Management of SSTI Flashcards

1
Q

what are some protecting factors of the skin? and what is the function of these protecting factors

A
  1. dry surface
  2. fatty acids
  3. acidic pH (around 5.6)
  4. renewal of the epidermis
  5. low temperature (compared to body core temp)
  • these factors inhibit excess microbial growth and entry into deeper layers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are some predisposing factors for SSTI

A
  1. high bacterial innocula (cut with dirty knife)
  2. excessive moisture
  3. reduced blood supply (reduced WBC to that area to fight infection)
  4. presence of bacterial nutrients (glucose in urine)
  5. poor hygiene
  6. sharing of personal items
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

characteristics of impetigo and ecthyma?

A

uncomplicated, managed as outpatient

  1. superficial infection
  2. Impetigo: non-bullous vs bullous (pus); impetigo common in children, on face or extremities
  3. ecthyma: superficial, but deeper than impetigo, scarring is common
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the causative organisms for impetigo & ecthyma?

A

S.aureus, B-hemolytic Streptococci (S.pyogenes)

(bullous form (pus) due to toxin-producing S.aureus strains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

do we need to culture for impetigo & ecthyma?

A

its optional as empiric therapy covers for s.aureus and b-hemolytic strep alr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

do we need to be concern and treat CA-MRSA?

A

Nope as prevalence is low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Treatment for mild impetigo

A

topical: Mupirocin BD for 5 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Treatment for severe cases of impetigo and all cases of ecthyma

A

Empiric therapy:

1a. Cephalexin or cloxacillin
1b. Clindamycin (pen allergic)

Culture directed:

2a. Pencillin VK (S.pyogenes)
2b. Cephalexin or cloxacillin (MSSA)

Treatment duration: 7 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

difference between furuncles (boils) and carbuncles

A

furuncles: infection of a hair follicle
carbuncles: involve few adjacent follicles, forms small abscess

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are considered purulent SSTIs?

A

furuncles, carbuncles, cutaneous abscesses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

risk factors of purulent SSTIs?

A
  • close physical contact
  • crowded living quarters
  • sharing personal items
  • poor personal hygiene
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

the causative organism for purulent SSTIs

A

S.aureus; polymicrobial for large skin abscesses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

do we need to culture for purulent SSTIs

A

not needed, but reasonable to culture pus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

treatment of purulent SSTIs

A

1st: InD

Adjunctive systemic Abx when:

  1. lack of response to InD (still red and swell)
  2. unable to completely drain completely
  3. extensive disease involving several sites
  4. extremes of age (young and old)
  5. immunosuppressed (chemo, organ transplant)
  6. SIRS criteria (systemic illness): fever >38c or <36c, HR > 90 beats/min, RR > 24 breaths/min, WBC >12 x 10^9/L or <4x10^9/L
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the adjunctive systemic abx for purulent abx

A

for MSSA only:

  • cephalexin (1st gen ceph, oral)
  • cloxacillin (anti-staph, oral)
  • cefazolin (1st gen ceph, oral/IV)

for MRSA, MSSA (if suspect MRSA)

  • clindamycin (Oral/IV)
  • Co-TS (Oral); trimethoprim/sulfamethoxazole
  • Doxycycline (Oral/IV)

Outpatient: 5-7 days
inpatient: 7-14 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the clinical manifestations (how does it look like) for cellulitis?

A
  • Acute inflammation of epidermis, dermis, and sometimes superficial fascia
  • Bacteria can invade lymphatic tissue and blood
  • Purulent/ non-purulent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the clinical manifestations (how does it look like) for Erysipelas?

A
  • Affects up to superficial dermis and lymphatic tissue

- non-purulent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What to take note with purulent cellulitis and purulent SSTIs?

A

Purulent cellulitis not = to

Furuncles, Carbuncles, Cutaneous abscesses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the visual difference btw Celluitis and Erysipelas?

A

Cellulitis: poorly demarcated area of erythema, purulent/non-purulent

Erysipelas: SHARPLY demarcated area of erythema with raised border

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are some complications of Cellulitis and Erysipelas?

A
  • Bacteremia
  • Endocarditis
  • Toxic shock
  • Glomerulonephritis
  • Lymphedema
  • Osteomyelitis
  • Necrotising soft-tissue infections (necrotising fasciitis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the causative organisms for C and E?

A
Staph Aureus (>> purulent infections)
b-haemolytic Strep (Strep pyogenes) (almost always the cause of erysipelas)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

For comorbidity of immunosuppresion, what is the pt at risk for additional causative organisms?

A

Strep pneumoniae, E. coli, Serratia marcescens, P. aeruginosa (more Gram -ve)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

For comorbidity of Chronic liver/renal disease, what is the pt at risk for additional causative organisms?

A

Vibrio spp, E.coli, P. aeruginosa (more -ve as well)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

When to consider cultures in situations for C & E?

A
  • purulent infections after I&D

- Immunosuppressed (chemo, transplant), signs of severe systemic illness (SIRS criteria)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What types of cultures can you collect?

A
  • Cutaneous aspirates
  • Tissue samples (biopsies)
  • Blood
  • Swabs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is considered a mild non-purulent infection for C&E?

What is the organism to cover?

A

no signs of systemic infection (no SIRS)

Strep spp (+ve)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is considered a moderate non-purulent infection for C&E?

What are the organisms to cover?

A

1 or more SIRS criteria

Strep spp +/- S.aureus (+ve gram)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is considered a severe non-purulent infection for C&E?

What are the organisms to cover?

A

> 2 SIRS criteria (3 and above) + hypotension, rapid progression, immunosuppressed, comorbidities

Strep spp and S.aureus and Gram -ve (Incl P. aeruginosa)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are the ABx used for mild non-purulent C&E?

A

PO Abx
“Penicillin VK” (most narrowest against streptococcus)
Cloxacillin / Cephalexin (covers MSSA, a bit broader thus not recommended)
Clindamycin (for penicilin allergy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the ABx used for moderate non-purulent C&E?

A

1 SIRS criteria: treat like mild Abx; Pen VK, Cloxa, Cepha, Clinda

2 or more SIRS criteria: IV ABx

  • “Cefazolin” (strep and MSSA)
  • Pen G
  • Clindamycin (pen allergy)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the ABx used for severe non-purulent C&E?

A

IV Abx:

  • Pip/Tazo (anti-pseudomonal pen)
  • Cefepime (4th gen)
  • Meropenem (carbapenem, reserved for ESBL resistant organisms)

If MRSA risk factor(s), add IV:

  • Vanco
  • Dapto
  • Linezolid
32
Q

What are the 3 MRSA risk factors?

A

1: immunosuppression
2: critically ill, hypotensive (in ICU)
3: previously failed Abx without MRSA activity

33
Q

What is the value for hypotension?

A

<100/60

34
Q

What is considered a mild purulent infection for C&E?

Which organisms to cover?

A

No signs of systemic infection (no SIRS)

Strep spp + S.aureus (+ve gram)

35
Q

What is considered a moderate purulent infection for C&E?

Which organisms to cover?

A

1 or more SIRS criteria

Strep spp + S.aureus (+ve gram)

36
Q

What is considered a severe purulent infection for C&E?

Which organisms to cover?

A

> 2 SIRS criteria (3 and above) + hypotension, rapid progression, immunosuppressed, comorbidities

Strep spp and S.aureus and Gram -ve (Incl P. aeruginosa)

37
Q

What are the ABx used for mild purulent C&E?

A

PO ABx

  • Cephalexin
  • Cloxacillin
  • Clindamycin

If MRSA risk factors:

  • Co-TS
  • Clinda
  • Doxy
38
Q

What are the ABx used for moderate purulent C&E?

A

1 SIRS criteria: follow like mild: Cepha, Cloxa, Clinda

2 = or more SIRS criteria: IV

  • Cloxacillin
  • Cefazolin
  • Clindamycin

MRSA risk factors:

  • Vanco
  • Daptomycin
  • Linezolid
39
Q

What are the ABx used for severe purulent C&E?

A

IV Abx:

  • Pip/Tazo (anti-pseudomonal pen)
  • Cefepime (4th gen)
  • Meropenem (carbapenem, reserved for ESBL resistant organisms)

If MRSA risk factor(s), add IV:

  • Vanco
  • Dapto
  • Linezolid
40
Q

What are the MO that causes cellulitis from bite wounds?

A

S. aureus, Strep spp, specific organisms

41
Q

What is the MO for animal bites?

A

Pasteurella multocida

42
Q

What is the MO for human bites?

A

Eikenella corrodens

43
Q

What is another specific organism in cellulitis from bite wounds?

A
  • Oral anaerobes (e.g. Prevotella spp., Peptostreptococcus spp.)
44
Q

What is the Abx treatment for bite wounds?

A
  • Augmentin
  • Ceftriaxone or Cefuroxime + Clinda or metronidazole (For anaerobe coverage)
  • Cipro/levo (FQs for pen allergy) + clinda/metronidazole

IV/Oral depends on severity of infection

45
Q

What is the first monitoring aspect to look out for?

A

assess clinical response in 48-72 hrs

46
Q

What is the first question that you will ask after assessing the clinical response?

A

Improved fever, pain, swelling, erythema, warmth?

No- consider resistant organisms and/or alternative causes

Yes - If initial IV Abx, change to PO
Afebrile for 48 hrs
Clinical improvement

47
Q

How long is the ABx duration for conditions that have gotten better? for purulent SSTI

A

at least 5 days

May extend if no sig improved

Immunocompromised may need 7-14 days

48
Q

Areas of Diabetic Foot Infections

A
skin ulceration (peripheral neuropathy)
wound (trauma)

soft tissue or bone infection below the malleolus (below ankle)

49
Q

complications of DFI

A
  • hospitalization

- osteomyelitis (bone infection) –> amputation

50
Q

pathophysiology of DFIs (3 things)

A
  1. neuropathy
    - peripheral: reduce pain sensation and response to pain
    - motor: muscle imbalance
    - autonomic: increase dryness, cracks and fissures
  2. Vasculopathy
    - early atherosclerosis
    - peripheral vascular disease
    - worsened by hyperglycemia or hyperlipidemia
  3. Immunopathy
    - impaired immune response
    - increase susceptibility to infection
    - worsened by hyperglycemia

all this lead to ulcer formation and wounds
–> causing bacterial colonisation, penetration, proliferation –> causing DFI

51
Q

Definition of DFI/pressure ulcer infection

A

(1) purulent discharge OR

(2) >= 2 signs and symptoms of inflammation
- -> erythema,
- -> warmth
- -> tenderness
- -> pain
- -> induration (area becomes firm; localised hardening of soft tissue)

52
Q

causative microorganisms for DFIs and pressure ulcers?

A

both usually polymicrobial

most common: s.aureus, streptococcus spp

gram -ve bacilli: e coli, klebsiella, proteus,
less common: P.aeruginosa
–> seen in chronic wounds or previously treated with Abx

anaerobes: peptostreptococcus, veillonella, Bacteroides spp
- -> seen in ischemic or necrotic wounds

53
Q

does culture need to be taken for DFI or pressure ulcers?

A

Mild DFIs = optional

Moderate-severe DFIs/ pressure ulcers

  • deep tissue culture after cleaning and before starting abx (if possible; don’t take if patient critically ill and need to start on abx immediately)
  • or biopsy specimens for pressure ulcers
  • AVOID skin swabs (for both DFIs and pressure ulcer)
  • do not culture uninfected wounds
54
Q

criteria for mild DFI/pressure ulcer

A

(1) infection of skin and SC tissue +

(2) if erythema: =<2cm around ulcer + No signs of SIRS

55
Q

criteria for moderate DFI/pressure ulcer

A

(1) infection of deeper tissue (e.g. bone, joints) OR

(2) if erythema: > 2cm around ulcer + No signs of SIRS

56
Q

criteria for severe DFI/pressure ulcer

A

Any sign of SIRS

57
Q

organisms to cover for mild DFI/pressure ulcer

A

Streptococcus spp + S.aureus

58
Q

organisms to cover for moderate DFI/pressure ulcer

A

Streptococcus spp + S.aureus +

gram -ve (+/- P.aeruginosa) + anaerobes

59
Q

organisms to cover for severe DFI/pressure ulcer

A

Streptococcus spp + S.aureus +

gram -ve (INCLUDING P.aeruginosa) + anaerobes

60
Q

when do we add empiric coverage for p.aeruginosa for DFIs or pressure ulcers?

A

(1) severe infection (IDSA) OR

(2) failure of abx not active against P.aeruginosa

61
Q

treatment for mild DFI/pressure ulcer

A

PO antibiotics:
cloxacillin, cephalexin, clindamycin

If MRSA risk factor(s), use PO:
trimethoprim/sulfamethoxazole
clindamycin
doxycycline

62
Q

treatment for moderate DFI/pressure ulcer

A

Initial IV Abx:

(1) amoxicillin/clavulanate (augmentin)
(2) ceftriaxone**
(3) ertapenem (not preferred as broad-spectrum; reserve for ESBL producing organism)

  • *if no anaerobe coverage, add IV:
  • metronidazole
  • clindamycin

if have MRSA risk factor(s); add IV:

  • vancomycin
  • daptomycin
  • linezolid

May step down to PO abx(s) after patient improves

63
Q

treatment for severe DFI/pressure ulcer

A

Initial IV Abx:

(1) piperacillin/tazobactam
(2) cefepime**
(3) Meropenem

  • *if no anaerobe coverage, add IV:
  • metronidazole
  • clindamycin

if have MRSA risk factor(s); add IV:

  • vancomycin
  • daptomycin
  • linezolid

May step down to PO abx(s) after patient improves

64
Q

when can be step down from IV to oral therapy?

A

if patient improves - seen in culture
OR
if no culture was obtained but patient improve in terms of sx and symptoms, choose oral abx with similar activity to IV abx

65
Q

duration of therapy for DFIs/pressure ulcer

A

No bone involved

(1) Mild: 1-2 weeks
(2) moderate: 1-3 weeks
(3) severe: 2-4 week

Bone involved:

(1) surgery (all infected bone and tissue removed (e.g. amputation): 2-5 days
(2) surgery (residual infected soft tissue): 1-3 weeks
(3) surgery (residual viable bone): 4-6 weeks
(4) No surgery or surgery (residual dead bone): >= 3 months

DO NOT continue Abx until complete wound healing (abx resolves infection but not the wound healing)

66
Q

DFIs non-pharmacological interventions and preventions

A

wound care

  • debridement (cleaning and remove infected tissues)
  • off-loading (supportive shoe, relieve pressure on wound area)
  • apply dressing to promote healing env and control excess exudation

Foot care

  • daily inspection
  • prevent wound and ulcers
67
Q

why do pressure ulcers occur (4 factors)

A

moisture, pressure (amt and duration), shearing force, friction

68
Q

pressure ulcers also known as?

A

decubitus ulcers, or bed sores

69
Q

risk factors of pressure ulcers?

A

(1) reduced mobility (spinal cord injuries, paraplegic)
(2) debilitated by severe chronic disease (multiple sclerosis, stroke, cancer)

(3) reduced consciousness
(4) sensory and autonomic impairment (incontinence; increases moisture)

(5) extremes of age
(6) malnutrition

70
Q

non-pharmacological intervention for pressure ulcers

A

(1) debridement of infected or necrotic tissue
(2) local wound care
- normal saline preferred
- avoid harsh chemicals

(3) relief of pressure
- turn or reposition every 2 hours
- also important for prevention

71
Q

dosing for abx covering strep and stap

A

(1) cephalexin: 250-500mg PO QDS*
(2) cloxacillin: 250-500mg PO QDS; 1-2g IV Q4-6H
(3) clindamycin: 300mg PO QDS; 600mg IV Q8H
(4) cefazolin 1-2g IV Q8H*

72
Q

dosing for abx covering anaerobes/ broad?

A

(1) augmentin: 625mg PO BD-TDS; 1.2g IV Q8H
(2) metronidazole: 500mg PO/IV TDS
(3) clindamycin

73
Q

dosing for abx covering P.aeruginosa

A

(1) piperacillin/tazobactam: 4.5g IV Q6-8H*

(2) cefepime: 2g IV Q8H*

74
Q

dosing for abx covering MRSA risk factors

A

(1) trimethoprim/sulfamethoxazole: 800/160mg PO BD*
(2) clindamycin
(3) doxycycline
(4) vancomycin: 15mg/kg Q8-12H*

75
Q

dosing for abx covering strep only

A

(1) pen G: 2-4 million units Q4-6H*

(2) pen VK: 250-500mg PO QDS