1. Infectious Diseases and Tropical Medicine Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
2. Nosocomial Infection Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
3. Student Research Committee, Schoolof Medicine, Guilan University of Medical Sciences, Rasht, Iran
4. Department of Microbiology, Virology and Microbial Toxins, School of Medicine, Guilan University of Medical Sciences, Tehran Road Km 6th, Rasht, 3363, Guilan, Iran