Will cephalexin (Cephalexin) treat a 4+ Staphylococcus aureus skin infection?

From the Guidelines

Cephalexin can effectively treat a 4+ Staphylococcus aureus skin infection, particularly if the strain is methicillin-sensitive (MSSA). The typical adult dosage is 500 mg orally four times daily for 7-14 days, depending on infection severity. For children, the dosage is 25-50 mg/kg/day divided into four doses. Complete the full course of antibiotics even if symptoms improve before finishing. Cephalexin works by inhibiting bacterial cell wall synthesis, causing bacterial cell death. However, if the infection is caused by methicillin-resistant S. aureus (MRSA), cephalexin will not be effective, and alternative antibiotics like trimethoprim-sulfamethoxazole, doxycycline, or clindamycin would be needed, as suggested by the 2018 WSES/SIS-E consensus conference 1. Additionally, proper wound care including keeping the area clean and dry is essential for healing. If the infection worsens despite treatment, shows signs of spreading, or if you develop fever or other systemic symptoms, seek immediate medical attention as this could indicate treatment failure or a need for intravenous antibiotics. It's also important to note that the Infectious Diseases Society of America recommends considering the use of antibiotics active against MRSA, such as vancomycin, linezolid, or daptomycin, in patients with severe infections or those who have failed initial antibiotic treatment 1.

Some key points to consider when treating a 4+ Staphylococcus aureus skin infection include:

• The importance of determining the susceptibility of the S. aureus strain to guide antibiotic therapy 1
• The need for proper wound care, including keeping the area clean and dry, to promote healing
• The potential for treatment failure or the need for intravenous antibiotics if the infection worsens or shows signs of spreading
• The consideration of alternative antibiotics, such as trimethoprim-sulfamethoxazole, doxycycline, or clindamycin, if the infection is caused by MRSA 1

It's essential to follow the most recent guidelines and consult with a healthcare professional for personalized treatment recommendations. The 2018 WSES/SIS-E consensus conference provides the most up-to-date guidance on the management of skin and soft-tissue infections, including those caused by S. aureus 1.

From the FDA Drug Label

1. 3 Skin and Skin Structure Infections Cephalexin capsules are indicated for the treatment of skin and skin structure infections caused by susceptible isolates of the following Gram-positive bacteria: Staphylococcus aureusand Streptococcus pyogenes.

• Cephalexin is indicated for the treatment of skin and skin structure infections caused by Staphylococcus aureus.
• The FDA drug label does not specify the severity of the infection (e.g., 4+) that can be treated with cephalexin.
• However, based on the information provided, cephalexin can be used to treat skin infections caused by Staphylococcus aureus, including a 4+ infection, as long as the isolate is susceptible to cephalexin 2.
• It is essential to note that susceptibility of the bacteria to cephalexin should be confirmed before treatment.

From the Research

Cephalexin Treatment for 4+ Staphylococcus aureus Skin Infection

• Cephalexin can be used to treat skin and soft tissue infections caused by Staphylococcus aureus, including methicillin-susceptible S. aureus (MSSA) infections 3, 4, 5.
• However, for serious MSSA infections, penicillinase-resistant penicillins are the preferred treatment, while cephalexin and other antibiotics may be used for less serious infections or in patients with penicillin hypersensitivity 3.
• The effectiveness of cephalexin in treating S. aureus skin infections has been demonstrated in several studies, with cure rates of 90% or higher achieved in some cases 4, 5.
• A study comparing cephalexin and dicloxacillin for the treatment of staphylococcal skin infections found that both antibiotics were equally effective, with uncommon treatment failures and recurrences 5.
• Another study suggested that antibiotics, including cephalexin, may be unnecessary after surgical drainage of uncomplicated skin and soft tissue abscesses caused by community strains of MRSA, with high cure rates observed in both the placebo and cephalexin arms 6.
• For children, twice- and thrice-daily cephalexin dosing regimens have been proposed for the treatment of MSSA infections, with the goal of improving treatment acceptability and adherence 7.

Considerations for Treatment

• The choice of antibiotic treatment for S. aureus skin infections depends on various factors, including the severity of the infection, the presence of penicillin hypersensitivity, and the susceptibility of the bacteria to different antibiotics 3, 4.
• Cephalexin is generally well-tolerated, but patients with immediate penicillin hypersensitivity should not receive cephalosporins, including cephalexin 3.
• The increasing prevalence of community-acquired MRSA infections may affect the choice of empirical antibiotic treatment for skin and soft tissue infections 6.