Background Methicillin susceptible Staphylococcus aureus (MSSA) bacteraemia continues to be associated with high clinical failure rates. Combination therapy has been proposed as an alternative to improve outcomes but there is a lack of clinical studies.

Purpose To evaluate if the combination of daptomycin plus cloxacilin achieves higher clinical success rates in the treatment of MSSA bacteraemia than cloxacilin alone.

Material and methods A single centre, retrospective, observational, comparative study was performed between January 2015 and August 2015. The subjects were patients with MSSA bacteraemia who received cloxacilin as monotherapy (standard therapy group) or the combination cloxacilin plus daptomycin. A revision of the clinical history of each patient was carried out to asses clinical, laboratoy and microbiological data.

The main outcome variable was 30 day all-cause mortality and 30 day all-cause hospital readmission. Secondary endpoints were: (i) percentage of patients who achieved a decrease in CRP levels to <50% of their initial value in the first 72 h of therapy; (ii) length of hospital stay (LOS); and (iii) percentage of patients with persistent bacteraemia after 72 h of initiation of therapy.

Results 14 patients met the study criteria. 7 (50%) patients received cloxacilin as monotherapy and 7 (50%) received the combination cloxacilin-daptomycin.

No differences in 30 day all-cause mortality were observed (14% (1/7 in the standard therapy group vs 14% (1/7) in the combination group). No statistical differences between groups were observed in all-cause readmission at 30 days (14% (1/7) in the standard group vs 0/7 in the combination group (p = 0.337)). Similarly, there were no differences in the secondary endpoints: LOS (median 32 vs 37 days, p = 0.86) and a decrease in CRP levels to <50% of their initial value in the first 72 h of therapy (42% (3/7) in the combination group vs 28% (2/7) in the standard therapy group (p = 0.611)). The rate of persistent bacteraemia did not differ between the two groups.

Conclusion Our data showed a benefit of adding daptomycin to cloxacilin in patients with MSSA bacteraemia. However, studies with a large number of patients are required to define the role of combination therapy in patients with MSSA bacteraemia.

References and/or Acknowledgements

1. Emerg Infect Dis 2011;17:1099-102

References and/or AcknowledgementsNo conflict of interest.