From the Guidelines
Methicillin-resistant Staphylococcus aureus (MRSA) infections are typically treated with vancomycin, linezolid, daptomycin, or trimethoprim-sulfamethoxazole (TMP-SMX), depending on the severity and location of the infection. For serious MRSA infections, intravenous vancomycin is often the first-line treatment, typically dosed at 15-20 mg/kg every 8-12 hours, with adjustments based on kidney function and drug levels, as recommended by the Infectious Diseases Society of America 1.
Treatment Options
- For less severe skin infections, oral options include:
- Linezolid (600 mg twice daily)
- TMP-SMX (1-2 double-strength tablets twice daily)
- Doxycycline (100 mg twice daily)
- Clindamycin (300-450 mg four times daily)
- Treatment duration typically ranges from 7-14 days for skin infections to 4-6 weeks for more serious infections like osteomyelitis or endocarditis.
Considerations
- MRSA has developed resistance to beta-lactam antibiotics (penicillins and cephalosporins) through the acquisition of the mecA gene, which produces an altered penicillin-binding protein that prevents these antibiotics from effectively binding to the bacterial cell wall, as discussed in the guidelines by the Infectious Diseases Society of America 1.
- The choice between vancomycin and linezolid may be guided by patient-specific factors such as blood cell counts, concurrent prescriptions for serotonin-reuptake inhibitors, renal function, and cost, as noted in the 2016 clinical practice guidelines by the Infectious Diseases Society of America and the American Thoracic Society 1.
- High-dose daptomycin can be used to limit the emergence of resistant mutants, especially in cases of MRSA bacteremia with vancomycin MIC ≥ 1 mg/L, as suggested by studies published in Intensive Care Medicine 1.
Recommendations
- Vancomycin or linezolid are recommended for the treatment of MRSA hospital-acquired and ventilator-associated pneumonia, as stated in the 2016 clinical practice guidelines by the Infectious Diseases Society of America and the American Thoracic Society 1.
- The use of rifampin as a single agent or as adjunctive therapy for the treatment of skin and soft-tissue infections (SSTIs) is not recommended, as indicated in the guidelines by the Infectious Diseases Society of America 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 (%) Methicillin-resistant S aureus 2/3 (67) 0/0 (-) The cure rates by pathogen for microbiologically evaluable patients are presented in Table 19. Pathogen Cured ZYVOX n/N (%) Comparator n/N (%) Methicillin-resistant S aureus 12/17 (71) 2/3 (67) Among patients with persisting or relapsing S. aureus infections, 8/19 daptomycin for injection-treated patients and 7/11 comparator-treated patients died The median time to clearance in patients with MSSA was 4 days and in patients with MRSA was 8 days. Failure of treatment due to persisting or relapsing S aureus infections was assessed by the Adjudication Committee in 19/120 (16%) daptomycin for injection-treated patients (12 with MRSA and 7 with MSSA)
The treatment options for Methicillin-resistant Staphylococcus aureus (MRSA) infections with antibiotics are:
- Daptomycin: with a success rate of 44% in patients treated with daptomycin for injection and 41.7% in patients treated with comparator, and 20/45 (44%) success rate in MRSA patients 2
- Linezolid: with a cure rate of 79% in microbiologically evaluable patients with MRSA skin and skin structure infection, and 71% in diabetic foot infections with MRSA 3
- Vancomycin: with a cure rate of 73% in microbiologically evaluable patients with MRSA skin and skin structure infection, and 67% in diabetic foot infections with MRSA 3
From the Research
Treatment Options for MRSA Infections
The treatment of Methicillin-resistant Staphylococcus aureus (MRSA) infections involves the use of various antibiotics. The choice of antibiotic depends on the severity and type of infection, as well as the patient's medical history and susceptibility of the MRSA strain to different antibiotics.
- Vancomycin has been the cornerstone of treatment for MRSA infections, but its effectiveness has been challenged by the emergence of less-susceptible strains and increased nephrotoxicity with high-dose therapy 4, 5, 6, 7.
- Linezolid is recommended for the treatment of skin and skin structure infections (SSSIs) and pneumonia caused by MRSA 4, 7.
- Daptomycin is an effective alternative for the treatment of MRSA bacteremia and right-sided endocarditis, as well as complicated SSSIs 4, 6, 8, 7.
- Ceftaroline is a new anti-MRSA cephalosporin that has shown promise in the treatment of acute bacterial skin and skin structure infections (ABSSSIs) and pneumonia 5, 6.
- Tedizolid is a new agent that has shown improved pharmacokinetics and reduced toxicity compared to linezolid, and is active against MRSA strains with reduced susceptibility to linezolid 5, 7.
- Telavancin and dalbavancin are alternative treatments for SSSIs caused by MRSA, but their use is limited by safety concerns and the emergence of resistance 4, 5, 8.
- Combination therapy with β-lactams and vancomycin or daptomycin is increasing, but further studies are needed to determine its effectiveness in the treatment of MRSA infections 5, 6.
Specific Treatment Options for Different Types of MRSA Infections
- For MRSA bacteremia, vancomycin, daptomycin, and ceftaroline are recommended treatment options 6.
- For MRSA endocarditis, vancomycin, daptomycin, and linezolid are recommended treatment options 6, 8.
- For hospital-acquired pneumonia (HAP) caused by MRSA, linezolid is a recommended treatment option 7.
- For SSSIs caused by MRSA, linezolid, daptomycin, ceftaroline, telavancin, and dalbavancin are recommended treatment options 4, 5, 8.