Twenty-three (11.4%) of the ‘symptomatic’ and 13 (8.4%) of the ‘asymptomatic’ organisms were

subsequently identified Crizotinib clinical trial as Campylobacter cinaedi. Six (3.0%) of the ‘symptomatic’ and no ‘asymptomatic’ organisms were subsequently identified as Campylobacter fennelliae. A third organism, labelled simply CLO3 [currently Helicobacter sp. strain CLO3 (CCUG 14564)] has never been formally named. The Campylobacter genus underwent a reclassification in 1991, which moved the two organisms identified within these studies, C. cinaedi and C. fennelliae, into the Helicobacter genus, with their resultant names being H. cinaedi (CCUG 18818) and H. fennelliae (CCUG 18820) (Vandamme et al., 1991). An interesting DNA Damage inhibitor facet of the Totten study involved an investigation of asymptomatic men from whom clinical isolates of H. cinaedi were obtained and concurrently examined for the presence of rectal leucocytosis. The authors demonstrated that rectal leucocytosis was significantly more likely in this group than in those who were culture negative for the organism (P=0.002). This may indicate a separate subclinical disease state within the asymptomatic cohort. No pathology samples were taken within this study to correlate this finding directly with tissue inflammation. The HIV status of the men was not given; however, the first studies to identify HIV came just a year before the publication of

the first Seattle paper, and so this omission is historically understandable (Barre-Sinoussi et al., 1983; Gallo et al., 1983). The correlation of clinical disease with the

level of immunosuppression of the host would have given an interesting insight into the apparently inconsistent pathogenicity of these organisms if this had been available. The organisms isolated within this study have been utilized to initiate experimental gastrointestinal illness within a primate model as described above (Flores et al., 1990); however, histological changes in the gut were not a prominent feature of the resultant disease. With relation to Koch’s four postulates click here (Koch, 1884; Marshall, 1995), these two Helicobacter species have potentially fulfilled the second, third and fourth criteria, but their level of fulfillment of the first can be debated (as they were also isolated in asymptomatic men who could conceivably have subclinical, but histologically relevant colitis). Nevertheless, these organisms are the Helicobacter spp. that are closest to being identified as the causative pathogens of a human colitic disease. Helicobacter cinaedi has also been isolated from other humans including from diarrhoeal faecal samples (Tee et al., 1987) and the blood and/or stool of three children and two adult females (CCUG 15432, CCUG 19503, CCUG 19504, CCUG 20698, CCUG 17733) (Vandamme et al., 1990). Limited clinical information was presented in this latter study, but at least one of the paediatric strains was from a diarrhoeal child.