Pneumococci, Listeria, Anthrax

Question 1

streptococcus pneumoniae morphology

Answer 1

gram pos diplococci, lancet shaped w/ capsule

Question 2

streptococcus pneumoniae epi

Answer 2

10% is asymptomatic colonizer, higher in children

no animal reservoir

Question 3

streptococcus pneumoniae pathogenesis

Answer 3

Ab to capsule is not generally stimulated

immuno compromised pts cannot use cilia or macrophages to clear lungs

capsule hinders phagocytosis

pneumococcus produces IgA protease which degrades IgA on respiratory epi

lytic enzyme called pneumolysin contributes to pathogenesis

Question 4

clinical syndromes from streptococcus pneumoniae

Answer 4

pneumonia, cough, fever, chills, pneuritic pain, rusty sputum etc

critical factor in recovery is Ab to capsule. immunocompromised pts are at major risk

other syndromes- otitis media, meningitis, sinusitis

Question 5

diagnosis of streptococcus pneumoniae

Answer 5

blood culture or sputum sample

Question 6

streptococcus pneumoniae vaccine

Answer 6

pneumovax- capsular polysaccharide recommended for older than 65

T cell independent Ag

Prevnar 13- capsular polysaccharides- conjugated to diphtheria proteins yielding a t cell dependent immun response. prevents pneumococcal meningitis

Question 7

listeria moncytogenes morphology

Answer 7

gram pos rod

beta hemolytic

obligate intracellular

motile

grows in the cold

Question 8

listeria moncytogenes epi

Answer 8

found in soil, humans and animals

usually animal to human transmission

pregnant women at risk- still birth

Question 9

listeria moncytogenes pathogenesis

Answer 9

invade mononuclear phagocytic cells

grows intracellularly

uses actin filaments to move from host cell to host cell

escapes from phagosome by secreting cytolysin- listeriolysin O

Question 10

listeria moncytogenes syndromes

Answer 10

meningitis, septicema, gastroenteritis

fatality = 20%

Question 11

anthrax morphology

Answer 11

aerobic, spore forming gram pos rod

Question 12

anthrax epidemiology

Answer 12

transmitted animal to animal, and rarely animal to human

Question 13

anthrax pathology

Answer 13

3 pathways- all from animal spores

cutaneous anthrax
inhalation anthrax
intestinal anthrax

pathology d/t 2 exotoxins and a protein that facilitates entry into host cells

protective Ag- facilitates entry
edema factor- adenylate cyclase which enters host cell
lethal factor- disrupts signal transduction for cell division

Question 14

anthrax snydromes

Answer 14

cutaneous- contamination of lesions w/ spores. can lead to bacteremia

inhalation anthrax- inhaled spores are phagocytozed by macrophages and germinate in lymph nodes. fatal if untreated

intestinal- ingestion from meat. rare

Question 15

anthrax vaccine

Answer 15

consisting of B anthracis proteins, used by troops and vets

Question 16

treatment for anthrax

Answer 16

cipro, tetracycline, penicillin