Nisseria

• What are the two main pathogens of the Neisseria genus?

  N. gonorrhoeae and N. meningitidis
• What type of infections are associated with N. gonorrhoeae?

  Gonococcal infections
• What type of infections are associated with N. meningitidis?

  Meningococcal infections
• How do gonococcus and meningococcus behave in terms of symptoms?

  They can colonize mucous surfaces with or without symptoms
• Are gonococcal infections typically lethal?

  No, they are rarely lethal
• Are meningococcal infections life-threatening?

  Yes, they are life-threatening
• What is the shape of Neisseria bacteria?

  Kidney/bean shaped

  
• What type of cell wall do Neisseria bacteria have?

  Typical Gram-negative cell wall with Lipooligosaccharide (LOS)

  
• What type of agar is used to culture Neisseria?

  Chocolate agar
• What special media are used for culturing Neisseria?

  Thayer-Martin and Modified New York City medium
• What growth conditions are required for Neisseria?

  1. 10% CO2, temperature range of 30-37°C, and 18-24 hours incubation
• How do Neisseria colonies appear after growth?

  Tiny and grayish
• Why are Neisseria considered fastidious?

  They die very quickly under normal environmental conditions
• What biochemical test is Neisseria known to be positive for?

  Oxidase test

  
• What is used to differentiate gonococcus from meningococcus?

  Carbohydrate fermentation

  
• What are some virulence factors of Neisseria?

  Pili, outer membrane proteins, LOS, phase variation, and serum resistant strains
• How do Neisseria attach to mucosal surfaces?

  By using pili and outer membrane proteins
• What role does IgA protease play in Neisseria pathogenesis?

  It inactivates mucosal IgA
• What is the clinical significance of disseminated gonococcal infection (DGI)?

  It occurs in 1-3% of females and can spread from the endocervix to deeper tissues

  
• What are the clinical diseases associated with gonococcus?

  • Gonococcal urethritis
  • Ophthalmia neonatorum
  • Rectal and pharyngeal infections
  • Complications: PID, infertility, ectopic pregnancy, DGI (arthritis, meningitis, endocarditis), GADS
• What specimens are used for diagnosing gonococcal infections?

  Urethral and cervical specimens

  
• What is the presumptive identification method for gonococcal infections?

  Gram stain showing Gram-negative intracellular diplococci (GNID)

  
• What is the first-line treatment for gonococcal infections?

  Ceftriaxone

  
• What additional treatment is recommended for patients infected with gonococcus who may also have Chlamydia?

  Azithromycin or doxycycline

  
• How does the growth of meningococcus compare to N. gonorrhoeae?

  Meningococcus is not as fastidious as N. gonorrhoeae
• What is the size of meningococcus colonies on blood agar after 24 hours?

  1.5 to 2 mm
• What is the important antigenic structure of meningococcus?

  Prominent polysaccharide capsule with 13 serogroups
• What are the important serogroups of meningococcus?


  A, B, C, Y, W-135
• What is the epidemiological significance of the 'Meningitis belt' in Africa?

  It is a region where epidemics of meningococcal disease occur

  
• What is the transmission method for meningococcus?

  Respiratory droplets
• What is the incubation period for meningococcal infections?

  2 to 3 days
• What is the peak age for serious meningococcal infections?

  6 months to 2 years
• What are the clinical diseases associated with meningococcus?

  • Purulent meningitis (may be associated with skin petechiae)
  • Meningococcemia (fulminant DIC, Waterhouse Friderichsen syndrome)
  • Rarely pneumonia
• What specimens are used for diagnosing meningococcal infections?

  CSF, blood, joint fluid, skin lesions

  
• What is the rapid diagnosis method for meningococcal infections?

  Latex agglutination using CSF, urine, or blood

  
• What biochemical tests are used to identify meningococcus?

  Glu +ve and Mal +ve
• What is the treatment for meningococcal infections?

  Penicillin, cephalosporins, and chloramphenicol

  
• What chemoprophylaxis is recommended for close contacts of meningococcal infections?

  Rifampicin and Ciprofloxacin
• What vaccination is available for meningococcal infections?

  Meningococcal polysaccharide ACW vaccine
• What are some other Gram-negative cocci that rarely cause disease?

  • Moraxella catarrhalis (previously N. catarrhalis, Branhamella catarrhalis)
  • May cause pneumonia