Abstract

Antibiotic resistant infections are caused by antibiotic resistant microorganisms. According to World Health Organization (WHO) antibiotic resistance is one of the major threats to global health,
food and development. The increasing rate of mortalities caused by antibiotic resistant infections has highlighted the need to find a way to tackle these resistant microbes. One of the ways to solve this problem is to introduce novel antibiotics, the likes of which bacteria have not encountered before. Most of the antibiotics are natural products derived from bacteria. Among these natural product producers, myxobacteria have proven themselves as one of the main sources of antibiotics.
These bacteria carry large numbers of gene clusters that can express different secondary metabolites for various purposes. Most of these gene clusters can encode secondary metabolites that not only help the bacteria to survive but also can be biologically active. Marine myxobacteria, in particular, produce biologically active natural products that are different from the ones terrestrial myxobacteria make. Therefore in this study we looked into an environment with unique conditions from terrestrial or marine, Gulf of Saint-Lawrence, to find novel strains from the marine myxobacterial clade. Sediment samples were extracted from six stations in Gulf of SaintLawrence. Based on the studies conducted on the DNA content of the sediments we learned that the primers that were previously designed to specifically target MMC were also detecting other strains of bacteria closely related to MMC. Furthermore, we isolated the RNA content of the sediment samples to get an insight into their metabolic activity. For this purpose we employed qPCR techniques to measure their abundance and ribosome content. Furthermore, in an attempt to
cultivate marine myxobacterial clade (MMC) we isolated the bacteria present in the sediment samples to use them as prey for marine myxobacterial clade. Based on qPCR studies we were able to conclude that the MMC were growing actively under estuary conditions. However, the attempt to cultivate the MMC on the bait plates led to emergence of vancomycin resistant Bacillus strains
along with other saprophytes on the plates. These findings suggest that members of the MMC are active under the Estuary condition and can be cultivated if subjected to the same condition as present in the Estuary of St-Lawrence.