Potential of Bacillus spp. Showing Antagonistic Activity against Some Bacterial and Fungal Pathogens

Abstract

The agricultural productivity losses and human health decline due to microbial pathogens have been a serious issue in Pakistan and rest of the world. Present work was designed to isolate soil borne microorganisms having antagonistic ability against notorious phyto and human pathogens. From the initial collection of 08 bacterial isolates, two potent strains of Bacillus were screened on the basis of their comparative efficacy against devastating fungal and bacterial pathogens. The strains AAM-1 and AK-47 showed excellent inhibitory indexes against selected pathogens. It was noted that both strains of Bacillus showed significant bio-control activity against plant pathogens like Aspergillus flavus, Fusarium moniliforme, Colletotricum falcatum, Botrytis cinerea, Aspergillus niger, Fusarium oxysporum, Phythopthora capsici and Rhizopus oryzae. In addition both isolates showed significant inhibitory indexes against selected human pathogens namely Salmonella typhi, Escherichia coli, Klebsella pneumoniae, Staphylococcus aureus, Acinitobacter baumannii and Listeria monocytogenes. The strain AAM-1 was efficient to suppress Fusarium species while AK-47 expressed significant antagonistic activity against Aspergillus species, Fusarium species, Botrytis cinerea and Colletotricum falcatum. On the basis of in vitro assay, it can postulated that the Bacillus strains AAM-1 and AK-47 can be used as bio-protective agent against various plant diseases and can also be used as a source of antibiotic production against aforesaid human pathogens. In addition, their applications as natural pesticides could be very helpful to prevent the adverse effects of chemical pesticides.