HELICOBACTER RODENTIUM SP-NOV, A UREASE-NEGATIVE HELICOBACTER SPECIESISOLATED FROM LABORATORY MICE

A spiral-shaped bacterium with bipolar, single, nonsheathed flagella w as isolated from the intestines of laboratory mice. The organism grew at 37 and 42 degrees C under microaerobic and anaerobic conditions, di d not hydrolyze urea, was weakly positive for catalase and oxidase, re duced nitrate to nitrite, did not hydrolyze indoxyl acetate or hippura te, and was resistant to cephalothin and nalidixic acid. This is the f irst urease-negative, murine Helicobacter spp. isolated from intestine s. Also, Helicobacter pullorum and this bacterium are unique among the genus Helicobacter in having nonsheathed flagella. The new bacterium appears to be part of the normal intestinal flora; although its pathog enic potential is unknown, this organism was also isolated from scid m ice with diarrhea that were co-infected with Helicobacter bills. On th e basis of 16S rRNA gene sequence analysis data and biochemical and ph enotypic criteria, the new organism is classified as a novel helicobac ter, for which we propose the name Helicobacter rodentium. The type st rain is MIT 95-1707 (= ATCC 700285).