id: ssti

Question 1

normal skin functions as protective barrier

Answer 1

• dry surface
• fatty acids
• acidic pH: 5.6
• renewal of epidermic
• low temp

Question 2

predisposing factors for SSTIs

Answer 2

• high bacterial innocula
• excessive moisture
• reduced blood supply
• presence of bacterial nutrients
• poor hygiene
• sharing or personal items

Question 3

MRSA-covering abx

Answer 3

ceftaroline (IV),
doxycycline (PO),
tmp/smx (PO),
vancomycin (IV/PO),
clindamycin (IV/PO), linezolid (IV/PO), daptomycin (IV)

Question 4

P.aeruginosa-covering abx

Answer 4

piper-tazo (PO/IV), ceftazidime (IV), cefepime (IV), meropenem/imipenem (IV), FQ (IV/PO), gentamicin/amikacin (IV)

Question 5

abx that does not req renal dose adj

Answer 5

cloxacillin, clindamycin, metronidazole, pen VK

Question 6

impetigo

Answer 6

most cases: mupirocin BD x5d

severe:
Pen VK (S.pyogenes)
Cephalexin
Cloxacillin
Clindamycin

Question 7

ecthyma

Answer 7

Pen VK (S.pyogenes)
Cephalexin
Cloxacillin
Clindamycin

Question 8

purulent SSTIs: furuncles, carbuncles, cutaneous abscesses

Answer 8

mainstay: I&D

MSSA: cloxacillin, cephalexin, clindamycin

MRSA: tmp/smx, clindamycin, doxycycline

x5-7d (outpatient)
x7-14d (inpatient)

Question 9

when is adjunctive abx required for purulent SSTIs?

Answer 9

• SIRS
• unable to drain completely
• lack of response to I&D
• extensive disease involving several sites
• immunocompromised (chemo/transplant)

Question 10

additional causative org for cellultis/erysipelas: immunosuppressed (chemo, transplant)

Answer 10

streptococcus pneumoniae, escherichia coli, serratia marcescens, pseudomonas aeruginosa

Question 11

additional causative org for cellultis/erysipelas: chronic liver/renal disease

Answer 11

vibrio spp, escherichia coli, pseudomonas aeruginosa

Question 12

mild, non-purulent cellulitis

Answer 12

Streptococcus spp
- pen VK
- cloxacillin
- cephalexin
- clindamycin

Question 13

moderate, non-purulent cellulitis

Answer 13

Streptococcus spp +/- S.aureus
- pen VK
- cloxacillin
- cephalexin
- clindamycin

IV:
- pen G
- cefazolin
- clindamycin

Question 14

severe, non-purulent cellulitis

Answer 14

Streptococcus spp + S.aureus + gram-neg (including pseudomonas aeruginosa)
- IV piper-tazo
- IV cefepime
- IV meropenem

MRSA risk factor, add IV:
- vanco
- dapto
- linezolid

Question 15

MRSA risk factor

Answer 15

• immunocompromised (chemo/transplant)
• critically ill (hypotensive, ICU)
• failed prev abx without mrsa coverage

Question 16

mild, purulent cellulitis

Answer 16

Streptococcus spp + S.aureus

PO
cloxacillin
cephalexin
clindamycin

MRSA:
tmp/smx, doxy, clinda

Question 17

moderate, purulent cellulitis

Answer 17

Streptococcus spp + S.aureus

PO/IV:
cloxacillin
cephalexin
clindamycin

MRSA: IV
vanco, dapto, line

Question 18

sever, purulent cellulitis

Answer 18

Streptococcus spp + S.aureus + gram-neg (including pseudomonas aeruginosa)
- IV piper-tazo
- IV cefepime
- IV meropenem

MRSA risk factor, add IV:
- vanco
- dapto
- linezolid

Question 19

cellulitis from bite wounds

Answer 19

Streptococcus spp + S.aureus + specific gram neg org (Pasteurella multocida, Eikenella corrodens), oral anaerobes

IV/PO:
amoxi-clav
ceftriaxone/cefuroxime/FQ + clinda or metro for anaerobes coverage

Question 20

duration of abx for cellulitis or erysipelas treatment

Answer 20

5d, immunosuppressed may need 7-14d

Question 21

criterias for pressure ulcer infection or DFI

Answer 21

• purulent discharge or
• > = 2 signs of inflammation: erythemia, warmth, tenderness, pain, induration

Question 22

mild DFI/pressure ulcers

Answer 22

infection of skin and SC tissue + erythema <2cm around ulcer + no SIRS

Streptococcus spp + S.aureus

PO cloxacillin, cephalexin, clindamycin

MRSA: tmp/smx, doxy, clinda

Question 23

moderate DFI/pressure ulcers

Answer 23

infection of skin and SC tissue + erythema >2cm around ulcer + no SIRS

Streptococcus spp + S.aureus + gran neg (+/- P.aeruginosa) + anaerobes

IV
amoxi-clav
ertapenem
ceftriaxone + metro/clinda

MRSA: vanco, dapto, linezolid

Question 24

severe DFI/pressure ulcers

Answer 24

SIRS

Streptococcus spp + S.aureus + gran neg (+ P.aeruginosa) + anaerobes

IV
piper-tazo
meropenem
cefepime + metro/clinda

MRSA: vanco, dapto, linezolid

Question 25

recommended duration of treatment, DFI: mild, no bone involved

Answer 25

1-2 weeks

Question 26

recommended duration of treatment, DFI: moderate, no bone involved

Answer 26

1-3 weeks

Question 27

recommended duration of treatment, DFI: severe, no bone involved

Answer 27

2-4 weeks

Question 28

recommended duration of treatment, DFI: surgery, all infected bone and tissue removed eg. amputation

Answer 28

2-5d

Question 29

recommended duration of treatment, DFI: surgery, residual infected soft tissue

Answer 29

1-3 weeks

Question 30

recommended duration of treatment, DFI: surgery, residual viable bone

Answer 30

4-6 weeks

Question 31

recommended duration of treatment, DFI: no surgery or residual dead bone

Answer 31

> = 3 months

Question 32

ammoxi/clav dosing

Answer 32

625mg BD-TDS
1.2g Q8H

Question 33

cefazolin dosing

Answer 33

1-2g q8h

Question 34

cefepime dosing

Answer 34

2g q8h

Question 35

cephalexin dosing

Answer 35

250-500mg QDS

Question 36

cloxacillin dosing

Answer 36

250-500mg QDS
1-2g Q4-6H

Question 37

clindamycin dosing

Answer 37

300mg QDS
600mg Q8H

Question 38

metronidazole dosing

Answer 38

500mg TDS (IV/PO)

Question 39

pen G dosing

Answer 39

2-4mill units q4-6h

Question 40

pen vk dosing

Answer 40

250-500mg QDS

Question 41

piper-tazo dosing

Answer 41

4.5g q6-8h

Question 42

tmx/smp dosing

Answer 42

960mg BD

Question 43

vanco dosing

Answer 43

15mg/kg q8-12h