Evaluation of the Presence of Gene Encoding Loa22 in Pathogenic Leptospira Serovars

 Leptospirosis is one of the most common zoonotic diseases worldwide, occurring mostly in tropical, subtropical, temperate, and humid regions with heavy rainfall. It is important to diagnose this condition correctly and promptly. Loa22 is an outer membrane protein exposed to the surface in some Leptospira serovars. The purpose of this study was to determine the presence of the gene encoding Loa22 protein in Leptospira interrogans serovars.

 The present study was conducted on 23 pathogenic leptospira serovars and two non-pathogenic leptospira serovars. These serovars were prepared from the Reference Laboratory for Leptospira, Department of Microbiology, Razi Vaccine, and Serum Research Institute, Karaj, Iran. After genomic DNA extraction using the standard phenol-chloroform method, loa22 gene was amplified by specific primers.

PCR was performed on the loa22 gene by producing a 671-bp fragment. The results showed that the loa22 gene was present in all 23 pathogenic leptospira serovars but not in the non-pathogenic L. biflexa. The specificity of tested primers was confirmed as well.

 The loa22 gene is a specific gene for pathogenic leptospira serovars that is not found in saprophytic serovars, so it is suggested that this gene be used to detect leptospira pathogenic serovars.