Clinical Micro

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which bacteria areaerobic gram negative coccobacilli?

hameophilus sp., Bordetella pertussis, Brucella sp., Francisella tularensis,
unique factors of Haemophilus
- small gram negative coccobacilli
- part of normal flora
- require X and V factors from blood
how many types of H. influenzae are there?

6 types
why is H. influenzae called influenzae?

it was first isolated during the influenza outbreak
which type of H. influenzae is most virulent?

Type B (Hib)
what is the transmission of H. influenzae?

Respiratory transmission
is H influenzae symptomatic?

mainly no, only Hib is symptomatic
what is the pathogenicity of Hib?
- meningitis in children
- severe sequelae
what are sequelae?

abnormal condition following or related to a previous disease
what sequelae are seen with Hib?
- deafness
- mental retardation
- seizures
how do you diagnose Hib?
- grow on chocolate blood agar
- grow with a satellite system of S. aureus
- needs both X and Y to grow
how can you prevent Hib?
- hype B capsule conjugate vaccine
- vaccine prevents sequelae
- dramatic reduction in childhood incidence since vaccine came out
H. ducreyi
- causes sexually transmitted disease called chancroid
- characterized by soft, ragged painful lesion on genitals
Gardnerella vaginalis
- part of normal flora of female
- can caus infection
how do you diagnose G. vaginalis

clue cells- epithelial cells covered with coccobacilli
Bordetella pertussis
- small gram negative coccobacilli
- virulent strains have capsule
- does not require X and Y
- also fastidious requiring blood agar
what are the virulence factors of B. pertussis
- pertussis toxin
- filamentous hemagglutinin
- extracellular adenylate cyclase
- endotoxin
what does the pertussis toxin do?

increase cAMP and increase insulin
what is the role of the filamentous hemagglutinin?

attach bacteria to the host cell
what does the extracellular adenylate cyclase do?

inhibits phagocytosis of the cell
what is unique about the non virulent strain of B. pertussis?

it can mutate to the virulent strain via phase shift by way of transpopon insertion
what is the epidemiology of B. pertussis?
- found worldwide
- mainly found in children
- droplet transmission
- most common childhood disease in the US (often fatal)
- vaccine decreased # of cases but on the rise again
what are the two stages of pertusses?
- catarrhal stage
- paroxysmal stage
describe the catarrhal stage of pertussis
- sneezing
- coughing
describe the paroxysmal stage of pertussis
- violent cough
- "woop" on inspiration
- increased mucus production
- can be fatal
treatment of pertussis

antibiotics are useless in severe cases
what are the two pertussis vaccines
- whole cell vaccine
- killed the cells
- intense side effects
- acellular vaccine
- isolated virulence factors
- reduced side effects and efficancy
describe Brucella
- non-motile
- gram negative
- cocoobacilli
- all have capsule, different antigens
epidemiology of brucella
- zoonosis-no human to human transmission
- from goats, sheep, cattle
- transmitted via milk
- can directly penetrate the skin

Author

bbeckers88

109405

Card Set

Clinical Micro

Description

cards for test 1

Updated

2011-10-16T21:28:25Z