What spirochetes cause meningitis?

Spirochetes That Cause Meningitis

The spirochetes that cause meningitis are Treponema pallidum (syphilis), Borrelia species (Lyme disease and relapsing fever), and Leptospira species (leptospirosis). 1

Primary Spirochetal Pathogens

Treponema pallidum

• Treponema pallidum causes neurosyphilis and is recognized as a cause of chronic meningitis (symptoms ≥4 weeks) 1
• This organism can cause meningitis and is specifically listed in FDA labeling as treatable with penicillin IV 2
• The spirochete enters the CNS very early in the disease course, may lay dormant, and can reactivate to cause late neurologic manifestations 3
• High-dose intravenous penicillin is the treatment of choice for active nervous system infection 3

Borrelia Species

• Borrelia recurrentis causes relapsing fever and is explicitly identified as a spirochetal agent causing meningitis 4
• Borrelia burgdorferi (and related genospecies) causes Lyme disease, which can manifest with meningitis, cranial neuritis, and radiculoneuropathy during disseminated disease 5
• Lyme borreliosis involves CNS seeding during the spirochetemic phase, with potential late disease flareups producing neurologic syndromes 6
• Doxycycline is indicated for treatment of spirochetal infections including Borrelia species 4

Leptospira Species

• Leptospira species cause leptospirosis, which is recognized as a spirochetal disease that frequently involves the central nervous system 6
• Unlike syphilis and Lyme disease, leptospirosis appears to be a more time-limited infection without reported long-term sequelae 3
• The organism enters the CNS during the spirochetemic phase 6

Clinical Context

Chronic vs. Acute Presentation

• Spirochetes are specifically listed among organisms expected to cause chronic meningitis (symptoms ≥4 weeks), alongside Mycobacterium tuberculosis and fungi 1
• All four spirochetal diseases (syphilis, leptospirosis, relapsing fever, and Lyme borreliosis) can involve the CNS during their spirochetemic phase 6

Diagnostic Approach

• Cerebrospinal fluid examination is very helpful in spirochetal infections of the CNS 6
• Inform the microbiology laboratory when unusual organisms such as spirochetes are suspected, as special procedures may be necessary 1
• Diagnosis generally relies on indirect tools, primarily assessment of host immune response to the organism 7

Important Clinical Pitfalls

• Do not delay specimen collection: Whenever possible, collect CSF specimens prior to initiating antimicrobial therapy 1
• Consider spirochetes in chronic presentations: While acute bacterial meningitis is typically caused by Streptococcus pneumoniae and Neisseria meningitidis, spirochetes should be considered when symptoms persist ≥4 weeks 1
• Both syphilis and Lyme disease can cause progressive nervous system damage if untreated, though damage is often more severe in neurosyphilis 7
• Early and accurate diagnosis is critical: Although both infections are readily curable with antimicrobial regimens, untreated disease can result in permanent neurologic damage 7