Adherence of Clostridium perfringens spores to human intestinal epithelial Caco-2 cells

Molecular identification of hyaluronate lyase, not hyaluronidase, as an intrinsic hyaluronan-degrading enzyme in Clostridium perfringens strain ATCC 13124

Clostridium perfringens, an opportunistic pathogen, produces mu-toxin hyaluronidases including endo-β-N-acetylglucosaminidases (Nags) as a virulence invasion factor. To clarify an intrinsic factor for degradation of host extracellular hyaluronan, we focused on hyaluronate lyase (HysA), distinct from endo-β-N-acetylglucosaminidases. C. perfringens strain ATCC 13124 was found to assimilate host-derived extracellular mucosubstances, hyaluronan and mucin, which induced expression of the hyaluronan-related genetic cluster, including hyaluronate lyase gene (hysA), but repressed endo-β-N-acetylglucosaminidase genes. This genetic cluster is conserved in some strains of C. perfringens. The recombinant strain ATCC 13124 hyaluronate lyase HysA showed an hyaluronan-degrading activity through β-elimination reaction. The hyaluronan-degrading enzyme in the culture supernatant of strain ATCC 13124 exhibited the lyase activity and was identical to the recombinant hyaluronate lyase on the native-PAGE gel, followed by activity straining. These results demonstrated that the intrinsic hyaluronan-degrading enzyme of C. perfringens strain ATCC 13124 is hyaluronate lyase HysA, but not hyaluronidases NagH, NagJ, and NagK.

Isolation of a Virulent Clostridium perfringens Strain from Elaphurus davidianus and Characterization by Whole-Genome Sequence Analysis

Clostridium perfringens (C. perfringens) is an important veterinary pathogen and a noteworthy threat to human and animal health. Recently, there has been a significant rise in the number of moose fatalities caused by this rare, endemic species in China. Currently, there is an increasing trend in conducting whole-genome analysis of C. perfringens strains originating from pigs and chickens, whereas fewer studies have been undertaken on Elaphurus davidianus-originating strains at the whole-genome level. Our laboratory has identified and isolated five C. perfringens type A from affected Elaphurus davidianus. The current study identified the most potent strain of C. perfringens, which originated from Elaphurus davidianus, and sequenced its genome to reveal virulence genes and pathogenicity. Our findings show that strain CX1-4 exhibits the highest levels of phospholipase activity, hemolytic activity, and mouse toxicity compared to the other four isolated C. perfringens type A strains. The chromosome sequence length of the CX1-4 strain was found to be 3,355,389 bp by complete genome sequencing. The current study unveils the genomic characteristics of C. perfringens type A originating from Elaphurus davidianus. It provides a core foundation for further investigation regarding the prevention and treatment of such infectious diseases in Elaphurus davidianus.

Focal duodenal necrosis in chickens: attempts to reproduce the disease experimentally and diagnostic considerations

Focal duodenal necrosis (FDN) is an intestinal disease of egg-layer chickens characterized by multifocal necrosis of the duodenal loop and proximal jejunum. Affected flocks usually have decreased egg weights and drops in egg production. Previous studies have associated this condition with Clostridium perfringens infection. We tried to reproduce FDN by experimental infection of egg-laying chickens using different netB-positive and netB-negative C. perfringens strains, and duodenal homogenate obtained from FDN lesions. Chickens challenged with C. perfringens and/or duodenal homogenate developed duodenitis after challenge. Gross lesions included mucosal erosions, hyperemia, mucosal hemorrhages, and watery intestinal content. Microscopic lesions included mild enterocyte degeneration and necrosis, and mild-to-moderate hemorrhage and lymphoplasmacytic and heterophilic infiltration of the lamina propria. Two netB-positive C. perfringens strains closely related to necrotic enteritis pathogenic strains, by genomic composition, were re-isolated from lesions. Necrosis of intestinal crypts was observed in chickens challenged with duodenal homogenate with or without C. perfringens coinfection. Characteristic microscopic FDN lesions with significant necrosis and loss of villus enterocytes were not reproduced.