title: Comparative Genome Analyses of Streptococcus suis Isolates from Endocarditis Demonstrate Persistence of Dual Phenotypic Clones.
abstract: Many bacterial species coexist in the same niche as heterogeneous clones with different phenotypes; however, understanding of infectious diseases by polyphenotypic bacteria is still limited. In the present study, encapsulation in isolates of the porcine pathogen Streptococcus suis from persistent endocarditis lesions was examined. Coexistence of both encapsulated and unencapsulated S. suis isolates was found in 26 out of 59 endocarditis samples. The isolates were serotype 2, and belonged to two different sequence types (STs), ST1 and ST28. The genomes of each of the 26 pairs of encapsulated and unencapsulated isolates from the 26 samples were sequenced. The data showed that each pair of isolates had one or more unique nonsynonymous mutations in the cps gene, and the encapsulated and unencapsulated isolates from the same samples were closest to each other. Pairwise comparisons of the sequences of cps genes in 7 pairs of encapsulated and unencapsulated isolates identified insertion/deletions (indels) ranging from one to 104 bp in different cps genes of unencapsulated isolates. Capsule expression was restored in a subset of unencapsulated isolates by complementation in trans with cps expression vectors. Examination of gene content common to isolates indicated that mutation frequency was higher in ST28 pairs than in ST1 pairs. Genes within mobile genetic elements were mutation hot spots among ST28 isolates. Taken all together, our results demonstrate the coexistence of dual phenotype (encapsulated and unencapsulated) bacterial clones and suggest that the dual phenotypes arose independently in each farm by means of spontaneous mutations in cps genes.
authors.affiliation: Research Center for Food Safety, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Tohya
authors.affiliation: Research Center for Food Safety, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Takayasu
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Department of Microbiology, Kyoto University Graduate School of Medicine, Kyoto, Kyoto, Japan.
authors.forename: Fumito
authors.initials: F
authors.lastname: Maruyama
authors.affiliation: Research Center for Food Safety, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Sakura
authors.initials: S
authors.lastname: Arai
authors.affiliation: Department of Microbiology, Kyoto University Graduate School of Medicine, Kyoto, Kyoto, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ota
authors.affiliation: Public Health Ontario, Toronto, Ontario, Canada.
authors.forename: Taryn B T
authors.initials: TB
authors.lastname: Athey
authors.affiliation: Public Health Ontario, Toronto, Ontario, Canada.|Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Nahuel
authors.initials: N
authors.lastname: Fittipaldi
authors.affiliation: Department of Microbiology, Kyoto University Graduate School of Medicine, Kyoto, Kyoto, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Nakagawa
authors.affiliation: Research Center for Food Safety, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Sekizaki
mesh_terms: D000818:Animals; D016667:Bacterial Capsules / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002999:Clone Cells; D055028:Comparative Genomic Hybridization; D004696:Endocarditis / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D015870:Gene Expression; D005816:Genetic Complementation Test; D016680:Genome, Bacterial; D054643:INDEL Mutation; D020071:Interspersed Repetitive Sequences; D005810:Multigene Family; D059645:Mutation Rate; D010641:Phenotype; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D065288:Serogroup; D013290:Streptococcal Infections / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D017011:Streptococcus suis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology* / Q000473:pathology; D014774:Virulence
chemical_list: D001426:Bacterial Proteins