for prophylaxis of close contacts of meningococcal disease patients 1, 3
- When ciprofloxacin resistance is present in a local area, doxycycline is among the alternative recommended antibiotics for prophylaxis, along with rifampin, ceftriaxone, and azithromycin 3
- Doxycycline has been used in combination with ceftriaxone for treating pharyngeal N. gonorrhoeae infections, suggesting similar effectiveness against the related Neisseria species N. meningitidis 1
Treatment Considerations
- While N. meningitidis is generally susceptible to doxycycline, it is not typically used as first-line therapy for invasive meningococcal disease 1
- For invasive meningococcal infections including meningitis, cephalosporins (particularly ceftriaxone) are preferred due to their excellent CSF penetration and established efficacy 5
- Penicillin remains effective against most N. meningitidis strains, with reduced susceptibility occurring in only about 16% of community-acquired cases 1
Resistance Concerns
- Some N. meningitidis strains may exhibit elevated tetracycline and doxycycline MICs due to efflux-mediated resistance encoded by tet(B), though this appears to be relatively uncommon 2
- Minocycline (another tetracycline) may retain activity against some strains with resistance to other tetracyclines 2
- Ongoing surveillance for antibiotic resistance is essential, as resistance patterns can change over time 3
Clinical Recommendations
- For prophylaxis of close contacts of meningococcal disease patients, doxycycline can be considered as an alternative when ciprofloxacin resistance is present 3
- For treatment of invasive meningococcal disease, including meningitis, cephalosporins like ceftriaxone remain the preferred agents 5
- When treating suspected meningococcal infections in areas with known resistance patterns, antimicrobial selection should be guided by local susceptibility data 1
- In cases of confirmed meningococcal meningitis, doxycycline should not be used as monotherapy due to the availability of more established treatment options with better CNS penetration 1, 5
Important Caveats
- Susceptibility testing of meningococcal isolates should be performed whenever possible to guide therapy, especially in areas with emerging resistance 1
- Resistance patterns can vary geographically and change over time, necessitating ongoing surveillance 3, 2
- While doxycycline is generally effective against N. meningitidis, its use in clinical practice is primarily for prophylaxis rather than treatment of invasive disease 3, 6