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1.
Reference streptococcal antisera and sera collected from swine infected experimentally (by intranasal inoculation or contact exposure) with group E Streptococcus (GES) were studied in a tube agglutination system using whole GES cells. Specificity studies revealed common group specific antigen among GES serotypes I and III, GES strains devoid of type specific antigen (untypable by ring precipitin testing) and group P and group U Streptococcus. The group specific antigens were not agglutinated by GES type specific antisera or by group specific antisera against Streptococcus groups A, B, C, D, F, G, H, K, L, M, N, or O. Results of the study suggested that GES serotypes I and III are invalid; i.e., they are devoid of type specific antigen. Groug E Streptococcus type specific antigens II, IV, and V were agglutinated significantly only by their homologous antisera. Experimentally infected swine developed significant titers against both the group and type specific antigen of GES. Antibodies appeared from three to eight weeks postexposure and persisted for the duration of the experiment (six months). The potential utilization of the whole cell agglutination (WCA) test for detection of GES carrier swine is discussed. 相似文献
2.
Lymph nodes, spleens, and tonsils from swine infected experimentally with Group E Streptococcus (GES, the causative agent of jowl abscess) were examined grossly and bacteriologically. Forty-two abscessed lymph nodes were seen among 14 infected swine. Pure cultures of GES were recovered from each abscess. Approximately half of 112 pools of grossly normal lymph nodes yielded GES as did half of 14 tonsils and 14 spleens. All GES recovered were morphologically and serologically identical to the strain used to create the experimental infection. 相似文献
3.
The loss of viability and ultrastructural changes were studied in group E Streptococci (GES) after in vitro phagocytosis in immune swine macrophages. There was a 50% reduction in the viability of intracellular GES during the first 60 minutes of incubation and a total loss of viability by 300 minutes as compared to the control tubes where the GES increased. Loss of viability in phagocytized group E Streptococci was associated with the appearance of degenerative changes in the bacterial cytoplasm. This was followed by disruption of the bacterial cell membrane and its separation from the bacterial cell wall. No definite evidence of cell wall degeneration could be found. Unphagocytized organisms incubated for similar periods and fixed in the same manner did not lose viability nor have any degenerative changes. 相似文献
4.
A microtitration agglutination test was developed and evaluated for detecting infection of swine with group E streptococci type IV, the most common causative agent of streptococcic lymphadenitis of swine. Whole cell agglutinogens representing group and type antigens of group E streptococci were tested in the microtitration agglutination test against reference antisera to Streptococcus groups A, B, C, D, E, F, G. H, K, L, M, N, O, P, Q, R, S and U, as well as specific antisera to types II, IV and V of group E. Group E specific agglutinogens were unsatisfactory in the microtitration agglutination test because of cross reactions with group P and U antisera and because of poor reproducibility of the test. Type specific agglutinogens of group E streptococci reacted only with their respective homologous antisera and not with any heterologous group antisera. None of the group E streptococci agglutinogens reacted with 52 normal swine sera. Agglutinogen made from group E streptococci type IV was selected for further evaluation in the microtitration agglutination test because group E streptococci types II and V are considered to be of minor importance in the etiology of streptococcic lymphadenitis of swine. Swine experimentally infected with a type IV strain developed significant titers in the microtitration agglutination test. All swine tested negative before exposure and seroconverted (titer ≥4) two to six weeks postexposure. The microtitration agglutination test was used by two different laboratories to test 187 duplicate samples of serum from infected swine. A total of 94.1% of the tests were read at either the same titer (48.1%) or a difference of not more than one dilution (46.0%) at the two laboratories. There was disagreement between the two laboratories in the test-positive test-negative status of 19 of the sera (10.2%). Titers of two of the sera differed by two dilutions (<4 at one laboratory and 8 at the other). The remaining 17 sera differed in titer by only one dilution (<4 at one laboratory and 4 at the other). 相似文献
5.
The modified direct complement-fixation test, supplemented with unheated normal calf serum, was used to demonstrate antibodies in sera of swine immunized to African swine fever virus. These antibodies did not react in the ordinary direct non-supplemented complement-fixation test. African swine fever complement-fixing antigen in infected swine tissue is not denatured by extraction with fat solvents. Consequently, good antigens devoid of non-specific reactivity were obtained by extraction with a mixture of acetone and ether. The virus was detected in infected swine tissue harvested one day after beginning of pyrexia. The modified direct complement-fixation test demonstrated cross-reactions between the six strains of virus studied. 相似文献
6.
Swine (n = 10) were given a concentrated whole-culture adsorbate bacterin made from group E Streptococcus (GES). Two doses of bacterin were given subcutaneously 3 weeks apart. Control swine (n = 10) were given a blank preparation made from sterile culture medium. Swine were challenge exposed 3 weeks after the 2nd injection of bacterin by being penned continuously for 8 weeks with carrier swine infected with GES. A significant (P less than or equal to 0.009) immune response to vaccination with the bacterin was observed. Vaccinated swine, but not control swine, developed antibodies to an antiphagocytic factor (as detected with bactericidal and long-chain tests) before challenge exposure. Vaccinated swine also developed 51.2% (20 vs 41) fewer abscesses after challenge exposure than did control swine. Control swine developed a greater serologic response to challenge exposure, indicating a more extensive infection with GES. 相似文献
7.
Serum from both immune and nonimmune ten-week-old swine contained factors which promoted phagocytosis of group E Streptococci (GES). The factors in nonimmune serum, which were heat labile at 70°C for ten minutes, were less efficient than the factors present in immune serum. Bactericidal activity of the polymorphonuclear (PMN) leukocytes against GES was observed with serum from both immune and nonimmune ten-week-old swine, as well as with serum from normal sows and piglets. However, the bactericidal activity of PMN leukocytes in serum from either normal sows or immune ten-week-old swine was greater than the bactericidal activity of PMN leukocytes in either piglet serum or serum from nonimmune ten-week-old swine. When the serum was either heated to 70°C for ten minutes or treated with 2-mercaptoethanol, bactericidal activity of PMN leukocytes against GES was only observed in the presence of immune serum. 相似文献
8.
Swine were given a series of injections of soluble or whole cell antigens of group E Streptococcus (GES). In experiment 1, swine given autoclaved extracts developed greater amounts of antibody to antiphagocytic factor (as detected with bactericidal and long-chain tests) than did swine given pepsin-extracted or whole cell antigens, and the swine given extract developed fewer abscesses when challenge exposed with live virulent GES added to their feed. In experiment 2, swine given injections of concentrated autoclaved extract develped higher antiphagocytic factor antibody titers than did control swine given injections of physiologic saline solution. When challenge exposed with live virulent GES by exposure to carrier swine, swine that were given extract developed 71.4% fewer abscesses than did the control swine. Furthermore, 58.3% of the abscesses in the swine that were given extrac" were less than 1 cm in diameter as compared with 38.2% of the abscesses in the controls, suggesting that the development of some abscesses was arrested in vaccinated swine. Data indicate that a degree of immunity to streptococcal lymphadenitis of swine can be induced by vaccinating swine with nonliving GES antigen. 相似文献
9.
The bacterial flora and the pH of the large intestine of dysenteric swine during acute subacute and chronic phases have been submitted to quantitative and qualitative studies. The methods used are based on primary isolation and differentiation of the bacteria by the use of selective media and the subsequent differentiation using the replica plating technique. The most characteristic changes are the following: 1. A significant increase of the pH of the chyme in the large intestine during acute dysentery 2. A significant increase of Vibrio, Escherichia coli and Staphylococcus in the colon and cecum during acute dysentery. 3. A significant increase of Shigella in the colon and cecum during subacute dysentery. 4. The almost total disappearance of Aeromonas and of the yeasts in the large intestine during acute, subacute and chronic dysentery. 5. A significant decrease of Klebsiella, in the cecum, during acute dysentery and of the fungi during subacute dysentery. 6. Decrease of Streptococcus in the colon during acute dysentery. 7. The total quantitative flora of the large intestine do not change very much. 相似文献
10.
A mycoplasma was recovered from the untreated conjunctival membranes of nine sheep affected by Pink-eye. It was neither isolated from the conjunctiva of treated animals which were affected nor from the conjunctiva of normal animals either in contact or not in contact with affected animals. Bacteria found on normal conjunctival membranes were Neisseria ovis, Escherichia coli, Staphylococcus epidermididis, Streptococcus and Bacillus spp. Bacteria found in clinical cases of Pink-eye were N. ovis, E. coli, a Streptococcus and Pseudomonas spp. 相似文献
11.
Fourteen caesarean-derived, colostrum-deprived pigs and seven conventional swine were exposed to low passage, cloned, field isolates of Mycoplasma flocculare. Sera were collected at varying intervals postexposure (PE) and tested against M. flocculare and M. hyopneumoniae antigens in a semi-automated ELISA. Swine were killed six to 17 weeks PE and their lungs examined grossly for lesions and culturally for mycoplasmas. Pure cultures of M. flocculare were recovered from the lungs of 11 of 14 swine killed six to 12 weeks PE. Mycoplasmas were not isolated from the swine killed 15 to 17 weeks PE. Only one pig had gross lesions of pneumonia. Immunoassays revealed that swine were slow to seroconvert and titers (expressed in terms of optical density) were low. Three of 21 swine had antibodies to M. flocculare five weeks PE, five of 17 had seroconverted at seven to eight weeks and all surviving swine had antibodies to M. flocculare 76 days PE and beyond. Net optical density of positive sera was in the range of 0.201 to 0.412 (an optical density of 0.2 regarded as the breakpoint between negative and positive reactions in our ELISA). All of the sera were ELISA-negative when tested against M. hyopneumoniae antigen. This is regarded as a very significant finding. There has been concern that field sera might contain antibodies to M. flocculare and that such antibodies could render serodiagnostic tests for mycoplasmal pneumonia of swine nonspecific. Results of the present study suggest that swine infected with M. flocculare do not develop sufficient levels of antibodies to interfere with enzyme immunoassays for M. hyopneumoniae. 相似文献
12.
Complement-fixation (CF) and tube agglutination (TA) tests for demonstration of Vibrio fetus antibodies were conducted on the sera of three groups of ten heifers. One group was vaccinated subcutaneously with a commercial V. fetus var venerealis bacterin and challenged intra-utero, at the external os cervicus one month later; the second was infected only and the third vaccinated only. The vaccinated cattle developed high CF serum titers, but no such increase was observed in animals infected only. A moderate increase in serum antibody titers was demonstrated by the TA test following either infection or vaccination; although titers observed were not higher than those observed in the sera of some apparently normal uninfected animals. The group receiving both vaccine and challenge was the only one in which significant serum antibody titers were demonstrable by the TA test. The sera of these animals also had significant titers in the CF tests. The CF and TA tests detected serum antibodies produced by the parenteral inoculation of V. fetus antigen. These two tests were of limited value in detecting serum antibodies from animals with genital V. fetus var venerealis infection, although the formation of local antibodies was demonstrable by the vaginal mucus agglutination test. 相似文献
13.
The direct, the modified direct and the indirect complement-fixation tests were investigated as methods for the detection of antibodies for the enzootic pneumonia mycoplasma and for Mycoplasma hyorhinis in the serum of infected pigs and of immunized rabbits. Only the modified direct complement-fixation test in which the guinea-pig complement is supplemented with fresh, normal unheated calf serum was suitable for the detection of mycoplasma antibodies in sera of infected swine. Based on the close correlation between the production of typical lung lesions in experimentally infected pigs and the appearance of significant serum antibody titres, the modified direct complement-fixation test provides for the first time a sensitive, specific in vitro method for the detection of enzootic pneumonia in the live pig. This test also permitted the in vitro differentiation of the mycoplasma causing enzootic pneumonia from M. hyorhinis which causes polyserositis. Antibodies in the sera of rabbits were demonstrable by the ordinary direct complement-fixation test. However, in contast to the observation made with swine sera, only a slight quantitative antigenic difference between the enzootic pneumonia mycoplasma and M. hyorhinis was seen when the tests were performed with rabbit serum antibodiies. 相似文献
14.
The changes of antibody titers in the sera of colts infested naturally or artificially with Gasterophilus have been determined in relation to the life cycle of this arthropod using passive hemagglutination, complement fixation, double diffusion techniques and saline extracts of antigens from the third larval stages of Gasterophilus intestinalis and G. nasalis.In the sera of the infected animals the hemagglutinating antibodies were present at low titers at the third week post-infestation by using somatic extract of G. intestinalis and at the seventh week in case of G. nasalis. At eight weeks post-infestation the antibody titers reached their maximum 1:8192 (G. intestinalis) and 1:4096 (G. nasalis), then dropped at 12 weeks post-infestation. The complement fixing antibodies were present occasionally between the seventh and 11th weeks after infestation. Precipitating antibodies were absent in all sera. 相似文献
15.
Eight groups of 12-to 24-hour-old pigs were procured from a respiratory disease-free herd of swine and reared in isolation using a box-rearing procedure. They were inoculated intranasally at 3 days of age with different isolates of Bordetella bronchiseptica.It was found at necropsy 4 weeks post-inoculation that 4 isolates of swine origin, an isolate of rabbit origin and an isolate of cat origin caused mild to moderate turbinate atrophy in 22 of 24 pigs. An isolate of rat origin caused mild turbinate atrophy in 1 of 4 pigs and an isolate of dog origin caused no turbinate atrophy. Pneumonia was present in most of the pigs inoculated with the swine, cat and rabbit isolates. Bordetella bronchiseptica was recovered in heavy growth from the nasal and tracheal exudate collected at necropsy from pigs inoculated with the 4 isolates of swine origin and the isolate of cat origin. Fewer organisms were isolated from nasal exudate collected from pigs inoculated with the rat, dog and rabbit isolates. 相似文献
16.
Fifteen gnotobiotic pigs varying in age from three to eight weeks were exposed to 23 strains of V. coli isolated from swine with clinical and/or pathological signs of swine dysentery and also from clinically healthy pigs. Clinical or pathological signs of swine dysentery were not produced, although the organism was readly established in the sedimentary tract. Culture of feces, alimentary tract and environment revealed V. coli in large numbers, but no bacterial growth was obtained from other organs. The histopathology and serology are discussed. 相似文献
17.
Antimicrobial agents were added to the feed of swine for three weeks to determine the interrelationships of potentially pathogenic agents in the nasal tract, turbinate atrophy and weight gains. Bordetella bronchiseptica was not isolated from the groups fed the combination of chlortetracycline, penicillin and sulfamethazine. B. bronchiseptica was found in some pigs after the feeding trail, but this organism was not significantly associated with turbinate atrophy at the time of slaughter. Mycoplasma hyorhinis was not found in the nasal passages of the pigs that received feed containing high concentration chlortetracycline but was found in pigs that received other diets. Hemophilus suis was not significantly reduced by any of the treatments used. The organisms studied in the pigs were not isolated from the personnel handling the pigs. 相似文献
18.
Strains of hemolytic E. coli are implicated in edema disease and enteritis of swine. Immunological experiments were conducted to determine the specific role played by hemolytic E. coli in the etiology of these diseases. When cell-free extracts prepared from a frequently isolated E. coli — 0139:K82(B) were injected 48 hours apart into a healthy pig, symptoms of edema disease were produced on both occasions. Similar symptoms were produced when this extract was injected into a colostrum-deprived pig raised in isolation. The Schultz-Dale reaction revealed no difference between the contractions of the ilea of sensitized and non-sensitized guinea-pigs. In vitro treatment of a single non-sensitized guinea-pig uterus with extracts of five different strains of hemolytic E. coli produced sharp contractions in every trial. A similar treatment with extracts of four non-hemolytic E. coli strains also stimulated the non-sensitized guinea-pig uterus but the magnitude of the contractions was much less. These studies indicated that the cell-free extracts of hemolytic E. coli produced a marked nonspecific toxic reaction. 相似文献
19.
Caesarean-derived, colostrum-deprived swine were exposed to a broth culture of a low passage field isolate of Mycoplasma hyopneumoniae by intranasal inoculation. The intranasal-inoculated swine subsequently were commingled with their litter-mates to effect transmission via contact-exposure. Sera were collected from the swine at two to four week intervals for approximately one year postexposure and evaluated by the enzyme-linked immunosorbent assay (ELISA), indirect hemagglutination and complement fixation tests. The intranasal-exposed swine seroconverted earlier, developed higher titers and remained indirect hemagglutination and complement fixation positive longer than the contact-exposed swine. It was concluded that the antibody response of intranasal-exposed swine was artificially high and that sera from such swine were not suitable for evaluating the sensitivity of mycoplasmal pneumonia of swine serodiagnostic tests. The indirect hemagglutination test was relatively insensitive and technically cumbersome and the least promising as a practical field test. The complement fixation test appeared to be slightly more sensitive in detecting early antibody production (especially in contact-exposed swine) but it was the least sensitive in detecting late antibodies. The ELISA was generally the most sensitive procedure. Individual high ELISA titers were from ten to 32 times greater than maximum complement fixation and indirect hemagglutination titers. The most striking difference among the three tests was the persistence of high ELISA titers late in the study. All swine were ELISA positive at necropsy approximately one year postexposure despite the fact that lungs were devoid of lesions and culturally and immunofluorescent negative for M. hyopneumoniae. 相似文献
20.
In a study of the response of gnotobiotic pigs to coliform infections, 45 one-week-old germfree pigs were divided into five groups and each group was inoculated orally with a different strain of Escherichia coli. Three of these were enteropathogenic swine strains, P307[08:K87(B), K88 a,b (L):H19]; P570 [0138:K81]; P568[0141:K85a,b(B), K88a,b(L):H4], one was a virulent human strain, H224, [026:K60(B6)], and one was a non-enteropathogenic swine strain, P581[OX13:K68]. It was attempted to protect a portion of the pigs with orally administered specific antisera and sera from non-immunized specific pathogenfree (SPF) pigs. Observations were made on the clinical response, bacterial counts of feces and intestinal contents, gross pathological changes, distribution of the organisms in organs and serum hemagglutinin titers. Infection with E. coli P307 resulted in diarrhea, dehydration and death, unless the pig was protected with specific antiserum. The pigs infected with E. coli P570 had a transient diarrhea but retained their appetites and recovered. Those infected with the other three strains remained healthy throughout. No circulating hemagglutinating antibody against the test strains of E. coli could be detected in any of the pigs seven days or earlier post-inoculation. Relationship could not be established between the numbers of viable E. coli in the feces and the presence of clinical colibacillosis. Orally administered specific antiserum afforded protection against strain P307, but did not reduce the number of E. coli in the gut or alter their distribution in the internal organs. This suggested that the protective effect of specific antibody in the intestine was due to its action on a metabolite (enterotoxin) produced by E. coli P307 rather than the organism itself. 相似文献
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