What antibiotics are recommended for the treatment of cellulitis in a hospital setting?

From the Guidelines

For cellulitis treatment as a hospitalist, I recommend empiric therapy with cefazolin 1-2g IV every 8 hours for methicillin-susceptible Staphylococcus aureus (MSSA) and streptococcal coverage, as supported by the Infectious Diseases Society of America guidelines 1.

Key Considerations

• For patients with suspected methicillin-resistant Staphylococcus aureus (MRSA), use vancomycin 15-20 mg/kg IV every 8-12 hours (with appropriate monitoring of trough levels) or daptomycin 4-6 mg/kg IV daily, as recommended by the guidelines 1.
• For patients with beta-lactam allergies, consider clindamycin 600-900 mg IV every 8 hours, as an alternative option 1.
• Treatment duration typically ranges from 5-14 days, depending on clinical response, with the goal of minimizing morbidity, mortality, and improving quality of life.

Additional Recommendations

• Transition to oral therapy (such as cephalexin 500 mg four times daily, dicloxacillin 500 mg four times daily, or clindamycin 300-450 mg four times daily) when the patient shows clinical improvement with decreased erythema, edema, and fever resolution.
• Elevate the affected limb to reduce edema, ensure adequate pain control, and mark the borders of erythema to monitor progression.
• Obtain blood cultures for patients with systemic symptoms, immunocompromise, or severe infection, to guide antibiotic therapy and minimize the risk of complications.

Patient-Specific Factors

• The choice of antibiotics should target the most common causative organisms—beta-hemolytic streptococci and Staphylococcus aureus—while considering local resistance patterns and patient-specific factors such as allergies, renal function, and risk factors for resistant organisms 1.

From the FDA Drug Label

The cure rates in clinically evaluable patients were 90% in linezolid-treated patients and 85% in oxacillin-treated patients The cure rates by pathogen for microbiologically evaluable patients are presented in Table 18. Table 18 Cure Rates at the Test-of-Cure Visit for Microbiologically Evaluable Adult Patients with Complicated Skin and Skin Structure Infections PathogenCured ZYVOXn/N (%)Oxacillin/Dicloxacillinn/N (%) Staphylococcus aureus73/83 (88)72/84 (86) Methicillin-resistant S aureus2/3 (67)0/0 (-) Streptococcus agalactiae6/6 (100)3/6 (50) Streptococcus pyogenes18/26 (69)21/28 (75)

The answer to the question of antibiotics for cellulitis as a hospitalist is that linezolid can be used to treat complicated skin and skin structure infections, including those caused by Staphylococcus aureus and Streptococcus species. The cure rates for linezolid-treated patients were 90% in clinically evaluable patients, with cure rates by pathogen ranging from 67% for methicillin-resistant S aureus to 100% for Streptococcus agalactiae. 2

From the Research

Antibiotic Treatment for Cellulitis

• The treatment of cellulitis typically involves the use of antibiotics, with the choice of antibiotic depending on the suspected causative organism and the severity of the infection 3.
• Gram-positive bacteria, such as Staphylococcus aureus and Streptococcus pyogenes, are the most common causes of cellulitis, and beta-lactam antibiotics, such as cephalexin and cefazolin, are commonly used to treat these infections 3, 4.
• The duration of antibiotic treatment for cellulitis can vary depending on the severity of the infection and the presence of underlying medical conditions, such as diabetes mellitus or bloodstream infection 5.
• Studies have shown that the use of intravenous antibiotics, such as cefazolin, can be effective in treating cellulitis, with a median duration of treatment of 8 days 5, 6.
• Once-daily or twice-daily administration of intravenous antibiotics, such as cefazolin, can be effective in treating uncomplicated cellulitis, with no significant difference in outcomes between the two regimens 6.
• The use of ceftriaxone versus cefazolin for the treatment of methicillin-susceptible Staphylococcus aureus bacteremia has been studied, with no significant difference in clinical cure rates or safety events between the two groups 7.
• The choice of empiric antibiotic therapy for cellulitis should take into account the likelihood of infection with methicillin-resistant Staphylococcus aureus (MRSA), with cephalexin being a cost-effective option at current estimated MRSA levels 4.

Factors Affecting Treatment Duration

• Patient age, C-reactive protein levels, and the presence of underlying medical conditions, such as diabetes mellitus or bloodstream infection, can affect the duration of antibiotic treatment for cellulitis 5.
• The use of intravenous antibiotics, such as cefazolin, can be effective in treating cellulitis, with a median duration of treatment of 8 days 5.
• The presence of bloodstream infection or diabetes mellitus can increase the duration of treatment with intravenous antibiotics 5.

Antibiotic Options

• Cephalexin, cefazolin, and clindamycin are commonly used antibiotics for the treatment of cellulitis 3, 5, 4.
• Ceftriaxone has been studied as an alternative to cefazolin for the treatment of methicillin-susceptible Staphylococcus aureus bacteremia, with no significant difference in clinical cure rates or safety events between the two groups 7.
• Trimethoprim/sulfamethoxazole (TMP/SMX) is unlikely to be cost-effective for the treatment of simple cellulitis, except at very high likelihoods of MRSA infection 4.