The strains of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumonia and Enterococcus faecalis were obtained from Department of Microbiology, Raja Muthiah medical college and hospital, Annamalai University, Annamalai Nagar, India and were maintained on suitable agar medium at 4°C until testing.