What alternative antibiotic can be used for skin and soft tissue infection coverage in a patient with a penicillin allergy if vancomycin is being considered?

From the Guidelines

For patients with penicillin allergies who require alternative antibiotics for skin and soft tissue infection coverage, clindamycin is a suitable option, as evidenced by recent guidelines 1. When considering vancomycin for skin infections but needing an alternative due to penicillin allergy, it's crucial to select an antibiotic based on the likely causative pathogens, clinical severity of the infection, and patient-related factors such as drug allergies and comorbidities. Key considerations for choosing an alternative antibiotic include:

• The likely or proven causative pathogen(s) and their antibiotic susceptibilities
• Availability of the antibiotic
• Published evidence of efficacy for skin and soft tissue infections
• Clinical severity of the infection
• Patient-related factors, including history of drug allergies and comorbidities Given these considerations, clindamycin emerges as a viable alternative, effective against gram-positive pathogens including Staphylococcus aureus and Streptococcus species, at a dosage of 300-450 mg orally every 6-8 hours for 5-10 days, depending on infection severity 1. Other alternatives, such as doxycycline or minocycline, can be considered for MRSA coverage, while linezolid provides excellent gram-positive coverage but is more expensive and has potential side effects with prolonged use 1. Ultimately, the choice among these alternatives should be guided by the principles of antibiotic stewardship, including infection source control, empiric treatment with the narrowest spectrum, shortest duration, fewest adverse effects, safest, and least expensive route, and switching to targeted therapy based on cultured pathogens 1.

From the FDA Drug Label

The cure rates in microbiologically evaluable patients with MRSA skin and skin structure infection were 26/33 (79%) for linezolid-treated patients and 24/33 (73%) for vancomycin-treated patients The cure rates by pathogen for microbiologically evaluable patients are presented in Table 18. Pathogen Cured ZYVOX n/N (%) Oxacillin/Dicloxacillin n/N (%) Staphylococcus aureus 73/83 (88) 72/84 (86) Methicillin-resistant S aureus 2/3 (67) 0/0 (-)

For a patient with a penicillin allergy, linezolid can be used as an alternative antibiotic for skin and soft tissue infection coverage.

• Key points:
  • Linezolid has been shown to be effective against MRSA skin and skin structure infections.
  • The cure rates for linezolid-treated patients with MRSA skin and skin structure infections were 79%.
  • Linezolid can be used as an alternative to vancomycin in patients with penicillin allergy. 2

From the Research

Alternative Antibiotics for Skin and Soft Tissue Infections

In patients with a penicillin allergy, alternative antibiotics can be used for skin and soft tissue infection coverage.

• For less serious methicillin-susceptible S. aureus (MSSA) infections, first generation cephalosporins (e.g., cefazolin, cephalothin, and cephalexin), clindamycin, lincomycin, and erythromycin can be used, although cephalosporins are contra-indicated in patients with immediate penicillin hypersensitivity 3.
• For less serious non-multiresistant MRSA (nmMRSA) infections, lincosamides (e.g., clindamycin, lincomycin) or cotrimoxazole can be used 3.
• Other options for MRSA skin and soft tissue infections include linezolid, TMP-SMX, doxycycline, and minocycline, which have shown high clinical cure rates in in-vivo studies 4.

Considerations for Patients with Penicillin Allergy

When considering alternative antibiotics for patients with a penicillin allergy, it is essential to evaluate the patient's allergy history and determine the risk of an allergic reaction.

• Patients with low-risk allergy histories may be able to tolerate direct amoxicillin challenge, while those with moderate-risk histories may require penicillin skin testing 5.
• Clinicians should be familiar with which antibiotics are safe to use for different types of penicillin-allergic reactions and consider antimicrobial therapy with an antibiotic that does not cross-react with penicillins or beta-lactams 6.

Antibiotic Selection

The selection of an alternative antibiotic should be based on local antibiotic resistance patterns, the type of infection, potential adverse effects, and cost.

• Linezolid, TMP-SMX, and the tetracyclines (e.g., doxycycline and minocycline) are effective against MRSA, but have different adverse effect profiles and costs 4.
• Quinolones have bactericidal activity, but may have a higher risk of resistance and adverse effects 4.