Lecture 10 - Neisseria Flashcards
Name the two important species of Neisseria human pathogens
- N. meningitidis
2. N. gonorrhoeae
What type of oxygen dependence do Neiserria have?
Aerobic or Microaerophilic (mostly microaerophilic)
What kind of infections do they cause?
Purulent infections (pus forming)
T or F, Neisseria are Gram negative diplocci
True
Where is the typical place to find Neisseria?
Nasopharynx (mouth and upper respiratory tract)
Name the 4 virulence factors for N. Meningtidis
- Fimbrae (Allow attachment and resist phagocytosis)
- Capsule (Anti-phagocytic, Ag differences)
- IgA Protease
- ‘Blebs’ of LPS
How is N. meningitidis spread?
Spread by respiratory droplets typcially among individuals with prolonged contact
What is the only natural carrier of N. meningitidis?
Humans
N. meningitidis is primarily a disease of what age group? Why?
Young children
No Abs to opsonize strain, major window of opportunity as maternal IgG levels decline and humoral immunity is still developing
What 2 major diseases are caused by N. meningitidis?
- Meningococcal Sepsis (Meningococcemia)
2. Meningitis
Describe the mode of action in Meningococcemia?
Encapsulated strains move across lining of nose and throat into blood.
Rapidly multiply and release large quantities of endotoxin (blebs)
Endotoxins activate monocytes to produce large amounts of cytokines that result in SYSTEMIC inflammation and potentially septic shock
Describe the mode of action in Meningitis?
Bacteria do not grow rapidly in blood and have time to cross blood into fluid and membranes surrounding the brain.
Endotoxin is secreted and stimulates inflammatory cascade locally in CNS tissues and systemically which results in symptoms/signs of meningitis
Which is more common, meningitis or meningococcemia?
Meningitis
What is the treatment for N. meningitidis?
Vaccination
Antimicrobial prophylaxis
Stay away from crowded conditions where it can be transmitted easily.
Major cause of spread of this N. meningitidis?
Huge amounts of blebbed endotoxin released by N. memingitidis
How common a STI is N. gonorrhea
2nd most common STI in U.S.
Name the 6 virulence factors to N. gonorrhea
Fimbrae Local LPS IgA Protease Ag-variation of pili structure (gene conversion and phase variation) Surface receptors for host proteins Penicillin resistance
The virulence factors for N. gonorrhea are broken up into what 3 main categories?
- Attachment factor
- Damaging factors
- Avoidance Factors
How is N. gonorrhea spread?
Primarily by sexual contact. Only in humans. No other known resevoir
Are symptoms of N. gonorrhea infection more common in men or women?
Men are symptomatic while women are commonly asymptomatic or with mild symptoms
Do men or women have a greater risk of being infected with N. gonorrhea
Women have 50% chance. Men 25% chance. This is due to the larger epithelial area in vagina
Women who are infected with UNTREATED gonorrhea develop what?
PID (Pelvic Inflammatory Disease)
What is a treatment for N. gonorrhea
No current vaccine because of Ag-variation of bacterial surface epitopes
Penicillin is no longer used because gonorrhea bacterium have become resistant
Are newborns at risk for infection if their mother has N. gonorrhea infection?
Yes, they are typically treated with anti-microbial eye ointment to prevent eye infections of this bacteria
3 major consequences of PID
Sterility
Ectopic Pregnancy
Pelvic surgery
