Daptomycin Use for Antimicrobial Prophylaxis in Methicillin Resistant Staphylococcus Aureus (MRSA) Colonized Adult Patients Undergoing Primary Elective Hip, Knee, or Shoulder Arthroplasty

• Daptomycin efficacy in prevention of postoperative surgical site infection (SSI) [ Time Frame: 24 months ] [ Designated as safety issue: No ]
  Efficacy of daptomycin in preventing postoperative SSI will be determined for each enrolled subject on one month postoperative visit. Overall efficacy of daptomycin among the patient group who receive it will be compared to overall efficacy of vancomycin among the second patient group who receive vancomycin upon anticipated complete enrollment study at 24 months.
  
  

• Efficacy of daptomycin in preventing postoperative early prosthetic joint infection [ Time Frame: 30 months ] [ Designated as safety issue: No ]
  Efficacy of daptomycin in preventing postoperative early prosthetic joint infection will be determined for each enrolled subject on three months postoperative visit. Overall efficacy of daptomycin among the patient group who receive it will be compared to overall efficacy of vancomycin among the second patient group who receive vancomycin upon anticipated completion of the study at 30 months
  
  

This is a phase 4 randomized open label prospective pilot study comparing the use of daptomycin versus vancomycin for peri-operative antibiotic prophylaxis in patients undergoing elective primary knee, hip or shoulder arthroplasty and are at risk for infection with methicillin resistant Staphylococcus aureus. The study population will include males and non-pregnant, non-lactating females 18 years of age or older, with history of methicillin-resistant Staphylococcus aureus infection or colonization, and undergoing primary elective hip, knee or shoulder arthroplasty. The target enrollment is 100 patients, who will be randomized to daptomycin or vancomycin in two 50 patient study groups. After signing the informed consent, patients will undergo pre-enrollment nasal screening for methicillin resistant Staphylococcus aureus to identify eligible patients. Patients with positive MRSA nasal screen will proceed with enrollment and get randomized into one of the two study groups. In one group, patients will receive one dose of daptomycin 6 mg/kg to be infused over 30 minutes. In this group, the infusion should be started and completed within 60 minutes of surgical incision. In the second group, patients will receive one dose of vancomycin 15 mg/kg to be infused over 1-2 hours of surgical incision according to the dose to avoid red man syndrome. In this group, the infusion should be started and completed within 120 minutes of surgical incision. After surgery, a second similar dose of vancomycin will be given 12 hours after the first dose to patients with creatinine clearance (CLcr.) of ≥50 ml/min. All patients in both groups will be asked to shower with chlorhexidine skin cleanser (HIBICLENS®) once daily from the neck down for 7days before surgery and apply Mupirocin ointment 2% to their nostrils twice daily for 5 days before surgery.

The patients will be evaluated on the day of surgery, at 2-3 days postoperatively, on discharge, at one month and three months follow up visits. During these study evaluations, patients will be assessed clinically for signs and symptoms of wound, and prosthetic joint infection (including pain, tenderness, swelling, erythema, poor wound healing and wound drainage) prior to hospital discharge, and at one, and three months follow up visits. Blood work including complete blood counts, erythrocytic sedimentation rate, c-reactive protein, and cultures will be ordered if clinical findings suggest infection. Bacterial isolates causing infections will be tested locally for antibiotic susceptibilities including daptomycin and vancomycin and saved for further testing if needed. Adverse effects and tolerability will be documented with the use of both drugs in the two patient groups. Data will be collected and analyzed with appropriate testing. The primary endpoint will be the success in prevention of postoperative SSI and prosthetic joint infection at one month postoperative follow up visit.