Abstract
Leptospirosis is a bacterial zoonotic disease caused by different pathogenic serovars of the spirochaete bacterium Leptospira. It mainly survives in both temperate and tropical regions; the occurrence in the tropics is approximately 10 fold higher than in temperate regions. The present day medicines for the treatment of leptospirosis are only effective during the early phase of the disease and no medicines available after the disease become complicated. In this connection, the present study was carried out for the identification of potential anti-leptospiral compounds from marine actinomycetes. From 18 marine sediment samples nearly 141 isolates of actinobacteria were enumerated. The sediments were collected during the months of March to August 2013, along the coast Bay of Bengal, Palk Strait, Gulf of Mannar and Lakshadweep. Crude compounds were produced from the isolates, and all were screened against the Leptospira interrogans serovar Autumnalis strain N2 (Human isolate) to determine the anti leptospiral activity. In the primary screening, 5 samples were recorded by showing promising activity (strain no MSU5, P1, T10, PGM 15 and TCA6) and determined of having anti-leptospiral activity. In the secondary screening strains MSU5, T10 and P1 were showed significant activity. In both the screening MSU5 isolated from Manakudy mangroves, showed an effective inhibition activity against the serovars Autumnalis with a minimum inhibition concentration (MIC) at 125µg.mL-l. The standard antibiotic doxycycline exhibited the MIC with 200µg.mL-l. This is first report for analyzing marine actinomycetes compounds for antileptospiral activity. The study reveals that strain MSU5 shows promising antileptospiral activity against Leptospira serovar Autumnalis and may be a potential candidate for anti-leptospiral components.
