Phenotypic and Genotypic Characterization of Salmonella Typhi Virulence Factors Isolated From Patients with Typhoid Fever in Najaf Province /Iraq

Salmonella entericaserovar Typhi remains a major public health problem in many developing countries .The severity and pathogenesis of the disease depending on virulence factors. Previously, different virulence factors have been detected phenotypically and serologically for clinical and epidemiological investigation of salmonella. Beyond the phenotypic characterization, a reliable molecular methods are require. Therefore, this study was attempted To use different molecular methods for investigation the present of tviA , staA , and nested staA genes by monoplex –PCR. Sixty five S.typhi bacteril isolates that been isolated and diagnosed depending on the culture charecters and the present of 16SrRNA with 441bp. The results of monoplex PCR of virulence factors genes clarify that all isolates (100%) of S. typhi producers isolates carrying tviA , staA and nested staA gene that predominance gene among other genes under study, which was found in all bacterial isolates producers respectively. S. typhi isolates were showed possessing these genes which responsible for S. typhipathogenicity.