Antimicrobial producing bacteria isolated from tropical peat swamp soil

Abstract

Aims: The aims of this study were to isolate and characterize antimicrobial producing bacteria from tropical peat swamp forest soils. Methodology and results: Bacteria isolated from peat soil were screened for antimicrobial properties via agar overlay assay. Broth microdilution was performed using crude-cell free supernatant (CCFS) to determine the minimum inhibitory concentration (MIC). One isolate was selected due to its broad spectrum activity and identified as Burkholderia spp. with a maximum identity of 99% via 16s rRNA gene PCR. This isolate was able to produce antimicrobials that were active against several Gram positive bacteria, Gram negative bacteria and also yeast. The antimicrobial activity of the CCFS was stable at a pH range of 1 to 11, temperatures of −20 ° C to 80 ° C, and after treatment with several proteolytic enzymes: α-chymotrypsin, proteinase K and trypsin, indicating that the antimicrobial produced might not be proteinaceous in nature. It is possible that the isolate can produce polyketides, a type of antimicrobial compound produced by Burkholderia known to be resistant to proteolytic enzymes. However, further work needs to be done to confirm this. Conclusion, significance and impact of study: The presence of antimicrobial producing bacteria signified that tropical peat swamps are indeed a potential source for antimicrobials to combat infections.