Bacteria

Question 1

Staphylococcus: coagulase-positive species

Answer 1

S. aureus

Question 2

Staphylococcus: coagulase-negative species

Answer 2

S. epidermis

S. saprophyticus

Question 3

Coagulase: diagnostic and bacterial function

Answer 3

Coagulase+ results likely indicate S. aureus; serves as virulence factor, reacts with prothrombin to coat bacteria in fibrin layer

Question 4

Gram-positive, catalase-positive genus

Answer 4

Staphylococcus

Question 5

Catalase: diagnostic and bacterial function

Answer 5

Catalase+ results may indicate presence of Staphylococci species; serves as virulence factor, inactivates bactericidal hydrogen peroxide

Question 6

Staphylococcus aureus: higher carriage rates seen in

Answer 6

diabetes, IDU, HIV, dialysis

Question 7

Staphylococcus aureus: risk factors

Answer 7

skin barrier compromise, venous catheters, pacemakers, prosthetic joints, IDU, hemodialysis, recent surgery

Question 8

Staphylococcus aureus: implicated in

Answer 8

boils, carbuncles, furuncles, uncomplicated cellulitis, SSTI surgical infections, necrotizing fasciitis, pneumonia, bacteremia, endocarditis, meningitis, osteomyelitis, septic arthritis, mastitis, pyomyositis

Question 9

Staphylococcus aureus: sites of infection

Answer 9

bloodstream, SST, hair follicles, breast, deep organ abscess, cardiac valves, bone, lung, GI tract, CNS

Question 10

Hospital-acquired staphylococcal bacteremia: consider ordering

Answer 10

Echocardiography

Question 11

Uncomplicated Staphylococcal skin infections: MRSA treatment

Answer 11

I&D + TMP/SMX DS 1-2 tabs/day x5-10d or DOX 100 mg BID x5-10d or clindamycin 300-450mg TID x5-10d

Question 12

Staphylococcal aureus: when to consider decolonization

Answer 12

Recurrent SSTI: mupirocin 2% to nares BID x5-10d + hibiclens washes 5-14d or dilute bleach bath BIW x3 mos

Question 13

Amox-Clav: MSSA

Answer 13

Good activity

Question 14

Amox-Clav: MRSA

Answer 14

Poor activity

Question 15

MRSA Bacteremia: Treatment

Answer 15

Vancomycin 15mg/kg IV q8-12h + loading dose

Question 16

MRSA/MSSA Severe SSTI: Empiric Treatment

Answer 16

Vancomycin 15mg/kg IV q12

Question 17

MSSA SSTI: Oral Treatment

Answer 17

Cephalexin 500mg PO QID x5-10d

DOX 100mg PO BID x5-10d

Question 18

DOX: MSSA

Answer 18

Good activity

Question 19

DOX: MRSA

Answer 19

Good activity

Question 20

Cephalexin: MSSA

Answer 20

Good activity

Question 21

Cephalexin: MRSA

Answer 21

Poor activity

Question 22

TMP/SMX: MSSA

Answer 22

Good activity

Question 23

TMP/SMX: MRSA

Answer 23

Good activity