From the Guidelines
Bactrim (trimethoprim-sulfamethoxazole) provides good coverage against many strains of Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus (MRSA), and is typically dosed at 1-2 tablets twice daily for 7-14 days, depending on infection severity. For MRSA skin and soft tissue infections, Bactrim is an effective option, but its use should be guided by local resistance patterns and susceptibility testing 1. The dosage and duration of treatment may vary depending on the severity of the infection and the patient's clinical response.
Key Points
- Bactrim is effective against MRSA, but resistance rates vary geographically 1
- Bactrim works by inhibiting bacterial folate synthesis, making it difficult for bacteria to develop resistance 1
- For severe or invasive MRSA infections, Bactrim should not be used as monotherapy and may need to be combined with other antibiotics 1
- Patients should be monitored for side effects, including rash, gastrointestinal upset, and rarely but seriously, Stevens-Johnson syndrome or bone marrow suppression 1
Treatment Guidelines
- For outpatients with purulent cellulitis, empirical therapy for CA-MRSA is recommended pending culture results, and Bactrim is an option 1
- For hospitalized patients with complicated SSTI, empirical therapy for MRSA should be considered pending culture data, and Bactrim may be used in combination with other antibiotics 1
- The use of Bactrim should be guided by local resistance patterns and susceptibility testing, and alternative antibiotics should be considered if resistance is suspected 1
Important Considerations
- Bactrim should not be used as monotherapy for severe or invasive MRSA infections 1
- Patients with a history of sulfa allergy or intolerance should be cautious when using Bactrim 1
- Bactrim may interact with other medications, including warfarin and phenytoin, and patients should be monitored for potential interactions 1
From the Research
Bactrim's Staph and MRSA Coverage
Bactrim, also known as trimethoprim-sulfamethoxazole (TMP-SMX), has been studied for its effectiveness against Staphylococcus aureus (Staph) and methicillin-resistant Staphylococcus aureus (MRSA) infections. The following points summarize the key findings:
- Most MRSA isolates are still susceptible to TMP-SMX, as well as linezolid and the tetracyclines, but less susceptible to quinolones, clindamycin, and erythromycin 2.
- In-vivo studies indicate a high clinical cure rate with linezolid, TMP-SMX, doxycycline, and minocycline for MRSA skin and soft tissue infections (SSTIs) 2.
- TMP-SMX has been compared to vancomycin for the treatment of Staph aureus infections, with vancomycin showing superior efficacy and safety, especially for methicillin-sensitive Staph aureus (MSSA) infections 3.
- However, TMP-SMX may be considered as an alternative to vancomycin in selected cases of MRSA infection, particularly when vancomycin is not suitable 3.
- Other studies have evaluated the activity of various antibiotics, including clindamycin, daptomycin, doxycycline, linezolid, and vancomycin, against community-associated MRSA (CA-MRSA) strains with inducible clindamycin resistance 4.
- The management of Staph aureus bacteremia, including MRSA, typically involves empirical antibiotic treatment with vancomycin or daptomycin, followed by adjustment of antibiotics based on susceptibility results 5.
Key Findings
- TMP-SMX is effective against MRSA, but its efficacy may be lower than other antibiotics such as vancomycin or daptomycin.
- The choice of antibiotic for MRSA treatment depends on various factors, including local antibiotic resistance, type of infection, potential adverse effects, and cost.
- Further clinical studies are needed to determine the most effective treatment options for MRSA infections, particularly for complicated cases or those with inducible clindamycin resistance.