Bacterial infections of the CNS

Question 1

what are the 6 virulence factors of N meningitidis?

Answer 1

LOS (endotoxin), IgA protease, capsule, pili, porins and Opa

Question 2

what determines if neisseria are pathogenic?

Answer 2

if they contain the virulence factors

Question 3

describe the morphology and metabolism of N meningitidis

Answer 3

gram negative diplococci that are facultative aerobes

Question 4

what are the results of catalase and oxidase tests with N meningitides? what sugars does it metabolize?

Answer 4

oxidase and catalase positive.

ferments maltose

Question 5

what cultures are used to grow N meningitides?

Answer 5

thayer martin if the sample comes from a nonsterile swab and chocolate agar if sample is taken from a normally sterile site like CSF and blood

Question 6

what is the host defense against a N meningitides infection? what disposes to complication?

Answer 6

IgG enhanced complement deposition and PMNs

complement deficiency

Question 7

what are some complications of gonococcal infection?

Answer 7

PID in women

septic arthritis, meningitis and endocarditis

Question 8

how are neonates protected from gonococcal infections?

Answer 8

protected from meningococcus by maternal, passive immunity and eyes are protected with prophylactic eye ointment after birth

Question 9

how are N meningitidis infections diagnosed?

Answer 9

culture and gram stain samples. also DNA tests available

Question 10

how is gonococcal infection prevented?

Answer 10

vaccine for meningococcus and condoms for gonococcus

Question 11

how is meningococcus treated?

Answer 11

with ceftriaxone and admission with complications. steroids for inflammation should be avoided

Question 12

what organism causes group B strep?

Answer 12

S agalactiae

Question 13

what is the morphology of group b strep? what type of hemolysis does it display? where does it usually reside?

Answer 13

it is gram positive and beta hemolytic cocci. normal flora

Question 14

when is group b strep pathogenic?

Answer 14

it is an opportunistic pathogen in neonates and elderly with predisposing conditions

Question 15

what symptoms does group b strep cause in neonates?

Answer 15

early pneumonia or late meningitis

Question 16

how is transmission of group b strep to neonates prevented?

Answer 16

intrapartum IV antibiotics

Question 17

what predispositions may elderly people have to group b strep infection?

Answer 17

diabetes and CHF

Question 18

what are the manifestations of group B strep in the elderly?

Answer 18

cellulitis, meningitis, abscess and endocarditis

Question 19

what are the treatments for group B strep?

Answer 19

penicillin, amoxicillin and vancomycin, surgery if necessary

Question 20

how is group B strep diagnosed?

Answer 20

by culture with gram staining, CAMP or hippurate testing

Question 21

what morphology does s. pneumoniae have? what is their result to catalase testing?

Answer 21

gram positive diplococci that form chains in culture

catalase negative

Question 22

what 9 diseases does pneumococcus cause?

Answer 22

community acquired pneumonia, bacterial meningitis, bacteremia, otitis media, sinusitis, septic arthritis, osteomyelitis, peritonitis and endocarditis

Question 23

where is pneumococcus carried?

Answer 23

in upper respiratory tract of a healthy adult with or without vaccination

Question 24

describe the non invasive progression of pneumococcus

Answer 24

direct extension into sinuses, eustachian tubes and bronchi

Question 25

how is pneumococcal pneumonia diagnosed?

Answer 25

mild cases show clinical signs for treatment. in severe pneumonia, do x ray and swab for sensitivity testing

Question 26

how is pneumococcal pneumonia treated?

Answer 26

in mild cases- outpatient amoxicillin

severe cases- admit and give amoxicillin, fluoroquinolones and/or vancomycin. do sensitivity testing after initiation

Question 27

how is invasive pheumococcal infection spread? what does it cause?

Answer 27

spread hematogenously to meninges, joints, heart valves (strong inflammatory response)

Question 28

what are the spinal tap findings typical of bacterial meningitis?

Answer 28

elevated opening pressure, increased WBC, elevated protein, decreased glucose, elevated lactic acid and positive culture

Question 29

what treatment is given for pneumococcal meningitis?

Answer 29

vancomycin plus ceftriaxome initially. if resistance is detected, add rifampin, meropenem or chloramphenicol

Question 30

what indications exist for steroid use with meningitis?

Answer 30

if the infectious agent is pneumococcus and it is early in the antibiotic course

Question 31

what prevention is available for pneumococcal infection?

Answer 31

prevnar7 and 13 vaccines with 7 and 13 strains respectively