Epidemiology and Molecular Variations in Methicillin Resistant Staphylococcus aureus Isolated from Different Clinical Samples of Private Hospitals of Salem District, India

Methicillin resistant Staphylococcus aureus is one of the major bacterial disease in humans and animals worldwide. It causes opportunistic infections acquired from different sources like patients and hospital staff mainly through their hands besides from their normal flora. The present investigation deals with the prevalence and molecular aspects of 50 Staphylococcus aureus isolates collected from various private hospitals of Salem, Tamil Nadu. The methicillin resistance screening by MIC method showed that 90% (40 strains) of the isolates were resistant to methicillin. Among the 40 strains 6 highly resistant ones were chosen and subjected to DNA sequencing so as to compare the sequence variation within the MRSA strains. Variation occurred in the base pairs among the six strains sequenced indicating that real mutation had occurred with the replacement of base pairs C by T in 1371 bp of S2 strain and A by G in 1376 bp of S5strain, a point mutation with the th th replacement of T by A in 8 bp of S6 and in 178 bp & 1333 bp of S2strain and addition of a nucleotide A in th th rd 1397 bp of S3 strain and these changes might be responsible for their methicillin resistance. th