What is the appropriate treatment for a 48-year-old patient with a hand skin infection caused by Methicillin (Oxacillin) Resistant Staphylococcus aureus (MRSA) and Beta Hemolytic Streptococcus Group G, who has been previously treated with Bactrim (Sulfamethoxazole/Trimethoprim), Keflex (Cephalexin), and Clindamycin?

From the Guidelines

The patient should continue with clindamycin 300-450mg three times daily for 7-10 days, as it is sensitive to the isolated MRSA and has no inducible resistance, or switch to oral linezolid 600mg twice daily for 7-10 days, as both are appropriate treatment options based on the susceptibility results. The patient has a hand skin infection with cultures showing heavy growth of methicillin-resistant Staphylococcus aureus (MRSA) and Group G Streptococcus. According to the guidelines by the Infectious Diseases Society of America 1, the recommended treatment for MRSA skin and soft tissue infections includes vancomycin, linezolid, daptomycin, or trimethoprim-sulfamethoxazole (Bactrim). Since the patient has already tried Bactrim twice without resolution, and considering the susceptibility results, clindamycin and linezolid are suitable alternatives. Clindamycin is bacteriostatic, but it has shown effectiveness against MRSA, and the D-test negative result indicates no inducible resistance. Linezolid is also bacteriostatic but has limited clinical experience and is more expensive. The infection should be reassessed after 48-72 hours of therapy to ensure clinical improvement. Additionally, warm compresses, elevation of the hand, and proper wound care should be implemented. If the infection involves deeper tissues or if there's no improvement with oral antibiotics, surgical consultation and debridement may be necessary. Keflex (cephalexin) is not effective against MRSA, explaining the previous treatment failure.

Some key points to consider in the management of this patient include:

• The importance of proper wound care and elevation of the affected area to promote healing and reduce the risk of further complications.
• The need for close monitoring of the patient's response to treatment, with reassessment of the infection after 48-72 hours to determine if the chosen antibiotic is effective.
• The consideration of surgical consultation and debridement if the infection is severe or not responding to antibiotic therapy.
• The patient's previous treatment failures with Bactrim and Keflex, which suggests the need for alternative antibiotic therapy that is effective against MRSA.

It is essential to follow the guidelines and recommendations from reputable sources, such as the Infectious Diseases Society of America 1, to ensure the best possible outcome for the patient.

From the FDA Drug Label

The clinical success rates determined at 7–14 days after last dose of therapy (IV and oral) (TOC visit) were 88% (227/257) for daptomycin for injection and 86% (114/132) for comparator. Of the 235 ITT patients, there were 141 (60%) males and 156 (66%) Caucasians across the two treatment groups Eighty-nine patients (38%) had bacteremia caused by methicillin-resistant S. aureus (MRSA) In the ITT population, there were 182 patients with bacteremia and 53 patients with infective endocarditis as assessed by the Adjudication Committee, including 35 with right-sided endocarditis and 18 with left-sided endocarditis The 182 patients with bacteremia comprised 121 with complicated S. aureus bacteremia and 61 with uncomplicated S. aureus bacteremia.

The patient has a methicillin-resistant Staphylococcus aureus (MRSA) infection.

• Daptomycin is effective against MRSA, with a clinical success rate of 88% in one study 2.
• The patient's previous treatments, including Bactrim, Keflex, and Clindamycin, may not be effective against MRSA.
• Clindamycin susceptibility testing showed the isolate was susceptible, but Daptomycin may be a better option due to its high clinical success rate against MRSA.
• Given the patient's age and the presence of MRSA, Daptomycin could be considered as a treatment option.

From the Research

Treatment of Methicillin-Resistant Staphylococcus aureus (MRSA) Infections

• The patient has been diagnosed with a hand skin infection caused by MRSA, as indicated by the wound aerobic culture results showing heavy growth of methicillin (oxacillin) resistant Staph aureus (MRSA) 3, 4, 5.
• The patient has been treated with Bactrim, Keflex, and Clindamycin, but the culture results show that the MRSA isolate is susceptible to Clindamycin, with a MIC of ≤0.5 3.
• The patient's treatment options for MRSA infections include vancomycin, daptomycin, and combination therapies, as recommended by studies 4, 5, 6, 7.

Management of Staphylococcus aureus Bacteremia

• Staphylococcus aureus bacteremia is a serious infection that requires prompt treatment, as it can cause metastatic infection and has a high case fatality rate 4.
• The management of Staphylococcus aureus bacteremia includes identifying the source of infection, pursuing source control, and administering antibiotics active against MRSA, such as vancomycin or daptomycin 4, 5, 6, 7.
• The patient's wound gram stain results show few WBC's, moderate gram-positive cocci in pairs, and few gram-positive cocci in chains, which is consistent with a Staphylococcus aureus infection 3.

Antibiotic Susceptibility and Resistance

• The patient's MRSA isolate is susceptible to several antibiotics, including ceftaroline, ciprofloxacin, clindamycin, daptomycin, linezolid, and vancomycin, as indicated by the MIC results 3.
• The patient's MRSA isolate is resistant to oxacillin and tetracycline, as indicated by the MIC results 3.
• The use of rifampin alone for antimicrobial therapy is not recommended, as it can lead to the development of resistance 3.