With the emergence of antimicrobial-resistant microorganisms, daily infections that in the past were easily treatable have become difficult to control or, in some cases, impossible to treat. Thus, antimicrobial resistance has become a top global public health and development threat. Consequently, the need for new antibiotics is a critical action point in the strategy to control the issue. Isolates from exceptional and challenging habitats offer a rich source for discovering new species with antimicrobial potential.
This study evaluates the antimicrobial activity of three bacterial strains isolated from soil samples of Angola termite mounds. Identification, using phylogenetic analysis based on 16S rDNA sequences, indicates that they are three potentially new species belonging to the genus Micromonospora, which is recognized for its potential to produce natural bioactive compounds.
In vivo assays, whole-cell biosensors, and genome mapping was then applied to determine their potential as antibiotic producers. The antimicrobial activity was evaluated using indicator microorganisms of the Gram-positive (Bacillus subtilis), Gram-negative (Escherichia coli), and fungi (Penicillium chrysogenum). A collection of Bacillus subtilis whole-cell biosensors was screened to elucidate the mechanism of actions of the antimicrobial response. Antimicrobial activity against Gram-positive bacteria was observed for the three isolates, showing their potential as producers of antibiotic compounds, and studies are carried out to determine the mechanism of action. In vivo antimicrobial assays with pathogenic microorganisms, as well as polyphasic taxonomic studies and genome mining for secondary metabolite gene clusters of the three isolates are currently ongoing.