Rapid diagnosis of leptospirosis in patients with different clinical manifestations by 16S rRNA gene based nested PCR.

Leptospirosis, a zoonosis of global importance and it is underreported in India and more than 50,000 severe cases are reported each year. Here we present the evaluation of 16S rRNA based nested PCR assay for the rapid identification of human leptospires using serum and urine samples. The study includes 261 suspected cases for leptospirosis with different clinical manifestations. 16S rRNA based nested PCR assay was compared and evaluated against the conventional serological methods such as MAT and ELISA. The technique enabled amplification of a 289 bp product with notable percentage of positivity in all sample groups including 94.8 in pediatric cases, 93 in pregnant women, 94.2 in renal failure, 87.8 in jaundice and 94.6 in common febrile cases. The sensitivity and specificity was 94.4% and 100%, respectively. The technique proved to be prompt and effective for the diagnosis of leptospiral infection at the acute phase of the disease. PCR based approach detects leptospiral DNA from the clinical samples both at the acute and leptospiruria phase on comparison with its counter parts where detection is made possible only after 7 days or 7-30 days post-infection. In this regard PCR based diagnosis of leptospirosis should be made available for clinicians for the early diagnosis and prompt treatment of the disease.