Colorectal Bacteria Research Articles

Bioprospecting of fruit extract and endophytic bacteria isolated from dewandaru (Eugenia uniflora L.) as antibacterial against colorectal bacteria

Colorectal cancer (CRC) is the third most commonly diagnosed malignancy and the fourth leading cause of cancer-related deaths in the world. The gut bacteria are an important player in the development of colorectal cancer. Dewandaru (Eugenia uniflora L.) have been used as a traditional medicine to treat various diseases. Many of antibacterial metabolites produced by the fruit and its endophytic bacteria. This study aimed to find Antibacterial activity of ethanolic extract of dewandaru fruit using Kirby - Bauer disk diffusion method and to determine Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) using Dilution Tube Method (DTM). Endophytic bacteria were isolated from dewandaru fruit by using sterilization treatment followed by serial dilution agar plate and streak technique. All the isolates and ethanolic extract with different concentration were evaluated for the antimicrobial activity against colorectal bacteria (Streptococcus bovis, Enterococcus faecalis, Escherichia coli and Salmonella enterica). The results showed resistant– strong inhibitory zone category of fruit extract and isolated endophytic bacteria. The isolates were identified as Bacillus cereus, Bacillus amyloliquefaciens, and Bacillus sp.

Molecular Characterization of Rectal Mucosa-Associated Bacterial Flora in Inflammatory Bowel Disease

Colorectal bacteria may play a role in the pathogenesis of inflammatory bowel disease (IBD). To test the hypothesis that, in affected patients, the numbers of potentially protective mucosal bacteria might be reduced and pathogenic species increased, we compared rectal mucosa-associated flora in patients with IBD and normal controls. Snap-frozen rectal biopsies taken at routine diagnostic colonoscopy from 33 patients with ulcerative colitis, 6 patients with Crohn's disease, and 14 controls with normal colonoscopy were processed, and individual bacterial groups were counted using fluorescent in situ hybridization. Bacteria were mostly found apposed to the epithelial surface and within crypts. Epithelium-associated counts of bifidobacteria in active [median 15/mm of epithelial surface (range, 4-56), n = 14] and quiescent ulcerative colitis [26/mm (range, 11-140), n = 19] were lower than in controls [56/mm (range, 0-144), n = 14; P = 0.006 and P = 0.03, respectively]. Conversely, epithelium-associated Escherichia coli counts were higher in active [82/mm (range, 56-136)] than inactive ulcerative colitis [6/mm (range, 0-136), P = 0.0001] or controls [0/mm (range, 0-16), P < 0.0001]. Epithelium-associated clostridia counts were also higher in active [3/mm (range, 0-9)] than inactive colitis [0/mm (range, 0-9), P = 0.03] or controls [0/mm (range, 0-1); P = 0.0007]. Epithelium-associated E. coli counts were higher in Crohn's disease [42/mm (range, 3-90), n = 6] than controls (P = 0.0006). E. coli were also found as individual bacteria and in clusters in the lamina propria in ulcerative colitis and Crohn's disease but in none of the controls (P < 0.01). Numbers of Lactobacillus and Bacteroides showed no differences between patient groups. The reduction in mucosa-associated bifidobacteria and increase in E. coli and clostridia in patients with IBD supports the hypothesis that an imbalance between potentially beneficial and pathogenic bacteria may contribute to its pathogenesis.