Gram negative cocci Flashcards
what are the gram negative cocci?
- Neisseria
- Moraxella
- Acinetobacter
Nisseria
what are the medical imp. Species of nisseria?
- Neisseria meningitidis
- Neisseria gonorrhoeae
what is the biology of Neisseria meningitidis?
- Encapsulated gram negative diplococcus *
- Oxidase + , catalase + *
- Breaks down maltose & glucose (MeningoCoccos) *
where can we find neisseria meningitidis?
Human nasopharynx
how does neisseria meningitidis spread?
INHALATION respiratory droplets
neisseria meningitidis is the most common cause of meningitis in what in age group?
2 – 18 yrs *
what are the virulence factors for Meningococcal meningitis?
- Polysaccharide capsule
- IgA protease
- Endotoxin
- Risk factors for severe infection:
what is another name for neisseria meningitidis?
Meningococcal meningitis
what is the virulence factor that acts as Antiphagocytic, antigenic?
Polysaccharide capsule
what is the virulence factor that Promotes colonization of oropharynx?
IgA protease
give an example of an endotoxin in meningococcus?
Lipooligosaccharide (LOS)
what does Lipooligosaccharide (LOS) cause?
Endotoxic shock (septic shock)
what are the Risk factors for severe infection with meningococcus?
- complement deficiency (C5-C8)
- Asplenia
what are the predisposing factors for meningococcus?
- Recent antecedent viral resp. tract infection
- Smoking (active/passive)
what Age groups affected* with meningococcus?
- Adolescents/young adults (Outbreaks in institutions, schools, military barracks, dormitories *)
- In USA – infants less than 1 yr (highest incidence)
what will meningococcus cause?
meningitis
what symptoms are seen in meningitis with meningococcal infection?
- High fever (rapid onset)
- Nuchal rigidity (stiff neck)
- Photophobia (sensitivity to light), confusion, headache, vomitting
- Petechia (purpural rash) *
- Rapidly fatal
how do you call infection of meningococcus in the blood?
Meningococcemia
what symptoms are seen in meningococcemia?
- Thrombosis
- Disseminated intravascular coagulation
- Petechiae (small hemorrhages under the skin)*
- Septic shock
what is Waterhouse-Friderichsen syndrome *?
Bilateral adrenal hemorrhage & acute adrenal gland insufficiency *
what symptoms are seen in Waterhouse-Friderichsen syndrome *?
- Ecchymoses (large purple skin haemorrhages)
- DIC (disseminated intravascular coagulation)
- Hypotension & Shock
- Uncommon condition but fatal
how do you diagnose N. meningitidis?
- Gram stain CSF * (Numerous PMNs & GN diplococci *)
- culture in Blood agar with 5-10% CO2 (capnophilic) *
- Sugar utilization: Maltose & Glucose (MeninGococcus) * (increased protein, decreased sugar *)
- CSF Bacterial Antigen detection *
- Detects capsular antigen, rapid test
how do you treat N. meningitidis?
Ampicillin/Penicillin G
what if there is drug resistance to ampicillin/penicillin G?
Ceftriaxone
All close contacts with N. meningitidis should be given what?
prophylaxis – rifampin or ciprofloxacin
what is the vaccine against N. meningitidis?
what does the vaccine use?
Conjugate meningococcal vaccine (MCV4) *
capsular polysaccharides
the CDC recommends to be vaccinated at what age?
a booster dose should be given at what age?
11-12 year olds
booster = 16 y/o*