Neisseria gonorrhoeae (Gonococcus)

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• Neisseria gonorrhoeae (Gonococcus)
• N. gonorrhoeae causes the sexually transmitted
  disease gonorrhoea.
• The gonococcus was first described by Neisser in
  1879 in gonorrheal pus.
• Gonococci resemble meningococci very closely in
  many properties.

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• MORPHOLOGY
• Gram negative diplococci with adjacent sides
• concave, being typically kidney shaped.
• They are usually found with in the polymorphs.
• They possess pili on their surface.

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• CULTURE CULTURAL CHARACTERISTICS
• Gonococci are fastidious organisms do not grow on
  ordinary culture media.
• They are aerobic but may grow anaerobically also.
• The optimum temperature for growth is 35-36C
  optimum pH is 7.2-7.6.
• It is essential to provide 5-10 CO2.

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• Media used
• a) Non selective media Chocolate agar,
• 
  Mueller-Hinton agar.
• b) Selective media Thayer Martin medium with
  antibiotics (Vancomycin, Colistin Nystatin.

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• Colony morphology Colonies are small, round,
  translucent, convex or slightly umbonate with
  finely granular surface lobate margins.

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• Biochemical reactions
• Oxidase test Positive
• Ferments only glucose
• but not maltose.

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• PATHOGENICITY
• Source of infection
• 1. Asymptomatic carriers
• 2. Patients
• Mode of infection
• 1. Venereal infection (sexual contact)
• 2. Nonvenereal infection

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• Antigenic structure virulence factors
• 1. Pili They help in adherence of bacteria to
  host epithelial cells they are antiphagocytic.
• 2. Lipooligosaccharide Endotoxic.
• 3. Outer membrane proteins 3 types
• a) Protein I (por)- it is a porin helps in
  adherence.
• b) Protein II (opa)- helps in adherence.
• c) Protein III (rmp)- it is associated with
  protein I.
• 4. IgA1 protease Splits inactivates IgA.

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Antigenic structure virulence factors
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• Mechanism of pathogenesis
• Gonococci adhere to epithelial cells of
  urethra or
• other mucosal surface through pili
• Cocci penetrate through the intercellular
  space
• They reach the sub epithelial connective
  tissue
• causes inflammation
• Leads to clinical manifestations
• Incubation period 2-8 days.

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• Disease
• A) In men
• The disease starts as an acute urethritis
  with a
• mucopurulent discharge
• The infection extends to the prostate,
  seminal
• vesicles epididymis
• In some it may become chronic urethritis
  leading to
• stricture formation
• The infection may spread to the periurethral
  tissues,
• causing abscesses multiple discharging sinuses
• (Watercan perineum)

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• B) In women
• The initial infection is urethritis cervicitis
  but vaginitis
• does not occur in adult female
  (vulvovaginitis can
• occur in prepubertal girls)
• The infection may extend to Bartholins
  glands,
• endometrium fallopian tubes causing
• Pelvic Inflammatory Disease (PID)
• Rarely peritonitis may develop with
  perihepatic
• inflammation (Fitz-Hugh-Curtis syndrome)

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• C) In both the sexes Proctitis, pharyngitis,
• conjunctivitis, bacteraemia which may lead to
• metastatic infection such as arthritis,
• endocarditis, meningitis, pyemia skin rashes.
• D) In neonates Opthalmia neonatorum (a
• nonvenereal gonococcal conjunctivitis in the
• newborn) results from direct infection during
• passage through birth canal.

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• LABORATORY DIAGNOSIS
• Specimens collected
• A) In men
• a) Acute infection- Urethral discharge
• b) Chronic infection-
• Morning drop
• Discharge collected after prostatic massage
• Centrifuged deposit of urine
• B) In women
• Urethral discharge
• Cervical swabs

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• C) In both the sexes Blood, CSF, synovial fluid,
  
• throat swab, rectal swab material from skin
• rashes.
• Transport If there is delay in processing than
  the
• specimens should be sent in Stuarts medium.

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• Methods of examination

A) Direct microscopy 1. Gram staining Smear
provides a presumptive evidence of gonorrhea in
men. Gram negative diplococci are found. But it
is unreliable in women.
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• 2. Immunofluorescence

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• B) Culture
• Media used
• Colony morphology
• Grams smear
• Reveals Gram negative
• cocci in pairs with
• adjacent sides concave.
• Biochemical reactions

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• C) Serology
• Complement fixation test,
• Precipitation,
• Passive agglutination,
• Immunofluorescence,
• Radioimmunoassay.

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• TREATMENT
• Previously Penicillin was drug of choice but
  resistance developed rapidly.
• Penicillin resistant is due to production of
  penicillinase enzyme the strains are called as
  penicillinase producing Neisseria gonorrhoeae
  (PPNG).
• Now Ceftriaxone or Ciprofloxacin plus Doxycycline
  or Erythromycin is useful.

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• EPIDEMIOLOGY
• Gonorrhoea is an exclusively human disease.
• The only source of infection is a human carrier
  or less often a patient.
• Asymptomatic carriage in women makes them a
  reservoir to spread infection among their male
  contact.
• Gonorrhoea is an venereal disease (STD).

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• PROPHYLAXIS
• Early detection of cases,
• Tracing of contacts,
• Health education,
• General measures,
• Vaccination has no role in prophylaxis.

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• NONGONOCOCCAL (NONSPECIFIC) URETHRITIS
• Urethritis due to causative agents other than
  gonococcus.
• Etiology
• a) Bacteria- Chlamydia trachomatis
• Mycoplasma urealyticum
• Ureaplasma urealyticum
• b) Parasites- Trichomonas vaginalis
• c) Viruses- Herpes simplex
• Cytomegalovirus
• d) Fungi- Candida
• NGU can be a part of Reiters syndrome- a
  clinical condition characterized by urethritis,
  arthritis conjunctivitis.

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