Inhibitory Potential of Actinobacteria Isolated from Neelum Valley, Kashmir, Pakistan Against Typhoidal Salmonella

Azka Arshad, Shahid Nawaz, Usman Aftab, Rukhama Haq and Imran Sajid

Abstract

Given the emerging antimicrobial resistance (AMR), finding new antimicrobials and chemotherapeutics is a need of the hour. The under-explored habitats harbouring untapped microbial diversity are considered attractive targets to look for new potent bioactive compounds. In this study, N=32 actinobacteria strains were recovered from the soil of Neelum Valley, Kashmir, Pakistan, to screen their inhibitory activity and metabolomic potential against MDR typhoidal Salmonella. The TLC pattern and HPLC-UV-MS analysis of the extracts of isolated strains showed the presence of a variety of bioactive compounds. The actinobacteria strains B6, D13, B11.2 and others were found to be the most prolific producers of diverse secondary metabolites. In the screening for inhibitory activity against MDR typhoidal Salmonella, the extracts of strains B6, B16, B21 and D13 were found to be the most active exhibiting up to 20 mm zone of inhibition. Similarly, the cytotoxicity potential of the extracts against Artemiasalina by determining %larval mortality, the extract of strain Kel 1311A showed 91% mortality followed by the extracts of strains AzB1, kel 1391, B13, B8, and B4 showed % mortality up to 87.3%. 90%, 88% and 85.41% respectively. The HPLC-UV/MS analysis revealed the presence of a variety
of compounds with molecular weights of 400, 510 and 519 Daltons in the extract of strain B4 and 651, 356, 378 and 400 Daltons in the extracts of strain D13. The study suggested that actinobacteria living in the soil of Neelum Valley Kashmir are a rich source of novel bio-active, cytotoxic and anti-microbial compounds.