Mycobacterium avium subspecies paratuberculosis (MAP) and Crohn’s disease: the debate continues

Abstract

Crohn’s disease (CD) in humans and Johne’s disease (JD) in ruminants share numerous clinical and pathologic similarities. As Mycobacteria avium subspecies paratuberculosis (MAP) is known to fulfill Koch’s postulates as the cause of JD, there has been considerable debate over the past century about whether MAP also plays a role in CD. With recent advances in MAP identification techniques, we can now demonstrate a higher presence of MAP in CD patients compared to the general population. However, it remains unclear if MAP is playing a bystander role or is directly pathogenic in these patients. Studies have shown that there may be an immune response targeting MAP in these patients, which may underlie a pathologic role in CD. Clinical studies have yielded conflicting results as to whether anti-MAP therapy improves clinical outcomes in CD, leading to the lack of its inclusion within evidence-based clinical guidelines. Additionally, many of these studies have been small case series, with only a few randomized controlled trials published to date. In this article, we will discuss the historical context of MAP in CD, review clinical and laboratory data surrounding detection of MAP and possible pathogenesis in human disease, and suggest future directions which may finally provide some clarity to this debate.

Mycobacterium avium ssp. paratuberculosis and Crohn’s Disease—Diagnostic Microbiological Investigations Can Inform New Therapeutic Approaches

“…However, there is growing global research interest in the role of MAP in association with human and animal diseases [5]. The decision to assign MAP to MAC should be reconsidered given the zoonotic potential of the organism and the dwindling availability of diagnostic tests and therapeutics for CD [6][7][8][9].…”

Mycobacterium avium and Klebsiella pneumoniae co-infection in the domestic ferret (Mustela putorius furo) – Case Report

“…Infection is usually through inhalation or injured skin [39], which is consistent with the most common form of MAC infection being a pulmonary disease [40], at least in adults. In children, however, a relatively common form of the disease caused by MAC is peripheral lymphadenopathy [41]. The continuing debate about the possible participation of Mycobacterium avium sp.…”

“…The continuing debate about the possible participation of Mycobacterium avium sp. paratuberculosis in the pathogenesis of Crohn's disease also cannot be forgotten [41][42][43]. For these reasons, monitoring mycobacteria in pets is highly important.…”

Mycobacterium avium subsp. paratuberculosis in Wild Boar (Sus scrofa) in Portugal

“…PCR assay is one of the most up-to-date methods used for various purposes since it can detect small amounts of DNA and operates more rapidly compared to other techniques [24]. Public health concerns about the presence of MAP in food, such as meat and milk, are increasing [27,28] due to accumulating data that link MAP to human Crohn's disease (CD), a chronic, incurable, low-grade inflammation of the terminal ileum [28][29][30][31][32][33][34][35][36].…”