title: Ileal symbiont intracellularis, an obligate intracellular bacterium of porcine intestines showing a relationship to Desulfovibrio species.
abstract: A new genus and species of obligate intracellular-bacteria found in porcine intestines are described. Growth on any bacteriological medium deprived of living cells has not been demonstrated. The organism has been grown intracellularly in cell culture. The 16S rRNA gene sequence data, DNA probe results, and microscopic observations provide evidence that these bacteria differ from those in other described genera and that they belong to the delta subdivision of the class Proteobacteria. We have amplified and sequenced the 16S ribosomal DNA of four preparations of the intracellular bacterium from pigs. For this, intracellular organisms were released and purified from the infected cells without culture techniques. After DNA purification, the polymerase chain reaction with primers complementary to highly conserved eubacterial sequences was used to amplify regions of 16S ribosomal DNA which were subsequently cloned (in some cases) and sequenced directly by standard techniques. The sequences obtained from each preparation were identical and were most similar to that of a sulfate-reducing proteobacterium, Desulfovibrio desulfuricans ATCC 27774 (91% similarity). An oligonucleotide probe complementary to a hypervariable region of the 16S rRNA sequence of the bacterium hybridized with intracellular organisms obtained from porcine intestines. The bacterium is a gram-negative, curved rod with tapered ends. It multiplies intracellularly in the cytoplasm of ileal epithelial cells by septation. The vernacular name Ileal symbiont (IS) intracellularis is proposed for this bacterium. The type strain of IS intracellularis is strain 1482/89 grown in cell culture from a pig affected by proliferative enteropathy. It is deposited in the National Collection of Type Cultures, Colindale, London, as NCTC 12656.
authors.affiliation: Department of Veterinary PathoBiology, College of Veterinary Medicine, University of Minnesota St. Paul 55108.
authors.forename: C J
authors.initials: CJ
authors.lastname: Gebhart
authors.forename: S M
authors.initials: SM
authors.lastname: Barns
authors.forename: S
authors.initials: S
authors.lastname: McOrist
authors.forename: G F
authors.initials: GF
authors.lastname: Lin
authors.forename: G H
authors.initials: GH
authors.lastname: Lawson
mesh_terms: D000818:Animals; D001483:Base Sequence; D015342:DNA Probes; D003901:Desulfovibrio / Q000145:classification; D006090:Gram-Negative Bacteria / Q000145:classification* / Q000302:isolation & purification / Q000648:ultrastructure; D007082:Ileum / Q000382:microbiology*; D007413:Intestinal Mucosa / Q000382:microbiology*; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D013552:Swine / Q000382:microbiology*; D013559:Symbiosis
chemical_list: D015342:DNA Probes; D012336:RNA, Ribosomal, 16S