Antibiotics guidelines for skin and soft-tissue infections (SSTIs)

Cellulitis is an acute spreading infection that involves subcutaneous tissue; most commonly caused by Group A Streptococcus and Staphylococcus aureus. Trauma, underlying skin lesions and spread from adjacent infections such as osteomyelitis can lead to the development of cellulitis. Clinically rapidly intensifying pain and redness is a common presentation. Fever and lymphadenopathy may be present. The borders in cellulitis are not well demarcated. Rarely organisms like H. influenza and Pneumococcus may also cause cellulitis.

Table: Antibiotics guidelines for skin and soft-tissue infections (SSTIs)
Condition Organism Antibiotic Duration Comments

Cellulitis

S.pyogenes S.aureus

Cefazolin
Or cephalexin Or
Amoxicillin-clavulanate
+/- Clindamycin

5-7 days (longer if clinically indicated)

-Obtain blood/ pus cultures before starting antibiotics
-Consider poly-microbial pathogens in diabetics
-Consider risk factors for MRSA and presence of TSS before using clindamycin

Necrotizing fasciitis

S. pyogenes
S.aureus, anaerobes, Gram negative organisms (polymicrobial)

 Piperacillin-tazobactam +
Clindamycin

Generally, 14 days if adequate source control achieved

Early surgical debridement essential
Send blood and intraoperative specimens for bacterial cultures.
Consider use of IVIG for streptococcal NF/TSS 

Necrotizing fasciitis

Aeromonas/
V.vulnificus
(suspect when history of exposure to  fresh water or salt water respectively)

Ciprofoxacin +
Doxycycline

Generally, 14 days if adequate source control achieved

 

Erysipelas

Propionibacterium acnes/MSSA

Amoxicillin-clavulanate

5-7 days

 

Abscess

S. pyogenes,
Oral anaerobes

Clindamycin OR
Ampicillin-sulbactum ORAmoxicillin-clavulanate

5-7 days

 

S.aureus,
facultative gram
negative anaerobes

Linezolid OR Vancomycin PLUS Ciprofloxacin

Generally, 14 days