Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “paratuberculosis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
PubMed2004

Detection of viable Mycobacterium avium subsp. paratuberculosis using luciferase reporter systems.

Plasmid- and phage-based firefly luciferase reporter constructs were evaluated as rapid detection systems for viable Mycobacterium avium subsp. paratuberculosis (MAP). A MAP strain bearing a luciferase-encoding plasmid was detectable at 100 cells/mL in skim milk and 1000 cells/mL in whole milk. Three luciferase-encoding mycobacteriophage were evaluated for detection of wild-type MAP. The best of these, phAE85, allowed detection of >1000 cells/mL within 24-48 h. Membrane filtration did not improve the sensitivity of detection for either plasmid or phage reporters. Luciferase reporters show promise for rapid detection of viable MAP.

Animals↗
PubMed2006

Modified culture protocol for isolation of Mycobacterium avium subsp. paratuberculosis from raw milk.

A modified culture method using C18-carboxypropylbetaine (CB-18) and microscopic screening was evaluated for time to and limit of detection of Mycobacterium avium subsp. paratuberculosis (MAP) in raw milk. Bulk-tank milk samples were spiked with six different concentrations (10(1) to 10(6) CFU/mL) of MAP. Samples were processed using two different protocols. The first protocol involved specimen processing with the zwitterionic detergent C18-carboxypropylbetaine (CB-18) and lytic enzymes followed by culture on modified Middlebrook 7H10 agar plates with microscopic screening. The second protocol used 0.75% hexadecylpyridinium chloride (HPC) for specimen processing, followed by culture on Herrold's egg yolk medium (HEYM). Both protocols were repeated eight independent times, and the detection limit and time to detection were compared. The presence of MAP in spiked milk samples was detected between 14 and 45 days (N [number of samples], 46; mean, 22.7; median, 19.5) using the CB-18 and microscopic screening method, and between 21 and 63 days (N, 47; mean, 31; median, 28) using HEYM (P < 0.001). Time to detection also varied with MAP concentration (P < 0.001). Higher concentrations of MAP were detected earlier than lower concentrations and this finding was independent of the method used (P = 0.479). The two methods had similar detection limits but the modified culture method reduced the time to detect MAP in raw milk for the majority of concentrations.

Animals↗
PubMed1991

Antimicrobial activity of rifabutin in combination with two and three other antimicrobial agents against strains of Mycobacterium paratuberculosis.

The inhibitory and bactericidal, synergistic, and antagonistic activities of rifabutin combined with ciprofloxacin, ethambutol, clofazimine, cefazolin, and amikacin in dual and triple combinations against various human and animal isolates of Mycobacterium paratuberculosis were determined. Synergism was observed when rifabutin was combined with either cefazolin or clofazimine in double combinations. The greatest amount of synergy occurred with the rifabutin-cefazolin combination in which bactericidal synergism was present with all strains. Of the triple combinations examined, only rifabutin in combination with ethambutol and cefazolin or streptomycin and cefazolin showed bactericidal synergism against most of the strains. Although antagonism was not observed in any double combination with rifabutin, antagonism was shown with several of the triple combinations. The rifabutin-cefazolin and rifabutin-streptomycin-cefazolin combinations were found to have the greatest bactericidal synergism at concentrations well within achievable serum and tissue levels and may be appropriate choices for chemotherapeutic use.

4-Quinolones↗
PubMed1992

p43, the protein product of the atypical insertion sequence IS900, is expressed in Mycobacterium paratuberculosis.

The novel mycobacterial insertion sequence IS900 was analysed by coupled transcription-translation, of both strands independently, in a cell-free E. coli extract using an exogenous promoter. This revealed only one protein product, p43, as predicted from the nucleotide sequence. The protein was readily translated in recombinant E. coli, using the tac promoter, though it did not appear as a major product by SDS-PAGE analysis. A synthetic peptide was used to generate and affinity-purify a specific anti-p43 antibody, which clearly identified the protein in recombinant E. coli. p43 was relatively stable in exponential phase and stationery phase bacteria, though a 28 kDa processed form was seen to accumulate over a period of hours. Both forms appeared in the soluble fraction of the bacterial lysate. The anti-p43 antibody also identified p43, as a 28 kDa processed product, in Western blots of protein extracts from Mycobacterium paratuberculosis, indicating a level of expression which would be unusually high for a classical transposase. These data have important implications for the relationship between IS900 and its host.

Amino Acid Sequence↗
PubMed2003

Iodixanol development of a laboratory-scale technique to monitor the persistence of Mycobacterium avium subsp. paratuberculosis in Cheddar cheese.

Mycobacterium avium subsp. paratuberculosis (Map) is a potential human pathogen known to be present in raw milk from infected dairy herds. Current pasteurisation regimes do not totally inactivate Map resulting in the possibility of viable cells being present in pasteurised milk used for Cheddar cheese production. A laboratory-based method, ensuring strict safety precautions, was developed to manufacture 800-g Cheddar blocks, experimentally contaminated (postpasteurisation) with two different strains of Map. The composition of the model Cheddar produced was consistent with commercial product. Syneresis of the cheese curd caused a 1 log10 concentration of Map numbers from milk to cheese for a strain isolated from pasteurised milk. The type strain NCTC 8578 did not show a similar concentration effect, but did however survive the Cheddar manufacturing process. A small percentage (<5%) of the Map load for each strain was recovered in the whey fraction during the process.

Cheese↗
PubMed2006

Sensitive detection of Mycobacterium avium subsp. paratuberculosis in bovine semen by real-time PCR.

AIMS: To develop a fast and sensitive protocol for detection of Mycobacterium avium subsp. paratuberculosis (MAP) in bovine semen and to make a critical evaluation of the analytical sensitivity. METHODS AND RESULTS: Processed semen was spiked with known amounts of MAP. Semen from different bulls as well as semen of different dilutions was tested. The samples were treated with lysing agents and beadbeating and the DNA was extracted with phenol and chloroform. Real-time PCR with a fluorescent probe targeting the insertion element IS900 detected as few as 10 organisms per sample of 100 mul semen. PCR-inhibition was monitored by inclusion of an internal control. Pre-treatment with immunomagnetic separation was also evaluated, but was not shown to improve the overall sensitivity. CONCLUSIONS: Real-time PCR is a sensitive method for detection of MAP in bovine semen. Lysis by mechanical disruption followed by phenol and chloroform extraction efficiently isolated DNA and removed PCR-inhibitors. SIGNIFICANCE AND IMPACT OF THE STUDY: The high sensitivity of the applied method allows reliable testing of bovine semen used for artificial insemination to prevent the spread of Johne's disease, caused by MAP.

Animals↗
PubMed1992

Expression of Escherichia coli beta-galactosidase in Mycobacterium bovis BCG using an expression system isolated from Mycobacterium paratuberculosis which induced humoral and cellular immune responses.

A promoter sequence, PAN, was isolated from Mycobacterium paratuberculosis and characterized. This promoter lies adjacent to, and outside, the 3' end of an IS900 insertion element. IS900 contains an open reading frame, ORF2, on the complementary strand which codes for the putative transposase of this insertion sequence. A DNA fragment containing PAN and part of ORF2 was fused to the lacZ gene and inserted into the replicative shuttle vector pRR3. Mycobacterium smegmatis and Mycobacterium bovis BCG (BCG) transformed with this plasmid exhibited beta-galactosidase activity. However, lacZ was only expressed in Escherichia coli under the control of PAN, when ORF2 was deleted. Immunization of mice with the recombinant M. bovis BCG expressing lacZ resulted in the induction of a high humoral and cellular response directed against beta-galactosidase. The PAN-ORF2 expression system may prove to be particularly useful for cloning and expression of heterologous genes in the BCG vaccine strain.

Amino Acid Sequence↗
PubMed1990

Immunohistochemical methods for the visualization of Mycobacterium paratuberculosis in bovine tissues.

The peroxidase-antiperoxidase (PAP), streptavidin-biotin (SB), and avidin-biotin-complex (ABC) techniques have been evaluated for the visualization of Mycobacterium paratuberculosis (Mp) in formalin-fixed, paraffin-embedded bovine tissues. The used immunoperoxidase techniques were comparatively better than the Ziehl-Neelsen stain, specially for the demonstration of small number of mycobacteria in tissue sections.

Animals↗
PubMed2004

Clinical paratuberculosis as a cause for higher culling rate in cows with left displaced abomasum and diarrhoea in a holstein dairy herd.

The present report identifies a statistically significant (P < 0.001) higher postoperative culling rate in cows with left displaced abomasum (LDA) exhibiting diarrhoea, compared with cows with LDA and normal faeces from a large Holstein dairy herd (odds ratio = 34). Paratuberculosis was histopathologically confirmed in 77.0% of cows with LDA exhibiting diarrhoea.

Abomasum↗
PubMed2004

Mycobacterium avium ssp. paratuberculosis--combined serological testing and classification of individual animals and herds.

Several serological tests for detection of antibodies to Mycobacterium avium ssp. paratuberculosis, which is the causative agent of Johne's disease are validated, some of which are available commercially. These tests differ in sensitivity and specificity. Test results reported to farmers or veterinarians are therefore dependent upon the test in use. In the present study, three commercially available tests are used to test 2748 bovine sera from 119 Bavarian herds serologically. Serological results are compared with individual animals and on herd level. A scheme for serological testing and classification of herds as well as of individual animals based on a combination of serological test results is proposed.

Animal Husbandry↗
PubMed2005

Development of an IMS-PCR assay for the detection of Mycobacterium avium ssp. paratuberculosis in water.

AIMS: To develop a sensitive detection method for Mycobacterium avium ssp. paratuberculosis (Map) in water by modifying and optimizing an existing immunomagnetic separation polymerase chain reaction (IMS-PCR) technique. METHODS AND RESULTS: Sterile distilled water (50 ml) spiked with 10(6) Map ml(-1) was subjected to either filtration (0.45 microm pore size) followed directly by IS900 PCR (method 1) or centrifugation (2500 g for 20 min) followed by IMS and IS900 PCR (method 2). Method 2 permitted the detection of Map, whereas method 1 did not. Method 2 was then optimized by adding different concentrations of Tween 80 (0.05, 0.1, 0.2, 0.4 and 0.6% v/v) to water samples spiked with Map (10(6)-1 CFU ml(-1)) prior to centrifugation, and assessing the impact of this action on the detection sensitivity of subsequent IMS-PCR. The optimum Tween 80 concentration was found to be 0.4%, which permitted the detection of 10 Map CFU ml(-1) in spiked water samples by IMS-PCR. CONCLUSIONS: This method will be used to determine the incidence of Map in water destined for domestic use in future studies. SIGNIFICANCE AND IMPACT OF THE STUDY: A sensitive method for the detection of Map in water involving addition of 0.4% Tween 80, centrifugation and IMS-PCR was developed.

Bacteriological Techniques↗
PubMed2006

Mycobacterium avium ssp. paratuberculosis and its potential survival tactics.

Mycobacterium avium ssp. paratuberculosis (Map) is an important animal pathogen with a potential, but as yet unproven, role in human disease. This review briefly describes the characteristics of Map that distinguish it from other Mycobacterium spp., presenting new information arising from completion of the sequencing of the Map genome. It then focuses on the potential mechanisms Map might employ to survive and disseminate in the environment, including interaction with protozoa and insects, dormancy, biofilm formation and aerosolization.

Aerosols↗
PubMed2002

Cytokine effects on maturation of the phagosomes containing Mycobacteria avium subspecies paratuberculosis in J774 cells.

Mycobacterium avium subspecies paratuberculosis (M. a. ptb) is an intracellular pathogen of macrophages. Intracellular survival of several species of pathogenic mycobacteria is dependent on inhibition of maturation of the phagosomes containing these pathogens into functional phagolysosomes. In activated macrophages, however, this capacity is reduced, leading to increased bacterial killing. It is the hypothesis of this study that there is increased acidification and maturation of the phagosome containing M. a. ptb in interferon gamma and lipopolysaccharide (IFN-gamma/LPS) activated macrophages. In activated macrophages colocalization of M. a. ptb with either a marker of acidic compartments (Lysotracker Red) or compartments containing a late phagosome maturation marker lysosome-associated membrane protein-1 (Lamp-1) were evaluated by laser confocal microscopy. Intracellular survival of M. a. ptb in activated macrophages was evaluated directly using differential fluorescent live/dead staining. The results of this study demonstrated increased colocalization of both Lysotracker Red and Lamp-1 with FITC labeled M. a. ptb, which correlated with decreased survival of M. a. ptb within activated macrophages.

Animals↗
PubMed1997

Identification and differentiation of mycobacteria using the PAN promoter sequence from Mycobacterium paratuberculosis as a DNA probe.

A 165 bp DNA fragment containing the PAN promoter from Mycobacterium paratuberculosis was used as a probe in Southern blots to detect the presence of related sequences in other species of mycobacteria. Among the species tested homologous sequences appeared to be present in representative pathogens belonging to the Mycobacterium tuberculosis complex, the MAIS complex, Mycobacterium kansasii and also the non-pathogenic vaccine strain Mycobacterium bovis BCG. In addition, the probe could differentiate between these species on the basis of a restriction fragment length polymorphism (RFLP). No hybridization was observed with DNA extracted from a selected group of other slow-growing and fast-growing mycobacteria nor from a selection of other bacterial pathogens. It appears that the PAN sequence is identifying genomic regions common to the major pathogenic groups of mycobacteria.

Base Sequence↗
PubMed2002

Interpretation of the gamma interferon test for diagnosis of subclinical paratuberculosis in cattle.

A group of 252 cattle without clinical signs of paratuberculosis (paraTB) in 10 herds infected with paraTB and a group of 117 cattle in 5 herds without paraTB were selected. Whole-blood samples were stimulated with bovine, avian, and johnin purified protein derivative (PPD) and examined for gamma interferon (IFN-gamma) release. For diagnosis of paraTB, satisfactory estimated specificities (95 to 99%) could be obtained by johnin PPD stimulation irrespective of interpretation relative to bovine PPD or no-antigen stimulation alone, but numbers of test positives in the infected herds varied from 64 to 112 with different interpretation criteria. For a limited number of test-positive animals, no change in the test results could be observed with increasing antigen concentrations but IFN-gamma responses were significantly reduced (P < 0.0001) and four out of seven reactors tested negative when stimulation was performed on day-old samples. Denmark is free of bovine tuberculosis, but cross-reactivity with paraTB could be documented for cattle more than 14 months old in paraTB-infected herds compared with those in non-paraTB-infected herds. In both paraTB-free and paraTB-infected herds, false positives were observed when the test was applied to calves less than 15 months of age. Until novel antigen formulations more specific for these diseases are available, interpretation of the IFN-gamma test must be individually adjusted to fit specific needs and the context within which the test is applied and, for paraTB, the test seems most appropriate for use as a supportive tool for evaluation of disease-preventive measures in young stock.

Animals↗
PubMed1987

Lipoarabinomannan and lipid-free arabinomannan antigens of Mycobacterium paratuberculosis.

Lipoarabinomannan (LAM) and lipid-free arabinomannan (AM) were prepared from Mycobacterium paratuberculosis. Purification of LAM was done by ultracentrifugation of the phenol-water-extracted crude polysaccharide, followed by affinity and anion exchange chromatography. AM was purified from the supernatant of the ultracentrifuged polysaccharide or from alkaline-extracted material by gel filtration and anion exchange chromatography. Chemical analysis revealed arabinose and mannose in LAM (1.4:1) and AM (3.5:1) and the presence of palmitic, stearic, and tuberculostearic acids for a total of 7.8% lipid in LAM. Traces of phosphorus were found in the AMs, particularly LAM (0.05%). Nuclear magnetic resonance confirmed the presence of alpha-arabinosyl residues and the acylated nature of LAM. LAM exhibited lipid-dependent aggregation, as indicated by a Triton-induced decrease in molecular weight. By using bovine sera, LAM was found to be active in the complement fixation test, whereas AM was inactive and inhibited this activity. Thus, the presence of AM in crude polysaccharide could explain the variable complement fixation results. Triton-dissociated LAM exhibited a precipitin (Cl) in common with that of AM, confirming shared determinants. LAM in its lipid-dependent aggregated form, however, exhibited a second precipitin (C2), which may be due to the disparity in antigen size or a novel epitope. The lipid content of LAM rendered it 100 times more effective for coating plates in the enzyme immunoassay than lipid-free AM.

Antibodies, Bacterial↗
PubMed1993

Isolation and partial characterization of glycolipid fractions from Mycobacterium avium serovar 2 (Mycobacterium paratuberculosis 18) that inhibit activated macrophages.

Glycolipid fractions from Mycobacterium avium serovar 2 (Mycobacterium paratuberculosis 18) inhibited the killing of Candida albicans by activated bovine peripheral-blood-derived macrophages. Fractions were derived by using the matrix solid-phase dispersion technique, which is a new method of simultaneous lysis and partial fractionation of components of bacterial cells. Further purification of active fractions was performed by concanavalin A affinity chromatography, centrifugal filtration, and differing solvent solubility. Three different fractions were isolated and partially characterized. Two of these fractions have characteristics typical of glycolipids, and the third fraction has characteristics compatible with a peptidoglycolipid. This peptidoglycolipid fraction has been purified and named MIF-A3.

Acetonitriles↗