Skin and Soft-Tissue Infections

Bite wound 

High risk bite wounds for which antibiotic prophylaxis recommended:  

Moderate or severe bite wounds, especially if edema or crush injury 

Puncture wounds, especially if penetration of bone, tendon sheath, or joint 

Deep or surgically closed facial bite wounds 

Hand or foot bite wounds 

Genital area bite wounds 

Wounds in immunocompromised and/or asplenic people 

Cat bite wounds 

Pasteurella multocida (animal) 

Eikenella corrodens (human) 

Staphylococcus spp 

Streptococcus spp 

Oral anaerobes 

Oral (prophylaxis or treatment): 

Amoxicillin-clavulanate (Augmentin)
22.5 mg amoxicillin/kg/dose (max 875 mg amoxicillin/dose) enterally bid  

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IV (if needed for established infection): 

Ampicillin-sulbactam (Unasyn)
50 mg ampicillin/kg/dose (max 2000 mg ampicillin/dose) IV q6h  

Penicillin or cephalosporin allergy with higher risk for allergic reaction: 

Trimethoprim-sulfamethoxazole (Bactrim/Septra)
5 mg trimethoprim/kg/ dose  (max 160 mg trimethoprim/dose) enterally bid  

AND 

Clindamycin
10 mg/kg/dose (max 600 mg/dose) enterally tid  

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IV (if needed for established infection): 

Consult ID/ASP 

Duration: 

3-5 days for prophylaxis of high risk bite wounds (see 1st column) 

7-10 days for treatment of established infection, guided by severity and clinical course 

Also consider need for Tetanus and/or Rabies prophylaxis 

Necrotizing fasciitis or other necrotizing soft tissue infection 

Diagnosis is supported by signs of systemic toxicity with toxic-shock-like symptoms, severe pain or pain out of proportion to physical findings, altered mental status, rapidly advancing infection, crepitus, hemorrhage, sloughing.

Intraoperative findings include  presence of grayish fascia, lack of resistance of normally adherent muscular fascia to blunt dissection, lack of bleeding of the fascia during dissection and presence of foul-smelling "dishwater" pus

Group A streptococcus 

Can be polymicrobial including anaerobes, Clostridium spp, with skin flora 

Vancomycin  
(follow link for dosing & monitoring) 

AND  

Piperacillin-tazobactam
100 mg piperacillin/kg/dose (max 4000 mg piperacillin/dose) IV q6h  

AND 

Clindamycin
10 mg/kg/dose (max 900 mg/dose) IV q8h  

Penicillin or cephalosporin allergy with higher risk for allergic reaction: 

Consult ID/ASP for guidance on alternative therapy 

Urgent Surgery consult recommended 

ID consult recommended 

Therapy should be modified as indicated based on isolated pathogen(s), including narrowing the initial regimen to target identified pathogen(s) and stopping clindamycin after initial clinical improvement.  

Duration: 7-14 days, guided by response to therapy. Continue until further debridement is not necessary, patient has clinically improved, and is afebrile for 48-72 hours 

Group A streptococcus 

Staphylococcus aureus  

Outpatient: 

Cephalexin
25 mg/kg/dose (max 500 mg/dose) enterally tid  

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Inpatient/need for IV therapy: 

Cefazolin
25 mg/kg/dose (max 2000 mg/dose) IV q8h  

Penicillin or cephalosporin allergy with higher risk for allergic reaction: 

Clindamycin
10 mg/kg/dose (max 900 mg/dose) IV q8h  

OR  

Clindamycin
10 mg/kg/dose (max 600 mg/dose) enterally tid 

Duration: 5 days for non-severe infection 

ID consult recommended for severe infection, indicated by hemodynamic instability, end-organ dysfunction, or extensive local progression  

Staphylococcus aureus 

Other pathogens depending on specific exposures/risk factors 

Incision and drainage (I&D) is recommended for source control, though previous recommendations suggested I&D alone as an option for small abscesses without surrounding cellulitis, more recent studies have shown faster resolution when antibiotic therapy is given following I&D   

Outpatient/non-severe infection: 

Cephalexin  
25 mg/kg/dose (max 500 mg/dose) enterally tid  

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Inpatient/need for IV therapy: 

Cefazolin
25 mg/kg/dose (max 2000 mg/dose) IV q8h  

Severe infection (hemodynamic instability, end-organ dysfunction, or extensive local progression): 

ID consult  

Penicillin or cephalosporin allergy with higher risk for allergic reaction 

OR 

History of documented MRSA infection or carriage within the last 6 months 

OR 

MRSA identified and susceptible to trimethoprim- sulfamethoxazole 

AND 

Age >=1 month:  

Trimethoprim-sulfamethoxazole (Bactrim)
5 mg trimethoprim/kg/dose (max 160 mg trimethoprim/dose) enterally bid 

Severe infection (hemodynamic instability, end-organ dysfunction, or extensive local progression): 

ID consult 

With abscess I&D, send routine bacterial culture, follow-up result and modify therapy as indicated 

Duration: 5 days following source control for non-severe infection 

Dog/cat:
Streptococci
Pasteurella spp.
Staphylococci
Oral anaerobes

Human:
Viridans streptococci
Eikenella spp.
Oral anaerobes

Only 5% of dog bites become infected, whereas 30-50% of cat bites become infected.

Evaluate tetanus vaccine history and administer if indicated.

Consult with local health department about rabies vaccination if rabies status unknown.

Prophylaxis in high risk patients or in high risk bite:
High risk patient = post splenectomy, immunocompromised, advanced liver disease/EtOH use disorder
High risk bite = deep tissue involvement (bone, tendon, joint etc.), penetrating injury (including most cat bites), bites on the hand, foot, genital or face

Prophylaxis: 5 days

Treatment: 10 days