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1.
《Veterinary microbiology》1998,60(1):45-57
Smooth lipopolysaccharides (SLPS) from Brucella abortus contain A-epitopes against which the majority of serum antibodies are directed during infections. SLPS from Yersinia enterocolitica 0:9 possesses identical epitopes, which are the cause for serological cross-reactivity. All Brucella spp. possess M- and C-epitopes which are not present in Y. enterocolitica 0:9. In order to examine the usefulness of these M- and C-epitopes for discrimatory serological testing, a panel of sera were used in this study, comprising sera from Y. enterocolitica 0:9-infected heifers, sera from B. abortus-infected cattle of comparable strength in the serological brucellosis tests to the sera from Y. enterocolitica 0:9-infected heifers, sera from B. abortus-infected bovines with strong serological reactions and sera from animals free from B. abortus or Y. enterocolitica infections. These sera were tested in blocking ELISAs with seven M- and one C-epitope-specific monoclonal antibodies in combination with SLPS from B. melitensis M16 high in M-epitopes as antigen. Strong B. abortus sera inhibited most strongly, while negative sera showed no or little inhibition. Sera with weak or intermediate titres blocked to a lower extent. Unexpectedly, the sera from Y. enterocolitica 0:9-infected heifers showed inhibition behaviour virtually identical to the comparable sera from B. abortus infected animals. Absorbing out of the A-epitope specific serum antibodies with either Y. enterocolitica 0:9 SLPS or with Y. enterocolitica 0:9 bacteria, indicated the presence of M- or C-epitope-specific serum antibodies in some sera from B. abortus-infected cattle but not in the sera from Y. enterocolitica 0:9-infected animals. These results demonstrate that the M- or C-epitope-specific antibody response in sera from B. abortus infected cattle is only of limited value for the serological discrimination between B. abortus and Y. enterocolitica 0:9 infections. 相似文献
2.
Ribosomes from Brucella abortus strain 19 were isolated by differential centrifugation. The 70S ribosomes were purified by pelleting through 0.5 M ammonium chloride and 30% sucrose. The resulting ribosomes were designated washed ribosomes and consisted of 64–65% RNA and 35–36% protein with sedimentation coefficients of 50S and 30S. When the washed ribosomes were tested by immunodiffusion against immune bovine sera, no precipitins were detectable. The immunogenic responses of the washed ribosomes were determined in guinea pigs, lemmings, and calves. Inoculation dosages as low as 1.0 microgram in guinea pigs and 0.1 microgram in lemmings protected against challenge with virulent B. abortus. Results of similar studies in a limited number of calves indicated that a dose of 1 mg may be protective. Brucella ribosomes did not appear to elicit marked undesirable side effects when used as immunizing agents. 相似文献
3.
《Veterinary microbiology》1997,57(4):361-371
The course of immunological reaction in 10 Yersinia enterocolitica 0:9 experimentally-infected heifers was followed using the conventional brucellosis tests complement fixation test (CFT), serum agglutination test (SAT) and brucella card test (BCT), and a recently developed Brucella antigen-specific gamma interferon (IFN-γ) test. Initially, the animals were exposed orally to 1010 colony-forming units (CFU) of Y. enterocolitica 0:9. Four weeks later, they were inoculated intravenously with 108 CFU of Y. enterocolitica 0:9 cells. After oral inoculation, the response in the conventional brucellosis tests was minimal. Only after intravenous inoculation were CFT and SAT titres and BCT reactions comparable to natural, false positive brucellosis reactors. After oral exposure the Brucellergen-stimulated release of IFN-γ peaked at values above the cut-off stimulation index of 2.5 in 80% of the heifers. After intravenous inoculation, stimulation indices above 2.5 were present in only 10% of the animals. Two B. abortus infected control cattle showed stimulation indices of 3.1 and 3.4, and a negative control animal exhibited a stimulation index of 1.0. These findings show, in contrast to a previous study, that the Brucellergen-specific IFN-γ assay cannot be used as a specific and discriminatory test for B. abortus infections. 相似文献
4.
Infection of normal adult cattle and sporadic serological Brucella abortus reactors, which no longer had diagnostic titers to B. abortus, with a culture of Escherichia coli isolated from a cow (or its environment) resulted in the production of a primary IgM serum antibody response to both B. abortus and E. coli. Cattle injected with heat killed E. coli and guinea pigs or young calves lacking natural agglutinins to B. abortus injected with live E. coli, produced serum antibody only to E. coli. The subsequent reinjections of live E. coli into the former two groups of cattle resulted in all but one animal in each group producing IgM ‘secondary’ responses to B. abortus of decreasing magnitude, while the anti-E. coli responses increased and eventually switched to synthesis of IgG class antibody. The remaining two animals produced a series of ‘secondary’ responses of IgM antibody to B. abortus similar in amplitude and duration to the primary immune response. The anti-E. coli agglutinins of these two animals increased in titer and IgG class antibody to E. coli was evident after several injections of E. coli. These results indicate that infection of cattle by E. coli can cause a problem in the serological fiagnosis of B. abortus infection. Speculations on the cause of this cross-reaction and ways of minimizing misdiagnosis are discussed. 相似文献
5.
Brucellosis is an important zoonotic bacterial disease widespread in the world. The key step of control this disease is accurate diagnosis and elimination of diseased animals. The classic diagnostic methods, such as tube agglutination test, are inaccurate and nonspecific, because of cross-reaction with Yersinia enterocolitica serotype O:9. Previously, several proteins were reported as Brucella main immunogens. In this study, we used animal infection model to evaluate antibody production against OMP16, BP26, BLS, BCSP31, VirB12, SodC and GroEL proteins and investigated their application in diagnosis of brucellosis. The results showed that the BP26 and BLS are two best immunogenic proteins. In further study, we detected 44 clinical bovine sera using western blot, showing that the BP26 and BLS reacted with 30 Brucella-positive sera, but false-positive results were also shown in 14 Brucella-free sera. In an indirect ELISA assay, compared to lipopolysaccharide-based ELISA, the conformance of the BP26-based ELISA was 92.68 % in Brucella-positive sera, but only 52.94 % in Brucella-free sera. The BLS-based ELISA can hardly differentiate positive sera from negative sera. Besides, truncated fragments of the BP26 protein cannot exclude false-positive results in detection of Brucella-free sera. Altogether, although Brucella main immunogenic proteins have good reaction with Brucella-positive sera, false-positive reaction with Brucella-free sera may lead to misdiagnosis of brucellosis, suggesting that it should be more careful to use these immunogenic proteins as antigen targets to diagnosis of brucellosis. 相似文献
6.
AIMS: To study the adhesion properties of a biotype 4, serotype O:3 (human pathogenic) strain of Yersinia enterocolitica and to determine if adhesion in vitro and colonisation in vivo can be prevented by competition with a biotype 1A, serotype O:6,30 (non-pathogenic) strain. To study interaction between Y. enterocolitica biotype 4, serotype O:3 and cultured epithelial cells using the synthetic tripeptide arginine-glycine-aspartic acid (RGD). METHODS: The human intestinal epithelial (HEp-2) cell line was used for in vitro studies. Inocula of Y. enterocolitica biotype 4, serotype O:3 radiolabelled using tritium were incubated with HEp-2 cells and RGD tripeptide, or with Y. enterocolitica biotype 1A, serotype O:6,30 sequentially or concurrently, then washed and lysed, and radioactivity measured to determine the effect of RGD on adhesion, and competitive exclusion of pathogenic by non-pathogenic bacteria. For in vivo studies, two groups of 5-week-old piglets (n=5/group) were sequentially inoculated orally with 5x109 colony forming units (cfu) of either a non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica followed by a pathogenic biotype 4, serotype O:3 strain, or vice versa. Pigs were monitored for carriage of strains using bacterial culture and a multiplex polymerase chain reaction (PCR). RESULTS: The RGD tripeptide significantly inhibited adherence of the pathogenic Y. enterocolitica strain to cultured epithelial cells, suggesting that adhesion involved the RGD tripeptide sequence. The non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica prevented adhesion of the pathogenic strain to cells in vitro when allowed to adhere first. Pathogenic Y. enterocolitica was consistently isolated from rectal swabs from 80-100% of pigs on all sampling occasions but not from oral swabs after 14 days in pigs first inoculated with the non- pathogenic strain or at 26 days in pigs first inoculated with the pathogenic strain. CONCLUSIONS: A non-pathogenic strain of Y. enterocolitica reduced adhesion of a human pathogenic strain in vitro but not in vivo. 相似文献
7.
The effects of iron excess and desferrioxamine in pretreated guinea‐pigs on the immune response (production of Yops) and on the histological changes in infections with Yersinia enterocolitica 0:3 and Y. enterocolitica 0:8 were investigated. The prior overload of the guinea‐pigs with Dextrofer or treatment with Desferal increased the pathogenic activity of Y. enterocolitica 0:3 and led to a generalized infection. Immunoblot analysis showed that in conditions of iron overload the expression of outer membrane proteins (Yops) of Y. enterocolitica 0:8 was blocked. This was accompanied by weak changes in the tissues. The iron‐limited conditions stimulated production of a low molecular weight protein (17 kDa) on day 6 and easier proliferation of the bacterium. This in vivo study intends to show that in Y. enterocolitica infections a leading role is played not only by iron itself but also by the bacterial strain. 相似文献
8.
F. Hilbink S.G. Fenwick E.J. Thompson R. Kittelberger M. Penrose G.P. Ross 《New Zealand veterinary journal》2013,61(5):175-178
The level of non-specific reactions found in the brucellosis serology of ruminants in New Zealand was very low until July 1992. This changed when, in an export consignment of 1071 deer, 35% reacted in the Brucella abortus tube agglutination test with titres varying from 50 to 200 IU. The reactors were also positive in the Rose-Bengal agglutination test and most of them reacted in the complement fixation test with titres varying from 10 to 80 IU. Yersinia enterocolitica 0:9 was later isolated from one deer of this consignment. It was the first isolate of this serotype recovered in New Zealand from an animal. Shortly after, false reactors occurred more frequently than before in sera from Brucella abortus accredited free cattle herds. As the involvement of Yersinia enterocolitica 0:9 was suspected in these cases, faecal samples from reactors and in-contact animals were cultured for this organism. Yersinia enterocolitica 0:9 was isolated from nine of 19 herds showing one or more false Brucella abortus seroreactions. Prior to 1990, Yersinia enterocolitica serotype 0:9 had not been isolated in New Zealand, despite the recovery of a number of other bio— or serotypes of the organism from humans and animals. From 1990 onward, serotype 0:9 began to be isolated from human faecal samples with increasing frequency. Since the first isolations from deer and cattle in 1992, it has now also been recovered from a cat and an alpaca and from cattle without any association with false positive Brucella abortus reactions. All serotype 0:9 isolates were of biotype 2. 相似文献
9.
&#x;. Wojciech Z. Staroniewicz A. Jakubczak M. Ugorski 《Zoonoses and public health》2004,51(5):238-244
Thirty‐five Yersinia enterocolitica strains isolated from humans, pigs and foxes were analysed by genotyping including intergenic transcribed sequence (ITS) profiling, REP‐ and ERIC‐PCR. ERIC‐PCR revealed the presence of seven different genotypes. Amplification of the 16S‐23S rDNA spacer region by ITS profiling gave similar results with nine different genotypes. REP‐PCR was found to be more discriminatory for typing of Y. enterocolitica than ERIC‐PCR and ITS profiling. Fifteen different DNA patterns were obtained by this technique. Based on data obtained by three methods it was found that: (i) Y. enterocolitica strains belonging to the same serotype can represent different genotypes and vice versa; (ii) isolates recovered from humans, pigs and foxes exhibit limited heterogeneity and, independent of the origin, one or two prevailing genotypes were always observed; and (iii) many human Y. enterocolitica isolates shared common genotypes with porcine isolates. 相似文献
10.
H. Fukushima R. Nakamura Y. Ito K. Saito M. Tsubokura K. Otsuki 《Veterinary microbiology》1983,8(5):469-483
Pigs were examined on five farms for carrier status of Yersinia enterocolitica. Yersinia enterocolitica biovar 4, serovar 3, phagovar VIII was isolated consistently from the feces of fattening pigs on one farm and sporadically from those of similar pigs on the other farms and of sows on all five farms, during a one-year period of weekly surveys. Seasonal variation was not a feature of fattening pigs on a highly contaminated farm. In other pigs, however, the organisms were not isolated during the summer months. On a highly contaminated farm, the organisms were excreted in the feces of 8 to 15-week-old pigs within 1–3 weeks of entering pens which were thought to be contaminated with the organisms. On a detailed observation of natural infection of Y. enterocolitica in eight pigs, the organism appeared in the pigs' feces within 2–7 weeks of them being moved to a pen which had been washed thoroughly after becoming contaminated, by a previous group of pigs, with feces containing 105 viable organisms per g. Thus, Y. enterocolitica is apparently transmitted from infected feces or picked up from the floor of a contaminated pen, and the regular schedule of pig movement among the pens is an important factor in the spread of Y. enterocolitica within a piggery. Intestinal colonization continues for a long time and does not occur by re-infection. The organisms were not isolated from eight pigs at the time of slaughter, and their serum O-agglutinin titers were or less. Thus, circulating antibody may not inhibit intestinal colonization by Y. enterocolitica. 相似文献
11.
K Nielsen 《Veterinary immunology and immunopathology》1990,24(4):373-382
Sera from calves immunized with Yersinia enterocolitica serotypes O:9 or O:16 were tested by indirect enzyme linked immunosorbent assay (ELISA) using lipopolysaccharide (LPS) preparations from Brucella abortus or Y. enterocolitica O:9 or O:16 for their antibody content of the IgG1 or IgG2 subclasses. High IgG1 responses were present with the three antigens in both groups although some individual variations between animals were noted. The IgG2 responses were modest and in some cases not above background 'noise'. Thus IgG2 antibody was not measurable in sera from serotype O:9 injected calves when using serotype O:16 LPS or in serotype O:16 injected calves when using B. abortus or serotype O:9 LPSs. A competitive ELISA using B. abortus O-polysaccharide and a monoclonal antibody to B. abortus LPS (initially designed to differentiate the antibody responses of cattle naturally infected with B. abortus from those vaccinated with strain 19) was used on sera from both groups of calves. Using this test, no antibody was detected in the group immunized with serotype O:16 and except for one animal in the serotype O:9 immunized group, only low levels of antibody were transiently in evidence. One animal in this group responded with quite high levels of competing antibody which, however, declined towards the end of the test period. The competitive ELISA may prove a useful serological tool for differentiating vaccinal and field infection titers to B. abortus and also to eliminate cross-reactions observed with Y. enterocolitica serotypes. 相似文献
12.
C. C. Chukwu 《The Veterinary quarterly》2013,33(2):134-142
Summary The lymphocyte transformation test (using an in vitro whole‐blood lymphocyte stimulation procedure) and the Brucellin skin test were applied to five heifers infected with virulent Brucella abortus strain 544, five cows inoculated with Yersinia enterocolitica serotype 09, and four non‐exposed cows. Lymphocytes from Brucella‐inoculated animals persistently gave very high blastogenic reactions indicative of active Brucella infection. The test was persistently negative in Yersinia‐infected and non‐exposed cattle. Four of thefive cowsinfected with Yersinia enterocolitica type 09 and allfour control cattle were persistently negative to the delayed hypersensitivity skin reaction with brucellin. All cattle infected with Yersinia enterocolitica type 09 were strongly positive to the Rose Bengal, Serum agglutination, Complement fixation and Antibovine globulin tests using Brucella abortus antigens. One lactating cow infected with Yersinia enterocolitica type 09 was positive to Brucella milk ring test. These results indicate that standard Brucella serological tests are unreliable in differentiating the two infections in cattle and that both the Lymphocyte transformation and brucellin skin tests could be used to differentiate bovine brucellosis from yersiniosis. 相似文献
13.
《Veterinary immunology and immunopathology》2015,163(3-4):194-201
Triggering receptor expressed on myeloid cells-2 (TREM-2) is a cell surface receptor primarily expressed on macrophages and dendritic cells. TREM-2 functions as a phagocytic receptor for bacteria as well as an inhibitor of Toll like receptors (TLR) induced inflammatory cytokines. However, the role of TREM-2 in Brucella intracellular growth remains unknown. To investigate whether TREM-2 is involved in Brucella intracellular survival, we chose bone marrow derived macrophages (BMDMs), in which TREM-2 is stably expressed, as cell model. Colony formation Units (CFUs) assay suggests that TREM-2 is involved in the internalization of Brucella abortus (B. abortus) by macrophages, while silencing of TREM-2 decreases intracellular survival of B. abortus. To further study the underlying mechanisms of TREM-2-mediated bacterial intracellular survival, we examined the activation of B. abortus-infected macrophages through determining the kinetics of activation of the three MAPKs, including ERK, JNK and p38, and measuring TNFα production in response to lipopolysaccharide (LPS) of Brucella (BrLPS) or B. abortus stimulation. Our data show that TREM-2 deficiency promotes activation of Brucella-infected macrophages. Moreover, our data also demonstrate that macrophage activation promotes killing of Brucella by enhancing nitric oxygen (NO), but not reactive oxygen species (ROS) production, macrophage apoptosis or cellular death. Taken together, these findings provide a novel interpretation of Brucella intracellular growth through inhibition of NO production produced by TREM-2-mediated activated macrophages. 相似文献
14.
Theron G Snider Stewart McConnell L.Garry Adams Kenneth R Pierce 《Comparative immunology, microbiology and infectious diseases》1981,4(1):9-19
Neonatally thymectomized and normal Holstein-Friesian calves were exposed to bovine viral diarrhea virus and challenged 22 days later. Baseline values in non-specific mitogen induced lymphocyte blastogenesis and serologic responses to tetanus toxoid and Brucella abortus strain 19 were established in neonatally thymectomized and normal calves.Neither viral recovery nor protective antibody production followed the very low level primary exposure to bovine viral diarrhea virus. The expected clinical response to an appropriate challenge inoculum did not occur, however, suggesting an immune response to bovine viral diarrhea virus had been initiated by the primary exposure. Five of eight calves developed protective serum levels of bovine viral diarrhea antibody. This may represent an example of immunologic priming. Exposure to low levels of bovine viral diarrhea virus also has potential implications in the pathogenesis of chronic bovine viral diarrhea wherein low level exposure may interfere with the development of protective levels of bovine viral diarrhea antibody as was observed in three calves.Circulating lymphocyte concentrations and results of non-specific mitogen stimulation of lymphocytes revealed a reduced phytohemagglutinin response in conjunction with a slightly increased response to bacterial lipopolysaccharide and pokeweed mitogen in the presence of moderate lymphopenia. The capacity of lymphocytes to respond to phytohemagglutinin was unchanged but an increased total response, as occurred in control thymectomized and intact calves, did not occur.The response to tetanus toxoid, a thymus-independent antigen, was increased following exposure to bovine viral diarrhea virus, perhaps reflecting an alteration in thymic-independent regulation. The lack of a differential response to Brucella abortus strain 19 implied competence in thymus-dependent helper cells. 相似文献
15.
A whole blood lymphyocyte transformation (WBLT) assay was used to detect anti-brucella lymphocyte reactivity in guinea pigs. Brucella antigens stimulated an antigen-specific lymphoproliferative response in WBLT assays from infected guinea pigs. The response was best detected from 6 to 16 weeks after challenge inoculation with viable 2308. Lymphocytes were not stimulated by unrelated bacterial antigens and control animals did not respond to the Brucella antigens. The responding cell population was characterized as mostly T lymphocytes. The WBLT assay was found to be specific for the detection of anti-brucella lymphocyte reactivity. However, a negative response was not definitive, which indicated a need for repeated testing to establish that a guinea pig did not have anti-brucella lymphocyte sensitization. 相似文献
16.
Zhi-qiang Li Dan Gui Zhi-hua Sun Jun-bo Zhang Wen-zhi Zhang Hui Zhang Fei Guo Chuang-fu Chen 《Journal of veterinary science (Suw?n-si, Korea)》2015,16(4):467-473
Brucellosis is a zoonotic disease that causes animal and human diseases. Vaccination is a major measure for prevention of brucellosis, but it is currently not possible to distinguish vaccinated animals from those that have been naturally infected. Therefore, in this study, we constructed the Brucella (B.) abortus 2380 wbkA mutant (2308ΔwbkA) and evaluated its virulence. The survival of 2308ΔwbkA was attenuated in murine macrophage (RAW 264.7) and BALB/c mice, and it induced high protective immunity in mice. The wbkA mutant elicited an anti-Brucella-specific immunoglobulin G response and induced the secretion of gamma interferon. Antibodies to 2308ΔwbkA could be detected in sera from mice, implying the potential for use of this protein as a diagnostic antigen. The WbkA antigen would allow serological differentiation between infected and vaccinated animals. These results suggest that 2308ΔwbkA is a potential attenuated vaccine against 16M. This vaccine will be further evaluated in sheep. 相似文献
17.
BackgroundBrucellosis is the most common zoonotic diseases worldwide. The aim of this study was to develop and evaluate the diagnostic performance of an indirect-ELISA (I-ELISA) method based on whole cell Brucella abortus S99 lysates for detection of IgM anti-Brucella antibodies in a human serum.Materials and methodsThe study was conducted in two species-rich endemic areas of Iran (Tehran and Lorestan provinces). Serum samples of 102 patients and 150 healthy individuals were tested by the new kit and the commercial Vircell kit for the presence of anti-Brucella IgM antibodies. The disease status was confirmed by Wright agglutination test. The difference in the mean optical densities (OD) recorded by the new and the Vircell kits for patients and healthy individuals were tested using Two-tailed Student t-test. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the new kit were informed using Receiver operating curve analysis. The results were used to guide the choice of cutoff. Agreements in ODs recorded by the new and the Vircell kit was visually inspected using Bland-Altman plot.ResultsThe new I-ELISA showed excellent diagnostic performance (sensitivity and PPV = 95.7%, specificity and NPV = 97.8%) for the diagnosis of brucellosis. The cut-off area for the antibody index (AI) was determined to be 8–10, where AIs less than 8 and greater than 10 were considered Brucella-negative and -positive, respectively. AIs of 8–10 show equivocal results, requiring re-testing. The Vircell kit showed low (36.8%) sensitivity and perfect (100%) specificity on the same samples. The Bland-Altman plot showed low agreement between both tests in recording the OD values for the same individuals.ConclusionThe new I-ELISA based on whole cell Brucella abortus S99 showed a good performance for the detection of Brucella spp. Lack of agreement between the new and the Vircell kit suggest that the performance of ELISA kits might be dependent on the geographical area under study. Hence, validation of the new and the Vircell kits is recommended prior to their implementation in other geographical areas. 相似文献
18.
M. Her D.‐H. Cho S.‐I. Kang J.‐S. Lim H.‐J. Kim Y.‐S. Cho I.‐Y. Hwang T. Lee S.‐C. Jung H.‐S. Yoo 《Zoonoses and public health》2010,57(3):155-161
Seven of 18 elk on a deer farm were found by the official Rose‐Bengal agglutination test (RBT) and tube agglutination test to be brucellosis reactors/suspects. Evaluation with the competitive ELISA (C‐ELISA) and the fluorescence polarization assay (FPA) tests revealed that six and five sera were positive respectively. The seven reactors/ suspects were slaughtered and their blood and tissues were collected. Brucella species could be isolated from three of the slaughtered animals, with nine isolates being obtained from the popliteal, supramammary and submandibular lymph nodes, vaginal discharge, mammary tissue and spleen. Brucella genus‐specific PCR based on 16S rRNA and AMOS‐PCR, which is specific for differential Brucella species, revealed that all nine isolates were Brucella abortus. These nine were further confirmed to be B. abortus biovar 1 by classical biotyping scheme assays. This is the first report of an outbreak of brucellosis in domestic elk in Korea. Our observations suggest that deer should be included in the routine Brucella surveillance programme for the effective control and prevention of brucellosis in Korea. 相似文献
19.
Karin S?derqvist Sofia Boqvist Georges Wauters Ivar V?gsholm Susanne Thisted-Lambertz 《Acta veterinaria Scandinavica》2012,54(1):39
Background
Pigs are regarded as the main reservoir for human pathogenic Yersinia enterocolitica, which is dominated by bioserotype 4/O:3. Other animals, including sheep, have occasionally been reported as carriers of pathogenic strains of Y. enterocolitica. To our knowledge, this is the first study performed in the Nordic countries in which the presence of Y. enterocolitica in sheep is investigated.Methods
Tonsils and faecal samples collected from sheep slaughtered on the island Gotland (Sweden) from September 2010 through January 2011 were analysed for presence of Y. enterocolitica. In an attempt to maximize recovery, several cultural strategies were applied. Various non-selective media were used and different temperatures and durations of the enrichment were applied before subculturing on Cefsulodin Irgasan Novobiocin (CIN) agar. Presumptive Y. enterocolitica colonies were subjected to urease, API 20E and agglutination test. Yersinia enterocolitica isolates were biotyped, serotyped, and tested for pathogenicity using a TaqMan PCR directed towards the ail-gene that is associated with human pathogenic strains of Y. enterocolitica.Results
The samples collected from 99 sheep yielded 567 presumptive Y. enterocolitica colonies. Eighty urease positive isolates, from 35 sheep, were identified as Y. enterocolitica by API 20E. Thirty-four of 35 further subtyped Y. enterocolitica isolates, all from faecal samples, belonged to biotype 1A serotype O:5, O:6. O:13,7 and O:10. One strain was Yersinia mollaretii serotype O:62. No human pathogenic strains of Y. enterocolitica were found in the investigated sheep. Other species identified were Y. kristensenii (n = 4), Y. frederiksenii/intermedia (n = 3), Providencia rettgeri (n = 2), Serratia marcescens (n = 1) and Raoultella ornithinolytica (n = 1).Conclusions
This study does not support the hypothesis that sheep play an important role in transmission of the known human pathogenic Y. enterocolitica in the studied geographical region. However, because there are studies indicating that some strains of Y. enterocolitica biotype 1A may cause disease in humans, the relative importance of sheep as carriers of human pathogenic strains of Y. enterocolitica remains unclear. Tonsils do not appear to be favourable sites for Y. enterocolitica biotype 1A in sheep. 相似文献20.
A small but significant reduction in the number of Mycoplasma dispar colonising the respiratory tract after intratracheal challenge was observed in gnotobiotic-calves previously inoculated subcutaneously three times with formalin-killed organisms and oil adjuvant. Injection of M. dispar by the intramuscular route, with oil adjuvant, and 2 weeks later by the intratracheal route, without adjuvant, failed to induce immunity to subsequent intratracheal challenge.Following the subcutaneous injection of killed M. dispar, the amount of antibody detected by single radial haemolysis (SRH) increased markedly with increasing age in groups of calves with average ages of 16 to 155 days when first injected. Most calves aged less than 40 days failed to produce an antibody response to a singel injection of M. dispar. With M. bovis a smaller difference was observed between antibody levels generated in calves of different ages; also, calves less than 40 days old produced a detectable SRH antibody response following a single injection of killed M. bovis.IgG1 and IgG2 antibody to M. dispar and M. bovis were measured by ELISA. IgG1 appeared before IgG2 antibody and this was particularly pronounced in younger calves. Also, for both mycoplasmas IgG2 antibody levels were lower in younger than older calves. The IgG1 response to M. dispar was compared in three groups of calves with average ages of 16, 55 and 155 days and was greatest in the oldest and least in the youngest animals. In contrast, the IgG1 response to M. bovis varied little in calves of different ages. It therefore appears that the immune response of young calves to M. dispar is impaired or defective. 相似文献