Serotypes of Pasteurella haemolytica and Pasteurella trehalosi isolated from farm animals in Hungary.

The biochemical and serological characteristics of 486 P. haemolytica and 31 P. trehalosi strains (517 in total) isolated from different lesions of cattle, sheep, goats, pigs and poultry were examined. A total of 476 P. haemolytica strains (97.9%) showed the characteristics typical of the former biotype A of P. haemolytica, while 10 isolates (2.1%), all from poultry, could not be biotyped. A total of 481 strains (93.0%) could be assigned to one of the 17 serotypes of P. haemolytica-P. trehalosi and 36 strains (7.0%) could not. The majority (83.6%) of the cattle isolates were serotypes A1 and A2. Among strains isolated from sheep all serotypes of P. haemolytica could be identified with the exception of A14, but serotypes A1, A2, A6, A8 and A5 were the most frequent. The overwhelming majority (94%) of the caprine isolates were A2, other serotypes occurred only sporadically. The pig isolates, which could be isolated only very rarely, represented different serotypes, while none of the 10 strains isolated from poultry could be biotyped or serotyped.     

Pasteurella haemolytica serotypes from pneumonic goatlungs

Extract

Madam:– The significance of Pasteurella haemolytica as a pathogen of cattle and sheep is well established. However, less attention has bcen paid to its role as a pathogen of goats and this limited work relates mainly to tropical countries. (2)(3)(4)(5) The lack of information on this topic and the increase in economic importance of goats in New Zealand led us to undertake a preliminary survey to find which of the 15 serotypes of P. haemolytica are commonly isolated from pneumonic goats in this country.     

Protein electrophoretic pattern of Pasteurella haemolytica.

Electrophoresis in polyacrylamide gels of the constituent proteins of the 12 serotypes and an untypable strain of Pasteurella haemolytica showed a pattern of bands that divided the group into two. This division conformed to the A and T biotype groupings of Smith (1959) although the serotype A9 showed only minor band difference from the three T serotypes 3, 4 and 10. It was not possible by this method to separate all the type strains from each other by the specific recognition of the patterns of protein mobilities produced.     

Antibiotic sensitivity of Pasteurella haemolytica isolated by means of a fibreoptic endoscope from cases of pneumonic pasteurellosis in cattle

Bacterial isolations from tracheal and bronchial washes obtained with the aid of a fibreoptic endoscope were carried out over a 7 month period in a feedlot on calves suffering from acute pneumonic pasteurellosis. Pasteurella haemolytica and Pseudomonas aeruginosa represented the majority of isolates. Antibiotic sensitivities of the Pasteurella isolates are reported on.     

Prevention of experimental bovine pneumonic pasteurellosis with an extract of Pasteurella haemolytica.

A total of 36 calves were used in three experiments to test the efficacy of a potassium thiocyanate extract of Pasteurella haemolytica in protecting against experimental pneumonia. In each of experiments A and B, 12 calves were divided into three equal groups. The first group was vaccinated with an aerosol of a potassium thiocyanate extract twice, two weeks apart; the second group was vaccinated subcutaneously once only with the same extract. The third group of calves in both experiments remained as unvaccinated controls. In experiment C, six calves were vaccinated intramuscularly and six were left as controls. Approximately one month after vaccination all calves were challenged with an aerosol of bovine herpesvirus 1 (isolate 108) followed in 4 d by an aerosol of P. haemolytica type A1 (the same strain from which the potassium thiocyanate extract had been made). Varying degrees of protection against subsequent development of experimental pneumonic pasteurellosis in cattle were seen in vaccinated calves as compared to control calves in these experiments. The results indicate that protection of cattle against pneumonic pasteurellosis may prove possible with a sub-cellular extract of P. haemolytica.     

Visual assessment of pneumonic area in ovine lungs

Twelve veterinarians were asked to estimate the percentage of lung surface that appeared consolidated in eleven projected colour transparencies of pneumonic ovine lungs. The estimates were compared to the pneumonic area measured by image analysis. Although all observers had some experience in veterinary pathology there was considerable variation between individuals in the accuracy of their estimates. Large lesions were underestimated and small lesions overestimated by most observers.     

Immunoperoxidase evaluation of pneumonic lesions induced by Pasteurella haemolytica in calves

Calves inoculated with Pasteurella haemolytica serovar 1 developed lesions of coagulation necrosis in the lungs that were sharply demarcated by leukocytes. The P haemolytica antigen was detected in the area of coagulation necrosis in histologic sections, using an immunoperoxidase technique. In the central area of the necrotic tissue, the bacterial antigen was diffusely presented in the necrotic alveolar wall, fibrin, serous exudate, and degenerated leukocyte. The bacterial antigen also was found in some groups of degenerating leukocytes around the necrotic tissue. The bacterial colonies among these leukocytes had strong specific reactions against P haemolytica. The bacterial antigen was observed in the cytoplasm of macrophages in alveoli around the necrotic lesion. These findings confirmed that coagulation necrosis is an important lesion in calves with pneumonia caused by P haemolytica.     

Occurrence and diversity of plasmids in ovine isolates of Pasteurella haemolytica.

160 ovine isolates of Pasteurella haemolytica, representing each of the 16 serotypes and also untypable strains, were examined for plasmid content. Plasmid DNA was identified in, and prepared from, strains of serotypes A2, T3, A14 and A16 and also from an untypable strain. The relationship between the plasmids present in the different strains was examined both by restriction fragment profile analysis and by DNA/DNA hybridisation. Both methods gave broadly similar results and showed that each serotype tended to contain either a single plasmid species, or a limited range of species, and that structural similarities could traverse serotype boundaries. None of the plasmid-bearing strains showed any significant level of resistance to a range of antibiotics.     

Isolation of toxigenic strains of Pasteurella multocida from lungs of pneumonic swine

Lungs from 113 pneumonic pigs were examined for Pasteurella multocida. The lungs were smeared directly onto blood agar and homogenized in brain-heart infusion broth and then inoculated intraperitoneally in mice. Pasteurella multocida isolates were typed for serotypes A (by hyaluronidase inhibition of capsule) and D (by acriflavine autoagglutination). Strains were tested for toxin production by intradermal injection of 0.2 ml of filtered 24-hour culture supernatants into guinea pigs. Most lungs (70.8%) yielded isolations. Most isolants (87.5%) were type A and 12.5% were type D. Of the type D strains, 80% were toxigenic. Of the type A isolants, 18.2% were toxigenic.     

猪肺疫多杀性巴氏杆菌的分离鉴定

为了研究四川乐山某猪场爆发的保育猪严重呼吸道疾病的主要病原,试验采用病理剖检、病毒检测、细菌分离鉴定、生化鉴定、动物回归试验以及多杀性巴氏杆菌种特异性KMT基因的PCR检测对病原进行鉴定。结果表明:发病猪有严重肺炎症状,支气管内部有少量泡沫,腹股沟淋巴结出血、水肿,其他实质器官未见明显病理变化;病毒检测结果显示为蓝耳病病毒阳性,猪瘟病毒、伪狂犬病毒、圆环病毒2型阴性;从病猪肺脏中分离获得大肠杆菌和1株蓝耳病病毒继发的高致病性多杀性巴氏杆菌;该分离菌株对多种药物均高度敏感。     

Preliminary studies with a live streptomycin-dependent Pasteurella multocida and Pasteurella haemolytica vaccine for the prevention of bovine pneumonic pasteurellosis.

Twelve Pasteurella-free Holstein-Friesian calves were used in a study to test the efficacy of a live streptomycin-dependent Pasteurella multocida A:3 and streptomycin-dependent Pasteurella haemolytica A1 vaccine. The calves were inoculated intramuscularly twice at 14-day intervals with either the streptomycin-dependent vaccine, containing 1 X 10(6) colony forming units/mL P. multocida and 4 X 10(8) colony forming units/mL P. haemolytica, commercial bacterin, or phosphate buffered saline. Two weeks following the second vaccination, all calves were challenged by intranasal inoculation of 10(8) TCID50/4.0 mL infectious bovine rhinotracheitis virus followed three days later by intratracheal injection with 2.3 X 10(7) colony forming units/mL of a 16 hour culture of P. multocida A:3 and 2.6 X 10(8) colony forming units/mL of an 8 hour culture of P. haemolytica A1. Seven days after challenge with Pasteurella, calves were killed for collection of tissues at necropsy. Each calf was given a score based on macroscopic and microscopic lesions. The scores for the calves receiving live vaccines were significantly lower (p less than 0.025) than those for the controls. Also, the calves receiving live vaccines had a significant (p less than 0.05) increase in the level of serum antibody to P. haemolytica. The results of this preliminary study showed that the streptomycin-dependent vaccine offered better protection than the commercial bacterin against a virulent homologous challenge.     

Immunoperoxidase evaluation of pneumonic lesions in calves naturally infected with Pasteurella haemolytica

Immunoperoxidase technique was applied for pathological study on naturally occurring pneumonic tissues of calves from which Pasteurella haemolytica was isolated. Multifocal necrosis occurred in the lungs of 25 out of 42 calves (59.5%) and P. haemolytica antigen was detected in 22 out of the 25 calves (88.0%). The calves were divided into 3 groups according to the number of P. haemolytica isolated. The positive rate of the bacterial antigen detected by the technique was 66.6% (28/42) on the average, reaching up to 85.7% (18/21) in the group from which the largest number of P. haemolytica was isolated.     

Cytotoxin from an ovine strain of Pasteurella haemolytica: characterisation studies and partial purification

A cell-free, water-soluble cytotoxin from an ovine strain of Pasteurella haemolytica biotype A serotype 1 killed sheep bronchoalveolar macrophages at 37 degrees C, but not at 4 degrees C or 22 degrees C. The cytotoxin was stable over the pH range 2-12, resistant to heat at 60 degrees C but inactivated at 100 degrees C or by autoclaving. Trypsin also destroyed the cytotoxin, which is therefore thought to contain a protein component essential for biological activity. A preliminary purification of the crude cytotoxin using gel-filtration column chromatography resulted in the isolation of a biologically active fraction which resolved as a single protein band and one carbohydrate band on non-dissociating polyacrylamide gels. However, this fraction resolved into approximately 16 component bands on a sodium dodecyl sulphate polyacrylamide gel.     

Characterization of Pasteurella haemolytica strains isolated from goats in Hungary

Thirty-five Pasteurella haemolytica strains were isolated in Hungary from goat carcasses sent for postmortem examination from two farms with large goat flocks. All strains belonged to biotype A and with the exception of one strain of serotype A8 they belonged to serotype A2. No untypable strains were found by the indirect haemagglutination test.     

Presence of bacterial glycocalyx and fimbriae on Pasteurella haemolytica in feedlot cattle with pneumonic pasteurellosis.

This investigation was conducted to determine if Pasteurella haemolytica within feedlot cattle affected by pneumonic pasteurellosis express fimbriae (pili) and bacterial glycocalyx. Bacteriological culture of pulmonary tissue from three calves with fibrinous pneumonia resulted in heavy growth of P. haemolytica. Transmission electron microscopy of the lungs showed numerous microcolonies of gram-negative bacteria with morphology typical of Pasteurella haemolytica. The cells within these microcolonies possessed bacterial glycocalyces which stained with ruthenium red. Glycocalyx-encased microcolonies were also present in specimens examined by scanning electron microscopy. Typical P. haemolytica cells were evident in a tracheal specimen and these bacteria had radial glycocalyces consistent with polysaccharide and proteinaceous material condensed on linear structures suggestive of fimbriae. The pathogenetic importance of the bacterial glycocalyx and fimbriae in shipping fever pneumonia has yet to be established but their presence in clinical cases of Pasteurella pneumonia in feedlot cattle further supports a possible role in the initiation and progression of this disease as well as bacterial resistance to antimicrobial agents.