HELICOBACTER BILIS SP-NOV, A NOVEL HELICOBACTER SPECIES ISOLATED FROMBILE, LIVERS, AND INTESTINES OF AGED, INBRED MICE

A fusiform bacterium with 3 to 14 multiple bipolar sheathed flagella a nd periplasmic fibers wrapped around the cell was isolated from the li ver, bile, and lower intestine of aged, inbred mice. The bacteria grew at 37 and 42 degrees C under microaerophilic conditions, rapidly hydr olyzed urea, were catalase and oxidase positive, reduced nitrate to ni trite, did not hydrolyze indoxyl acetate or hippurate, and were resist ant to both cephalothin and nalidixic acid but sensitive to metronidaz ole. On the basis of 16S rRNA gene sequence analysis, the organism was classified as a novel helicobacter, Helicobacter bilis. This new heli cobacter, like Helicobacter hepaticus, colonizes the bile, liver, and intestine of mice. Although the organism is associated with multifocal chronic hepatitis, further studies are required to ascertain whether H. bills is responsible for causing chronic hepatitis and/or hepatocel lular tumors in mice.