mojde safari department of microbiology, qom branch, islamic azad university, qom, ir iran mana shojapour medical microbiology, molecular and medical research center, arak university of medical sciences, arak, ir iran majid akbari medical microbiology, molecular and medical research center, arak university of medical sciences, arak, ir iran ahmadali pourbabaee department of microbiology, qom branch, islamic azad university, qom, ir iran hamid abtahi medical microbiology, molecular and medical research center, arak university of medical sciences, arak, ir iran; molecular and medicine research center, arak university of medical sciences, arak, ir iran. tel: +98-8614173502, fax: +98-8614173526