Neisseria gonorrhoeae
One-Sentence Definition
Neisseria gonorrhoeae (gonococcus) is a Gram-negative diplococcus causing urethritis, cervicitis, pelvic inflammatory disease, and disseminated infection — now a critical AMR threat with shrinking therapeutic options.
Taxonomy & Morphology
- Gram-negative kidney-bean diplococci, often intracellular on smear
- Fastidious; CO₂-loving; Thayer-Martin / modern selective media
- Closely related to Neisseria meningitidis but niche = mucosa of urogenital tract, rectum, pharynx
Virulence Highlights
- Type IV pili — attachment; phase/antigenic variation (Antigenic Variation)
- Opa proteins; LOS; IgA protease
- Natural competence → rampant recombination (Bacterial Competence Systems)
Clinical Syndromes
- Urethritis, cervicitis; often asymptomatic in women
- PID, infertility, ectopic pregnancy risk
- Disseminated gonococcal infection (DGI): arthritis-dermatitis
- Ophthalmia neonatorum; pharyngeal/rectal infection
Diagnosis
- NAAT preferred for genital sites; culture still needed for AST
- Gram stain of urethral discharge (symptomatic men) — high PPV
- Extragenital NAAT where indicated
Treatment Notes (conceptual)
- Follow current CDC/WHO guidelines — regimens change with resistance
- Dual therapy historically; ceftriaxone backbone evolving by dose/region
- Test of cure for pharyngeal infection in many protocols
AMR
- Urgent threat: resistance to penicillins, tetracyclines, fluoroquinolones; rising cephalosporin/azithromycin MIC
- Mosaic penA alleles (cephalosporin); gyrase/parC; efflux (Mtr); rRNA mutations
- Culture-based AST essential for treatment failures
Genomics & Computational Notes
- Among the most recombining pathogens — always use Recombination in Bacterial Phylogenies
- WGS for AMR marker prediction and sexual-network epi
- Links: Machine Learning for AMR Prediction · Genotype to Phenotype Prediction
Related Notes
- Neisseria meningitidis · Antigenic Variation · ESKAPE Pathogens (AMR priority framing)
- MOCs: MOC - Bacteriology · MOC - Antimicrobial Resistance (AMR) · MOC - Public Health & Epidemiology
Active Recall
- Why is culture still required despite NAAT dominance?
- Which gene family is classically linked to cephalosporin MIC creep?
- How does competence accelerate gonococcal AMR evolution?