Helicobacter winghamensis sp nov., a novel Helicobacter sp isolated from patients with gastroenteritis

From 1997 to 1999 seven isolates of Campylobacter-like organisms from five patients that were exhibiting symptoms of gastroenteritis, including fever, stomach malaise, and diarrhea, were investigated. The organisms were isola ted from stool samples and found to exhibit a diverse colony morphology; he nce multiple isolates mere submitted from one of the patients. All isolates were found to be identical. The organisms were catalase, urease, alkaline phosphatase, and nitrate negative but oxidase and indoxyl acetate positive, They grew at 37 degreesC but:not at 42 degreesC, and three of the isolates from two different patients were sensitive to nalidixic acid and cephaloth in. Full 16S rRNA sequence analysis not only grouped these organisms within the Helicobacter genus but also differentiated them from previously identi fied Helicobacter species, The closest relative by phylogenetic analysis wa s Helicobacter sp, flexispira taxon 1, Electron microscopy showed that thes e isolates had one or two bipolar flagella; however, the periplasmic fibers , a characteristic of the known Helicobacter sp. flexispira taxa, were not observed. The present isolates also lacked a flagellar sheath, a trait shar ed with four other Helicobacter spp,, H. canadensis, H. mesocricetorum, H. pullorum, and H. rodentium. On the basis of the unique phenotypic propertie s of these isolates and 16S rRNA sequence analysis, we propose the classifi cation of a new Helicobacter species, Helicobacter winghamensis sp, nov.