Complicated Carriage with Methicillin-Resistant Staphylococcus aureus: Evaluation of the Effectiveness of Decolonization Regimens Advised in the Dutch National Guideline.

Methicillin-resistant Staphylococcus aureus (MRSA) colonization leads to increased infection rates and mortality. Decolonization treatment has been proven to prevent infection and reduce transmission. As the optimal antimicrobial strategy is yet to be established, different regimens are currently prescribed to patients. This study aimed to evaluate the efficacy of the decolonization treatments recommended by the Dutch guideline. A retrospective multicenter cohort study was conducted in five Dutch hospitals. All patients who visited the outpatient clinic because of complicated MRSA carriage between 2014 and 2018 were included. We obtained data on patient characteristics, clinical and microbiological variables relevant for MRSA decolonization, environmental factors, decolonization regimen, and treatment outcome. The primary outcome was defined as three negative MRSA cultures after treatment completion. Outcomes were stratified for the first-line treatment strategies. A total of 131/224 patients were treated with systemic antibiotic agents. Treatment was successful in 111/131 (85%) patients. The success rate was highest in patients treated with doxycycline-rifampin (32/37; 86%), but the difference from any of the other regimens did not reach statistical significance. There was no difference in the success rate of a 7-day treatment compared to that with 10 to 14 days of treatment (odds ratio [OR], 0.99; 95% confidence interval [CI], 0.39 to 2.53; P  = 1.00). Side effects were reported in 27/131 (21%) patients and consisted mainly of mild gastrointestinal complaints. In a multivariable analysis, an immunocompromised status was an independent risk factor for failure at the first treatment attempt (OR, 4.65; 95% CI, 1.25 to 17.25; P  = 0.02). The antimicrobial combinations recommended to treat complicated MRSA carriage yielded high success rates. Prolonged treatment did not affect treatment outcome. A randomized trial is needed to resolve whether the most successful regimen in this study (doxycycline plus rifampin) is superior to other combinations.