Microbio Flashcards
Characteristics of Strep pneumoniae?
- G+, lancet shaped cocci
- catalase negative
- alpha-hemolytic
- mucoid colonies (bc of capsule)
- bile soluble
- susceptible to optochin* (growth inhibition test, separates it from other Streps)
Who gets meningitis from Strep pneumoniae?
middle age and older adults
Characteristics of Neisseria meningitidis?
- G- diplococci (unique!)
- oxidase positive
- antiphagocytic capsule
- endotoxin: lipooligosaccharide
- culture from CSF is gold standard; may be inside WBCs
Who gets meningitis from Neisseria meningitidis?
Young adults
Which organism is likely to cause an epidemic of meningitis?
Neisseria meningitidis
Characteristics of Group B streptococci?
- G+ cocci in chains
- catalase negative
- beta-hemolytic
- bacitracin resistant
Who gets meningitis from Group B Strep?
Newborns
Characteristics of Listeria monocytogenes?
- G+
- Facultative anaerobe
Who gets meningitis from Listeria monocytogenes?
Newborns
- usually acquired transvaginally during birth if mother has eaten contaminated soft cheeses
Characteristics of Haemophilus influenzae?
Gram negative coccobacilli
- Oxidase positive
- requires X (hemin) and V (NAD or NADP) growth factors to culture; AKA grows on chocolate agar
Who gets meningitis from Haemophilus influenzae?
non-vaccinated infants and non-US
Characteristics of E. coli?
- G- rod
- facultative anaerobe
- normal gut flora in most people
Who gets meningitis from E. coli?
Newborns
How do organisms get into meninges to cause meningitis?
Hematogenous spread (via the blood)
How do organisms get to the brain to cause encephalitis?
Neuronal spread (up the axon of a neuron)
