An uncommon Helicobacter isolate from blood: Evidence of a group of Helicobacter spp. pathogenic in AIDS patients

An unusual Helicobacter sp, was isolated from the blood of a human immunode ficiency virus (HIV)-infected patient. This organism had spiral morphology, with single amphitrichous flagella, and was negative for hippurate hydroly sis, production of urease, and reduction of nitrate, 16S rRNA gene sequence analysis verified that the isolate was a species of Helicobacter, most clo sely related to an undescribed Helicobacter-like isolate from Vancouver, Br itish Columbia, Canada, and to Helicobacter westmeadii, a recently describe d species from Australia. Both organisms had also been isolated from the bl ood of HIV-infected patients. These blood isolates, along with Helicobacter cinaedi, form a cluster of closely related Helicobacter spp, that may repr esent an emerging group of pathogens in immunocompromised patients.