title: Delineation of the genus Actinobacillus by comparison of partial infB sequences.
abstract: A 426 bp fragment of infB, a housekeeping gene that encodes translation initiation factor 2, was sequenced from 59 clinical isolates and type strains of Actinobacillus species and sequences were compared. Partial sequences of 16S rRNA genes were also obtained. By comparing infB sequences, Actinobacillus pleuropneumoniae, Actinobacillus equuli, Actinobacillus suis, Actinobacillus ureae, Actinobacillus arthritidis, Actinobacillus hominis and two unnamed genomospecies showed more than 85 % similarity to the type strain of the type species of the genus, Actinobacillus lignieresii. The taxonomic position of Actinobacillus capsulatus was unresolved; this species is more remotely related to A. lignieresii. The two species A. lignieresii and A. pleuropneumoniae could not be clearly separated by infB sequence analysis. The phylogeny of the genus Actinobacillus based on infB analysis was essentially congruent with relationships inferred from 16S rRNA sequence comparisons and DNA hybridization studies. Discrepancies were encountered with single strains or taxa at the periphery of the genus. Greater intraspecies variation was observed with infB sequences than with 16S rRNA gene sequences, with notable exceptions. The apparent subdivision of some species by 16S rRNA analysis was most likely caused by RNA operon heterogeneity.
authors.affiliation: Department of Medical Microbiology and Immunology, University of Aarhus, Aarhus, Denmark.|Department of Clinical Microbiology, Aalborg Hospital, Aalborg, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Nørskov-Lauritsen
authors.affiliation: Department of Veterinary Microbiology, The Royal Veterinary and Agricultural University, Copenhagen, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Christensen
authors.affiliation: Department of Clinical Biochemistry, Aalborg Hospital, Aalborg, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Okkels
authors.affiliation: Department of Medical Microbiology and Immunology, University of Aarhus, Aarhus, Denmark.
authors.forename: Mogens
authors.initials: M
authors.lastname: Kilian
authors.affiliation: Department of Clinical Microbiology, State Serum Institute, Copenhagen, Denmark.
authors.forename: Brita
authors.initials: B
authors.lastname: Bruun
mesh_terms: D000188:Actinobacillus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D039881:Prokaryotic Initiation Factor-2 / Q000235:genetics*; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D039881:Prokaryotic Initiation Factor-2; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S