polymerase chain reaction method for rapid detection of Salmonella typhi

ABSTRACT

Salmonella enterica serotype Typhi is the causative pathogen of typhoid fever. Morbidity and mortality rates of the disease are 16x106 and 6x105 cases per year, respectively. Proper diagnosis of the disease and its suitable treatment have critical roles in morbidity and mortality reduction, especially in the developing countries. The traditional methods for detection of the organism are time consuming with low sensitivity. The aim of the present study is to design a new polymerase chain reaction [PCR] method for rapid detection of the organism. Target specific viaB genes were used for primer designing using Generunner j software. PCR tests were sat up using the standard Salmonella typhi genome. Besides, specificity of the method was determined using negative control bacterial genomes. For construction of positive control, determination of sensitivity of the method and limit of the detection, PCR products were cloned in a pTZ57RT plasmid vector. The agarose gel electrophoresis of PCR products showed 441 bands for the viaB genes. PCR tests for control negative genomes did not create any band on the agarose gel. Results of PCR, enzymatic digestion and sequencing confirmed the cloning process and the positive control construct. Considering the disadvantages of the classic methods for detection of the organism and the advantages of the molecular methods, the diagnostic kit proposes a suitable tool for rapid detection of the Salmonella typhi