In vitro antibacterial activity of cloves (Syzygium aromaticum) against MRSA

The process of microbial resistance against antibiotics makes it essential to seek for novel drugs. There have been many studies over the last years, in which a lot of plant species have been checked for their antimicrobial activities. Cloves (Syzygium aromaticum), which is a commonly used spice worldwide, have antibacterial, antifungal, antiviral, antioxidant, antimutagenic, anaesthetic, insecticidal, anti-inflammatory, antithrombotic, antiparasitic and antiulcerogenic activities [1]. Staphylococci are a well known cause of both hospital and community acquired infections. Isolates that have acquired methicillin resistance pose serious problems for treatment and eradication. After the introduction of the drug, Methicillin Resistant Staphylococcus aureus (MRSA) strains were reported in the early 1960s. Epidemics have occurred around the world and the clones have diversified since then. MRSA is still on the rise. Nowadays, the imminent threat of reduced susceptibility to vancomycin have emerged [2]. The purpose of this study was to evaluate antibacterial activity of cloves against MRSA. All 100 (one hundred) clinical MRSA isolates were screened by using agar dilution method. Both aqueous and ethanol extracts of cloves were obtained. All of the strains were found to be susceptible to both of the extract forms. At 1000 and 500mg/mL concentrations all of the isolates were found sensitive. At 250mg/mL, 11% of the isolates were sensitive. The isolates were multi- drug resistant, mostly against beta-lactams, aminoglycosides, tetracyclines, floroquinolones and macrolide antibiotics. In terms of a practical use of the cloves as an antibacterial drug, clinical studies are urgently needed.

References: [1] Chaieb, K. et al. (2007) Phytother. Res. 21:501–506.

[2] Fluit, A.C. and Schmitz, F.J. (2003) MRSA Current Perspectives. Caister Academic Press. Wymondham, UK.