title: Comparative genomic hybridization analysis shows different epidemiology of chromosomal and plasmid-borne cpe-carrying Clostridium perfringens type A.
abstract: Clostridium perfringens, one of the most common causes of food poisonings, can carry the enterotoxin gene, cpe, in its chromosome or on a plasmid. C. perfringens food poisonings are more frequently caused by the chromosomal cpe-carrying strains, while the plasmid-borne cpe-positive genotypes are more commonly found in the human feces and environmental samples. Different tolerance to food processing conditions by the plasmid-borne and chromosomal cpe-carrying strains has been reported, but the reservoirs and contamination routes of enterotoxin-producing C. perfringens remain unknown. A comparative genomic hybridization (CGH) analysis with a DNA microarray based on three C. perfringens type A genomes was conducted to shed light on the epidemiology of C. perfringens food poisonings caused by plasmid-borne and chromosomal cpe-carrying strains by comparing chromosomal and plasmid-borne cpe-positive and cpe-negative C. perfringens isolates from human, animal, environmental, and food samples. The chromosomal and plasmid-borne cpe-positive C. perfringens genotypes formed two distinct clusters. Variable genes were involved with myo-inositol, ethanolamine and cellobiose metabolism, suggesting a new epidemiological model for C. perfringens food poisonings. The CGH results were complemented with growth studies, which demonstrated different myo-inositol, ethanolamine, and cellobiose metabolism between the chromosomal and plasmid-borne cpe-carrying strains. These findings support a ubiquitous occurrence of the plasmid-borne cpe-positive strains and their adaptation to the mammalian intestine, whereas the chromosomal cpe-positive strains appear to have a narrow niche in environments containing degrading plant material. Thus the epidemiology of the food poisonings caused by two populations appears different, the plasmid-borne cpe-positive strains probably contaminating foods via humans and the chromosomal strains being connected to plant material.
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland. paivi.lahti@helsinki.fi
authors.forename: Päivi
authors.initials: P
authors.lastname: Lahti
authors.forename: Miia
authors.initials: M
authors.lastname: Lindström
authors.forename: Panu
authors.initials: P
authors.lastname: Somervuo
authors.forename: Annamari
authors.initials: A
authors.lastname: Heikinheimo
authors.forename: Hannu
authors.initials: H
authors.lastname: Korkeala
mesh_terms: D000818:Animals; D002475:Cellobiose / Q000235:genetics / Q000378:metabolism; D002876:Chromosomes, Bacterial; D003015:Clostridium Infections / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*; D003016:Clostridium perfringens / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D055028:Comparative Genomic Hybridization; D004768:Enterotoxins / Q000235:genetics* / Q000378:metabolism; D019856:Ethanolamine / Q000378:metabolism; D005387:Finland / Q000453:epidemiology; D005517:Foodborne Diseases / Q000453:epidemiology / Q000382:microbiology; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D007294:Inositol / Q000235:genetics / Q000378:metabolism; D005810:Multigene Family; D010802:Phylogeny; D010957:Plasmids; D012703:Serotyping
chemical_list: D004768:Enterotoxins; D002475:Cellobiose; D007294:Inositol; D019856:Ethanolamine