title: Contributions of NanI sialidase to Caco-2 cell adherence by Clostridium perfringens type A and C strains causing human intestinal disease.
abstract: Previous studies showed that Clostridium perfringens type D animal disease strain CN3718 uses NanI sialidase for adhering to enterocyte-like Caco-2 cells. The current study analyzed whether NanI is similarly important when type A and C human intestinal disease strains attach to Caco-2 cells. A PCR survey determined that the nanI gene was absent from typical type A food poisoning (FP) strains carrying a chromosomal enterotoxin (CPE) gene or the genetically related type C Darmbrand (Db) strains. However, the nanI gene was present in type A strains from healthy humans, type A strains causing CPE-associated antibiotic-associated diarrhea (AAD) or sporadic diarrhea (SD), and type C Pig-Bel strains. Consistent with NanI sialidase being the major C. perfringens sialidase when produced, FP and Db strains had little supernatant sialidase activity compared to other type A or C human intestinal strains. All type A and C human intestinal strains bound to Caco-2 cells, but NanI-producing strains had higher attachment levels. When produced, NanI can contribute to host cell attachment of human intestinal disease strains, since a nanI null mutant constructed in type A SD strain F4969 had lower Caco-2 cell adhesion than wild-type F4969 or a complemented strain. Further supporting a role for NanI in host cell attachment, sialidase inhibitors reduced F4969 adhesion to Caco-2 cells. Collectively, these results suggest that NanI may contribute to the intestinal attachment and colonization needed for the chronic diarrhea of CPE-associated AAD and SD, but this sialidase appears to be dispensable for the acute pathogenesis of type A FP or type C enteritis necroticans.
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Jihong
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA bamcc@pitt.edu.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: McClane
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology*; D018938:Caco-2 Cells; D003015:Clostridium Infections / Q000382:microbiology*; D003016:Clostridium perfringens / Q000145:classification* / Q000201:enzymology / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D006801:Humans; D007410:Intestinal Diseases / Q000382:microbiology*; D009154:Mutation; D009439:Neuraminidase / Q000235:genetics / Q000378:metabolism*
chemical_list: D009439:Neuraminidase