Neisseria 1_2

• What type of bacteria is Neisseria?

  Gram-negative cocci
• How are Neisseria bacteria arranged?

  In pairs (diplococci) with adjacent sides flattened together
• What are the biochemical characteristics of Neisseria?

  Oxidase and catalase positive, nonmotile, and fastidious
• Where can Neisseria be found in the human body?

  Inside (intracellular) and outside (extracellular) of pus cells
• How many species are in the genus Neisseria?

  29 species
• Which two species of Neisseria are pathogenic to humans?

  1. Gonorrhoeae and N. Meningitidis
• What is the common name for N. Gonorrhoeae?

  Gonococcus
• What is the common name for N. Meningitidis?

  Meningococcus
• What are the major virulence factors for N. Meningitidis?

  Polysaccharide capsule, pili, and IgA protease
• How does N. Meningitidis cause disease?

  It can colonize the nasopharynx without causing disease or lead to meningitis, sepsis, or pneumonia
• How many serogroups of N. Meningitidis are recognized?

  Thirteen serogroups
• Which serogroups of N. Meningitidis are associated with endemic and epidemic disease?

  Serogroups A, B, C, W135, X, and Y
• How is N. Meningitidis transmitted?

  By respiratory droplets among people in prolonged close contact
• What are the initial symptoms of meningitis caused by N. Meningitidis?

  Photophobia, severe headache, stiff neck, high fever, nausea, and vomiting
• What is the mortality rate of untreated meningitis caused by N. Meningitidis?

  Approaches 100%
• What is the mortality rate of meningitis when treated promptly with antibiotics?

  Less than 10%
• What is meningococcemia?

  A life-threatening septicemia with or without meningitis
• What are the characteristic clinical features of meningococcemia?

  Thrombosis of small blood vessels and multiorgan involvement
• What are common skin manifestations of meningococcemia?

  Small, petechial skin lesions on the trunk and lower extremities
• What syndrome may occur due to overwhelming disseminated intravascular coagulation (DIC) in meningococcemia?

  Waterhouse-Friderichsen syndrome
• What other infections can N. Meningitidis cause?

  Pneumonia, arthritis, and urethritis
• What specimens are used for laboratory diagnosis of N. Meningitidis?

  CSF or blood
• What are the culture conditions for N. Meningitidis?

  Cultured on chocolate or blood agar at 35° C to 37° C with 5% carbon dioxide
• What is the colony morphology of N. Meningitidis?

  Transparent or grey, shiny, and small colonies
• What does the Gram stain of N. Meningitidis reveal?

  Gram-negative diplococci (kidney shaped)
• What biochemical tests are positive for N. Meningitidis?

  Oxidase test positive and ferments glucose and maltose
• What does the CSF show in N. Meningitidis infection?

  Elevated protein and decreased glucose
• What is the purpose of the oxidase test?

  To identify bacteria that produce cytochrome oxidase
• What indicates a positive oxidase test?

  A blue/dark purple color within 5-10 seconds
• What is the primary virulence factor of N. Gonorrhoeae?

  Pili that mediate attachment to host cells
• What is the role of lipooligosaccharide in N. Gonorrhoeae?

  It has endotoxin activity
• What is the function of porin proteins in N. Gonorrhoeae?

  They promote intracellular survival by preventing phagolysosome fusion in neutrophils
• How is N. Gonorrhoeae primarily transmitted?

  By sexual contact
• What is the incubation period for gonorrhea in men?

  2 to 5 days
• What are the primary symptoms of gonorrhea in men?

  A purulent urethral discharge and dysuria
• What is the primary site of infection for N. Gonorrhoeae in women?

  The cervix
• What percentage of infected women have mild symptoms or are asymptomatic?

  At least 50%
• What are common symptoms experienced by symptomatic women infected with N. Gonorrhoeae?

  Vaginal discharge, dysuria, and abdominal pain
• What is gonococcemia?

  Disseminated infections with septicemia
• What are the clinical manifestations of disseminated gonococcemia?

  Fever, migratory arthralgias, suppurative arthritis, and a pustular rash