title: Secondary metabolites from Bacillus amyloliquefaciens isolated from soil can kill Burkholderia pseudomallei.
abstract: Bacillus species are Gram-positive bacteria found in abundance in nature and their secondary metabolites were found to possess various potential activities, notably antimicrobial. In this study, Bacillus amyloliquefaciens N2-4 and N3-8 were isolated from soil and their metabolites could kill Burkholderia pseudomallei, a Gram-negative pathogenic bacterium also found in soil in its endemic areas. Moreover, the metabolites were able to kill drug resistant isolates of B. pseudomallei and also inhibit other pathogenic bacteria such as Staphylococcus aureus, Escherichia coli and Acinetobacter baumannii but not the non-pathogenic Burkholderia thailandensis, which is closely related to B. pseudomallei. Since the antimicrobial activity of N3-8 was not partially decreased or abolished when treated with proteolytic enzymes or autoclaved, but N2-4 was, these two strains should have produced different compounds. The N3-8 metabolites with antimicrobial activity consisted of both protein and non-protein compounds. The inhibition spectrum of the precipitated proteins compared to the culture supernatant indicated a possible synergistic effect of the non-protein and peptide compounds of N3-8 isolates against other pathogens. When either N2-4 or N3-8 isolates was co-cultured with B. pseudomallei the numbers of the bacteria decreased by 5 log10within 72 h. Further purification and characterization of the metabolites is required for future use of the bacteria or their metabolites as biological controls of B. pseudomallei in the environment or for development as new drugs for problematic pathogenic bacteria.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Khon Kaen University, 123 Mitraparb Rd, Muang District, Khon Kaen Province, 40002, Thailand.|Melioidosis Research Centre, Khon Kaen University, 123 Mitraparb Rd, Muang District, Khon Kaen Province, 40002, Thailand.
authors.forename: Patcharaporn
authors.initials: P
authors.lastname: Boottanun
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Khon Kaen University, 123 Mitraparb Rd, Muang District, Khon Kaen Province, 40002, Thailand.|Melioidosis Research Centre, Khon Kaen University, 123 Mitraparb Rd, Muang District, Khon Kaen Province, 40002, Thailand.
authors.forename: Chotima
authors.initials: C
authors.lastname: Potisap
authors.affiliation: Center for Infectious and Inflammatory diseases, Institute of Biosciences and Technology, Texas A&M University, 2121W. Holcombe Blvd, Houston, TX, 77030, USA.
authors.forename: Julian G
authors.initials: JG
authors.lastname: Hurdle
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Khon Kaen University, 123 Mitraparb Rd, Muang District, Khon Kaen Province, 40002, Thailand. rasana@kku.ac.th.|Melioidosis Research Centre, Khon Kaen University, 123 Mitraparb Rd, Muang District, Khon Kaen Province, 40002, Thailand. rasana@kku.ac.th.
authors.forename: Rasana W
authors.identifier: http://orcid.org/0000-0002-3691-5064
authors.initials: RW
authors.lastname: Sermswan
keywords: Antimicrobial peptides; Bio-control; Pathogenic bacteria; Secondary metabolites