circulatory system infections

Question 1

causative agents

Answer 1

before antibiotics: strep, staph (cocci)
after antibiotics: gram negative rods
today: gram positives and negatives due to surgical procedures
salmonella typhi type 3 secretion
listeria monocytogenes

Question 2

Plague

Answer 2

haemotogenous spread, flea is vector
Yersinia pestis, enterobacteriacae, gram negative bacillus
pleomorphic
bubonic plague:
spreads through blood, bubos present, inflammation of lymph nodes

Question 3

opportunistic infection

Answer 3

hospital patients, immune suppression
pseudemonas aeruginosa 
acineterbacter 
steriotrophomonas maltophia only collistin and tigerclycin work against 
newborns:
listeria, group B strep

Question 4

endotoxic shock

Answer 4

gram negatives produce endotoxin
lipid A causes vasodilation - warm shock
blood vessels constrict to restore blood pressure - cold shock
small clots, damage to basement membrane, leaky blood vessels

Question 5

toxic shock syndrome

Answer 5

staph aureus produces TSST
non specific binding of MHC with T cell conserved regions
super antigen
polyclonal activation 
cytokine storm , organ failure

Question 6

diagnosing septacaemia

Answer 6

blood cultures
3 draws from different sites - all positive
colourmetric detection detects CO2 production
skin contamination

Question 7

antimicrobial treatment

Answer 7

empirical therapy - aminoglycosides and B lactam (and metronidazole if obligate anaerobe)

Question 8

endocarditis

Answer 8

infection of endocardial surfaces of heart - valves
mitral > aortic > tricuspid > pulmonic
predisposed damage then oral microoganisms form micro colony
staph aureus in tricuspid valve in IV drug users

Question 9

vegetations

Answer 9

microcolonies and fibrin and immune cell deposits
biofilm formation
friable - septic emboli

Question 10

prosthetic valve endocarditis

Answer 10

early (<1 year)
coagulase negative staph
staph aureus 
corynebacterium 
late (> 1 year)
transient bactereamia
viridans strep 
enterococci 
coagulase neg staph

Question 11

diagnosis

Answer 11

modified duke criteria 
2 major
1 major 3 minor
5 minor
major: 2X blood cultures positive 
echocardiogram positive 
minor
IV drug, fever, septic emboli Janeways lesions in skin, circulating immune complexes

Question 12

treatment

Answer 12

bacteriocidal

b lactam and aminoclycosides

Question 13

mycotic aneurysm

Answer 13

damage to artery wall due to inflammation

high pressure

Question 14

suppurative thrombophlebitis

Answer 14

veins
IV catheter association
microbial colonisation