export_circulatory bacteria

Question 1

Bacteremia

Answer 1

Bacteria in the blood

Question 2

What are the most common causes of bacteremia?

Answer 2

UTIs
RTIs

Skin/soft tissue infections

Question 3

Consequences of bacteremia

Answer 3

Transient and benign

Can result in sepsis/septic shock or endocarditis

Question 4

Sepsis

Answer 4

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

Question 5

Sepsis causes

Answer 5

Bacteremia OR

Bacteria releasing toxins into the blood

Question 6

SIRS symptoms

Answer 6

Fever OR hypothermia
Tachypnea

Tachycardia

Abnormal WBCs

Question 7

Severe sepsis

Answer 7

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

Question 8

Septic shock

Answer 8

Severe sepsis with hypotension

Question 9

Refractory septic shock

Answer 9

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

Question 10

Multiorgan failure

Answer 10

Dysfunction of more than one organ and development of DIC

Question 11

What microbial agent most commonly causes sepsis and septic shock?

Answer 11

Bacteria

Bacteremia NOT required

Question 12

Pathophysiology of sepsis/septic shock

Answer 12

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

Teichoic acid of Staph.

Capsule of S. pneumoniae

Polysaccharides of C. albicans

Question 13

How does LPS cause inflammation?

Answer 13

Binds to CD14 and TLR4 on APCs

Results in inflammatory response (TNF, IL-1, IL-6)

Question 14

S. aureus features

Answer 14

Catalase positive
Coagulase positive

Facultative intracellular

Question 15

TSST-1 features

Answer 15

Heat and proteolysis-resistant
Can penetrate mucosal barrier

Superantigen

Question 16

Strep. toxic shock syndrome features

Answer 16

Most patients have bactermia
Many have necrotizing fasciitis

Production of pyogenic exotoxins (SPEs)

Question 17

SPE features

Answer 17

Superantigen

Question 18

Diagnose sepsis

Answer 18

Blood cultures

Question 19

Treat sepsis

Answer 19

IV fluids for hypotension
Platelets to stop DIC

Antimicrobial therapy

Question 20

Antimicrobial therapy for sepsis

Answer 20

Vancomycin and gentamycin if unknown

Question 21

Where do most endocarditis infections occur?

Answer 21

On natural or prosthetic cardiac valves

Question 22

Acute endocarditis

Answer 22

High fever
Rapid damage to cardiac structures

Progresses to death quickly

Often caused by S. aureus

Question 23

Subacute endocarditis

Answer 23

Low grade fever
Night sweats

Weight loss

Slower damage to heart

Most commonly caused by Viridans strep. (less virulent)

Question 24

Other symptoms of endocarditis

Answer 24

New or unchanging heart murmur
Splenomegaly

Various skin lesions

Retinal lesions

Question 25

Janeway lesions

Answer 25

Painless lesions on palms or soles of feet

Question 26

Osler nodes

Answer 26

Painful subcutaneous nodules in the pads of digits

Question 27

Streptococcus features

Answer 27

Gram-positive cocci in chains

Catalase negative

Question 28

Viridans streptococci features

Answer 28

Large group of commensal bacteria
Associated with subacute endocarditis

Alpha or gamma hemolytic

Resistant to optochin

Question 29

Common Viridans streptococci species

Answer 29

S. mitis

S. salivarius

Question 30

Pathophysiology of endocarditis

Answer 30

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

Question 31

Diagnose endocarditis

Answer 31

Positive blood culture
Evidence of endocardial involvement

Fever, vascular phenomenon, etc.

Question 32

Endocarditis treatment

Answer 32

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