Evaluation of polymerase chain reaction assay for pathogenic Leptospira detection in stored urine

Pathogenic Leptospira spp. is the etiological agent of leptospirosis, a worldwide zoonotic infectious disease that causes jaundice, hemorrhages, renal failure and abortion in susceptible species. Urine is one of the preferred clinical samples for the detection of the agent. However due to its reliability, detection of leptospires in stored samples is challenged. Here we evaluated the capability of a polymerase chain reaction (PCR) assay for detecting pathogenic leptospira DNA in a non-sterile collected urine, stored at different times and temperatures. Our results indicate that the PCR protocol used detect pathogenic leptospira DNA but not non-pathogenic serovars or other nonleptospiral microorganisms. The sensitivity of the assay was of 100 Leptospira interrogans in 10 mL refrigerated neutralized urine within 72 h post collection. This protocol could be of considerable interest for public health workers, field veterinarians and laboratory scientists, in sampling and processing urine for the detection of pathogenic Leptospira spp.