Presence of Mycobacterium avium subsp. paratuberculosis (MAP) in Brazilian patients with inflammatory bowel diseases and in controls.

Isabel Azevedo Carvalho,Lize Maciel Pinheiro Guimarães,Pricila Aparecida Grasse Pietralonga,Ana Carolina Silva Faria,Maria De Lourdes Abreu Ferrari,David Germano Gonçalves Schwarz,Gabriel Domingos Carvalho,Abelardo Silva Júnior,Fabrício Luciani Valente,Maria Aparecida Scatamburlo Moreira,João Paulo Machado,Isis Freitas Espechit Braga

doi:10.1590/1516-3180.2014.8251809

Abstract

Mycobacterium avium subsp. paratuberculosis (MAP) has attracted the interest of researchers because of similarities between paratuberculosis and Crohn's disease (CD). The aim of this study was to evaluate the frequency of MAP through cultures, histology and polymerase chain reaction (PCR) on intestinal biopsies from Brazilian CD patients. Quantitative real time PCR (qRT-PCR) was performed on positive samples. Analytical cross-sectional study with control group at two federal universities. Fresh samples were collected from 25 patients; five with CD, eight with ulcerative colitis (UC) and 12 controls with non-inflammatory bowel disease (nIBD). Formalin-fixed paraffin-embedded (FFPE) samples from 143 patients were also collected: 44 CD, 49 UC and 56 nIBD. None of the fresh samples was positive for MAP. Five FFPE samples (one CD, two UC and two nIBD) and three fresh samples (one in each group) were positive through IS900-PCR. qRT-PCR was performed on these eight samples. Among the FFPE samples, there were 192.12 copies/μl in the CD group, 72.28 copies/μl in UC and 81.43 copies/μl in nIBD. Among the fresh samples, there were 432.99 copies/μl, 167.92 copies/μl and 249.73 copies/μl in the CD, UC and nIBD groups, respectively. The highest bacterial load was in the CD group. This study does not provide evidence for a role of MAP in the etiology of CD, although MAP DNA was detected in all three patient groups. This is the first report of MAP presence in human intestinal biopsies in Brazil.

Highlights

Crohn’s disease (CD) is a chronic inflammatory disease of the human gastrointestinal tract
Paratuberculosis is a form of chronic granulomatous enteritis, caused by Mycobacterium avium subsp. paratuberculosis (MAP), which affects all species of ruminants worldwide.[2]
MAP cultures Fresh samples from CD, ulcerative colitis (UC) or non-inflammatory bowel disease (nIBD) patients did not provide any positive result for viable MAP with any culture medium used in this study, even after 30 weeks

Summary

Introduction

Crohn’s disease (CD) is a chronic inflammatory disease of the human gastrointestinal tract. Paratuberculosis (MAP), which affects all species of ruminants worldwide.[2] Because of the similarities between paratuberculosis and CD, the possibility of an infectious etiology for this disease has been widely discussed and MAP has attracted the interest of many researchers.[3,4]. MAP has been detected by means of cultures and the polymerase chain reaction (PCR) in patients with CD.[3,5,6,7,8] Numerous theories about a possible cause for CD have been postulated over the years.[9] Scientific evidence supports the theory of an interaction between a persistent environmental stimulus (such as a microbial antigen) and genetic factors that regulate the immune response and/or function of intestinal mucosa.[10,11] it would be simplistic to conclude that one agent is solely responsible for the etiology of CD: a multifactorial cause is more likely.[4,12]

Methods

Results

Discussion

Conclusion