Presence Of Infection By Mycobacterium Avium Subsp. Paratuberculosis In The Blood Of Patients With Crohns Disease And Control Subjects Shown By Multiple Laboratory Culture And Antibody Methods

Mycobacterium avium subspecies paratuberculosis (MAP) has long been suspected to be involved in the etiology of Crohns disease (CD). An obligate intracellular pathogen, MAP persists and influences host macrophages. The primary goals of this study were to assess the degree of viable culturable MAP bacteremia in humans, definite identification of the organisms cultured and to assess if CD patients have a significantly higher rate of MAP infection compared to controls. A secondary goal was to compare the efficacy of three culture methods plus a phage assay and four antibody assays performed in separate laboratories, to detect MAP from the parallel samples. Culture and serological MAP testing was performed blind on whole blood samples obtained from 201 subjects including 61 CD patients, two patients with CD and concurrent ulcerative colitis (UC), 14 patients with UC only and 140 non-CD controls. Viable MAP bacteremia was detected in a significant number of study subjects across all groups. This included Pozzato culture (124/201 or 62% of all subjects, 35/61 or 57% of CD patients), Phage assay (113/201 or 56% of all subjects, 28/61 or 46% of CD patients), TiKa culture (64/201 or 32% of all subjects, 22/61 or 36% of CD patients) and MGIT culture (36/201 or 18% of all subjects, 15/61 or 25% of CD patients). A link between MAP detection and CD was observed with MGIT culture and one of the antibody methods (Hsp65) confirming previous studies. Other detection methods showed no association between any of the groups tested. Nine subjects with positive Phage assay (8/9) or MAP culture (1/9) were again positive with the Phage assay one year later. This study highlights viable MAP bacteremia is widespread in the study population including CD patients, those with other autoimmune conditions and asymptomatic healthy subjects.