Multi-locus sequence typing for species/serovar identification of clinical isolates of Leptospira spp

Abstract

Leptospirosis is an emerging zoonotic disease endemic in Kerala and close monitoring of emerging serovars is essential to adopt appropriate control strategies. Multi-Locus Sequence Typing (MLST) was reported to be less expensive compared to other cumbersome methods like whole genome sequencing. The present study was conducted to obtain isolates of Leptospira from infected animals and rats and for the identification of serovars using MLST. A total of 205 blood samples (dog, cat, cattle, goat), 43 urine samples (dog, cattle) and post-mortem kidney samples from various animals such as dog (n=12), cattle (n=2) and rat (n=25) were collected and subjected to polymerase chain reaction (PCR) using G1/G2 primers to identify the pathogenic Leptospira. Fifteen samples were found to be positive, these samples when inoculated in the Ellinghausen- McCullough-Johnson-Harris (EMJH) semi-solid medium to obtain ten isolates. These ten isolates were further subjected to secY, icdA and GyraseB PCR and sequenced. The obtained sequences were analysed using BLAST and were fed into specified MLST database of Leptospira scheme-3, the allelic profile and sequence type were generated. The MLST results obtained in the study indicated that the isolates S24 and S33 belonged to serovar Canicola, S40 and 47 were Sejroe and S19, S27, S55, S69 and S71 were Bataviae, Autumnalis, Pomona, Icterohaemorraghiae and Australis, respectively. It was concluded that MLST is a convenient method for identifying leptospiral serovars.