Novel Helicobacter species isolated from rhesus monkeys with chronic idiopathic colitis

Chronic, idiopathic diffuse colitis is a well recognised clinical and patho logical entity in captive rhesus monkeys, Six rhesus monkeys were diagnosed with clinically debilitating, chronic diarrhoea, Histologically; colonic t issues were characterised as chronic, moderate to severe colitis and typhli tis, with diffuse mononuclear inflammation of lamina propria, reactive lymp hoid hyperplasia and multifocal micro-abscesses. Colonic tissues were cultu red for Salmonella spp, and Shigella spp,; all results were negative. Sampl es were negative for Clostridium difficile A and B toxins, and special stai ns of colonic tissue for acid-fast bacteria were also negative. The sis dia rrhoeic monkeys tested gave negative results for serum IgG antibodies to he rpes B virus, STLV SRV and SIV. Colonic tissue from the six diarrhoeic and two clinically normal monkeys with histologically confirmed colitis from th e same colony were also subjected to micro-aerobic culture. Micro-aerobic c ultures from all eight monkeys incubated at 37 degreesC and 42 degreesC rev ealed pinpoint or spreading colonies on antibiotic-containing media. Bacter ia were identified as gramnegative, oxidase positive and urease negative. O f the nine strains characterised biochemically; two separate biotypes (corr esponding to different species by 16S rRNA analysis) mere identified. One b iotype (type 1), from non-diarrhoeic monkeys and the second biotype (type 2 ) from diarrhoeic animals with subclinical chronic colonic inflammation, di ffered by catalase activity, ability to reduce nitrate to nitrite and sensi tivity to cephalothin, Complete 16S rRNA analysis of five of the nine strai ns characterised biochemically indicated that the organisms isolated were t wo novel Helicobacter spp, By electron microscopy, these novel helicobacter s had spiral morphology with bipolar sheathed flagella, This is the first r eport describing the isolation of novel Helicobacter spp, from inflamed col ons of rhesus monkeys. Studies are needed to determine whether these novel Helicobacter spp, play a causal role in the initiation and progression of c hronic colitis in macaques, Further microbiological and histological analys is of this chronic idiopathic colitis syndrome in macaques may prove useful in understanding the aetiology and pathogenesis of inflammatory bowel dise ase in man.