Gram - Cocci (Kaul)

Question 1

Neisseria (species, appearance)

Answer 1

• gram - cocci
• n. Gonnorhea and n. Meningitidis
• kidney shaped diplococci

Question 2

N. Gonnorhea (distinguishing feature from n., virulence factors, infection)

Answer 2

• unencapsulated
• virulence factors: pili, opacity proteins, LOS (like LPS), IgA protease, transferrin/lactoferrin
• Infects mucous membranes (GI, urinary, eyes, throat), suppuration (pus) + fibrosis
• commonly asymptomatic in women

Question 3

N. gonorrhea clinical manifestation (4)

Answer 3

clinical manifestation:

1) GU infections (urethritis, cervicitis/salpingitis in women–>infertility)
2) Pharyngitis/rectal infections (anal/oral sex)
3) Opthalmia neonatorum (give prophylactic erythromycin/silver nitrate to babies to prevent blindness from gonorrhea mom)
4) Bacteremia (rare), septic arthritis in kids>adults

Question 4

N. gonorrhea diagnosis process (4), resistance, treatment

Answer 4

1) specimens from pus, smear, gram - diplococci
2) Culture on Thayer-Martin (selective for n. gonorrhea)
3) OXIDASE +
4) NAATs (nucleic acid amplification test)

Treatment:
Resistant to penicillin, tetracycline, quinolones
treat with ceftriaxone + azithromycin/doxycycline (for possible chlamydia)

Question 5

N. meningitidis (distinguishing factor, virulence factors, clinical manifestation,

Answer 5

• antigenic capsule (distinguish from n. gonorrhea)
• pili, LOS, Opa, IgA protease, iron extraction (same as gonorrhea)
• Infection: meningococcemia (in bloodstream, rapid multiplication cause fever, chills, joint/muscle pain, petechial rash). Progress to:
• Meningitis: purulent (pus) CNS, headache, stiff neck, light sensitivity, vomiting, altered mental state
• Fulminant meningococcemia/septicemia: LOS-mediated septic shock (common infants), purple blotchy hemmorhage, DIC, adrenal collapse

Question 6

N. meningitidis treatment, vaccine

Answer 6

• 3rd gen. cephalosporin (ceftriaxone), penicillin G
• Prophylactic rifampin for people in contact
  vaccine:
• tetravalent conjugate vaccine (MCV4) vs capsule polysaccharides A, C, Y, W-135
• Trumenba (vs B)

Question 7

N. meningitidis diagnosis steps

Answer 7

• gram stain blood, CSF, skin, nasopharyngeal samples
• Oxidase + (confirms neisseria)
• n. meningitidis by growth in maltose or glucose (gonorrhea only glucose)