title: Cholesterol suppresses antimicrobial effect of statins.
abstract: OBJECTIVE
  Isoprenoid biosynthesis is a key metabolic pathway to produce a wide variety of biomolecules such as cholesterol and carotenoids, which target cell membranes. On the other hand, it has been reported that statins known as inhibitors of isoprenoid biosynthesis and cholesterol lowering agents, may have a direct antimicrobial effect on the some bacteria. The exact action of statins in microbial metabolism is not clearly understood. It is possible that statins inhibit synthesis or utilization of some sterol precursor necessary for bacterial membrane integrity. Accordingly, this study was designed in order to examine if statins inhibit the production of a compound, which can be used in the membrane, and whether cholesterol would replace it and rescue bacteria from toxic effects of statins.
  
  
  METHODS
  To examine the possibility we assessed antibacterial effect of statins with different classes; lovastatin, simvastatin, and atorvastatin, alone and in combination with cholesterol on two Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and two Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria using gel diffusion assay.
  
  
  RESULTS
  Our results showed that all of the statins except for lovastatin had significant antibacterial property in S. aureus, E. coli, and Enter. faecalis. Surprisingly, cholesterol nullified the antimicrobial action of effective statins in statin-sensitive bacteria.
  
  
  CONCLUSIONS
  It is concluded that statins may deprive bacteria from a metabolite responsible for membrane stability, which is effectively substituted by cholesterol.
authors.affiliation: Department of Clinical Biochemistry, School of Medicine, Qom University of Medical Sciences, Qom, Iran; Institute for Health Research and Policy, London Metropolitan University, London, United Kingdom.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Haeri
authors.affiliation: Institute for Health Research and Policy, London Metropolitan University, London, United Kingdom.
authors.forename: Kenneth
authors.initials: K
authors.lastname: White
authors.affiliation: Islamic azad university, Qom branch, Qom-Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Qharebeglou
authors.affiliation: Department of Clinical Biochemistry, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
authors.forename: Malek Moein
authors.initials: MM
authors.lastname: Ansar
keywords: Bacteria; Hydroxymethylglutaryl coenzyme A; Statin; Sterol