Antarctic bacteria as producers of antibiotic volatile compounds inhibiting cystic fibrosis pathogens

Microorganisms from extreme environments, such as Antarctica, are interesting since they have adopted peculiar survival strategies e.g. the synthesis of unusual bioactive molecules inhibiting the growth of other bacteria. In this work 26 Antarctic bacterial strains affiliated to different genera were tested for their ability to produce new natural drugs active versus member of the Burkholderia cepacia complex (Bcc), relevant pathogens in Cystic Fibrosis (CF) patients. The experiments were performed adopting the cross-streaking method using as target a panel of 40 Bcc strains. Moreover we tested the influence of the growth media on the ability of these Antarctic bacteria to inhibit the growth of Bcc species. To this purpose cross-streak experiments were carried out using Petri dishes with a central septum. The tester strains were grown on three different media, MA, TYP and PCA whereas Bcc (target) strains were grown only on PCA medium. Data obtained clearly revealed that most of Antarctic bacteria completely inhibit the growth of all the Bcc strains, probably through the production of a combination of diffusible and volatile molecules. Furthermore the production of such molecules may vary depending on the medium the tester strains are grown in. Further experiments performed by the SPME-GC-MS technique, revealed the production of different compounds. Finally these data highlight the potentiality of Antarctic bacteria as novel sources of antibacterial substances. For this reason the genomes of these 26 Antarctic strains were sequenced and assembled and further analysis will be conducted in order to identify the gene sets involved in the production of the volatile compounds.