Suman Thakur1, Vivek Chauhan2, Kamlesh Sharma3, Mrinalini Singh2. 1. Department of Microbiology, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India. 2. Department of Community Medicine, Dr. YSPMC, Nahan, Himachal Pradesh, India. 3. Department of Medicine, IGMC, Shimla, Himachal Pradesh, India.