title: A novel subpopulation of Salmonella enterica serovar Infantis strains isolated from broiler chicken organs other than the gastrointestinal tract.
abstract: Salmonella enterica subsp. enterica serovar Infantis strains were isolated from broiler chickens from six farms in Japan and the pathogenicity associated with the recently reported 280kbp mega plasmid was examined by possession of the plasmid and histopathology of tissues from these chickens. S. Infantis strains were isolated from 10 of 24 chickens. Phylogenetic, network and Bayesian cluster analyses were used to determine whether these strains were in the previously defined Clusters 1-5. Phylogenetic analysis classified the strains isolated in this study in two groups (Groups A and B). Both groups contained strains from gastrointestional contents, but only Group A also contained strains from spleen, liver, and lymphoid tissues. Histopathology showed suppurative splenitis in a spleen from which Group A strains were isolated. Although network and Bayesian cluster analyses were unable to differentiate Group A and B strains from the previously defined Clusters 1-5, population genetic analysis indicated that Group A was a different population from Cluster 5, indicating that Group A would be a subpopulation of Cluster 5. The irp2 gene, which is in the mega plasmid carried by a pathogenic S. Infantis strain recently isolated in Israel, was found in both Groups A and B strains and in the previously reported Clusters 4 and 5 strains. These results suggested that Group A would be a novel subpopulation of the previously defined Cluster 5, and presence of the mega plasmid may not be related whether S. Infantis strains can infect certain organs.
authors.affiliation: Division of Bacteriology, Chiba Prefectural Institute of Public Health, 666-2 Nitona, Chuo, Chiba City, Chiba 260-8715, Japan. Electronic address: e.ykym@pref.chiba.lg.jp.
authors.forename: Eiji
authors.initials: E
authors.lastname: Yokoyama
authors.affiliation: Division of Bacteriology, Chiba Prefectural Institute of Public Health, 666-2 Nitona, Chuo, Chiba City, Chiba 260-8715, Japan.
authors.forename: Naoshi
authors.initials: N
authors.lastname: Ando
authors.affiliation: Laboratory of Animal Hygiene, Department of Animal Science, Tokyo University of Agriculture, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ohta
authors.affiliation: Laboratory of Animal Hygiene, Department of Animal Science, Tokyo University of Agriculture, Japan.
authors.forename: Akina
authors.initials: A
authors.lastname: Kanada
authors.affiliation: Genome Research Center, NODAI Research Institute, Tokyo University of Agriculture, Japan.
authors.forename: Yuh
authors.initials: Y
authors.lastname: Shiwa
authors.affiliation: Genome Research Center, NODAI Research Institute, Tokyo University of Agriculture, Japan.
authors.forename: Taichiro
authors.initials: T
authors.lastname: Ishige
authors.affiliation: Division of Pathology and Bacteriology, Fukuoka Institute of Health and Environmental Sciences, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Murakami
authors.affiliation: Division of Bacteriology, Chiba Prefectural Institute of Public Health, 666-2 Nitona, Chuo, Chiba City, Chiba 260-8715, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kikuchi
authors.affiliation: Laboratory of Animal Hygiene, Department of Animal Science, Tokyo University of Agriculture, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Murakami
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001499:Bayes Theorem; D002645:Chickens / Q000382:microbiology*; D016172:DNA Fingerprinting; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D007564:Japan / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D010957:Plasmids / Q000187:drug effects; D011201:Poultry Diseases / Q000453:epidemiology / Q000382:microbiology*; D012481:Salmonella Infections, Animal / Q000453:epidemiology / Q000382:microbiology*; D019779:Salmonella enterica / Q000145:classification* / Q000187:drug effects / Q000235:genetics; D065288:Serogroup
chemical_list: D000900:Anti-Bacterial Agents
keywords: Pathogenicity; Phylogeny; SNPs; Salmonella enterica subsp. enterica serovar Infantis