Neisseria gonorrhoeae

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Neisseria gonorrhoeae / (Redirected from DGI)

Background

  • Causes gonorrhea

Microbiology

Epidemiology

  • Resistance
    • About 50% resistance to fluoroquinolones
    • Rates of MDR gonorrhea is increasing in Canada, mostly driven by azithromycin resistance
    • XDR gonorrhea is still rare in Canada 1

Mechanisms of Resistance

  • β-lactamases, most commonly a TEM-1-type contained on a PcR plasmid
  • Altered penicillin-binding protein PBP-2, encoded by penA
  • Altered or downregulated porins, encoded by penB
  • Increased efflux pump, encoded by mtr

Clinical Manifestations

Genital Infections

  • Causes cervicitis and urethritis
  • In women, up to 70% are asymptomatic
    • In symptomatic women, the incubation period is about 10 days, followed by vaginal pruritis or mucopurulent discharge
    • May have intermenstrual bleeding or menorrhagia
  • In men and women with urethritis, it is usually asymptomatic
    • Incubation period is usually about 3 to 5 days, followed by urethral discharge and dysuria
  • Epididymitis in men is more commonly caused by Chlamydia trachomatis

Pelvic Inflammatory Disease

  • See Pelvic inflammatory disease, of which about 40% of cases are caused by Neisseria gonorrhoeae
  • Pelvic and abdominal pain, vaginal bleeding, and dyspareunia
  • May be febrile and acutely unwell

Fitz-Hugh-Curtis Syndrome

  • Aka perihepatitis, with inflammation of Glisson's capsule around the liver
  • More often associated with Chlamydia trachomatis

Bartholinitis

  • Inflammation of Bartholin's glands, which are behind the labia
  • Labial pain, swelling, tenderness, and discharge

Anorectal Gonorrhea

  • Often asymptomatic
  • Can cause anorectal pain, discharge, and pruritis
  • Anal intercourse not required, especially in women

Pharyngitis

Disseminated Gonococcal Infection

  • Occurs in about 1% of patients with gonorrhea, and most strains do not cause urethritis
  • Classically presents with either septic arthritis, or with a triad of tenosynovitis (often of wrists) dermatitis (with pustular lesions), and arthritis
  • Diagnosed with genital testing for gonorrhea, ± blood cultures or arthrocentesis
  • Other (rare) sites of dissemination include endocarditis, meningitis, and osteomyelitis

Conjunctivitis

  • Occurs in infants born to untreated, infected mothers, and rarely from spread by fomites or flies

Differential Diagnosis

Management

Test of Cure

  • Done at 3 to 7 days if by culture or 14 to 21 days if NAAT
  • Indications include:
    • Pharyngeal infection
    • Persistent signs or symptoms
    • Treated without ceftriaxone
    • Treated with fluoroquinolone, without susceptibility testing
    • Epidemiologic link to a resistant case
    • Documented microbiologic resistance
    • Epidemiologic link to treatment failure
    • Previous treatment failure
    • Uncertain adherence to treatment
    • Reexposure to untreated partener
    • Pregnancy
    • Disseminated gonococcal infection
    • Pediatric patient
    • Pelvic inflammatory disease with documented gonorrhea
    • Therapeutic abortion (increased risk of developing PID)

Further Reading