Management of SSTI Flashcards
what are some protecting factors of the skin? and what is the function of these protecting factors
- dry surface
- fatty acids
- acidic pH (around 5.6)
- renewal of the epidermis
- low temperature (compared to body core temp)
- these factors inhibit excess microbial growth and entry into deeper layers
what are some predisposing factors for SSTI
- high bacterial innocula (cut with dirty knife)
- excessive moisture
- reduced blood supply (reduced WBC to that area to fight infection)
- presence of bacterial nutrients (glucose in urine)
- poor hygiene
- sharing of personal items
characteristics of impetigo and ecthyma?
uncomplicated, managed as outpatient
- superficial infection
- Impetigo: non-bullous vs bullous (pus); impetigo common in children, on face or extremities
- ecthyma: superficial, but deeper than impetigo, scarring is common
what are the causative organisms for impetigo & ecthyma?
S.aureus, B-hemolytic Streptococci (S.pyogenes)
(bullous form (pus) due to toxin-producing S.aureus strains
do we need to culture for impetigo & ecthyma?
its optional as empiric therapy covers for s.aureus and b-hemolytic strep alr
do we need to be concern and treat CA-MRSA?
Nope as prevalence is low
Treatment for mild impetigo
topical: Mupirocin BD for 5 days
Treatment for severe cases of impetigo and all cases of ecthyma
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
difference between furuncles (boils) and carbuncles
furuncles: infection of a hair follicle
carbuncles: involve few adjacent follicles, forms small abscess
what are considered purulent SSTIs?
furuncles, carbuncles, cutaneous abscesses
risk factors of purulent SSTIs?
- close physical contact
- crowded living quarters
- sharing personal items
- poor personal hygiene
the causative organism for purulent SSTIs
S.aureus; polymicrobial for large skin abscesses
do we need to culture for purulent SSTIs
not needed, but reasonable to culture pus
treatment of purulent SSTIs
1st: InD
Adjunctive systemic Abx when:
- lack of response to InD (still red and swell)
- unable to completely drain completely
- extensive disease involving several sites
- extremes of age (young and old)
- immunosuppressed (chemo, organ transplant)
- 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
what are the adjunctive systemic abx for purulent abx
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
What are the clinical manifestations (how does it look like) for cellulitis?
- Acute inflammation of epidermis, dermis, and sometimes superficial fascia
- Bacteria can invade lymphatic tissue and blood
- Purulent/ non-purulent
What are the clinical manifestations (how does it look like) for Erysipelas?
- Affects up to superficial dermis and lymphatic tissue
- non-purulent
What to take note with purulent cellulitis and purulent SSTIs?
Purulent cellulitis not = to
Furuncles, Carbuncles, Cutaneous abscesses
What is the visual difference btw Celluitis and Erysipelas?
Cellulitis: poorly demarcated area of erythema, purulent/non-purulent
Erysipelas: SHARPLY demarcated area of erythema with raised border
What are some complications of Cellulitis and Erysipelas?
- Bacteremia
- Endocarditis
- Toxic shock
- Glomerulonephritis
- Lymphedema
- Osteomyelitis
- Necrotising soft-tissue infections (necrotising fasciitis)
What are the causative organisms for C and E?
Staph Aureus (>> purulent infections) b-haemolytic Strep (Strep pyogenes) (almost always the cause of erysipelas)
For comorbidity of immunosuppresion, what is the pt at risk for additional causative organisms?
Strep pneumoniae, E. coli, Serratia marcescens, P. aeruginosa (more Gram -ve)
For comorbidity of Chronic liver/renal disease, what is the pt at risk for additional causative organisms?
Vibrio spp, E.coli, P. aeruginosa (more -ve as well)
When to consider cultures in situations for C & E?
- purulent infections after I&D
- Immunosuppressed (chemo, transplant), signs of severe systemic illness (SIRS criteria)
What types of cultures can you collect?
- Cutaneous aspirates
- Tissue samples (biopsies)
- Blood
- Swabs
What is considered a mild non-purulent infection for C&E?
What is the organism to cover?
no signs of systemic infection (no SIRS)
Strep spp (+ve)
What is considered a moderate non-purulent infection for C&E?
What are the organisms to cover?
1 or more SIRS criteria
Strep spp +/- S.aureus (+ve gram)
What is considered a severe non-purulent infection for C&E?
What are the organisms to cover?
> 2 SIRS criteria (3 and above) + hypotension, rapid progression, immunosuppressed, comorbidities
Strep spp and S.aureus and Gram -ve (Incl P. aeruginosa)
What are the ABx used for mild non-purulent C&E?
PO Abx
“Penicillin VK” (most narrowest against streptococcus)
Cloxacillin / Cephalexin (covers MSSA, a bit broader thus not recommended)
Clindamycin (for penicilin allergy)
What are the ABx used for moderate non-purulent C&E?
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)