4.10 - Skin and Soft Tissue Infection

Ref: Stevens et al. Clin Infect Dis 2014; 59 (2): e10

Mild: Localized infection.
Moderate: Extensive generalized disease / infection / lesions OR evidence of systemic infection.
Severe: Evidence of severe sepsis or septic shock OR immunocompromised. 

Oral antibiotics can be used for mild and moderate infection.
Systemic (IV) antibiotics are indicated for severe infection, outbreaks of poststreptococcal glomerulonephritis.
Consider IV antibiotic if there is multiple abscesses or extremes of age or lack of response to incision and drainage alone.

A) Adults

Disease / Etiology

Preferred

Alternative

Comments

Purulent SSTI

Impetigo

 
Staphylococcus

Streptococcus pyogens

Localized 


Generalized Impetigo or Ecthyma

 




Topical Mupirocin q12H 5 - 7 days

Cloxacillin 500 mg PO q6H





Topical Fusidic Acid 2% q8 - 12H 5 - 7 days 

Cephalexin 500 mg PO q6H

OR

Co-amoxiclav 625 mg PO q8H
Duration 5 - 7 days


Incision and drainage indicated.
Send pus / exudate for C&S.
De-escalate once C&S result is available.




If penicillin allergic:
Erythromycin Ethylsuccinate 400 mg PO q6H

* if MRSA suspected, 
Clindamycin 300 mg PO q6H
Co-trimoxazole 480 mg 2 - 4 tablets q12H

Abscess, Carbuncles & Furuncles
Monomicrobial

 
Staphylococcus aureus
Streptococcus pyogens

Polymicrobial (regional skin flora)

Mild

 





Cloxacillin 500 mg PO q6H



 



Cephalexin 500 mg PO q6H
 
Incision and drainage indicated.
De-escalate once C&S result is available.
Duration 5 - 10 days depending on clinical improvement.













*** Risk for ESBL or failed Piperacillin / Tazobactam
 
** If MRSA is suspected, 
Vancomycin 15 - 20 mg/kg IV q8 - 12H 
 
Moderate
 
Co-amoxiclav 1.2 gm IV q8H


Cefazolin 1 gm IV q8H

±

Metronidazole 500 mg IV q8H

 
Severe
 
Piperacillin / Tazobactam 4.5 gm IV q6H


Imipenem 500 mg IV q6H***

OR

Meropenem 1 gm IV q8H***

Non Purulent SSTI

Erysipelas

 
Group A Streptococcus

Localized 







Systemic

 


Phenoxymethylpenicillin 500 mg PO q6H

OR

Amoxicillin 500 mg PO q8H


Cloxacillin 2 gm IV q6H



Cephalexin 500 mg PO q6H







Cefazolin 1 gm IV q8H


Duration: Continue for 5 days upon improvement

If documented past history of IgE medicated allergic reaction to beta lactam,

Erythromycin Ethylsuccinate 400 mg PO q6H

Clindamycin 600 mg PO q8H

Cellulitis

 
Group A Streptococcus
Staph aureus

Mild

Moderate

Severe







*If MRSA SSTI suspected in severe infection


**If CA MRSA suspected

 



Amoxicillin 500 mg PO q8H

Cloxacillin 2 gm IV q4 - 6H

Piperacillin / Tazobactam 4.5 gm IV q6H






Vancomycin 25 - 30 mg/kg  (max 2gm) IV loading dose, followed by 15 - 20 mg/kg IV q8 - 12H

Clindamycin 300 mg PO q6 - 8H





Cephalexin 500 mg PO q6H

Cefazolin 1 gm IV q8H

Imipenem 500 mg IV q6H***

OR


Meropenem 1 gm IV q8H***


Refer to ID if allergy to vancomycin


Doxycycline 100 mg PO q12H

OR

Co-trimoxazole 480 mg 2 - 4 tablets PO q12H

 
Duration: 5 - 10 days (depending on clinical response)

Blood C&S if moderate to severe infection.
De-escalate once C&S result is available.










To cover for MRSA if:
  • Had previous MRSA infection / colonization
  • Illicit drug user
  • Athlete
  • MSM
  • Penetration injury
  • Severe sepsis / shock
  • Failed initial antibiotic / impaired host defences
Optimise Vancomycin dose by doing therapeutic drug monitoring.

Note: Doxycycline and Bactrim do not cover streptococci.

Diabetic Foot Infection

 
Limited, mild to moderate infection, no osteomyelitis
Staph aureus
Streps
Anaerobes

 
Co-amoxiclav 625 mg PO q8H
or Co-amoxiclav 1.2 gm IV q8H

OR

Ampicillin / Sulbactam 375 mg PO q12H
or Ampicillin / Sulbactam 1.5 gm IV q8H

 
Cephalexin 500 mg PO q8H

+
  
Metronidazole 400 mg PO q8H
 
Duration: 5 - 7 days
 
Severe sepsis with septic shock, limb threatening

Piperacillin / Tazobactam 4.5 gm IV q6H
  
+

Clindamycin 600 mg - 900 mg IV q8H
 
Imipenem 500 mg IV q6H

+

Clindamycin 600 mg - 900 mg IV q8H
 
Duration: 7 - 14 days (subjected to clinical assessment)

With toxin production: Clindamycin 7 days

Surgical debridement URGENT.
Based on intraoperative culture and sensitivity, antibiotic should be streamlined.

 
Chronic, recurrent diabetic foot ulcer, no evidence of infection

 
No antibiotic, daily dressing
   

Necrotising Fasciitis

 
Monomicrobial
S pyogenes
S aureus
Clostridium spp


Polymicrobial
In diabetes / perianal abscess, post op wound infection (esp. abdominal wound)

 
Piperacillin / Tazobactam 4.5 gm IV q6H
  
+
  
Clindamycin 600 mg - 900 mg IV q8H

 
Imipenem 500 mg IV q6H

+

Clindamycin 600 mg - 900 mg IV q8H

 
Duration: 7 - 14 days (subjected to clinical assessment)

With toxin production: Clindamycin 7 days

Surgical debridement URGENT. 
Based on intraoperative culture and sensitivity, antibiotic should be streamlined.

Add Vancomycin if MRSA suspected.
 

Animal / Human Bites

 
Purulent:
Polymicrobial, mixed aerobes and anaerobes

Non Purulent Wounds:
Staphylococci
Streptococci

































Severe Sepsis
 
Co-amoxiclav 625 mg PO q8H
or Co-amoxiclav 1.2 gm IV q8H

OR

Ampicillin / Sulbactam 375 mg PO q12H
or Ampicillin / Sulbactam 3 gm IV q8H




























Piperacillin / Tazobactam 4.5 gm IV q6H

 
Cefuroxime 500 mg PO q12H
or Cefuroxime 750 mg IV q8H
+
Metronidazole 500 mg IV q8H
or Metronidazole 400 mg PO q8H

OR

Clindamycin 300 mg PO q8H
or Clindamycin 600 mg IV q6 - 8H
+
Doxycyline 100 mg PO q12H

OR

Co-trimoxazole (Trimethoprim component) 5 - 10 mg/kg/day in divided dose
or Co-trimoxazole (480 mg) 2 tablets PO q12H
+
Metronidazole 500 mg IV q8H
or Metronidazole 400 mg PO q8H
or Clindamycin 300 mg PO q8H
or Clindamycin 600 mg IV q6 - 8H


Imipenem 500 mg IV q6H


 
Post exposure prophylaxis antibiotics may be given for a 3- to 5-day course. 
If the wound is infected on presentation, a course of 10 days or longer is recommended.

For cat / dogs bites, Clindamycin has no Pasturella multocida cover.
Consider adding rabies vaccine if fulfill criteria.


 

For monkey bites, commonly
Herpes simiae
Herpes B
Monkey B virus
Herpesvirus B 



 
As above

+

Post-exposure prophylaxis Valacyclovir 1 gm PO q8H or Acyclovir 800 mg PO 5x/day should be given for 14 days

 


Surgical Site Infections

 
No systemic symptoms:
WBC not raised
Erythema < 5 cm around incision
Induration / necrosis

Systemic symptoms:
WBC raised
Erythema > 5 cm around incision
Induration / necrosis

Mild to Moderate

 
No antibiotics
Change dressing








Clean wound, trunk, head, neck, extremities:
Cephalexin 500 mg PO q6H

Wound of perineum, GIT, female genital tract:
Co-amoxiclav 625 mg PO q8H


 












Cefazolin 1 gm IV q8H



Cefuroxime 1.5 gm IV q8H
+
Metronidazole 500 mg IV q8H

 

 








If MRSA is suspected, add Vancomycin 25 - 30 mg/kg (max 2 gm) IV loading dose, then 15 - 20 mg/kg q8 - 12H.
 
Severe

 
Piperacillin / Tazobactam 4.5 gm IV q6H

 
Imipenem 500 mg IV q6H


B) Paediatrics

Disease / Etiology

Preferred

Alternative

Comments

Cellulitis

 
Furuncle / Carbuncle / Abscess formation
Staph aureus
 
Mild:
Cloxacillin 15 mg/kg PO q6H

Moderate to severe :
Cloxacillin 15 - 50 mg/kg IV q6H
±
Benzylpenicillin 50,000 units/kg IV q6H

 
Co-amoxiclav 15 - 25 mg/kg (as Amoxicillin) PO q12H
  
OR
  
Cephalexin 12.5 mg/kg q6H (Non MRSA and Strep)
 
Source control is important (whenever possible).

If patient receives adequate source control, antibiotic may not be needed.
Avoid topical antibiotics.

Impetigo

 
Non-Bullous Impetigo:
Streptococcus
GAS


Topical Mupirocin 2% q8H or Fucidin for 10 - 12 days
   
Consider Mupirocin to eliminate nasal carriage.
 
Bullous impetigo:
Staph aureus (MSSA/MRSA): non-exfoliative toxin producers

 
Cloxacillin 15 mg/kg PO q6H

OR

Cephalexin 12.5 mg/kg q6H

 
MSSA: Mupirocin / Fucidin ointment
 
Increasing reports of resistance to topical Fucidin.
 
Erysipelas:
Streptococcus sp (Groups A,B,C,G)
MSSA
MRSA (rare)
 
Co-amoxiclav 15 - 25 mg/kg (Amoxicillin component) PO q12H

Azithromycin 15 mg/kg PO q24H for 3 days

Mild cases:
Penicillin V 10 - 15 mg/kg PO q6H

 
Benzylpenicillin 25,000 units/kg/dose IV q6H
  
OR

Vancomycin 15 mg/kg q8H (allergic to penicillin)

OR

Linezolid (MRSA) 10 mg/kg (max 600 mg) q8H

 
Duration of treatment: 10 days

Necrotising Fasciitis

 
S pyogenes
MRSA
Pseudomonas




Polymicrobial:
Clostridium perfringens
Bacteroides fragilis
 
Piperacillin / Tazobactam 100 mg/kg (Piperacillin component) IV q6 - 8H 
+
Clindamycin 6 - 10 mg/kg (max 1.2 gm) IV q6H

Benzylpenicillin 50,000 units/kg IV q4 - 6H
+
Clindamycin 10 mg/kg (max 1.2 gm) IV q6H

 
If allergic to penicillin, call ID team.

Vancomycin or Linezolid in cases where MRSA is highly likely or isolated from wound.
 
NF in children often without a precipitating cause; can follow blunt trauma. Can present with streptococcal toxic shock syndrome.

Pseudomonas infection often follows burn or trauma. When a precipitating cause is identified, Varicella infection can precede NF by 3 - 4 days.

Consider urgent surgical debridement.