Abstract:
A study was undertaken to standardize the peR technique for the
diagnosis of leptospirosis and to compare the efficacy of peR with DFM and
culture in the diagnosis of leptospirosis.
Two sets of primers, namely, primers A and B derived from Leptospira
interrogans serovar canicola rrs (16S) gene and G I and G2 derived from genomic
library of L. interrogans serovar icterohaemorrhagiae, were evaluated to amplify
12 reference strains of leptospires representing the serovars viz., australis,
rachmati.; canicola, grippotyphosa, hardjo, hebdomadis, icterohaemorrhagiae,
pomona, poi, pyrogenes, tarassovi and patoc. The primers A and B specifically
amplified all the serovars tested, while the primers Gland G2 failed to amplify
the serovar patoc. The primers A and B which amplified a 331 base pair fragment
of leptospiral DNA were used for the routine detection of leptospires in clinical
samples.
Restriction enzyme digestion of the primer A and B amplified product
with the enzymes Dde I and MnI I and direct sequencing established the identity
of the amplified product.
A total of 192 samples were collected from different sources like human,
dogs and bovines with suspected history of leptospirosis and from rodents. All
were tested by peR and the positivity ranged from 33.3 to 54.2 per cent. Of the
samples collected 125 samples were tested by all the three techniques viz., peR,
DFM and culture and the results were compared.
The peR technique was found to be more sensitive, specific and rapid,
over conventional methods as it detected 41.6 per cent, compared to 25.6 per cent
by DFM and 2.4 per cent by culture, of the samples tested.
