Copp, B. R. | Search bioRxiv

bioRxiv2025

Using a "one-strain-many-compounds" (OSMAC) approach to screen a collection of diverse fungi from Aotearoa New Zealand for antibacterial activity against Escherichia coli

There is an urgent need to identify new chemical compounds with novel modes of action to help manage the antimicrobial resistance crisis. Fungi are prolific producers of secondary metabolites, including those with antimicrobial properties, and contain biosynthetic gene clusters that awaken only under certain growth conditions. In recent years, a wealth of novel fungal biosynthetic pathways and compounds have been identified, suggesting fungi remain a viable source for developing new antimicrobials. The International Collection of Microorganisms from Plants (ICMP) contains thousands of fungi and bacteria primarily sourced from Aotearoa New Zealand. Here, we report the results of our efforts to screen 32 fungal ICMP isolates for activity against Escherichia coli, a leading cause of deaths attributable to antimicrobial resistance. We used a one strain-many compounds (OSMAC) approach, growing the ICMP isolates on seven different media with different pH and various carbon and nitrogen sources. We also tested the isolates for activity at various ages. Our results indicate that several of the tested fungi possess anti-E. coli activity and are suitable for further study, including the aero-aquatic Ascomycete Hyaloscypha sp. ICMP 16864. Our results also provide further strong evidence for the impact of media on both fungal growth and bioactivity.

microbiology↗

bioRxiv2016

Effect of common and experimental anti-tuberculosis treatments on Mycobacterium tuberculosis growing as biofilms

Much is known regarding the antibiotic susceptibility of planktonic cultures of Mycobacterium tuberculosis, the bacterium responsible for the lung disease tuberculosis (TB). As planktonically-grown M. tuberculosis are unlikely to be entirely representative of the bacterium during infection, we set out to determine how effective a range of anti-mycobacterial treatments were against M. tuberculosis growing as a biofilm, a bacterial phenotype known to be more resistant to antibiotic treatment. Light levels from bioluminescently-labelled M. tuberculosis H37Rv (strain BSG001) were used as a surrogate for bacterial viability, and were monitored before and after 1 week of treatment. After treatment, biofilms were disrupted, washed and inoculated into fresh broth and plated onto solid media to rescue any surviving bacteria. We found that in this phenotypic state M. tuberculosis was resistant to the majority of the compounds tested. Minimum inhibitory concentrations (MICs) increased by 20-fold to greater than 1000-fold, underlying the potential of this phenotype to cause significant problems during treatment.

microbiology↗