IC14: SSTI Flashcards
Suggest Non-pharm measures for DFI
1) Wound care
o Debridement
o “Off‐loading” = relieving pressure on ulcer
o Apply dressings that promote a healing environment and control excess exudation
2) Foot care
o Daily inspection (check for cracks, dryness or wounds beginning to occur, remember to check bottom of foot as well)
o Prevent wounds and ulcers (don’t go barefoot even at home at least wear socks, avoid footwear that is too tight or too loose)
o Nail and foot care hygiene
* Wash feet with soap every day including between toes, dry feet properly
* Moisturise but don’t moisturise in between toes (could lead to fungal infections)
* Nail care: try to prevent ingrown toenails so don’t cut too thinly (leave a bit of gap) + cut straight across the nail rather than usual round/circular manner.
3) Optimal glycemic control and management of risk factors (e.g stop smoking)
Suggest Non-pharm measures for pressure ulcers
1) Debridement of infected or necrotic tissue
2) Local wound care
o Normal saline preferred
o Avoid harsh chemicals
3) Relief of pressure
o Turn or reposition every 2 hours
o Use different kind of mattresses that prevent pressure ulcers
o Also important for prevention
What are the risk factors for SSTI? (3 broad ones)
1) Disruption of the skin barrier
o Traumatic:
e.g Lacerations, recent surgery, burns, abrasions, crush injuries, open fractures, injection drug use (illicit drug), human and animal bites, insect bites
o Nontraumatic:
e.g Ulcers, tinea pedis (bacteria can enter through breaks in skin), dermatitis, toe web intertrigo, chemical irritants (disrupt chemical balance)
o Impaired venous and lymphatic drainage
e.g Saphenous venectomy, Obesity, Chronic venous insufficiency
o Peripheral artery disease
2) Conditions that predispose to infection
e.g Diabetes, Cirrhosis, Neutropenia, HIV, Transplantation and immunosuppressive medications
3) History of cellulitis
What is the clinical presentation of impetigo/ecthyma?
Impetigo: Erythematous papules that rapidly evolve into vesicles and pustules that rupture, with the dried discharge forming honey‐coloured crusts on an erythematous base. Lesions well localised, frequently many, bullous or non-bullous in appearance.
Ecthyma: ulcerative form of impetigo. Lesions extend deep into dermis from epidermis
Itching is common for both. Usually occur on exposed areas of the body e.g face and extremities
What is the clinical presentation of furuncle, carbuncle and skin abscesses?
Furuncle: An infection of the hair follicle in which purulent material extends through the dermis into the subcutaneous tissue, where a small abscess forms.
Carbuncle: Formed when furuncles coalesce and extend into subcutaneous tissues
Skin abscess: Collections of pus within the dermis and deeper skin tissues. Skin abscesses manifest as painful, tender, fluctuant and erythematous nodules
Furuncles progress to Carbuncle which progress to Skin abscess if left untreated.
What is the clinical presentation of cellulitis vs Erysipelas?
Erysipelas: affects upper dermis; Fiery red, tender, painful plaque (raised above surrounding skin) with well‐demarcated edges. Common on face, also lower extremities.
Cellulitis: Involves deeper and subcutaneous fats. Usually presents as an acute, diffuse, spreading, non-elevated, poorly demarcated area of erythema. Relatively rapid onset/progression. Almost always unilateral. Fever in 20–70% of patients. It is typically found on the lower extremities, although it can appear on any area of the skin. Might be poorly demarcated due to it being deeper infection.
TLDR;
1) Erysipelas are well demarcated, Cellulitis is not
2) Cellulitis affects deeper layers (subQ) vs upper dermis for erysipela
What is the pathogen usually implicated in purulent SSTIs?
S. Aureus
What is the pathogen usually implicated in non-purulent SSTIs?
Group A Strep (S. Pyogenes)
When would multiple organisms most likely be isolated from a properly obtained wound culture?
1) Skin abscess involving the perioral, perirectal or vulvovaginal areas
2) DFI
3) Pressure ulcer
Water exposure increases risk of infection of which organisms?
Aeromonas (freshwater exposure), Vibrio vulnificus (seawater exposure), Pseudomonas (“hot tub cellulitis”)
What are the most likely pathogens in Impetigo?
Staphylococci or Streptococci
Bullous form caused by toxin-producing strains of S. Aureus
What is the common pathogen in Ecthyma?
Group A Strep
State the empiric treatment for mild Impetigo.
TOP Mupirocin BID for 5 days
State both empiric and culture directed treatment for Impetigo/ Ecthyma
Empiric:
PO Cephalexin or Cloxacillin
PO Clindamycin (penicillin allergy)
Culture directed (MSSA): Cloxacillin or Cephalexin
Culture directed (GAS): Pen V or Amoxicillin
Duration: 7 days
What is the gold standard for treatment of purulent SSTIs?
Incision and drainage
When will systemic antibiotics be used for purulent SSTIs? (6)
1) Unable to drain completely
2) Lack of response to I&D
3) Extensive disease involving several sites
4) Extremes of age (immunocompromised)
5) Immunosuppressed (e.g. chemotherapy, transplant)
6) 2 or more signs of systemic illness:
- HR> 90,
- temperature > 38deg or < 36deg,
- RR > 24,
- high or low WBC
Suggest empiric treatment for Purulent SSTIs based on severity with no risk of MDRO or anaerobe. State treatment duration as well.
Mild: Incision and Drainage
Moderate: I&D + PO Cloxacillin or PO Cephalexin (PO Clindamycin if penicillin allergy)
Severe: I&D + IV Cloxacillin or IV Cefazolin (IV Clinda if Penicillin allergy or IV Vancomycin as last line unless risk of HA-MRSA)
5-10 days
Suggest empiric regimen for treatment of purulent SSTI occuring near the mouth that is of moderate-severe severity but no risk of MRSA. State the bacteria required to be covered.
State treatment duration as well.
Amoxicillin-Clavulanate.
Cover for MSSA, gram neg and anaerobes
5-10 days
Suggest empiric regimen for H.Z, a female who has returned from the USA (after attending a concert) less than 1 week ago and presents today with a purulent SSTI of moderate severity. State pathogen to be covered. State treatment duration as well.
Empiric:
PO Clindamycin or
PO Co-trimoxazole or
PO Doxycycline
Pathogen: CA-MRSA
5-10 days
P.G was admitted into hospital 1 week ago. Today, nurse noticed that he developed a severe skin abscess at abdomen area. What should the empiric regimen for P.G? State pathogen to be covered. State treatment duration as well.
Vancomycin OR
Daptomycin OR
Linezolid
Pathogen: HA-MRSA
5-10 days
Suggest empiric regimens for treatment of (categories: mild/moderate/severe, MRSA risk) non-purulent cellulitis and erysipelas, pathogens to be covered as well as treatment duration.
Mild: no systemic signs of infx
- PO Pen V, Cephalexin or Cloxacillin (Clindamycin if penicillin allergy)
- Pathogen covered: Grp A Strep
Moderate: with systemic signs and some purulence
- Pathogen covered: GAS and MSSA
- PO Cephalexin or Cloxacillin
- if IV to be initiated: IV Cefazolin or Clindamycin (if penicillin allergy), IV Cloxacillin also can
Severe: systemic signs, fail oral tx or immunocompromised
- Cover broad spectrum including Pseudomonas
- Meropenem, Pip/Tazo or Cefepime (Cefepime only for more superficial infections; has no anaerobe cover)
- If MRSA risk:
add on IV Vanco/ Dapto/ Linezolid
Duration: 5-10 days, maybe 14 days for immunocompromised
What are some non-antibiotic (includes non-pharm) ways to manage Erysipelas/ Cellulitis?
1) Rest and limb elevation to allow for drainage of edema and inflammatory substances
2) Treat other underlying conditions (e.g tinea pedis, skin dryness, limb edema)
What is the criteria for DFI/ Infected Pressure ulcer?
Purulent discharge OR
at least 2 signs or symptoms of inflammation.
SnS (Erythema, warmth, tenderness, pain, induration)
induration = thickening & hardening of skin
What are the most common organisms found in DFI/Pressure ulcer?
Staphylococcus aureus and Streptococcus spp.
What are the organisms that may be found in DFI/Pressure ulcer
Gram +ve: S. Aureus and Streptococcus
Gram -ve (chronic wound or previously treated with antibiotics):
1) Enteric gram negs (E. coli, Proteus, Klebsiella)
2) Pseudomonas less common
Anaerobes (Ischemic or necrotic wounds):
- Peptostreptococcus spp., Veillonella spp., Bacteriodes spp.
State the pathogens to be covered in a patient with DFI/Pressure ulcer that extends to Subcutaneous tissue, with erythema ≤ 2cm with no sign of systemic infection
S. Aureus (usually MSSA unless MRSA risk factor present) and Streptococcus
State the pathogens to be covered in a patient with DFI/Pressure ulcer that extends to the bones/joints, with erythema > 2cm with no sign of systemic infection
S. Aureus, Streptococcus, Enteric gram neg (E.coli, Klebsiella, Proteus) + anaerobes +- Pseudomonas
State the pathogens to be covered in a patient with DFI/Pressure ulcer that extends to bone/joints, with erythema > 2cm with signs of systemic infection
S. Aureus, Streptococcus, Enteric gram neg (E.coli, Klebsiella, Proteus) + anaerobes + Pseudomonas
State empiric regimens for DFI/Pressure ulcers according to severity (assume no risk of MRSA)
Mild:
PO Cephalexin or Cloxacillin (Clindamycin if Pen allergy)
Moderate (start IV):
1) Augmentin
2) Cefazolin/ Ceftriaxone + Metronidazole
Severe:
1) Pip/Tazo
2) Meropenem
3) Cefepime + Metronidazole
4) Ciprofloxacin + Clindamycin
When should Pseudomonas be empirically covered for DFI/Pressure ulcer?
1) Severe DFI/PU
2) Failure of antibiotics not active against Pseudomonas
Describe the various severity of DFIs
Mild: Infection of skin/SQ tissue with erythema ≤ 2cm and no sign of systemic infection
Moderate: Infection of deeper tissue (e.g bone/joint) with erythema > 2cm and no sign of systemic infection
Severe: Infection of deeper tissue (e.g bone/joint) with erythema > 2cm and with signs of systemic infection
When are microbiological cultures indicated for DFI?
Moderate to severe DFI
State the rough durations for treatment of DFI/pressure ulcer with bone involvement
(All infected bone + tissue removed) = 2-5 days
(Leftover infected tissue) = 1-3 weeks
(Residual viable bone) = 4-6 week
(No surgery or residual dead bone) = at least 3 months
State the rough durations for treatment of DFI/pressure ulcer without bone involvement
Mild: 1-2 weeks
Moderate: 1-3 weeks
Severe: 2-4 weeks
What are risk factors for Pressure ulcers? (6)
1) Reduced mobility (E.g. spinal cord injuries, paraplegic)
2) Debilitated by severe chronic diseases
(E.g. multiple sclerosis, stroke, cancer)
3) Reduced consciousness
4) Sensory and autonomic impairment
(e.g Incontinence -> wet bed = wet skin -> destruction of skin
5) Extremes of age
6) Malnutrition
Which SSTI(s) usually affects the epidermis?
Impetigo
Which SSTI(s) usually affects the dermis?
Erysipela, Ecthyma
Which SSTI(s) usually affects the hair follicles?
Carbuncle, Furuncle
Which SSTI(s) usually affects the subcutaneous fat?
Cellulitis
Describe each severity category (Mild/ moderate/ severe) of non-purulent SSTI and state pathogen to be covered.
Mild (without systemic signs of infection), mainly only cover Strep pyogenes.
Moderate (with systemic signs of infection, some purulence), to include MSSA cover
Severe (with systemic signs of infection, failed oral therapy or immunocompromised), to include broader coverage (Psedomonas) and explore possibility of necrotizing infections (anaerobes)
What should you monitor for SSTIs?
1) Clinical response
- Improvement of symptoms within 2-3 days of effective antibiotic initiation.
- If no improvement reassess indication and/or choice of antibiotic
- No lesion progression or complication development
- If patient feel better, consider switching to oral
2) Antibiotic ADR
3) Repeat microbiological testing not necessary (based on resolution of symptoms)
