Aim: Corallococcus species are diverse in the natural environment with ten new Corallococcus species having been characterised in just the last five years. As well as being an abundant myxobacterial genus they produce several secondary metabolites, including Corallopyronin, Corramycin, Coralmycin and Corallorazine. We isolated a novel strain Corallococcus spp RDP092CA from soil in South Wales, United Kingdom using Candida albicans as prey bait and characterised its predatory activities against pathogenic bacteria and yeast.
Methods and results: The size of the RDP092CA genome was 8.5 Mb with a G + C content of 71.4%. Phylogenetically, RDP092CA is closely related to Corallococcus interemptor, Corallococcus coralloides and Corallococcus exiguus. However, genome average nucleotide identity and digital DNA-DNA hybridisation values are lower than 95% and 70% when compared to those type strains, implying it belongs to a novel species. The RDP092CA genome harbours seven types of biosynthetic gene clusters (BGCs) and 152 predicted antimicrobial peptides. In predation assays, RDP092CA showed good predatory activity against Escherichia coli, Pseudomonas aeruginosa, Citrobacter freundii, Staphylococcus aureus but not against Enterococcus faecalis. It also showed good antibiofilm activity against all five bacteria in biofilm assays. Antifungal activity against eight Candida spp. was variable, with particularly good activity against Meyerozyma guillermondii DSM 6381. Antimicrobial peptide RDP092CA_120 exhibited potent antibiofilm activity with > 50% inhibition and > 60% dispersion of biofilms at concentrations down to 1 μg/ml.
Conclusion: We propose that strain RDP092CA represents a novel species with promising antimicrobial activities, Corallococcus senghenyddensis sp. nov (=NBRC 116490T = CCOS 2109T), based on morphological, biochemical, and genomic features.
Keywords: antimicrobial peptide; biofilm; corallococcus; genome sequences; predation.
© The Author(s) 2024. Published by Oxford University Press on behalf of Applied Microbiology International.