Comparison adhesive and invasive features of Crohn's disease-associated adherent-invasive Escherichiacoli(AIEC) strain growing in BMSM (BrothMixing sterile mucosal content) medium

To date Adherent-Invasive Escherichia coli (AIEC) with pathogenic traits that is compatible with many characteristic of this disease is the most likely strain to case specific damage to the people who are genetically susceptible to Crohn's disease (CD) in the gut flora that is one of factors playing a role in development CD. However AIEC usually is being accepted as pathobiont because of this strain is also isolated from healthy individuals. Besides, the exact localization of these strains in healthy intestinal mucosa is not possible to be detected due to the fact that specific molecular targets belonging these strains have not been determined yet. Undoubtedly, determining exact localization of this strains in the healthy intestinal mucosa will be provide significant data related to role of AIEC in development CD. In our study, we designed Broth Mixing Sterile Mucosal Content (BMSM) mediums composed of certain rates of cell culture medium or Luria-Bertani (LB) medium and mucosal contents obtained from colonic region (CR) and ileal region (IR) belonging to FVB/N and Balb/c mice that we used different times. Thus, We aimed to obtain some clues about the exact localization of AIEC strain, LF82 in healthy intestinal mucosa via both using bacterial culture of LF82 in BMSM mediums and comparing adhesive and invasive abilities of LF82 with cell infections experiments including BMSM mediums. Results of adhesion and invasion experiments that using I-407 cell line, usually were similar and agree each other in both mice type. The results showed that LF82 exhibit rather different behaviors in terms of proliferation and adhesive/invasive features in each BMSM mediums prepared from different part of intestine. Moreover, these differences were stronger and significant in BMSM medium prepared from IR than in BMSM medium prepared from CR. After 3 hours cell infection period, cell culture medium including BMSM medium prepared from IR, inhibited adhesion of LF82 and after gentamicin treatment following additional one hour incubation period, ıt also had inhibited strongly invasion of LF82. In this BMSM medium, while rate of LF82 associated to the cell surface were almost half rates according control, rate of intracellular LF82 was more less than 5 % when rate of intracellular LF82 in control defined as 100 %. According bacterial culture results however, more bacterial proliferation was seen in both BMSM medium prepared from IR and CR than LB medium. Moreover, it was interesting to observe that BMSM medium prepared from IR was the best medium in term of the proliferation capability of LF82. Likewise after overnight incubation period, LF82 number growing in BMSM medium prepared from IR, was about twice in compared with LF82 number growing in LB medium. In conclusion, this study which we performed with an original approach offered significant clues regarding to ileum being more likely localization site for AIEC strain, LF82 rather than colon in the healthy intestinal mucosa. Key Words: AIEC, LF82, Crohn's Disease (CD), Broth Mixing Sterile Mucosal Content (BMSM), Adhesion, Invasion.