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P052 Intestinal total bacteria concentration and translocation of bacteria in inflammatory bowel disease

S. Vrakas1, M. Gazouli*2, K. Mountzouris3, G. Michalopoulos1, G. Karamanolis4, G. Papatheodoridis5, C. Tzathas1

1Tzaneion General Hospital, Gastroenterology Department, Piraeus, Greece, 2Medical School, National & Kapodistrian University, Biology, Athens, Greece, 3Agriculture University, Nutritional Physiology and Feeding, Athens, Greece, 4Medical School, National & Kapodistrian University, Gastroenterology Unit, Second University Surgical Department, Athens, Greece, 5Medical School National & Kapodistrian University, Gastroenterology, Athens, Greece

Background

The gut microbiota is believed to play a central role in the development of the inflammatory bowel diseases (IBD) Crohn’s disease (CD) and ulcerative colitis (UC). It has been suggested that live commensal intestinal bacteria are present in the adipose tissue and the peripheral blood where they can induce inflammation. Because this process can trigger inflammation, the aim of the present study was to evaluate the intestinal bacteria concentration and translocation of bacteria in IBD.

Methods

Both blood and tissue biopsy samples were collected from children (n = 6) and adult patients with active CD (n = 3) and UC (n = 6), as well as from healthy individuals (n = 9) who underwent screening colonoscopy. Most of the patients were newly diagnosed, and none of them received antibiotics. All of the adults received 5-ASA, and 3 of them anti-TNF. Samples were taken before starting and after 12–20 weeks of anti-TNF treatment. For each sample (tissue and blood), the purified DNA was eluted and analysed for total bacteria, using suitable primers targeting 16S rRNA gene by real-time polymerase chain reaction (PCR). Reference microbial strain E. coli used for standard curve construction. Total tissue and blood bacterial DNA were determined by interpolating the Ct values obtained from the samples into the appropriate standard curve.

Results

The total bacterial count was similar in tissue biopsies and blood samples. However, adult UC patients had increased bacterial count (87.02 ± 1.02 ng/ul in tissues and 84.53 ± 0.5 ng/ul in blood) compared with CD (74.58 ± 0.52 ng/ul in tissues and 75.55 ± 0.51 ng/ul in blood) (p < 0.05). In children samples, bacterial count, in both tissue (48.38 ± 7.74 ng/ul) and blood (49.15 ± 5.89 ng/ul) samples, was significantly lower than adult’s samples (p < 0.001). In all cases, adult and children patients, the bacterial count was significantly higher than in controls (34.02 ± 0.03 in tissues and 43.1 ± 0.14 in blood) (p < 0.001). Interestingly, when we compared the samples of patients who received anti-TNF treatment before and after the treatment, we showed that the bacterial count diminished significantly after TNF treatment in the levels to control samples in both tissues (before anti-TNF 81.4 ± 9.4 vs after anti-TNF 29.43 ± 6.54 ng/ul, p < 0.01) and blood samples (before anti-TNF 80.12 ± 6.33 vs after anti-TNF 50.32 ± 7.03 ng/ul, p < 0.01).

Conclusion

Our results indicate the translocation of bacteria from the gastrointestinal system in the circulation in IBD patients, and the bacterial count in the bloodstream could be a less invasive indicator of response to anti-TNF treatment. Further studies to identify the bacterial species in this case are in process.