Application of PCR-based DNA sequencing technique for the detection of Leptospira in peripheral blood of septicemia patients

• Published in: Malaysian Journal of Microbiology 2012-03, Vol.8 (1), p.26-33
• Main Authors: Ram, S., Vimalin, J. M., Jambulingam, M., Tiru, V., Gopalakrishnan, R. K., Naraharirao, M. H.
• Format: Article
• Language: English
• Subjects: DNA sequencing; Leptospira; LipL32 gene; Polymerase chain reaction
• ISSN: 2231-7538; 1823-8262; 2231-7538
• DOI: 10.21161/mjm.32311

Aim: Isolation, dark field detection and microscopic agglutination test (MAT) are considered ―gold standard‖ tests for diagnosis of Leptospirosis. Several PCR assays are reported but very few have been evaluated for detection of Leptospirosis. Therefore, this study was undertaken. This study aims to design and standardize polymerase chain reaction (PCR) - based DNA sequencing technique for the detection of pathogenic Leptospira from peripheral blood of patients clinically diagnosed with septicemia. Methodology and Results: Two hundred and seven (207) blood samples from patients were diagnosed with septicemia which includes 100 bacterial (other than Leptospira) culture positive and 107 bacterial culture negative samples were studied. Primers for Nested PCR targeting LipL32 gene of Leptospira interrogans were designed and the specificity of primers was tested against serum samples positive/negative by either MAT or dark field microscopy. PCR amplified products were further confirmed by DNA sequencing. The standardized nPCR was sensitive and specific to Leptospira interrogans. Twenty-one (21%) out of 100 culture positive blood samples, three (2.8%) out of 107 culture negative samples showed nPCR positivity and were confirmed as Leptospira interrogans by DNA sequencing (p