Evaluation and comparison of native and recombinant LipL21 protein-based ELISAs for diagnosis of bovine leptospirosis

A 21-kDa leptospiral lipoprotein (LipL21) was evaluated for its diagnostic potential to detect bovine leptospirosis by ELISA. Both native LipL21 (nLipL21) and recombinant LipL21 (rLipL21) proteins were tested and compared regarding diagnostic efficiency, and no statistically significant difference was observed. The sensitivity of rLipL21 ELISA for 62 microscopic agglutination test (MAT) positive sera was 100% and the specificity with 378 MAT negative sera was 97.09%. Thus, rLipL21 protein-based ELISA could be used as an alternative to MAT for the diagnosis of bovine leptospirosis.

Molecular fingerprinting of clinical isolates of Mycobacterium bovis and Mycobacterium tuberculosis from India by restriction fragment length polymorphism (RFLP)

Forty mycobacterial strains comprising clinical Indian isolates of Mycobacterium tuberculosis (28 field isolates +1H37 Rv) and Mycobacterium bovis (10 field isolates +1 AN5) were subjected to restriction fragment length polymorphism analysis (RFLP) using IS6110 and IS1081 probes. Most of these strains originated from dairy cattle herd and human patients from Indian Veterinary research Institute (IVRI) campus isolated from the period of 1986 to 2000. Our study showed presence of 8 copies of IS6110 in most of the M.tuberculosis (96.6%) strains irrespective of their origin with the exception of one M.tuberculosis strain with presence of an extra copy (3.4%). All M.bovis strains showed a single copy of IS6110 on the characteristic 1.9kb restriction fragment. RFLP analysis with IS1081 invariably showed the presence of 5 copies in all isolates of M.bovis and M.tuberculosis at the same chromosomal location. Similarity of IS6110 RFLP fingerprints of M.tuberculosis strains from animals and human suggested the possibility of dissemination of single M.tuberculosis strain among animals as well as human. It was not possible to discriminate within the isolates of either M.tuberculosis or M.bovis, when IS1081 was used as target sequence. The IS6110 RFLP is a valuable tool for disclosing transmission chain of M. tuberculosis and M. bovis among humans as well as animals