Molecular detection of pathogenic leptospiral serovars by PCR, based on lipL21 gene


1 Leptospira Reference Laboratory, Razi vaccine and Serum Research Institute, Karaj, Iran

2 Department of human bacterial vaccines, Razi vaccine and Serum Research Institute, Karaj, Iran


Leptospirosis is a zoonotic disease with global distribution that caused by pathogenic spirochetes of the genus Leptospira. Accurate diagnosis for differentiation of leptospirosis from other pyrogenic infections prevailing in the same locality and is imperative for proper treatment. Therefore a molecular diagnostic test with high specificity and sensitivity such as PCR is essential. Gene encoding of outer membrane proteins of Leptospira are potential candidates that may be useful as diagnostic and analysis of the disease. In this study, lipL21 gene was used for detection and differentiation of pathogenic from saprophytic leptospiral serovars in PCR assays. The leptospiral lipL21 gene expressed only in pathogenic Leptospira spp. The bacteria were inoculated into the EMJH (with 5% rabbit serum) and extraction of the genomic DNA was done by standard Phenol-Chlorophorm method. The specific primers for proliferation of lipL21 gene were designed. The lipl21 gene was observed in pathogenic leptospira and was not in saprophytic leptospires. The specificity and sensitivity of PCR was evaluated. PCR assay with high specificity and sensitivity may prove to be a rapid method for diagnosing acute leptospirosis and designed a positive control to optimize this diagnostic test. The results showed that molecular detection of pathogenic leptospiras based on lipL21 gene can be used for laboratory diagnosis of leptospirosis.