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Flashcards in export_circulatory bacteria Deck (32):
1

Bacteremia

Bacteria in the blood

2

What are the most common causes of bacteremia?

UTIs
RTIs

Skin/soft tissue infections

3

Consequences of bacteremia

Transient and benign
Can result in sepsis/septic shock or endocarditis

4

Sepsis

Systemic inflammatory response syndrome (SIRS) with a suspected microbial etiology (i.e. SIRS with an infection)

5

Sepsis causes

Bacteremia OR
Bacteria releasing toxins into the blood

6

SIRS symptoms

Fever OR hypothermia
Tachypnea

Tachycardia

Abnormal WBCs

7

Severe sepsis

Sepsis with one or more signs of organ dysfunction (reduced urine output, systemic acidosis, etc.)

8

Septic shock

Severe sepsis with hypotension

9

Refractory septic shock

Septic shock that lasts more than 1 hour and does not respond to fluids/drugs

10

Multiorgan failure

Dysfunction of more than one organ and development of DIC

11

What microbial agent most commonly causes sepsis and septic shock?

Bacteria
Bacteremia NOT required

12

Pathophysiology of sepsis/septic shock

Gram-negative (LPS or Lipid A)
Gram-positive (TSST-1)

Teichoic acid of Staph.

Capsule of S. pneumoniae

Polysaccharides of C. albicans

13

How does LPS cause inflammation?

Binds to CD14 and TLR4 on APCs
Results in inflammatory response (TNF, IL-1, IL-6)

14

S. aureus features

Catalase positive
Coagulase positive

Facultative intracellular

15

TSST-1 features

Heat and proteolysis-resistant
Can penetrate mucosal barrier

Superantigen

16

Strep. toxic shock syndrome features

Most patients have bactermia
Many have necrotizing fasciitis

Production of pyogenic exotoxins (SPEs)

17

SPE features

Superantigen

18

Diagnose sepsis

Blood cultures

19

Treat sepsis

IV fluids for hypotension
Platelets to stop DIC

Antimicrobial therapy

20

Antimicrobial therapy for sepsis

Vancomycin and gentamycin if unknown

21

Where do most endocarditis infections occur?

On natural or prosthetic cardiac valves

22

Acute endocarditis

High fever
Rapid damage to cardiac structures

Progresses to death quickly

Often caused by S. aureus

23

Subacute endocarditis

Low grade fever
Night sweats

Weight loss

Slower damage to heart

Most commonly caused by Viridans strep. (less virulent)

24

Other symptoms of endocarditis

New or unchanging heart murmur
Splenomegaly

Various skin lesions

Retinal lesions

25

Janeway lesions

Painless lesions on palms or soles of feet

26

Osler nodes

Painful subcutaneous nodules in the pads of digits

27

Streptococcus features

Gram-positive cocci in chains
Catalase negative

28

Viridans streptococci features

Large group of commensal bacteria
Associated with subacute endocarditis

Alpha or gamma hemolytic

Resistant to optochin

29

Common Viridans streptococci species

S. mitis
S. salivarius

30

Pathophysiology of endocarditis

Vegetations (composed of platelets, fibrin, bacteria, and inflammatory cells)
These will damage the heart and result in death if not treated

31

Diagnose endocarditis

Positive blood culture
Evidence of endocardial involvement

Fever, vascular phenomenon, etc.

32

Endocarditis treatment

Aggressive antimicrobial therapy, that is prolonged (i.e. longer than 4 weeks)