Detection of Salmonella in Blood by PCR using iroB gene

Abstract

Background: Salmonella, a genus of more than 2500 serological variants (serovars), includes many organisms that can cause human disease. Enteric fever remains an important public health problem in developing countries. Non typhoidal Salmonella generally produce a self limited gastroenteritis in healthy individuals whereas in extremes of age and immunocompromised cause severe fatal disease. The protean manifestations make this disease a true diagnostic challenge. Aim: The present study was carried out to optimize PCR for detecting the Salmonella genus using iroB gene and evaluate its use in the rapid diagnosis of typhoid and non typhoidal salmonellosis. Materials and Methods: The study was carried out between August 2009 and July 2011 on blood samples from patients attending JIPMER hospital, Pondicherry, India with clinical suspicion of enteric fever and salmonellosis. Whole blood was used DNA extraction and conventional PCR done with iroB and fliC primers. Blood culture and Widal test were performed for all the patients. Statistical Analysis: Performed using Fischer’s exact test with Graphpad Instat 3. Results: PCR results were compared with blood culture. Sensitivity and specificity of PCR with fliC gene are 95.6% and 93.3% respectively. Sensitivity and specificity of PCR with iroB gene are 96.6% and 93.3% respectively. Conclusion: With iroB gene, additional cases of Salmonella Paratyphi A and non typhoidal Salmonella were detected when compared to fliC gene.

Keywords

• non typhoidal salmonella
• irob gene
• flic gene