Bacterial infections of the circulatory system Flashcards Preview

Year 1 Microbiology > Bacterial infections of the circulatory system > Flashcards

Flashcards in Bacterial infections of the circulatory system Deck (28):
1

Is bacteremia required for sepsis?

No

2

Systemic inflammatory response syndrome (SIRS) is two or more of what conditions?

1. Fever or hypothermia 2. Tachypnea 3. Tachycardia 4. Abnormal WBC count (leukocytosis or leukopenia)

3

What is severe sepsis?

Sepsis with one or more signs of organ failure

4

What is septic shock?

Severe sepsis + hypotension

5

What is refractory septic shock?

Septic shock that lasts for 1 hour and does not respond to fluid and pharmacologic treatment

6

What is multiorgan failure?

Dysfunction of one or more organs + disseminated intravascular coagulation (DIC)

7

What leads to DIC?

1. Early cytokines in systemic inflammation 2. IL-6 --> tissue factor --> DIC

8

What initiates septic shock?

LPS, lipid A, TSST-1, polysaccharides of C. albicans, teichoic acid of staph, capsule of S. pneumo

9

What is the pathophysiology of LPS-induced sepsis?

1. LPS binds to CD14 and TLR4 on phagocytes / APCs 2. Immune system activated 3. Inflammation / septic shock via TNFa, IL-1, IL-6

10

What is the gram stain for staph aureus?

Gram positive

11

What is the catalase test for staph aureus?

Catalase positive

12

What is the coagulase test for staph aureus?

Coagulase positive

13

How does strep TSS differ from staph TSS?

1. Strep TSS is usually accompanied by bacteremia 2. Strep TSS may also include necrotizing fasciitis

14

What virulence factors are responsible for the clinical manifestations of strep TSS?

SpeA and SpeC

15

During septic shock what percentage of patients will be positive for blood cultures?

40-70%

16

What are the localized sites of infection for staph aureus and strep pyogenes?

Generalized erythroderma (looks like sunburn)

17

What is the most common cause of acute endocarditis?

Staph aureus

18

What is the most common cause of subacute endocarditis?

Viridans strep

19

What are the clinical features of acute endocarditis?

1. High fever 2. Rapid damage to heart 3. Death within weeks

20

What are the clinical features of subacute endocarditis?

1. Low fever 2. Slow damage to heart 3. Death over weeks to months 4. Skin lesions (splinter hemorrhages, Roth spots, Janeway lesions, Osler nodes)

21

What are the viridans strep species associated with subacute endocarditis?

S. mitis and S. salivarius

22

What is the hemolysis pattern for viridans strep?

Alpha or gamma

23

What is the treatment for subacute bacterial endocarditis?

Penicillin + aminoglycoside (vancomycin for resistant strains)

24

Viridans strep species are resistant to what agent?

Optochin

25

What are the two main predisposing causes of infective endocarditis?

1. Susceptible cardiovascular substrate 2. Source of bacteremia

26

What are the major criteria for bacterial endocarditis?

1. Positive blood culture with typical organism 2. Evidence of endocardial involvement

27

What are the minor criteria for bacterial endocarditis?

1. Predisposition 2. Fever 3. Vascular phenomena 4. Immunologic phenomena 5. Microbiologic evidence

28

What is the treatment for bacterial endocarditis?

Aggressive and prolonged antimicrobial therapy