Genome sequencing of multidrug resistant novel Clostridium sp. BL8 reveals its potential for pathogenicity

BACKGROUND: The human gut microbiome is important for maintaining the health status of the host. Clostridia are key members of the human gut microbiome, carrying out several important functions in the gut environment. Hence understanding the role of different Clostridium species isolated from human gut is essential. The present study was aimed at investigating the role of novel Clostridium sp. isolate BL8 in human gut using genome sequencing as a tool. FINDINGS: The genome analysis of Clostridium sp. BL8 showed the presence of several adaptive features like bile resistance, presence of sensory and regulatory systems, presence of oxidative stress managing systems and presence of membrane transport systems. The genome of Clostridium sp. BL8 consists of a wide variety of virulence factors like phospholipase C (alpha toxin), hemolysin, aureolysin and exfoliative toxin A, as well as adhesion factors, proteases, Type IV secretion system and antibiotic resistance genes. In vitro antibiotic sensitivity testing showed that Clostridium sp. BL8 was resistant to 11 different tested antibiotics belonging to 6 different classes. The cell cytotoxicity assay confirmed the cytotoxic effect of Clostridium sp. BL8 cells, which killed 40% of the Vero cells after 4 hrs of incubation. CONCLUSIONS: Clostridium sp. BL8 has adapted for survival in human gut environment, with presence of different adaptive features. The presence of several virulence factors and cell cytotoxic activity indicate that Clostridium sp. BL8 has a potential to cause infections in humans, however further in vivo studies are necessary to ascertain this fact

Liebetanzomyces polymorphus gen. et sp. nov., a new anaerobic fungus (Neocallimastigomycota) isolated from the rumen of a goat

An extended incubation strategy to culture slow growing members of anaerobic fungi resulted in the isolation of a novel anaerobic fungus from the rumen of a goat after 15 days. The novel genus, represented by type strain G1SC, showed filamentous monocentric thallus development and produced uniflagellate zoospores, hence, showing morphological similarity to the genera Piromyces, Buwchfawromyces, Oontomyces and Pecoramyces. However, strain G1SC showed genetic similarity to the genus Anaeromyces, which, though produces uniflagellate zoospore, also exhibits polycentric thallus development. Moreover, unlike Anaeromyces, strain G1SC did not show hyphal constrictions, instead produced a branched, determinate and anucleate rhizoidal system. This fungus also displayed extensive sporangial variations, both exogenous and endogenous type of development, short and long sporangiophores and produced septate sporangia. G1SC utilised various complex and simple substrates, including rice straw and wheat straw and produced H2, CO2, formate, acetate, lactate, succinate and ethanol. Phylogenetic analysis, using internal transcribed spacer 1 (ITS1) and D1/D2 domain of large-subunit (LSU) rRNA locus, clearly showed a separate lineage for this strain, near Anaeromyces. The ITS1 based geographical distribution studies indicated detection of environmental sequences similar (93–96%) to this strain from cattle faeces. Based on morphological and molecular characterisation results of strain G1SC, we propose a novel anaerobic fungus Liebetanzomyces polymorphus gen. et sp. nov., in the phylum Neocallimastigomycota