title: Only a subset of C. canimorsus strains is dangerous for humans.
abstract: Capnocytophaga canimorsus are gram-negative bacteria living as commensals in the mouth of dogs and cats. C. canimorsus cause rare but life-threatening generalized infections in humans that have been in contact with a dog or a cat. Over the last years we collected 105 C. canimorsus strains from different geographical origins and from severe human infections or healthy dogs. All these strains were analyzed by 16S rDNA sequencing and a phylogenetic tree revealed two main groups of bacteria instead of one with no relation to the geographical origin. This branching was confirmed by the whole-genome sequencing of 10 strains, supporting the evidence of a new Capnocytophaga species in dogs. Interestingly, 19 out of 19 C. canimorsus strains isolated from human infections belonged to the same species. Furthermore, most strains from this species could grow in heat-inactivated human serum (HIHS) (40/46 tested), deglycosylate IgM (48/66) and were cytochrome-oxidase positive (60/66) while most strains from the other species could not grow in HIHS (22/23 tested), could not deglycosylate IgM (33/34) and were cytochrome-oxidase negative (33/34). Here, we propose to call Capnocytophaga canis (Latin: dog) the novel, presumably less virulent dog-hosted Capnocytophaga species and to keep the name C. canimorsus for the species including human pathogens.
authors.affiliation: Département de Biologie, Université de Namur , 5000 Namur, Belgium.
authors.forename: Francesco
authors.initials: F
authors.lastname: Renzi
authors.affiliation: Département de Biologie, Université de Namur , 5000 Namur, Belgium.
authors.forename: Melanie
authors.initials: M
authors.lastname: Dol
authors.affiliation: Département de Biologie, Université de Namur , 5000 Namur, Belgium.
authors.forename: Alice
authors.initials: A
authors.lastname: Raymackers
authors.affiliation: Biozentrum der Universität Basel , CH-4056 Basel, Switzerland.
authors.forename: Pablo
authors.initials: P
authors.lastname: Manfredi
authors.affiliation: Département de Biologie, Université de Namur , 5000 Namur, Belgium ; Biozentrum der Universität Basel , CH-4056 Basel, Switzerland.
authors.forename: Guy Richard
authors.initials: GR
authors.lastname: Cornelis
mesh_terms: D000818:Animals; D002206:Capnocytophaga / Q000145:classification* / Q000201:enzymology / Q000235:genetics / Q000472:pathogenicity; D002415:Cats; D016384:Consensus Sequence; D004275:DNA, Ribosomal / Q000737:chemistry* / Q000302:isolation & purification; D004283:Dog Diseases / Q000382:microbiology* / Q000635:transmission; D004285:Dogs; D003576:Electron Transport Complex IV / Q000378:metabolism; D016680:Genome, Bacterial / Q000235:genetics; D055106:Genome-Wide Association Study; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology* / Q000635:transmission; D006801:Humans; D007075:Immunoglobulin M / Q000378:metabolism; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods / Q000592:standards; D011134:Polysaccharides / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012463:Saliva / Q000382:microbiology; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal; D007075:Immunoglobulin M; D011134:Polysaccharides; D012336:RNA, Ribosomal, 16S; D003576:Electron Transport Complex IV
keywords: ANI; bacterial taxonomy; commensalism; genome comparison; pathogenesis