Toxin genes The CDT B gene was not detected in any of the C. concisus isolates, but was present in C. jejuni 81-176 (Additional file 3). The zot gene was detected in 80% of C. concisus isolates from healthy humans (i.e., four of five isolates), 22% of isolates from diarrheic humans (i.e., two of nine see more isolates), and the type strain. The S-layer RTX gene was present in C. concisus CHRB3287 and CHRB2004, although amplification was weak for the latter isolate. The zot and S-layer RTX genes were not detected in C. jejuni 81-176. Discussion The observed high level of genetic diversity amongst
the isolates of C. concisus is in agreement with previous studies [1, 2, 10], and highlights the complex nature of this species. Cluster analysis of AFLP profiles indicated that the isolates examined in the current study comprised at least two distinct clusters. Similarly, Aabenhus et al.  denoted four AFLP clusters among 62 C. concisus isolates of which the majority (n = 56) were assigned to one of two main clusters. Results of PCR assays targeting the 23S rRNA and cpn60 genes largely corresponded with the AFLP grouping, and lend support to the suggested genetic relationship between the isolates. As C. concisus is Evofosfamide clinical trial a common inhabitant of the oral cavity, it is to be expected that it may be isolated from both healthy
and diarrheic individuals. Examining isolates from healthy individuals, it was observed that the majority of isolates belonged to genomospecies A and their AFLP profiles clustered together (AFLP cluster 1) along with the type stain of oral origin. This AFLP cluster also included one genomospecies A isolate (CHRB 1609) from a many diarrheic individual. Further studies are needed to determine whether
this group of isolates represents inhabitants of the oral cavity that have survived gastro-intestinal transit or whether they are intestinal-associated. The majority (94%) of isolates from diarrheic individuals were assigned to ALFP cluster 2. Among these isolates, 71% were assigned to genomospecies B, while only 11% of diarrheic isolates belonged to genomospecies A. Engberg et al.  reported a similar predominance of genomospecies B isolates among diarrheic fecal isolates, of which 33% and 67% were assigned to genomospecies A and B, respectively. Likewise, Aabenhus et al.  reported that 34% and 53% of fecal isolates from diarrheic patients were assigned to genomospecies A and B, respectively. Our observation that isolates from genomospecies B were exclusively obtained from diarrheic individuals suggests a potential role for these isolates in intestinal Pexidartinib clinical trial disease. A comparative molecular examination of strains belonging to genomospecies A and B may shed light on their respective pathogenic potential. Examination of the pathogenic properties amongst C. concisus isolates determined that epithelial invasion and translocation were higher for isolates assigned to AFLP cluster 2 (of which 94% were from diarrheic individuals).