Molecular Identification of Methicillin Resistant Staphylococcus (Mrsa) by Polymerase Chain Reaction (Pcr) Technology

Abstract

 Introduction of penicillin in the year 1940 had greatly improved the prognosis for patients with severe staphylococcal infections, but after a few years of clinical use, resistance appeared owing to production of β-lactamases. Methicillin was designed to resist β lactamase degradation, but Methicillin Resistant Staphylococcus aureus (MRSA) strains were soon identified. Since then, these staphylococcal strains have spread worldwide. Until recently, Methicillin Resistant Staphylococci were predominantly nosocomial pathogens causing hospital acquired infections but Methicillin Resistant Staphylococal (MRS) strains are now being increasingly isolated from community acquired infections as well.  B-lactam antibiotics such as methicillin inactivate Penicilling Binding Proteins PBP’s 1, 2 and 3 in the bacterial cell wall which have an enzymatic role in the synthesis of Peptidoglycans. However Methicillin Resistant Staphylococcus Aureus soon acquired a new gene called mecA which encodes for a new PBP called PBP2 a which has low affinity for B-lactam Antibiotics  thus conferring resistance to these organisms. MRSA prevalence increased from 12% in 1992 to 80.83% in 1999. Indian literature shows that MRSA incidence was as low as 6.9% in 1988 and reached to 24% and 32.6% in Vellore and Lucknow in 1994 and was of the same order in Mumbai, Delhi and Bangalore in 1996 and in Rohtak and Mangalore in 1999. However, in some of the centres it was as high as 87%.