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1.
Three-week-old turkeys were passively immunized with convalescent serum or treated with tracheal washings from turkeys infected with Bordetella avium. Western blot analysis of the convalescent serum and tracheal washings revealed at least two bands of interaction with outer membrane protein preparations of B. avium. Adherence of B. avium in vivo to tracheal mucosa was determined and compared in treated and untreated turkeys. Passive immunization with convalescent serum reduced adherence of B. avium to the tracheal mucosa in a dose- and time-dependent manner. Adherence was significantly inhibited (P less than 0.01) when turkeys were treated intravenously with 1 ml of undiluted serum either 1 or 6 hours previously. Incubation of the bacterial inoculum with convalescent tracheal washings or application of the washings to tracheal segments before adherence determination in vivo resulted in a significant (P less than 0.01) decrease in adherence. These results indicate that adherence of B. avium to tracheal mucosa is inhibited by substances (antibody) present in both serum and tracheal secretions of convalescent turkeys.  相似文献   

2.
鸡大肠埃希氏菌菌毛表达、血凝谱及粘附特性研究   总被引：4，自引：0，他引：4  
对６株具有不同致病性的鸡大肠埃希氏菌分离株体外菌毛的表达、对１３种不同红细胞血凝谱及血凝方式、对鸡胚成纤维细胞（ＣＥＦ）及在体内外对１日龄鸡气管组织的粘附特性进行了研究,结果表明,具有致病性的菌株,在体外适宜的条件下,能表达菌毛,非致病性菌株不表达。不同菌株的血凝谱及血凝方式具有差异,除中等致病性菌株ＭＧ３０e对大鼠红 细胞（ＲＢＣＦ）的凝集不能被Ｄ－甘露糖抑制,表现为抗甘露糖型血凝（ＭＲＨＡ）外,  相似文献   

3.
Electron microscopy revealed pili on all isolates of Bordetella avium and B. avium-like bacteria examined. Trypticase soy broth (TSB) and 2% peptone agar were the best media for promoting pilus expression. Cultures grown at 37 or 42 C had similar pilus production, whereas cultures grown at 18 C produced few or no pili. Pilus expression of the Art Vax strain was best when that strain was grown in TSB, but the strain yielded fewer pili than B. avium and B. avium-like isolates grown under the same cultural conditions. B. avium pili had a diameter of 2.0 nm, ranged in length from 370 nm to 1500 nm, and had a protein subunit molecular mass of about 13,100 daltons. Purified pili from B. avium did not hemagglutinate guinea pig erythrocytes, and a 1:20 dilution of hyperimmune antisera against B. avium pili did not block the hemagglutinating activity of whole-cell preparations of B. avium. In the indirect immunofluorescence test, B. avium isolates and the Art Vax strain adhered to the tracheal explants of turkeys, but B. avium-like isolates did not. Purified pili from B. avium adhered to the surface of the mucosal lining of the tracheal explants, and hyperimmune antisera against B. avium pili blocked the in vitro adherence of whole-cell preparations of B. avium. It was concluded that pili of B. avium are involved in the in vitro attachment of that bacterium to the mucosal surface of turkey tracheal explants.  相似文献   

4.
An in vivo model was developed for studies characterizing the adherence of Bordetella avium to the tracheal mucosa of turkeys. Three-week-old turkeys were anesthetized, and the cervical part of the trachea was isolated after tracheostomy was done. A hemostat was applied craniad to the tracheostomy site to occlude the tracheal lumen. Isolated tracheal segments were filled with an aqueous bacterial inoculum for 1 minute, and then excess inoculum and the hemostat were removed. After 1 hour, a 1-cm section was excised from each tracheal segment, and adherent viable bacteria were quantified. Modifications of the procedure were evaluated to produce a model that was technically simple to do, economical, and reproducible. To examine the validity of the model, adherence of B avium was compared with that of Escherichia coli and Staphylococcus aureus. Adherence of B avium to tracheal mucosa was 17 times greater than that with E coli and 1,550 times greater than that with S aureus. Colonization of the tracheal mucosa by B avium was demonstrated in tracheal sections obtained 6 hours after filling with bacterial inoculum. Because the ciliary clearance mechanism of the tracheal segments remained functional, washing of the tracheal lumen had no effect on numbers of associated bacteria. An important advantage of this model over in vitro models is the excellent preservation of the tracheal mucosal surface.  相似文献   

5.
Adherence of Bordetella avium to the tracheal mucosa of turkeys was evaluated, using bacteria grown under different culture conditions. Several solid and liquid media were used at incubation times of 12, 24, 36, or 48 hours with incubation temperatures of 18, 26.5, or 35 C. Adherence of B avium was greatest when the bacteria were grown on solid media at 35 C. Use of Bordet-Gengou or brain-heart infusion agar was associated with significantly greater (P less than 0.05) adherence compared with adherence of bacteria grown on other media. Adherence was greatest, using cultures in the stationary phase of growth; however, with some media, adherence diminished when incubation was extended beyond 36 hours. Adherence of B avium was reduced but not completely prevented when cultures were incubated at 18 C.  相似文献   

6.
The interaction between Mycoplasma gallisepticum (MG) and the tracheal mucosa of the young chicken was studied. The use of a selective plating method permitted differentiation between a pathogenic tylosin-resistant strain (227) and a less pathogenic tylosin-sensitive vaccine strain (F). Both MG strains adhered to the tracheal mucosa and colonized equally well. In mixed infection, the presence or absence of the second strain did not change the efficiency of colonization by either strain. When chickens were exposed to the vaccine strain 24 hr or 2 weeks before superinfection by the pathogen, there was no significant reduction in the efficiency of superinfection, despite the presence of 10(6) colony-forming units of MG strain F in the trachea. However, chickens had an increased ability to resist superinfection 5 weeks after exposure via the air sac. These results suggest that the biological mechanism underlying protection of F-strain-vaccinated chickens against adventitious infection by the homologous species does not involve competition for adherence sites or blockage by prior colonization.  相似文献   

7.
L H Arp  S M McDonald 《Avian diseases》1985,29(4):1066-1077
Effects of temperature on growth of three strains of Bordetella avium were determined in young turkeys and in vitro. Colonization of the tracheal mucosa by two virulent strains of B. avium was significantly greater in cold-stressed turkeys than in heat-stressed turkeys. The avirulent vaccine strain, ART-VAX, colonized tracheas of cold-stressed turkeys to a limited extent but failed to colonize heat-stressed turkeys. Growth rates of the three B. avium strains were determined in brain-heart infusion broth at 30, 35, 40, and 45 C. All three strains grew best at 35 C but were killed by 45 C. Compared with virulent strains, ART-VAX grew markedly less at all temperatures, and most cultures of ART-VAX grew at 40 C only after a variable period of declining numbers of viable bacteria. This study indicates that temperature affects growth of B. avium in vivo and in vitro and that growth of the ART-VAX strain is fundamentally different from growth of virulent strains.  相似文献   

8.
An in vitro culture system for swine tracheal epithelial cells was developed to study the adherence of swine mycoplasmas. Swine tracheal epithelial cells were isolated by enzymatic digestion and cultured on microporous membranes. Growth medium was placed under the membrane support to create air-liquid interface feeding resulting in the cells growing cilia and microvilli on the apical surface. Two strains of Mycoplasma hyopneumoniae (pathogenic strain 91-3 and non-pathogenic type strain J) and two strains of Mycoplasma flocculare (type strain Ms42 and field isolate 7160T) were used in this study. The morphology of the cultured tracheal cells was evaluated by transmission electron microscopy. Adherence of M. hyopneumoniae and M. flocculare and damage to the cilia were demonstrated using scanning electron microscopy. The pathogenic M. hyopneumoniae strain 91-3 adhered to cilia inducing obvious damage. The non-pathogenic M. hyopneumoniae strain J did not adhere to mature cilia. Both M. flocculare strains Ms42 and 7160T adhered to mature and budding cilia. No obvious ciliary damage was observed with strain Ms42. Minimal damage consisting of a slight tangling of the cilia occurred after adherence by strain 7160T. This model will enable us to further study the role of adherence of mycoplasmas on the pathogenesis of swine pneumonia.  相似文献   

9.
Bordetella bronchiseptica strains were examined to determine whether the surface hydrophobicity of the bacteria correlates with their adherence to porcine nasal epithelial cells. The relative hydrophobicity of the bacteria, measured by their retention to a column of hydrophobic phenyl-Sepharose gel and their aggregation in ammonium sulfate solution, correlated well with their adhesive properties. Phase I cells in X-mode, which adhered well to the epithelial cells, were conspicuously hydrophobic. The cells in C-mode and degraded phases, which adhered poorly to the epithelial cells, were relatively hydrophilic. These observations provide evidence for the suspected role of hydrophobic interactions in the adherence of B. bronchiseptica to porcine nasal mucosa.  相似文献   

10.
79 strains of P. multocida were investigated, mostly isolated from porcine nasal cavities, and a mannose-resistant hemagglutination with guinea pig and human group 0, but not with porcine erythrocytes was found. Fimbriae as adhesins were demonstrated only on 2 strains. A correlation between capsular type, hemagglutination, fimbriation and toxigenicity on the examined P. multocida strains was not observed. Three strains were investigated for the adherence to the nasal mucosa of neonatal pigs; aggregates shown by scanning electron microscopy indicate colonization; a correlation of adherence with surface proteins and slime production of P. multocida is discussed.  相似文献   

11.
To study adherence of Actinobacillus pleuropneumoniae to porcine lower respiratory epithelium, a cell culture model was developed using primary cultures of porcine lung epithelial cells (LEC). Adherence assays were performed and results were compared with data obtained with swine kidney cells (SK6). A. pleuropneumoniae efficiently adhered to LEC with up to 62 bacteria per cell after 2h of incubation. Reference strain of serotype 3 (R3) adhered better to LEC than reference strains of serotypes 1 (R1), 7 (R7) and 8 (R8). Overall the adherence to LEC was more rapid and up to 30-fold more efficient than adherence to SK6 cells. In search for the mechanism involved in the adherence event, we tested the effect of LPS which has previously been demonstrated to cause adherence of the pathogen to upper respiratory epithelium. Adherence assays with LPS transposon mutants demonstrated unaltered (mutant with modification in core/lipid A moiety) or even three-fold more adherence (mutants lacking O antigen) compared to the parent micro-organisms. Purified LPS of strains R1, R3, R7 and R8 did not inhibit adherence of R8 to LEC either, suggesting that LPS and particularly the O-antigen are not essential for adherence of A. pleuropneumoniae to LEC. The efficient, LPS-independent adherence of A. pleuropneumoniae to LEC cells indicates that A. pleuropneumoniae may carry different, cell type-specific adhesins and that primary cultures of lower respiratory epithelium are valuable infection models in studying A. pleuropneumoniae pathogenesis.  相似文献   

12.
Adherence of Moraxella bovis to cell cultures of bovine origin   总被引：5，自引：0，他引：5  
The adherence of five strains of Moraxella bovis to cell cultures was investigated. M bovis adhered to cultures of bovine corneal epithelial and Madin-Darby bovine kidney cells but not to cell types of non-bovine origin. Both piliated and unpiliated strains adhered but piliated strains adhered to a greater extent than unpiliated strains. Antiserum against pili of one strain inhibited adherence of piliated strains but caused only slight inhibition of adherence to the unpiliated strains. Treatment of bacteria with magnesium chloride caused detachment of pili from the bacterial cell and markedly inhibited adherence of piliated strains but caused only slight inhibition of adherence by the unpiliated strains. The results suggested that adhesion of piliated strains to cell cultures was mediated via pili but that adhesins other than pili may be involved in the attachment of unpiliated strains of M bovis to cells.  相似文献   

13.
Virulence factors were studied in 82 strains of Escherichia coli isolated from the urine of dogs with urinary tract infections. The most frequently expressed O antigens were 2, 4, 6, 25, and 22/83. Most strains were K nontypeable. Mannose-sensitive hemagglutination (MSH) with canine erythrocytes was observed in 71 strains and mannose-resistant hemagglutination (MRH) was observed in 32 strains. Strains that caused MSH of erythrocytes from dogs also caused MSH of erythrocytes from guinea pigs. Most strains that caused MRH of human A1P1 erythrocytes also reacted with erythrocytes of dogs. Of 22 strains (27%) that agglutinated human A1P1 erythrocytes, but not A1p erythrocytes, 17 (77%) had specificity for globo A, but did not react with the galactose alpha 1----4galactose beta disaccharide receptor. The remaining 5 strains and 2 others that simultaneously expressed an X adhesin agglutinated galactose alpha 1----4galactose beta-coated latex beads. Bacterial adherence to canine uroepithelial cells from the bladder was most often observed in strains expressing MSH, less often observed in strains expressing MRH, and least often observed in strains that failed to induce hemagglutination. Adherence of MSH strains to canine uroepithelial cells was inhibited by alpha-methyl-D-mannoside. As a group, MRH strains expressing globo-A- and galactose alpha 1----4galactose beta-specific adhesins did not have strong adherence. Strains of E coli isolated from dogs with urinary tract infections most commonly expressed type-1 fimbriae, and the main mechanism of in vitro adherence to canine uroepithelial cells involved a mannose-sensitive mechanism. Overrepresentation of globo-A-specific adhesins did not appear to be related to adherence of canine uroepithelial cells.  相似文献   

14.
When Salmonella typhimurium and Clostridium perfringens were tested in conventional chickens, larger numbers of S typhimurium and C perfringens adhered to Eimeria tenella-infected ceca than to uninfected ceca. In germ-free chickens, S typhimurium and C perfringens adhered to the E tenella-infected cecal mucosa more than to the uninfected cecal mucosa, but fewer Bacteroides vulgatus and Bifidobacterium thermophilum adhered to the E tenella-infected ceca than to the uninfected ceca. Many bacteria adhered to the lesions caused by E tenella as observed by scanning electron microscopy. On the basis of our findings, we suggest that infection with E tenella upsets the balance of competitive adherence of bacteria, allowing more colonization of S typhimurium and C perfringens.  相似文献   

15.
In vitro experiments were undertaken to study the adhesion and colonization to tracheal mucosa, lung and aorta explants from freshly killed rabbits of two different strains of Pasteurella multocida. Serotype A:3 (capsulated, fimbriae +, haemagglutination -, dermonecrotic toxin -) isolated from a rabbit with rhinitis, and serotype D:1 (non-capsulated, fimbriae +, haemagglutination +, dermonecrotic toxin +) isolated from a dead rabbit with septicaemia, were used. When the explants were observed under the scanning electron microscope, the type D strain was highly adherent to trachea and aorta explants compared to the type A strain. Adhesion to lung explants was best achieved by the type A strain after 45 min incubation, but after 2 h incubation no significant difference was observed between the strains. Our data indicate that the presence of fimbriae and the absence of capsule seem to enhance the adherence of P. multocida type D strain to tracheal tissue. The capsular material of P. multocida type A strain and the toxin of the type D strain seem to influence the adherence to lung tissue in rabbit. Adhesion of strain D to aorta may indicate the expression of receptors on the endothelium to that strain and may also explain the ability of certain strains to cause septicaemia.  相似文献   

16.
Adherence of Streptococcus suis to porcine endothelial cells   总被引：3，自引：0，他引：3  
Streptococcus suis can cause invasive diseases in pigs and humans, such as meningitis or arthritis. Adherence to and invasion of endothelial cells might represent important steps in survival and spread of S. suis within the host. We tested in vitro adherence and invasion of S. suis strains using a porcine brain microvascular and aortal endothelial cell line. Four S. suis strains were tested with and without prior treatment with porcine serum containing anti-S. suis antibodies. Strains included a capsular serotype 2 strain and its non-encapsulated isogenic mutant strain, as well as two non-typeable (NT) strains, which expressed no capsule under our experimental conditions. Strains adhered to both cell lines to different extents depending on encapsulation and pre-treatment with porcine immune serum. The serotype 2 strain showed almost no adherence, whereas the non-encapsulated mutant strain adhered strongly. Similarly, both NT strains adhered substantially better than the serotype 2 strain. Pre-treatment of bacteria with porcine serum increased adherence of the encapsulated serotype 2 strain and decreased adherence of the non-encapsulated strains. None of the strains was able to efficiently invade either of the two cell lines, except for one NT strain, which showed a very low extend of invasion. Our results suggest that S. suis can adhere to but not invade porcine endothelial cells, and that this interaction may involve different bacterial surface structures, such as capsular polysaccharides and/or binding sites for serum components.  相似文献   

17.
OBJECTIVE: To determine glycosaminoglycan (GAG) concentration and immunohistochemical staining characteristics of type-I, -II, and -X collagen from cartilage affected by osteochondritis dissecans (OCD) in dogs. ANIMALS: 31 dogs with OCD and 11 clinically normal purpose-bred dogs. PROCEDURE: Cartilage samples were evaluated microscopically, and GAG content was determined. Immunohistochemical staining was performed for type-I, -II, and -X collagen. Sections were subjectively evaluated for location and intensity of staining. RESULTS: Cartilage affected by OCD had a variety of pathologic changes and significantly lower GAG concentrations than did normal cartilage. Normal cartilage had no detectable type-I collagen. For dogs < 9 months of age, cartilage affected by OCD had significantly more type-I collagen but significantly less type-X collagen than did control cartilage. For dogs > 12 months of age, cartilage affected by OCD contained significantly more type-I collagen than did control cartilage. There was a significant negative correlation between immunoreactivity of type-I collagen and that of type-II and -X collagen. A significant positive correlation was found between immunoreactivity of type-II and -X collagen. CONCLUSIONS AND CLINICAL RELEVANCE: Cartilage affected by OCD contains less GAG, more type-I collagen, and less type-X collagen, compared with normal cartilage. A direct correlation between these changes and the etiopathogenesis of OCD was not established.  相似文献   

18.
Using the radiopharmaceutical 99mtechnetium-sulfur colloid, the tracheal mucus transport rate (TMTR) was measured in healthy unanesthetized turkeys and in turkeys infected with Bordetella avium. The TMTR of uninfected turkeys was 35.6 +/- 14.4 cm/min. The TMTR of B. avium-infected turkeys was normal on days 0 through 14 postexposure (PE), despite heavy bacterial colonization of the tracheal epithelium. On day 21 PE, the TMTR of B. avium-infected turkeys was significantly depressed (P less than or equal to 0.01) compared with that of control turkeys. Depressed transport was associated with extensive loss of ciliated epithelium from the tracheal mucosa and replacement of the normal mucosa by immature nonciliated epithelium or metaplastic squamous epithelium.  相似文献   

19.
Streptococcus suis is an important swine pathogen that may be present in the tonsils of pigs that show no signs of illness. Because adhesion to host cells may be important in the carrier state, this study was undertaken to investigate adhesion to host cells by S. suis mutant strains defective in expression of a 39-kDa protein. Mutant strains of S. suis were generated by transposon Tn916 mutagenesis and were tested for adhesion to embryonic bovine tracheal cells and porcine tracheal rings. Compared with the parent strain, there was a significant reduction in adherence of 3 mutant strains to both bovine tracheal cells and porcine tracheal rings.  相似文献   

20.
Chickens from lines selectively bred for either a high-antibody (HA) or low-antibody (LA) response to sheep erythrocytes were injected intravenously with Mycobacterium avium while being held in low, medium, or high levels of social stress for 5 days (first environment). During the remaining 6 weeks, they were held under either low or medium levels of social stress (second environment). Infection led to lesions consisting of granulomas, some of which had necrotic centers. There was a positive correlation between numbers of lesions with necrotic centers and M. avium cells recovered from livers. The numbers and nature of lesions were influenced by both genetic and environmental factors. Numbers of necrotizing lesions increased with stressfulness of the first environment. Total numbers of lesions were reduced by the medium-stress second environment, and the total number of necrotizing lesions was reduced among LA chickens in the low-stress second environment.  相似文献   

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