Background: Leptospirosis is a worldwide re-emerging infectious disease caused by pathogenic leptospires including
Leptospira interrogans.
Objective: In the present study, a loop-mediated isothermal amplification (LAMP) was developed to detect L. interrogans
using lipL32 as a gene target.
Material and Method: Four specific primers were designed based on the conserved region of lipL32 gene of various
serovars of pathogenic leptospires. LAMP reaction was performed at 65°C for 1 hour. The LAMP products were detected by agarose gel electrophoresis and fluorescence dye.
Results: The lipL32 LAMP assay showed highly specificity to the reference stains of L. interrogans serovar Autumnalis, Bataviae, Javanica, Pyrogenes, Icterohaemorrhagiae, and Saigon. No product was produced from non-pathogenic leptospire (L. biflexa), human, or Escherichia coli. The lower limit of detection analyzed by agarose gel electrophoresis and fluorescence dye visualization was 0.02 pg/μl which equivalent to 4 genomic equivalents/reaction. Moreover, the clinical strain of leptospires
including pathogenic and intermediate group of L. interrogans were detected by lipL32 LAMP.
Conclusion: The developed lipL32 LAMP is high specificity and sensitivity that can be applied to detect pathogenic leptospires
in clinical samples.

Keywords: Loop-mediated isothermal amplification, LAMP, Leptospira interrogans, LipL32, Detection, Leptospirosis