Treating MRSA bloodstream infection
MRSA bacteraemia is the most dangerous form of the infection. Treatment combines prompt intravenous antibiotics, a search for where the bacteria are coming from, and weeks of therapy guided by repeat blood cultures.
How MRSA reaches the bloodstream
The commonest routes are an intravenous line or dialysis catheter, an untreated skin or wound infection, bone and joint infection, pneumonia, and injecting drug use. Once in the blood, MRSA can settle on heart valves, vertebrae, joints and prosthetic material, creating secondary foci that dictate how long treatment must run. Background on the condition itself is on the MRSA bacteremia page.
First-line therapy
Treatment starts immediately with intravenous vancomycin or daptomycin. Vancomycin dosing is guided by therapeutic drug monitoring; daptomycin is given once daily with weekly creatine kinase checks. Daptomycin must never be used for MRSA pneumonia because lung surfactant inactivates it.
- Repeat blood cultures every 48–72 hours until negative
- Echocardiography in every case of S. aureus bacteraemia
- Remove infected lines and drain any collection promptly
- Infectious-diseases consultation, which independently improves survival
Persistent or complicated infection
Cultures still positive after 72 hours mean the source has not been controlled. Re-image, remove devices, and escalate: high-dose daptomycin (8–10 mg/kg) combined with ceftaroline is the most widely used salvage regimen. Rifampicin is added only for infection on prosthetic material, never alone and never before the blood has cleared. Untreated, bloodstream infection progresses to sepsis.
Every drug used for MRSA
Each entry links to a full page covering the mechanism, dose regime, how the drug was developed, side effects and its other uses.
| Drug | Route | Main role in MRSA |
|---|---|---|
| Vancomycin Vancocin | Intravenous (oral capsules only for gut C. difficile) | The long-standing first-line intravenous antibiotic for serious MRSA infection, including bloodstream infection and endocarditis. |
| Daptomycin Cubicin | Intravenous | A rapidly bactericidal lipopeptide used for MRSA bloodstream infection, right-sided endocarditis and complicated skin infection — but never for pneumonia. |
| Linezolid Zyvox, Zyvoxid | Oral and intravenous (identical dosing) | An oxazolidinone with complete oral absorption and excellent lung penetration, widely used for MRSA pneumonia and refractory skin infection. |
| Trimethoprim-sulfamethoxazole Bactrim, Septrin, co-trimoxazole | Oral (intravenous available) | A cheap, widely available oral combination that is a first-line choice for community-acquired MRSA skin infection and abscess. |
| Doxycycline Vibramycin, Doxylar | Oral (intravenous available) | A tetracycline taken by mouth that reliably covers community-acquired MRSA skin infection and is well suited to outpatient treatment. |
| Clindamycin Dalacin C, Cleocin | Oral, intravenous and topical | A lincosamide that suppresses staphylococcal toxin production, useful in paediatric MRSA and in necrotising soft-tissue infection. |
| Ceftaroline Teflaro, Zinforo | Intravenous | The cephalosporin that binds PBP2a — a beta-lactam that actually works against MRSA, often used as salvage therapy in persistent bacteraemia. |
| Dalbavancin Dalvance, Xydalba | Intravenous | A long-acting lipoglycopeptide that can treat MRSA skin infection with a single infusion, avoiding a hospital stay or a long line. |
| Oritavancin Orbactiv, Kimyrsa | Intravenous | A single-dose lipoglycopeptide for acute MRSA skin infection, with three separate mechanisms of killing. |
| Teicoplanin Targocid | Intravenous and intramuscular | A once-daily glycopeptide used widely outside the United States as a more convenient, less nephrotoxic alternative to vancomycin. |
| Tedizolid Sivextro | Oral and intravenous | A second-generation oxazolidinone: once daily, a shorter course than linezolid, and less effect on blood counts. |
| Rifampicin (rifampin) Rifadin, Rimactane | Oral and intravenous — always in combination | Never used alone for MRSA, but added to other agents for infection on prosthetic material and bone because it kills bacteria inside biofilm. |
Doses shown across these pages are typical adult regimens for reference only. Prescribing decisions are made by a clinician using local guidance and susceptibility results.
Frequently asked questions
- Infectious Diseases Society of America. Clinical practice guidelines for the treatment of MRSA infections (2011)
- American Journal of Health-System Pharmacy. Therapeutic monitoring of vancomycin for serious MRSA infections: revised consensus guideline (2020)
- New England Journal of Medicine. Daptomycin versus standard therapy for bacteremia and endocarditis caused by Staphylococcus aureus (2006)
- American Heart Association. Infective endocarditis in adults: diagnosis, antimicrobial therapy and management of complications (2015)
Treatment hub
How MRSA treatment is chosen by site and severity.
Skin & soft-tissue infection
Drainage first, then which oral antibiotics and for how long.
Invasive wound infection
Surgical and traumatic wounds, debridement and source control.
Decolonisation
Mupirocin and chlorhexidine protocols to clear carriage.