CHICAGO—Statins appear to be converted by the liver into compounds with antimicrobial activity, data suggest.
Previous epidemiologic studies have suggested a link between statin therapy and a decreased risk of sepsis. Researchers believe statins indirectly modulate the immune system.
“We tested the statins just as if they were antibiotics,” said study investigator Jon Cohen, MD, professor of infectious diseases at Brighton & Sussex Medical School in Brighton, UK. “Statins do indeed have some direct antimicrobial effect and this effect was focused in particular on Gram-positive bacteria.”
Dr. Cohen and his colleagues tested the antimicrobial effects of two statins (simvastatin [Merck] and fluvastatin [Novartis]) on methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA, respectively) and vancomycin-sensitive and vancomycin-resistant enterococci (VSE and VRE). The drugs had been obtained in pure form from the manufacturers. Propranolol, another drug used for prevention of heart disease but not a lipid-lowering agent, was used as a control.
Simvastatin showed significant antimicrobial effect against MSSA and, to a lesser extent, against MRSA, Dr. Cohen reported at the Interscience Conference on Antimicrobial Agents and Chemotherapy. Fluvastatin had significantly less of an effect.
Typical peak plasma concentrations of simvastatin attained after a 40 mg oral dose are nearly 0.0209 mg/L, suggesting that the level of antibacterial activity seen with statins would have little clinical effect. “However, we were testing concentrations of the pure drug, and in the body, statins are broken down and metabolized. It may be that a metabolite of the statin might have a greater antimicrobial effect than the pure drug,” Dr. Cohen told Renal & Urology News. “So, there may be a class effect.”
The findings are preliminary and additional work is underway to determine if current use of statins might provide some modest antibacterial activity that could limit low grade bacteremias, for instance, in the context of catheter-related bacteremia. “Whether higher doses could be more efficacious (without causing undue toxicity) remains to be seen,” Dr. Cohen said.