Identification of Mycobacterium avium subsp. paratuberculosis in biopsy specimens from patients with Crohn's disease identified by in situ hybridization

Serological and epidemiological investigation of Mycobacterium avium subspecies paratuberculosis in bovines in Pakistan

OBJECTIVE

This study aimed to investigate the prevalence of paratuberculosis in cattle and buffaloes at twelve public dairy farms in Punjab, Pakistan.

METHODS

A total of 2,181 more than two-year-old animals (1,242 cattle and 939 buffaloes) were tested by avian tuberculin, i.e., killed purified protein derivative of Mycobacterium avium paratuberculosis and indirect enzyme linked immunosorbent assay (ELISA). Blood and fecal samples were collected from tuberculin positive animals. These samples were further processed by indirect ELISA. The data were analyzed using frequency analysis and logistic analysis procedures.

RESULTS

The prevalence of paratuberculosis at public dairy farms was 3.8%, as determined by tuberculin+ELISA test. It varied from 0.71% to 13.5% with a 100% herd prevalence. Multivariate logistic regression analysis revealed that species, milk production, total animals, total small ruminants, and total buffaloes were significantly associated with the occurrence of paratuberculosis. Odd ratio analysis revealed that with a one-kilogram increase in body weight, there will be a 0.006% increase in disease occurrence. With the increase in one animal in small ruminants and buffaloes, there will be 0.008% and 0.42% greater chances of developing paratuberculosis, respectively. Bivariate logistic regression analysis of cattle and buffaloes revealed that farm number, age, and total number of cattle were significantly associated with the occurrence of paratuberculosis. A one-month increase in lactation length increases the chance of tuberculosis by 0.004%; similarly, a one-liter increase in milk production increases the chance of disease by 10%. With each additional buffalo in the herd, there will be a 0.007% greater chance for the occurrence of paratuberculosis.

CONCLUSION

This study concluded that tuberculin testing can be used in conjunction with ELISA to screen animals for paratuberculosis in countries with scarce resources, such as Pakistan. The efficacy of disease diagnosis can be improved by combining multiple tests.

Seroprevalence of Mycobacterium avium subsp. paratuberculosis in Swiss dairy herds and risk factors for a positive herd status and within-herd prevalence

Introduction

Bovine paratuberculosis (PTB) is a chronic enteric disease caused by Mycobacterium avium subsp. paratuberculosis (MAP). Control of PTB is important given its negative economic consequences and the potential zoonotic role of MAP in Crohn's disease in humans.

Methods

To determine the seroprevalence of MAP in Swiss dairy herds and to identify risk factors associated with seropositive herd status and high within-herd seroprevalence, 10,063 serum samples collected from cattle over 12 months of age in 171 Swiss dairy farms were analyzed using a commercial ELISA test. Eight herds were excluded due to non-interpretable ELISA results. Risk factors associated with seropositive herd status and high within-herd seroprevalence were investigated with regression models using results from a questionnaire on management practices possibly associated with the introduction or spread of MAP in the remaining 163 herds. Univariable logistic regression was performed, carrying forward for multivariable regression analysis when p < 0.2.

Results

The calculated between-herd true seroprevalence was 3.6% (95% CI, 0.96-8.4%). Due to the low within-herd seroprevalence, it was not possible to calculate the true seroprevalence at animal level; the apparent within-herd seroprevalence ranged from 2.3 to 5.5% with a median of 3.6% in nine positive farms. Herd size (p = 0.037) and the common grazing of lactating cows with cows from other herds (p = 0.014) were associated with seropositive herd status, while heifers sharing alpine pasture with dairy cattle from other herds were associated with a decreased probability of the herd to test seropositive (p = 0.042). Reliable identification of significant risk factors associated with MAP spread and high seroprevalence of PTB within seropositive herds was not possible due to low observed seroprevalence within herds and low sensitivity of the ELISA test.

Discussion

These results highlight the limitation of serology for MAP diagnosis in small herds with low infection prevalence.

More Insights about the Efficacy of Copper Ion Treatment on Mycobacterium avium subsp. paratuberculosis (MAP): A Clue for the Observed Tolerance

Background: Scientific evidence is scarce for the antimicrobial effect of copper on bacteria characterized as more resistant. Using Mycobacterium avium subsp. paratuberculosis (MAP), a highly resistant microorganism, as a pathogen model, copper ion treatment has shown a significant bactericidal effect; however, the sustainability of MAP against copper toxicity was also reported in several studies. Accordingly, the present study aimed to evaluate the impacts of copper on MAP. Methodology: This study considered physicochemical properties and copper concentration in a buffer since it could modulate MAP response during the application of copper treatment. Results: Despite the efficacy of copper ions in significantly reducing the MAP load in Phosphate Buffered Saline, some MAP cells were able to survive. The copper concentration generated by the copper ion treatment device increased significantly with increasing exposure times. MAP bacterial load decreased significantly when treated with copper ions as the exposure times increased. An increase in pH decreased oxygen consumption, and an increase in conductivity was reported after treatment application. Conclusions: Even with higher concentrations of copper, the efficacy of MAP control was not complete. The concentration of copper must be a key element in achieving control of highly resistant microorganisms.

A Mycobacterium species for Crohn's disease?

In ruminants Mycobacterium avium subspecies paratuberculosis (MAP) is the causative organism of a chronic granulomatous inflammatory bowel disease called Johne's disease (JD). Some researchers have hypothesised that MAP is also associated with Crohn's disease (CD), an inflammatory bowel disease in humans that shares some histological features of JD. Despite numerous attempts to demonstrate causality by researchers, direct microbiological evidence of MAP involvement in CD remains elusive. Importantly, it has not been possible to reliably and reproducibly demonstrate mycobacteria in the tissue of CD patients. Past attempts to visualise mycobacteria in tissue may have been hampered by the use of stains optimised for Mycobacterium tuberculosis complex (MTB) and the lack of reliable bacteriological culture media for both non-tuberculous mycobacteria (NTM) and cell-wall-deficient mycobacteria (CWDM). Here we describe a Ziehl-Neelsen (ZN) staining method for the demonstration of CWDM in resected tissue from patients with Crohn's disease, revealing the association of CWDM in situ with host tissue reactions, and posit this as a cause of the tissue inflammation. Using the ZN stain described we demonstrated the presence of CWDM in 18 out of 18 excised tissue samples from patients diagnosed as having Crohn's disease, and in zero samples out of 15 non-inflammatory bowel disease controls.

Molecular characterisation of Mycobacterium avium subsp. paratuberculosis in Australia

BACKGROUND

Mycobacterium avium subsp. paratuberculosis (Map) causes Johne's disease (JD), a chronic enteritis widespread in ruminants, resulting in substantial economic losses, especially to the dairy industry. Understanding the genetic diversity of Map in Australia will assist epidemiological studies for tracking disease transmission and identify subtype characteristics for use in development of improved diagnostic typing methods. Here we investigated the phylogenetic relationships of 351 Map isolates and compared different subtyping methods to assess their suitability for use in diagnostics and accuracy.

RESULTS

SNP-based phylogenetic analysis of 228 Australian isolates and 123 publicly available international isolates grouped Type S and Type C strains into two distinct lineages. Type C strains were highly monomorphic with only 20 SNP differences separating them. Type S strains, when aligned separately to the Telford strain, fell into two distinct clades: The first clade contained seven international isolates while the second clade contained one international isolate from Scotland and all 59 Australian isolates. The Australian Type B strain clustered with US bison strains. IS1311 PCR and Restriction Enzyme Analysis (REA) intermittently generated incorrect results when compared to Long Sequence Polymorphism (LSP) analysis, whole genome SNP-based phylogenetic analysis, IS1311 sequence alignment and average nucleotide identity (ANI). These alternative methods generated consistent Map typing results. A published SNP based assay for genotyping Map was found to be unsuitable for differentiating between Australian and international strain types of Map.

CONCLUSION

This is the first phylogenetic analysis of Australian Map isolates. The Type C lineage was highly monomorphic, and the Type S lineage clustered all Australian isolates into one clade with a single Scottish sheep strain. The Australian isolate classified as Type B by IS1311 PCR and REA is likely to be descended from bison and most closely related to US bison strains. Limitations of the current typing methods were identified in this study.

Australian Veterinarians' Perceptions Regarding the Zoonotic Potential of Mycobacterium avium Subspecies Paratuberculosis

Public concerns over exposure to Mycobacterium avium subspecies paratuberculosis (MAP) or MAP components via foods of animal origin could have negative trade consequences, despite the absence of conclusive scientific evidence of a causal association between Mycobacterium avium subspecies paratuberculosis (MAP) and Crohn’s disease (CD). This study was conducted among Australian veterinarians to understand (a) their perceptions regarding the role of MAP in the causation of CD (an ordinal outcome), and (b) their consideration of the adoption of the precautionary principle against Johne’s disease (JD; a binary outcome). Ordinal and binary logistic regression analyses were performed to evaluate the association of explanatory variables with the above outcomes, respectively. Almost one-third of the respondents (32.2%) considered that MAP was likely to be involved in the causation of CD whereas more than two-thirds (69.8%) agreed with the adoption of the precautionary principle against JD. Veterinarians who were concerned about exposure to and/or getting infected with MAP were more likely to consider MAP as a causative agent of CD (odds ratio: 7.63; 95% CI: 1.55, 37.63) and favor the adoption of the precautionary principle against JD (odds ratio: 6.20; 95% CI: 1.90, 20.25). Those perceiving MAP as a causative agent of CD were also more likely to favor the adoption of the precautionary principle against JD (odds ratio: 13.2; 95% CI: 1.26, 138.90). The results suggest that Australian veterinarians, particularly those who consider MAP as a causative agent of CD are concerned about exposure to MAP and favor the adoption of the precautionary principle against JD. These findings can be useful for animal health authorities for designing JD control programs and policies.

Prevalence of Mycobacterium avium subspecies paratuberculosis IS 900 DNA in biopsy tissues from patients with Crohn's disease: histopathological and molecular comparison with Johne's disease in Fars province of Iran

BACKGROUND

Crohn's disease is a chronic enteritis of humans that affects the gastrointestinal tract, especially the terminal ileum, cecum and colon. The etiology of this disease is still unknown but seems to be multifactorial. There are reports about the potential link between Crohn's disease in humans and the causative agent of Johne's disease in ruminants. Because of the prevalence of Johne's disease in the Fars Province of Iran, the aim of this study was to investigate the prevalence of MAP in the biopsy tissues of patients affected by Crohn's disease in this area.

METHODS

The study was performed from April 2015 to June 2017 at Namazi Hospital, Shiraz University of Medical Sciences, and School of Veterinary Medicine, Shiraz University, Shiraz, Iran. Intestinal biopsies of 30 patients (12 male and 18 female; mean age, 34 years; range 4-77 years) with the confirmed diagnosis of Crohn's disease and 30 patients diagnosed as non-inflammatory bowel disease (19 male and 11 female; mean age, 38 years; range 13-68 years) were studied by molecular, histopathological and histochemical methods. Also, similar numbers of adult goats affected by Johne's disease were studied, comparatively. DNA extractions of tissue specimens were subjected to PCR to amplify a 413-bp sequence of the IS900 gene.

RESULTS

Using IS900-PCR, the overall prevalence of MAP in patients affected by Crohn's disease and non-inflammatory bowel disease were 47 and 13%, respectively. In addition, the prevalence of MAP in goats affected by Johne's disease was 70%. Using acid-fast histochemical staining, only 7% of Crohn's disease patients were weakly positive as paucibacillary and 43% of Johne's disease cases were moderate to strongly positive as multibacillary. Histopathologically, granulomatous enteritis (83 and 90%), lymphoplasmacytic enteritis (17 and 14%), edema and lymphangiectasia (67 and 96%), and vasculitis (20 and 73%) were common findings in Crohn's and Johne's diseases, respectively.

CONCLUSION

Our findings demonstrate a remarkable association between MAP and CD in this population, and support an etiologic relationship between MAP infection in humans and the development of CD. MAP infection in human tissue may display species-specific pathologic findings, as occurs with other zoonotic pathogens.

Protein Kinase G Induces an Immune Response in Cows Exposed to Mycobacterium avium Subsp. paratuberculosis

To establish infection, pathogens secrete virulence factors, such as protein kinases and phosphatases, to modulate the signal transduction pathways used by host cells to initiate immune response. The protein MAP3893c is annotated in the genome sequence of Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of Johne's disease, as the serine/threonine protein kinase G (PknG). In this work, we report that PknG is a functional kinase that is secreted within macrophages at early stages of infection. The antigen is able to induce an immune response from cattle exposed to MAP in the form of interferon gamma production after stimulation of whole blood with PknG. These findings suggest that PknG may contribute to the pathogenesis of MAP by phosphorylating macrophage signalling and/or adaptor molecules as observed with other pathogenic mycobacterial species.

Genetic diversity ofMycobacterium aviumcomplex strains isolated in Argentina by MIRU-VNTR

Mycobacterium aviumsp.avium(MAA),M. aviumsp.hominissuis(MAH), andM. aviumsp.paratuberculosis(MAP) are the main members of theM. aviumcomplex (MAC) causing diseases in several hosts. The aim of this study was to describe the genetic diversity of MAC isolated from different hosts. Twenty-six MAH and 61 MAP isolates were recovered from humans and cattle, respectively. GenoType CM®and IS1311-PCR were used to identifyMycobacteriumspecies. The IS901-PCR was used to differentiate between MAH and MAA, while IS900-PCR was used to identify MAP. Genotyping was performed using a mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) scheme (loci: 292, X3, 25, 47, 3, 7, 10, 32) and patterns (INMV) were assigned according to the MAC-INMV database (http://mac-inmv.tours.inra.fr/). Twenty-two (22/26, 84·6%) MAH isolates were genotyped and 16 were grouped into the following, INMV 92, INMV 121, INMV 97, INMV 103, INMV 50, and INMV 40. The loci X3 and 25 showed the largest diversity (D: 0·5844), and the global discriminatory index (Hunter and Gaston discriminatory index, HGDI) was 0·9300. MAP (100%) isolates were grouped into INMV 1, INMV 2, INMV 11, INMV 8, and INMV 5. The HGDI was 0·6984 and loci 292 and 7 had the largestD(0·6980 and 0·5050). MAH presented a higherDwhen compared with MAP. The MIRU-VNTR was a useful tool to describe the genetic diversity of both MAH and MAP as well as to identify six new MAH patterns that were conveniently reported to the MAC-INMV database. It was also demonstrated that, in the geographical region studied, human MAC cases were produced by MAH as there was no MAA found among the human clinical samples.

Trends and advances in the diagnosis and control of paratuberculosis in domestic livestock

Paratuberculosis (pTB) is a chronic granulomatous enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP) in a wide variety of domestic and wild animals. Control of pTB is difficult due to the lack of sensitive, efficacious and cost-effective diagnostics and marker vaccines. Microscopy, culture, and PCR have been used for the screening of MAP infection in animals for quite a long time. Besides, giving variable sensitivity and specificity, these tests have not been considered ideal for large-scale screening of domestic livestock. Serological tests like ELISA easily detects anti-MAP antibodies. However, it cannot differentiate between the vaccinated and infected animals. Nanotechnology-based diagnostic tests are underway to improve the sensitivity and specificity. Newer generation diagnostic tests based on recombinant MAP secretory proteins would open new paradigm for the differentiation between infected and vaccinated animals and for early detection of the infection. Due to higher seroreactivity of secretory proteins vis-à-vis cellular proteins, the secretory proteins may be used as marker vaccine, which may aid in the control of pTB infection in animals. Secretory proteins can be potentially used to develop future diagnostics, surveillance and monitoring of the disease progression in animals and the marker vaccine for the control and eradication of pTB.

Paratuberculosis in sheep: Histochemical, immunohistochemical and in situ hybridization evidence of in utero and milk transmission

To investigate in utero and milk transmission of Mycobacterium avium subsp. paratuberculosis (MAP), tissues from thirteen pregnant sheep, naturally infected and serologically positive to MAP, were examined by means of histochemistry, immunohistochemistry and in situ hybridization. Soon after parturition, ewes were euthanized and tissues samples were collected and prepared. The offspring (18 lambs) were divided into three groups to investigate different routes of MAP transmission. Lambs were sacrificed at three months old and the tissue samples collected, formalin-fixed and paraffin embedded. Hematoxylin and eosin and Ziehl-Neelsen staining methods were performed on fixed tissues for general examination and for detection of acid-fast bacteria. Additionally, immunohistochemical and in situ hybridization techniques were used to detect MAP antigen and MAP DNA respectively. This study of a flock of MAP-infected sheep indicates both in utero and milk transmission of MAP from dams to their offspring. Importantly, this study detected the presence of MAP in the mammary gland and mammary lymph nodes of adult ewes therefore indicating a significant route for the potential exposure to humans from this bacterial infection.

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

CONTEXT AND OBJECTIVE

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.

DESIGN AND SETTING

Analytical cross-sectional study with control group at two federal universities.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Facts, myths and hypotheses on the zoonotic nature of Mycobacterium avium subspecies paratuberculosis

Mycobacterium avium subspecies paratuberculosis (MAP) is the causative agent of paratuberculosis (Johne's disease [JD]), a chronic granulomatous enteritis in ruminants. JD is one of the most widespread bacterial diseases of domestic animals with significant economic impact. The histopathological picture of JD resembles that of Crohn's disease (CD), a human chronic inflammatory bowel disease of still unresolved aetiology. An aetiological relevance of MAP for CD has been proposed. This and the ambiguity of other published epidemiological findings raise the question whether MAP represents a zoonotic agent. In this review, we will discuss evidence that MAP has zoonotic capacity.

Effect of inflammatory bowel disease therapies on immunogenicity of Mycobacterium paratuberculosis proteins

BACKGROUND AND AIMS

The link between Mycobacterium avium subsp. paratuberculosis (MAP) and Crohn's disease (CD) is supported by several studies that have reported the detection and isolation of MAP from human tissues, but causation has not yet been proven. Preliminary studies have shown higher levels of antibodies in sera from CD patients against secreted protein from MAP within human macrophages when compared to healthy controls. The immunogenicity of this protein in CD patients under different treatment regimes was evaluated.

MATERIALS AND METHODS

Sera of 110 CD patients, 82 ulcerative colitis (UC), and 150 healthy controls were collected and the presence of antibodies against the mycobacterial protein tyrosine phosphatase PtpA was assayed using ELISA.

RESULTS

A statistically significant difference in the level of antibodies against PtpA was measured in untreated CD patients versus healthy controls, but variation in the antibody levels was observed when patients were subjected to different treatment regimens. UC patients showed no differences in the levels of antibodies against PtpA when compared to healthy controls.

CONCLUSIONS

CD patients under different drug treatments show a clear difference in the levels of antibodies against a protein secreted by MAP, suggesting that if MAP is active in the progress of CD, some treatments can be detrimental to its survival.

Molecular identification of Mycobacterium avium subspecies paratuberculosis in oral biopsies of Crohn's disease patients

Oral lesions may be found in patients with Crohn’s disease (CD), in a percentage up to 20%. The aim of this study was to investigate a possible relationship between Mycobacterium avium subsp. paratuberculosis (MAP) and oral lesions in CD patients. 23 oral biopsies were examined performing IS900 Nested PCR; 9 of them were positive: 8 from CD patients and 1 from a control. Our purpose is to go on with this study, amplifying the number of subjects examined and testing subjects with oral lesions related to diseases other than CD to verify the specific association between MAP and oral lesions in CD patients.

M. paratuberculosis Heat Shock Protein 65 and Human Diseases: Bridging Infection and Autoimmunity

Mycobacterium avium subspecies paratuberculosis (MAP) is the known infectious cause of Johne's disease, an enteric inflammatory disease mostly studied in ruminant animals. MAP has also been implicated in the very similar Crohn's disease of humans as well as sarcoidosis. Recently, MAP has been associated with juvenile sarcoidosis (Blau syndrome), autoimmune diabetes, autoimmune thyroiditis, and multiple sclerosis. While it is intuitive to implicate MAP in granulomatous diseases where the microbe participates in the granuloma, it is more difficult to assign a role for MAP in diseases where autoantibodies are a primary feature. MAP may trigger autoimmune antibodies via its heat shock proteins. Mycobacterial heat shock protein 65 (HSP65) is an immunodominant protein that shares sequential and conformational elements with several human host proteins. This molecular mimicry is the proposed etiopathology by which MAP stimulates autoantibodies associated with autoimmune (type 1) diabetes, autoimmune (Hashimoto's) thyroiditis, and multiple sclerosis. This paper proposes that MAP is a source of mycobacterial HSP65 and acts as a trigger of autoimmune disease.

In silico screened Mycobacterium avium subsp. paratuberculosis (MAP) recombinant proteins upregulated under stress conditions are immunogenic in sheep

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of Johne's disease (JD) in ruminants. MAP is known to enter a dormant phase outside the host, typically on soil. In vitro experiments have reported regulation of certain MAP genes when exposed to stressors similar to what is thought to produce dormancy. It is believed that in vivo regulation of dormancy genes and associated proteins by MAP may play a role in evading the host defence mechanisms and induce the host immune response against these dormancy-related proteins. Five proteins encoded by dormancy-related genes that were previously found to be upregulated under stress conditions and predicted through in silico analysis to possess immune epitopes (three hypothetical proteins and two proteins involved in fatty acid metabolism) were selected. Recombinant proteins were produced, purified and evaluated by indirect enzyme-linked immunosorbent assay (ELISA) for immunogenicity using a panel of sera obtained from sheep unexposed and exposed to MAP. The antibody levels of the exposed group were significantly higher than the unexposed group (P<0.001). Individually, the five proteins were found to discriminate between sera from sheep exposed to MAP compared to unexposed sheep. At 91% diagnostic specificity, the diagnostic sensitivity of the recombinant antigen ELISA ranged from 24% to 42% and AUC(ROC) from 0.7015 to 0.8405.

Recent research on bovine paratuberculosis in South Korea

Bovine paratuberculosis (Johne's disease), a chronic and debilitating disease of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP), is a major cause of chronic ruminant enteritis. A national eradication program has been in place in South Korea since the first report of the disease in 1967; however, only limited data on bovine paratuberculosis in South Korea are available. Some research, such as investigations of the reactivity of animal sera against MAP antigens, has been done in localized areas and in limited animal species. Compared with the worldwide situation, the development of diagnostic methods in South Korea has shown similar results even though some data were obtained from international collaborative studies. MAP is considered by some to be zoonotic, noting an association with Crohn's disease, although this issue is still controversial; however, research into this association is limited. Decisions based on disease priorities have hampered active progress in research on the disease. In this paper, we reviewed the available results generated from South Korea compared with global research. Finally, we propose a theme for future research.

Crohn's disease and the mycobacterioses: a quarter century later. Causation or simple association?

It has been more than 25 years since Mycobacterium paratuberculosis was first proposed as an etiologic agent in Crohn's disease based on the isolation of this organism from several patients. Since that time, a great deal of information has been accumulated that clearly establishes an association between M. paratuberculosis and Crohn's disease. However, data are conflicting and difficult to interpret and the field has become divided into committed advocates and confirmed skeptics. This review is an attempt to provide a thorough and objective summary of current knowledge from both basic and clinical research from the views and interpretations of both the antagonists and proponents. The reader is left to draw his or her own conclusions related to the validity of the issues and claims made by the opposing views and data interpretations. Whether M. paratuberculosis is a causative agent in some cases or simply represents an incidental association remains a controversial topic, but current evidence suggests that the notion should not be so readily dismissed. Remaining questions that need to be addressed in defining the role of M. paratuberculosis in Crohn's disease and future implications are discussed.

Molecular pathogenesis of bovine paratuberculosis and human inflammatory bowel diseases

Paratuberculosis (Ptb), caused by Mycobacterium avium subsp. paratuberculosis (Map), is a chronic enteritis that affects many ruminants and other wild animals worldwide. Ptb is a great concern in animal health and in etiology of human Crohn's disease (CD). In the present study, we detected Map-specific insertion sequence IS900 of DNA in tissue sections surgically removed from lesions of patients with CD (29 samples), ulcerative colitis (UC) (17 samples), and non-inflammatory bowel disease (IBD) (20 samples). We then compared the histopathological findings of 29 CD and 17 UC cases with those of 35 cases of bovine Ptb, since few comparative pathological studies of human IBD and Ptb have been conducted. The QPCR examination indicated positive results in 13.37% of CD cases, 3.57% of UC cases, and 10% of non-IBD cases. Human CD tissues typically exhibited destructive full thickness enteritis with severe lympho-plasma infiltration and scattered additional granulomas; UC lesions exhibited much less inflammation than CD lesions. Non-IBD control samples did not exhibit pathological changes. Human CD and UC lesions were very different from Ptb lesions that are characterized by predominant granuloma formation. Immunohistochemistry for Map antigen and acid-fast staining were negative in all human IBD cases but were always positive in Ptb cases. Our present comparative study strongly suggests that we reconsider the previous hypothesis that "Map infection" causes CD, even though human intestines were considered to have been exposed to the Map antigen containing the DNA.

Mycobacterium paratuberculosis and autism: is this a trigger?

Autism is a heterogeneous group of life-long neurologic problems that begin in childhood. Success in efforts to understand and treat autism has been mostly elusive. The role of autoimmunity in autism has gained recognition both for associated systemic autoimmune disease and the presence of brain autoantibodies in autistic children and their family members. There is an acknowledged genetic susceptibility to autism--most notably allotypes of complement C4. C4 defects are associated with several autoimmune diseases and also confer susceptibility to mycobacterial infections. Mycobacterium avium ss. paratuberculosis (MAP) causes an enteric inflammatory disease in ruminant animals (Johne's disease) and is the putative cause of the very similar Crohn's disease in humans. Humans are widely exposed to MAP in food and water. MAP has been also linked to ulcerative colitis, irritable bowel syndrome, sarcoidosis, Blau syndrome, autoimmune (Type 1) diabetes, Hashimoto's thyroiditis and multiple sclerosis. Environmental agents are thought to trigger autism in the genetically at risk. Molecular mimicry is the proposed mechanism by which MAP is thought to trigger autoantibodies. Autoantibodies to brain myelin basic protein (MBP) is a common feature of autism. This article considers the subset of autoimmunity-related autism patients and postulates that MAP, through molecular mimicry to its heat shock protein HSP65, triggers autism by stimulating antibodies that cross react with myelin basic protein (MBP).

High prevalence of Mycobacterium avium subspecies paratuberculosis ('Indian bison type') in animal attendants suffering from gastrointestinal complaints who work with goat herds endemic for Johne's disease in India

OBJECTIVES

In this study we aimed to estimate the prevalence of Mycobacterium avium subspecies paratuberculosis (MAP) in animal attendants who were chronic colitis patients or who had inflammatory bowel disease and were suspected for Crohn's disease; these animal attendants worked with goat herds endemic for Johne's disease. Microscopic examination and culture tests were used. For comparison purposes a group of healthy human subjects (not suffering with colitis) was also screened.

METHODS

Stool samples obtained from 98 human subjects (58 animal attendants suspected for Crohn's disease and 40 healthy humans) were screened for the presence of MAP by microscopic examination and culture. Of the 58 animal attendants screened, 38 had abdominal pain, 29 had suffered episodes of diarrhea, 39 had experienced weight loss, 27 had fever, and 32 had a history of raw milk consumption. Animal attendants had had contact of variable duration with goat herds endemic for Johne's disease (1-5, 6-10, 11-15, and >15 years). Forty stool samples from healthy humans with no symptoms/history of contact with animals were also screened. IS900 PCR and IS1311 PCR restriction endonuclease analysis were used to characterize and genotype the MAP colonies.

RESULTS

MAP was recovered from 34 of the 98 human subject stool samples (34.7%). Of the 98 samples, 16.3% (n=16) were acid-fast. None of the 40 healthy human subjects were positive for MAP by microscopy, but five (12.5%) were positive for MAP by culture. Of the 58 animal attendants, 16 (27.6%) were positive by microscopy and 29 (50%) were positive by culture. MAP were recovered from 68.4% of animal attendants with abdominal pain, 72.4% of those with diarrhea, 71.8% of those with weight loss, 44.4% of those with fever, and 46.9% of those who had a history of raw milk consumption. Of the 29 culture-positive animal attendants, 48.3% had worked for >15 years, 27.6% for 11-15 years, 20.7% for 6-10 years, and 3.4% for 1-5 years with goat herds endemic for Johne's disease. Of the 34 culture isolates, 28 (82.4%) showed good quality DNA on agarose gel and were positive by IS900 PCR. Of the 28 IS900-positive DNA samples, 23 (82.1%) were genotyped as 'Indian bison type' and five (17.9%) as 'cattle type'.

CONCLUSIONS

The prevalence of MAP was higher in attendants suffering from gastrointestinal problems who worked with goat herds endemic for Johne's disease, than in humans with no history of contact with animals. The risk of developing gastrointestinal problems with clinical symptoms indistinguishable from inflammatory bowel disease was higher in humans who were in contact with goat herds endemic for Johne's disease as compared to healthy humans, and the risk was correlated with the duration of association with the endemic goat herds.

Detection of Mycobacterium avium subsp. paratuberculosis by a Direct In Situ PCR Method

In situ detection of Mycobacterium avium subsp. paratuberculosis is useful for diagnosis and research of paratuberculosis. The aim of this paper was to detect this agent in formalin-fixed, paraffin-embedded tissue samples by a direct in situ PCR. The technique was performed on ileum or ileocaecal lymph node samples from 8 naturally infected cattle and 1 healthy calf, by using p89 and p92 primers for amplification of IS900 sequence. Moderate positive signal was detected in all positive samples and not in negative control, but tissues resulted were affected in many cases due to the enzymatic treatment and the high temperature exposition. Although the technique was useful for Map detection, the signal was lower than immunohistochemistry probably because of the fixation process. In one case, signal was higher, which might be due to the detection of spheroplasts. Thus, the described method should be recommended when others resulted negative or for spheroplasts detection.

Evaluation of "Indigenous Absorbed ELISA Kit" for the Estimation of Seroprevalence of Mycobacterium avium Subspecies paratuberculosis Antibodies in Human Beings in North India

In present pilot study aimed to estimate, presence of Mycobacterium avium subspecies paratuberculosis (MAP) antibodies in the human serum samples originating from North India using "Indigenous absorbed ELISA kit" (ELISA kit). The phase I, "ELISA kit" was optimized using protoplasmic antigen from native isolate of MAP "Indian Bison type" recovered from the biopsies of Crohn's disease patients. The phase II, sensitivity and specificity of the kit were estimated as 40.0 and 83.3%, respectively, when evaluated in 40 human serum samples (5 Crohn's disease and 22 ulcerative colitis patients and 13 healthy human subjects) with defined MAP status with respect to stool culture. Seroprevalence of MAP antibodies was higher in CD patients (80.0%) as compared to ulcerative colitis patients (4.5%) and normal human subjects (15.3%). The phase III, seroprevalence of MAP antibodies was estimated as 23.4%, on the basis of the screening of 452 human serum samples (without history) from different geographical regions of North India. Region-wise, 34.0, 33.3, 32.8, 25.0, 23.0, 17.7, and 12.5% samples were positive from the states of Punjab, Uttarakhand, New Delhi, Himachal Pradesh, Haryana, Uttar Pradesh and Jammu and Kashmir, respectively. Study reported moderately higher presence of MAP antibodies in human population, which necessitates programs to reduce the bioburden of MAP in the environment and in animal population.

How accurately can we detect Mycobacterium avium subsp. paratuberculosis infection?

Mycobacteria have thwarted detection by scientists for centuries. Mycobacterium paratuberculosis is one of the most fastidious of the Mycobacteriaceae, and has been implicated in both animal and human diseases. In domestic livestock, M. paratuberculosis has been associated with Johne's disease, which given its increasing incidence, is currently a cause for concern, due to the potential for M. paratuberculosis to enter our food chain. In addition, a tenuous link has been reported between M. paratuberculosis and Crohn's disease, however evidence to support this link is hampered by the lack of accurate methodologies for detection of M. paratuberculosis in humans. This review compares the sensitivity and specificity of traditional and more recent techniques to the culture and molecular detection of M. paratuberculosis. While serology and culture are popular choices for the livestock industry they have not produced useful data for human infection. Although the advent of molecular biology has enabled faster diagnosis of M. paratuberculosis in human infection, there is currently no gold standard such as culture on which to validate these findings. Even with DNA/RNA detection methods, there is the ever present issue of the genetic relatedness of M. paratuberculosis to other mycobacteria of the Mycobacterium avium complex, some of which also infect humans with very different pathological outcomes. Recent developments in this field include more rapid methods of M. paratuberculosis culture as well as the development of more accurate and sensitive PCR assays. The application of these techniques should offer a greater insight as to the role of M. paratuberculosis in human gastrointestinal diseases.

Persistent enteric mycobacterial infection enhances sensitivity to acute mucosal injury

Antigen presenting cells such as intestinal macrophages are dynamic effector cells that play a critical role in maintaining mucosal homeostasis. However, it is not known how occult intestinal infections alter the response of the intestinal mucosa to subsequent intestinal injury. The aim of this study was to evaluate how persistent subclinical intestinal infection with Mycobacterium avium subsp. paratuberculosis ( Map) would influence acute dextran sulfate sodium (DSS)-mediated intestinal inflammation. BALB/c mice were infected intraperitoneally with Map. Following an incubation period of 90 d, mice were administered 2% DSS in the drinking water for six days. Prior to and during treatment with DSS, mice were evaluated for clinical signs of disease and body weights were recorded. At termination of the experiment, body weights, frequency of rectal blood, and gross and histological cecal lesions were evaluated, and tissues were collected for isolation of Map. Subclinical and persistent intestinal Map infection was established based on the absence of both weight loss and rectal blood and the isolation of Map from the small and large intestines in mice infected with Map only. Following treatment with DSS, Map-infected mice had increased weight loss, increased frequency of rectal blood, and exacerbation of gross lesions and increased cecal lesion scores. Also, there was a significant reduction in Map isolated from the small intestines of Map-infected and DSS-treated mice. In conclusion, subclinical Map infection sensitizes the host to enhanced acute DSS-mediated intestinal inflammation.

Immunogenicity of Mycobacterium avium subsp. paratuberculosis proteins in Crohn's disease patients

The association between Mycobacterium avium subsp. paratuberculosis (MAP) and Crohn's disease (CD) is supported by several studies reporting the detection or isolation of MAP from human tissues, but a direct association is still debatable.

OBJECTIVE

To evaluate the survival of MAP in human intestinal cells and to measure the presence of antibodies against two mycobacterial proteins necessary for the survival of the bacterium in the sera of CD patients.

MATERIAL AND METHODS

Human-derived intestinal cells were infected with three isolates of MAP and the survival of the microorganism was determined. The presence of antibodies against protein tyrosine phosphatase A (PtpA) and protein kinase G (two proteins secreted within the host in the early stages of the invasion) in the sera of CD patients was evaluated. Sera of 20 CD patients and 20 controls were collected and the presence of the antibodies was assayed using enzyme-linked immunosorbent assay (ELISA). Secretion of the PtpA in vivo was visualized by immunostaining.

RESULTS

MAP survived in intestinal cells, and immunostaining of PtpA showed that the protein was secreted within these cells. Wilcoxon rank sum test revealed that CD patient sera had significantly higher titer of antibodies specific for both of these antigens compared to controls. ELISA results for either protein were not statistically different between men and women.

CONCLUSIONS

The presence of specific antibodies against mycobacterial proteins essential for establishing an infection in the host suggests that MAP can potentially be active in CD patients, and a serological test can be developed for early detection of MAP in CD patients.

The intestinal microbiota in inflammatory bowel diseases: time to connect with the host

PURPOSE OF REVIEW

The aim of this review is to report recent findings regarding the role of the gut microbiota in inflammatory bowel disease pathogenesis.

RECENT FINDINGS

After a description of the current knowledge on inflammatory bowel diseases-associated dysbiosis, we will focus on the recent functional studies that analyzed the cross relationship between the gut microbiota and the host.

SUMMARY

Recently published studies have provided an insight into the altered dialog between the intestinal microbiota and the host leading to gut inflammation. Further investigation will allow identifying new therapeutic targets either in the microbiota or the host.

Specific detection of unamplified mycobacterial DNA by use of fluorescent semiconductor quantum dots and magnetic beads

Here we present the development of a specific DNA detection method using fluorescent semiconductor quantum dots (QDs) and magnetic beads (MBs) for fast detection of Mycobacterium spp., dispensing with the need for DNA amplification. Two biotinylated oligonucleotide probes were used to recognize and detect specific complementary mycobacterial target DNA through a sandwich hybridization reaction. Cadmium selenite QDs conjugated with streptavidin and species-specific probes were used to produce a fluorescent signal. MBs conjugated with streptavidin and a genus-specific probe were used to isolate and concentrate the DNA targets. The application of the proposed method to isolated bacteria produced the expected result in all cases. The minimum detection limit of the assay was defined as 12.5 ng of DNA diluted in a sample volume of 20 microl. In order to obtain an indication of the method's performance with clinical samples, we applied the optimized assay to the detection of Mycobacterium tuberculosis in DNA isolated from bronchoalveolar lavage specimens from patients with tuberculosis and Mycobacterium avium subsp. paratuberculosis in DNA isolated from feces and paraffin-embedded tissues in comparison with culture, Ziehl-Neelsen staining, and real-time PCR. The concordance of these methods compared to the proposed method with regard to positive and negative samples varied between 53.84% and 87.23% and between 84.61% and 100%, respectively. The overall accuracy of the QD assay compared to real-time PCR was 70 to 90% depending on the type of clinical material. The proposed diagnostic assay offers a simple, rapid, specific, and cost-effective method for direct detection and identification of mycobacterial DNA in clinical samples.

Expression of a Gene Encoding 34.9 kDa PPE Antigen of Mycobacterium avium subsp. paratuberculosis in E. coli

Mycobacterium avium subsp. paratuberculosis (Map) contains PPE family antigens which are Proline and glutamic acid rich and may play important role as T cell antigens. Hence the identification and generation of antigens are necessary for immunological characterization. In the present study, the epitopic region of a unique PPE gene encoding 34.9 kDa protein from Map was amplified by polymerase chain reaction. The gene was cloned into Escherichia coli vector pQE30 UA. The recombinant plasmid designated as pQPPE was transformed into E. coli M15 and induced with IPTG revealed the high level expression of 37.1 kDa His-fusion protein (34.9 kDa PPE and 2.2 kDa His-tag), which was confirmed by immunoblotting. Recombinant PPE protein was then purified by Ni-NTA agarose chromatography. The polyclonal antiserum raised against purified recombinant PPE protein reacted with expressed 37.1 kDa His-fusion protein as well as with Map sonicate. The protein elicited significant delayed type hypersensitivity (DTH) skin reaction in mice sensitized with Map. The results indicated that the recombinant PPE protein of Map was associated with cellular immune response.

Is Mycobacterium avium subsp. paratuberculosis, the cause of Johne's disease in animals, a good candidate for Crohn's disease in man?

Mycobacterium avium subspecies paratuberculosis (MAP) causes Johne's disease or paratuberculosis, a gastro intestinal inflammatory condition in ruminants and other animals, which is similar to Crohn's disease (CD) that occurs in man. The role of MAP in the causation of CD has been under intense investigation in the last few decades. This review summarizes the status of MAP in animals and the food chain and its association with CD in man.

Where are all the Mycobacterium avium subspecies paratuberculosis in patients with Crohn's disease?

Mycobacterium avium subspecies paratuberculosis (MAP) causes a chronic granulomatous inflammation of the intestines, Johne's disease, in dairy cows and every other species of mammal in which it has been identified. MAP has been identified in the mucosal layer and deeper bowel wall in patients with Crohn's disease by methods other than light microscopy, and by direct visualization in small numbers by light microscopy. MAP has not been accepted as the cause of Crohn's disease in part because it has not been seen under the microscope in large numbers in the intestines of patients with Crohn's disease. An analysis of the literature on the pathology of Crohn's disease and on possible MAP infection in Crohn's patients suggests that MAP might directly infect endothelial cells and adipocytes and cause them to proliferate, causing focal obstruction within already existing vessels (including granuloma formation), the development of new vessels (neoangiogenesis and lymphangiogenesis), and the "creeping fat" of the mesentery that is unique in human pathology to Crohn's disease but also occurs in bovine Johne's disease. Large numbers of MAP might therefore be found in the mesentery attached to segments of intestine affected by Crohn's disease rather than in the bowel wall, the blood and lymphatic vessels running through the mesentery, or the mesenteric fat itself. The walls of fistulas might result from the neoangiogenesis or lymphangiogenesis that occurs in the bowel wall in Crohn's disease and therefore are also possible sites of large numbers of MAP. The direct visualization of large numbers of MAP organisms in the tissues of patients with Crohn's disease will help establish that MAP causes Crohn's disease.

Peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) assay for specific detection of Mycobacterium immunogenum and DNA-FISH assay for analysis of pseudomonads in metalworking fluids and sputum

Specific and rapid detection and quantification of mycobacteria in contaminated metalworking fluid (MWF) are problematic due to complexity of the matrix and heavy background co-occurring microflora. Furthermore, cross-reactivity among neighboring species of Mycobacterium makes species differentiation difficult for this genus. Here, we report for the first time a species-specific peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) method for Mycobacterium immunogenum, a non-tuberculous Mycobacterium species prevalent in MWF and implicated in occupational lung disease hypersensitivity pneumonitis and pseudo-outbreaks. A novel species-specific 14-bp PNA probe was designed for M. immunogenum based on its 16S rRNA gene sequence and was validated for specificity, by testing against a panel of other phylogenetically closely related rapidly growing mycobacteria and representative species of gram-positive, gram-negative, and acid fast organisms. In addition, a DNA-FISH protocol was optimized for co-detection of Pseudomonas, the most predominantly co-occurring genus in contaminated MWF. Reliable quantification for both the test organisms was achieved at or above a cell density of 10(3)cellsml(-1), a recognized minimum limit for microscopic quantification. The mycobacterial PNA-FISH assay was successfully adapted to human sputum demonstrating its potential for clinical diagnostic applications in addition to industrial MWF monitoring, to assess MWF-associated exposures and pseudo-outbreaks.

Analysis of bacterial bowel communities of IBD patients: what has it revealed?

The bacterial community, in whole or in part, resident in the bowel of humans is considered to fuel the chronic immune inflammatory conditions characteristic of Crohn's disease and ulcerative colitis. Chronic or recurrent pouchitis in ulcerative colitis patients is responsive to antibiotic therapy, indicating that bacteria are the etiological agents. Microbiological investigations of the bacterial communities in stool or of biopsy-associated bacteria have so far failed to reveal conclusively the existence of pathogens or bacterial communities of consistently altered composition in IBD patients relative to control subjects. Confounding factors need to be eliminated from future studies by using better-defined patient populations of newly diagnosed and untreated individuals and by improved sampling procedures.

Detection of Mycobacterium avium subspecies paratuberculosis from patients with Crohn's disease using nucleic acid-based techniques: a systematic review and meta-analysis

This study is a systematic review and meta-analysis of studies using nucleic acid-based techniques to detect Mycobacterium avium paratuberculosis (MAP) in patients with Crohn's disease (CD) compared with controls. Database searches were conducted and risk difference estimates were calculated using meta-analysis. Fifty-eight studies were reviewed, 47 of which were included in the analysis. The pooled estimate of risk difference from all studies was 0.23 (95% confidence interval [CI], 0.14-0.32) using a random effects model. Similarly, MAP was detected more frequently from patients with CD compared with those with ulcerative colitis (risk difference 0.19, 95% CI, 0.10-0.28). Year of study, assay type, and inclusion of children explained some but not all of the observed heterogeneity. The data confirms the observation that MAP is detected more frequently among CD patients compared with controls. However, the pathogenic role of this bacterium in the gut remains uncertain. Our analysis demonstrates that there is an association between MAP and CD, across many sites, by many investigators, and controlling for a number of factors; however, this association remains controversial and inconclusive. Future studies should determine whether there is a pathogenic role.

Presence and characterization of Mycobacterium avium subspecies paratuberculosis from clinical and suspected cases of Crohn's disease and in the healthy human population in India

OBJECTIVES

To investigate and characterize Mycobacterium avium subspecies paratuberculosis (MAP) in patients with Crohn's disease, attendants of animals with suspected infection, and healthy humans, using multiple diagnostic tests.

METHODS

A total of 119 samples (35 stool, 76 serum, three blood clots, and five biopsies) were collected from five patients with Crohn's disease, eight attendants of animals with Johne's disease, and 93 apparently normal control subjects (Agra region) from North India. Samples were screened for the presence of MAP by smear examination, culture of stool, blood clot and biopsies, and ELISA. Colonies obtained by culture were further characterized using polymerase chain reaction (PCR) with IS900 MAP-specific primers.

RESULTS

Using all diagnostic modalities, MAP and/or MAP antibodies were identified in 100% (5/5) of subjects with Crohn's disease; 75.0% (6/8) of attendants of MAP infected animals were positive and 38.0% (27/71) of apparently normal controls were also positive. Most sensitive test was ELISA (100%, 5/5), followed by culture (80.0%, 4/5), and acid-fast staining. Ziehl-Neelsen staining was positive in 37.5% (3/8) of subjects with active animal husbandry practices. In 71 serum samples from control subjects, seroprevalence of MAP was 38.0% using indigenous protoplasmic antigens (PPA) and 36.6% using commercial PPA. Of the serum samples from the Crohn's disease patients, 100% (5/5) were positive by ELISA using indigenous PPA and 40.0% (2/5) were positive by ELISA using commercial PPA. IS900 PCR was used to characterize tiny colonies of MAP that grew extremely slowly on Herrold's egg yolk medium, and of 15 (42.8%) cultures, 14 (93.3%) were typed as MAP.

CONCLUSIONS

Paper documented the presence of MAP in all patients with Crohn's disease, in some animal attendants who had the history of working with goat herds infected with Johne's disease and in few normal healthy individuals. Presence of Ziehl Neelsen positive MAP. In the stool of attendants working with MAP-infected animals was unique to humans. ELISA based on antigens derived from indigenous MAP 'bison type' genotype of goat origin was most sensitive modality for screening Crohn's disease patients.

Epidemiological evidence for Mycobacterium avium subspecies paratuberculosis as a cause of Crohn's disease

Mycobacterium avium subspecies paratuberculosis is the causative agent of Johne's disease, a chronic enteritis in ruminants including cattle, sheep, goats, and farmed deer. Recently, this bacterium has received an increasingly wide interest because of a rapidly growing body of scientific evidence which suggests that human infection with this microorganism may be causing some, and possibly all, cases of Crohn's disease. Recent studies have shown that a high percentage of people with Crohn's disease are infected with M. avium subsp. paratuberculosis; whether the association of this bacterium and Crohn's disease is causal or coincidental is not known. Crohn's disease is a gastrointestinal disease in humans with similar histopathological findings to those observed in the paucibacillary form of Johne's disease in cattle. The search for risk factors in Crohn's disease has been frustrating. However, epidemiologists have gathered enough information that points to an association between M. avium subsp. paratuberculosis and Crohn's disease. This paper reviews epidemiological models of disease causation, the major philosophical doctrines about causation, the established epidemiological criteria for causation, and the currently known epidemiological evidence of M. avium subsp. paratuberculosis as a possible cause of Crohn's disease.

Anti-mycobacterial therapy in Crohn's disease heals mucosa with longitudinal scars

BACKGROUND

A possible causative link between Crohn's disease and Mycobacterium avium ss paratuberculosis has been suggested.

AIM

To report unique scarring in Crohn's disease patients treated with anti-Mycobacterium avium ss paratuberculosis therapy.

PATIENTS

A retrospective review of 52 patients with severe Crohn's disease was conducted. Thirty-nine patients who had at least one follow-up colonoscopy during treatment were included.

METHODS

Patients received rifabutin (up to 600 mg/day), clofazimine (up to 100 mg/day) and clarithromycin (up to 1 g/day) - anti-Mycobacterium avium ss paratuberculosis therapy - for 6 months to 9 years. Ramp-up dosing was used. Colonoscopies and histological analyses monitored progress.

RESULTS

Twenty-two patients (56.4%, 22/39) healed with unusual scarring, which appeared as branched, ribbon-like, elevated lines. In 2/6 patients (33.3%) who had > 3 years of treatment after scarring occurred, scars receded, becoming imperceptible as full healing occurred. Histologically, a marked reduction in inflammation occurred in 15/39 patients (38.5%). Of these, 6/15 patients (40%) displayed restoration of normal mucosa. Longitudinal scarring occurred in 12/15 patients (80%) with improved histology.

CONCLUSIONS

The presence of scarring fading to normal mucosa on anti-MAP therapy implies a more profound healing not seen with standard anti-inflammatory and immunosuppressant drugs. Longitudinal scarring and consequent healing with normal histology should become a standard treatment goal for Crohn's disease.

Mycobacterium avium in the postgenomic era

The past several years have witnessed an upsurge of genomic data pertaining to the Mycobacterium avium complex (MAC). Despite clear advances, problems with the detection of MAC persist, spanning the tests that can be used, samples required for their validation, and the use of appropriate nomenclature. Additionally, the amount of genomic variability documented to date greatly outstrips the functional understanding of epidemiologically different subsets of the organism. In this review, we discuss how postgenomic insights into the MAC have helped to clarify the relationships between MAC organisms, highlighting the distinction between environmental and pathogenic subsets of M. avium. We discuss the availability of various genetic targets for accurate classification of organisms and how these results provide a framework for future studies of MAC variability. The results of postgenomic M. avium study provide optimism that a functional understanding of these organisms will soon emerge, with genomically defined subsets that are epidemiologically distinct and possess different survival mechanisms for their various niches. Although the status quo has largely been to study different M. avium subsets in isolation, it is expected that attention to the similarities and differences between M. avium organisms will provide greater insight into their fundamental differences, including their propensity to cause disease.