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.     

Genetic analysis of virulence factors of Mannheimia (Pasteurella) haemolytica A1

Sixteen 3-week-old calves were intratracheally inoculated with Mycoplasma bovis. Follow-up consisted of regular bronchoalveolar lavages (BALs) and clinical examinations. Animals were slaughtered from 4 to 21 days after inoculation. Counts were made of the mycoplasmas and other bacteria systematically isolated from the BAL liquids and lung lobes after slaughter. On the 6th day, spectinomycin 20mg/kg was given intramuscularly in three repeated doses at 24h intervals to six randomly chosen calves. All animals had developed a persistent M. bovis infection with a maximum BAL count on the 6th day (start of treatment). Co-occuring Pasteurella multocida infection was found in most animals with a maximum rate on the 14th day. The extent of lung surface lesions varied widely (0-64%) but was greater in the later slaughtered calves. Average counts of M. bovis and P. multocida in the BAL liquids were lower in treated calves than in untreated ones but the difference was not statistically significant. However, M. bovis and P. multocida counts in the lungs of the treated group were significantly lower than in the untreated group (p=0.003 and 0.009, respectively).     

Deoxyribonucleic acids from Pasteurella multocida and Pasteurella haemolytica]

Pasteurella multocida and P. haemolytica strains contain between 1.5 and three per cent phosphorus, between nine and 14 per cent nitrogen, between two and four per cent DNA, and between five and 18 per cent RNA, the precise figures depending on culturing conditions. High-molecular DNA may be isolated by means of bacteriolysis, using deoxycholate or dodecylsulphate and the usual steps of purification, with yield and purity differing by strains. DNA with sufficient purity can be obtained from Sepharose 2 B by gel chromatography. The isolated DNA yields were characterised, base values being between 37 and 38 per cent GC for P. haemolytica and between 41 and 48 per cent GC for P. multocida. Highly suitable precursors to DNA synthesis for tritium labelling are 3H-thymidine, which is incorporated in excess of 3H-thymine by a factor of 255, as well as 3H-uracil, with its activity being recovered also from the pyrimidine bases of DNA via pyrimidine biosynthesis.     

The effect of Pasteurella haemolytica and the leukotoxin of Pasteurella haemolytica on bovine lung explants.

Bovine lung explants were used in a study designed to compare the pathogenic effects of Pasteurella haemolytica type 1, a nonpathogenic organism Neisseria subflava, or the crude leukotoxin of P. haemolytica on alveolar macrophages and lung parenchymal cells. Concentrated, purified peripheral blood neutrophil suspensions were added with the bacteria to some explants. Duplicate pairs of cultures from each treatment group were fixed at regular intervals up to 24 hours after seeding and morphological changes were assessed by light and electron microscopy. Pasteurella haemolytica caused deterioration of alveolar macrophages within one hour but did not affect parenchymal cells for more than 12 hours. Neisseria subflava did not affect alveolar macrophages initially, but caused an accelerated deterioration after four hours. After 24 hours, bacterial overgrowth caused similar deterioration of all cells in explants seeded with either bacterium. Alveolar macrophages phagocytosed large numbers of N. subflava but rarely ingested P. haemolytica. Added neutrophils did not have any discernible effect on any of the explants and did not potentiate bacterial effects. Addition of crude leukotoxin of P. haemolytica to the culture medium significantly accelerated alveolar macrophage deterioration without apparent effect on parenchymal cell survival. These results support the hypothesis that the severe tissue destruction of fulminant pneumonic pasteurellosis is not a direct result of bacterial infection.     

Studies on strains of Pasteurella haemolytica not typable by the indirect haemagglutination test

Thirty strains of Pasteurella haemolytica which were untypable by the indirect haemagglutination (IHA) test were examined serologically by rapid plate agglutination (RPA), agar gel diffusion (AGD), crossed immunoelectrophoresis (CIE) and counter current immunoelectrophoresis (CCIE) tests. Nine serogroups were identified by CCIE. Serogroup specificity, dependent on two antigens, was present in heated saline extracts of cells. Single representative strains from two serogroups were not pathogenic for specific pathogen-free lambs.     

Pasteurella haemolytica infections in sheep

Summary Pasteurella haemolytica causes two distinct disease syndromes in sheep. P. haemolytica biotype A causes septicaemia in young lambs and pneumonia in all ages of sheep. Biotype T produces an acute systemic disease affecting principally the upper alimentary tract and lungs in young adult sheep. The bacteriology, epidemiology and clinical and necropsy findings of the two diseases are described and the current situation regarding their experimental reproduction and immunology is reviewed.     

Pasteurella haemolytica infections in sheep

Summary

Pasteurella haemolytica causes two distinct disease syndromes in sheep. P. haemolytica biotype A causes septicaemia in young lambs and pneumonia in all ages of sheep. Biotype T produces an acute systemic disease affecting principally the upper alimentary tract and lungs in young adult sheep. The bacteriology, epidemiology and clinical and necropsy findings of the two diseases are described and the current situation regarding their experimental reproduction and immunology is reviewed.     

Long-chain fatty acids of Pasteurella multocida nad Pasteurella haemolytica

The relative contents of long-chain fatty acids in P. multocida and P. haemolytica were investigated. A dependence on the composition of the broth was established. Accordingly, comparative quantitative studies on fatty acid contents have to be conducted using bacteria grown with the same lot of broth medium. As for P. multocida, there were significant differences between the serovars (C14 in TDHM and C16, delta 2C18 in BPL). These differences are, however, not significant to replace serotyping. Highly significant differences were also detected between P. multocida isolates from nasal swabs and pneumonic lungs (interims of C14, delta C16 on BPL and BRU). The largest differences were measured for strains grown on BRU, which is interpreted as an expression of virulence. Significant differences were found between biotypes A and T of P. haemolytica, namely for C14, C16 in TDHM, and C14, delta C16, C16, C18 in BPL medium.     

An outbreak of Pasteurella multocida pneumonia in lambs during a field trial of a vaccine against Pasteurella haemolytica

A vaccine against pneumonic pasteurellosis was evaluated for efficacy at two dilutions in lambs transported by sea from New Zealand to Saudi Arabia. The experimental vaccine was a killed Pasteurella haemolytica serotype A1 and A2 preparation. There was no evidence of either dilution of the vaccine leading to a lower pneumonia death or lesion rate than for the control group. However, bacteriological examinations to establish the causality of the pneumonia cases showed Pasteurella multocida to be the dominant organism, while P. haemolytica types A1 and/or A2 occurred at only a very low incidence.     

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.     

Actin polymerization enhances Pasteurella haemolytica leukotoxicity

Pasteurella haemolytica leukotoxin is cytotoxic to bovine leukocytes, causing increased cell membrane permeability, osmotic swelling, release of cytosolic proteins and cell lysis. These studies were designed to test if leukotoxin causes release of the cytoskeletal protein, actin, from bovine leukemia cells and if purified actin-influenced bacterial growth or leukotoxin production. Culture supernatants caused a 7-fold decrease in viability of bovine leukemia cells and increased cell permeability that was accompanied by release of beta-actin into the cell culture supernatant. Exposing P. haemolytica to purified actin solutions induced the conversion of monomeric G-actin to polymerized F-actin. This conversion was partially inhibited by bovine P. haemolytica immune, but not pre-immune, serum. Loss of streptomycin resistance following treatment of the organism with acridine orange ablated the polymerizing activity. Incubation of P. haemolytica in the presence of purified F-actin did not affect growth but resulted in culture supernatant that had 3.0-3.9-fold greater leukotoxicity compared to medium alone or medium containing G-actin, heat-denatured actin or albumin. The effect of actin on leukotoxicity was concentration-dependent and directly associated with increases in secreted leukotoxin. The interaction between P. haemolytica and actin is potentially detrimental to the host by inducing polymerization of actin into insoluble filaments and by enhancing leukotoxicity.     

Incubation of Pasteurella haemolytica and Pasteurella multocida lipopolysaccharide with sheep lung surfactant

Lipopolysaccharides (LPS) were extracted from a serotype of each of 2 species of Pasteurella isolated from sheep with respiratory tract infections. Lipopolysaccharides from P haemolytica 82-25 (serotype 1A) or P multocida P-1573 (serotype 12) were mixed with sheep lung surfactant and were incubated for 6 hours at 37 C. After incubation, LPS-surfactant mixtures were centrifuged overnight in sucrose density gradients, and fractions were analyzed. Binding occurred between LPS and surfactant vesicles resulting in a stable complex with densities greater than those with the surfactant alone. The surfactant alone had a density of 1.052 to 1.060 g/ml. Diffuse bands of surfactant had a density of 1.075 to 1.092 when incubated with P haemolytica LPS and a density of 1.069 to 1.105 when incubated with P multocida LPS.     

A survey of potential virulence markers from avian strains of Pasteurella multocida

Twenty-four isolates of Pasteurella multocida from clinical cases of fowl cholera and the Clemson University vaccine strain were surveyed for the presence of potential virulence markers. Membrane proteins, enzymatic activity of the membrane proteins, and carbohydrate fermentation patterns were also determined to demonstrate phenotypic relationships within the groups. Few differences were found in these phenotypic characteristics among the isolates. Almost all the organisms produced siderophore and were hemolytic on turkey red blood cells. No extracellular enzyme or bacteriocin activity was detected and little antibiotic resistance was found. However, many organisms contained plasmids and demonstrated some degree of resistance to complement. Both characteristics were correlative markers in Pasteurella multocida isolated from birds with fowl cholera.     

Efficacy of a streptomycin-dependent, live Pasteurella haemolytica vaccine against challenge exposure to Pasteurella haemolytica in cattle

A streptomycin-dependent, live Pasteurella haemolytica vaccine was given in 1 or 2 doses to 2 groups of weaned calves; 2 other groups of calves were not vaccinated. All calves in the vaccinated groups and calves in 1 of the nonvaccinated groups were stressed by transport, intratracheally inoculated with bovine herpesvirus type-1 (Cooper strain), and then intratracheally inoculated with P haemolytica type A1. The 4th group of calves (nonvaccinated controls) was not stressed and were not intratracheally inoculated with virus or bacteria. Mean daily weight gains, total clinical sign scores, lung lesion scores, plasma fibrinogen concentrations, and antibody titers against P haemolytica were determined at various intervals. Calves that had been vaccinated twice had greater mean daily weight gains and lower total clinical sign scores and lung lesion scores than did nonvaccinated, challenge-exposed calves, but the difference was not significant (P greater than 0.05). Calves vaccinated once had the greatest mean daily weight gains, the lowest total clinical sign scores, and the lowest lung lesion scores when compared with the other 2 challenge-exposed groups of calves. Mean daily weight gains and total clinical sign scores of calves vaccinated once were significantly different (P less than 0.05) than those of calves vaccinated twice. Nonvaccinated, nonchallenge-exposed control calves did not develop clinical signs of disease, did not develop lung lesions, and had consistently positive daily weight gains, and had scores in these areas that were significantly different (P less than 0.05) from those of all challenge-exposed groups of calves. Increases in plasma fibrinogen concentrations corresponded to infection with P haemolytica.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Serological types of Pasteurella haemolytica in Kenya

The 12 known serotypes of P. haemolytica and two biotypes A and T were found to occur in Kenya. Biotype T was more common in disease conditions than biotype A, which was more common in the nasal passages of healthy animals. Only biotypes A strains were recovered from cattle and the majority were serotypes 1 and 2, but serotypes 4 and 11 were also isolated. All serotypes were found to occur in sheep and goats, but serotypes 3, 4, 6, 8 and 10 were more commonly associated with pneumonia. It was observed that chickens could harbour both biotypes A and T in pathological conditions. Biotype A serotype 2 was isolated from an adult wildebeest, but the prevalence of P. haemolytica in wild animals needs furter investigation.