Unexpected antimicrobial effect of statins

Objectives: Epidemiological studies of statins have suggested a link between statin therapy and a decreased risk of sepsis. It has been proposed that the mechanism underlying this apparent protective effect of statins relates to their known immunomodulatory and anti-inflammatory effects. The aim of this study was to explore the antimicrobial effect of statins. Methods: Simvastatin (Merck) and fluvastatin (Novartis) were both tested against six of each of methicillin-susceptible and -resistant Staphylococcus aureus (MSSA + MRSA), and vancomycin-sensitive and -resistant enterococci (VSE + VRE) using a microtitre dilution method. The test was repeated five times for both statins against all 24 isolates. Vancomycin, linezolid and propranolol were used as controls, as appropriate. Results and discussion: Simvastatin showed a significant antimicrobial effect against MSSA (mean MIC 29.2 mg/L) and to a lesser extent against MRSA (mean MIC 74.9 mg/L). Fluvastatin had a significantly less marked antimicrobial effect. Propranolol showed no antimicrobial effect. Simvastatin has a considerable antimicrobial effect in vitro and further testing of it is warranted.