An atypical strain of Pasteurella gallinarum: pathogenic, phenotypic, and genotypic characteristics.

The pathogenicity of a strain of Pasteurella gallinarum isolated in Fresno County, Calif., was compared with the American Type Culture Collection (ATCC) strain. Broiler chickens were inoculated intranasally with 10(7) colony-forming units (CFU) and intramuscularly with 10(5) CFU of each strain. The only notable lesions were in chickens inoculated intramuscularly with 10(5) CFU of the Fresno strain, which developed severe myositis at the inoculation site, pericarditis, perihepatitis, airsacculitis, and synovitis. P. gallinarum was reisolated from these lesions. Phenotypic characteristics of the two strains were identical except in reactions in ONPG broth and fermentation of xylose. Protein-banding patterns for the two strains were identical except for a single band difference in the 35-kilodalton region. Restriction endonuclease analysis confirmed that the Fresno strain was a distinct one. Plasmid analysis revealed that the ATCC strain had two plasmids and the Fresno strain had none.     

Severe mortality in broiler chickens associated with Mycoplasma synoviae and Pasteurella gallinarum.

Severe economic loss due to high mortality and condemnation rates occurred on two commercial broiler facilities. Chickens had moderate-to-severe airsacculitis, pericarditis, perihepatitis, tracheitis, and synovitis. Pasteurella gallinarum was isolated from 16 of 18 pericardia, four of 14 livers, 11 of 16 air sacs, six of seven joints and one of 28 tracheas in pure culture. In addition, Mycoplasma synoviae was isolated from trachea and air sac. Lesions were suggestive of an Escherichia coli septicemia, but E. coli was isolated from only four of 28 tracheas and one of 14 livers in pure culture. A coronavirus was isolated from trachea and lung. Whether this coronavirus represented a vaccine or field strain of infectious bronchitis was not determined. These findings suggested that the severe lesions were due to a concomitant infection with an atypical strain of P. gallinarum.     

Random amplification of polymorphic DNA and phenotypic typing of Zimbabwean isolates of Pasteurella multocida

Eighty-one isolates presumptively identified as Pasteurella multocida from a variety of diseases in animals in Zimbabwe were subjected to biochemical characterization, capsular typing and RAPD analysis. The majority of isolates (over 80%) were assigned into named taxa and were predominantly P. multocida subsp. multocida and P. multocida subsp. septica, whilst the remainder were unassigned. Serogroup A was predominant among the three capsular types (A, B and D) of P. multocida detected. Three main RAPD clusters and three subclusters were observed among the majority of isolates (93.8%), whilst the remainder was found to be weakly related. Nine different groups of strains with similar RAPD profiles (100% similarity) were also observed. The reference strain of capsular serogroup F clustered with the reference strain of P. multocida subsp. septica, whilst all other serogroups clustered with reference strains of subsp. multocida and gallicida. Notably, serogroups A and D were observed to be closely related to the reference strain of subsp. multocida. The relationship between biotype, capsular type, host origin and disease manifestation was not clear-cut. However, most pig isolates of subsp. multocida clustered together as did most cattle isolates of subsp. multocida. RAPD tended to separate subsp. multocida from septica.     

Salmonella gallinarum field isolates of the biovars pullorum and gallinarum

In 40 cases salmonellae of the serovar Salmonella (S.) gallinarum were culturally isolated from domesticated gallinaceous birds submitted for diagnostic purposes in the period of 1979-1989. On the basis of the cultural and biochemical features found 35 of them could be assigned to the biovar Pullorum and 5 to the biovar Gallinarum. Of 35 isolates of the biovar Pullorum, 29 were isolated from pure bred chickens of small fancy-exhibition type flocks, 4 from floor-housed adult brown hybrid laying hens and one each from broiler chicks and pheasant chicks (Phasianus colchicus). Acute to subacute courses of the pullorum disease were observed in the 4 flocks of brown hybrid hens. Of 5 isolates of the biovar Gallinarum, 4 were isolated from adult brown hybrid laying hens kept in battery cages and one from floor-housed brown hybrid pullets of the laying type. First cases of fowl typhoid occurred early in the summer of 1988. The disease was characterized by a peracute course in the 4 flocks of brown laying hens and by a more acute course in the pullet flock. The primary source of the fowl typhoid producing organisms was not elucidated.     

牦牛肺炎病原多杀性巴氏杆菌和殊异支原体的分子鉴定与分析

青海省刚察县某牦牛产业基地牦牛发生咳嗽,鼻孔有分泌物流出,呼吸困难等症状的疾病。为快速确诊发病牛的致病原因,及时防控和治疗,从发病和病死的牦牛中,采集鼻腔拭子和肺脏、胸腔积液,利用PCR方法进行分子鉴定与分析。结果显示:此牛场中引发肺炎的病原是A型多杀性巴氏杆菌和殊异支原体两种病原体混合感染,测序结果显示5个有效样品中鉴定的为完全相同的病原,P.multocida-GC1的Kmt基因与参考序列中国株CP031554/3/2/1同源性在99%以上,M.dispar-GC1与参考序列的16S rRNA基因同源性在97%以上。同时在遗传进化角度再次分析确认了鉴定的P.multocida与中国和俄罗斯的A型多杀性巴氏杆菌聚成一大支;鉴定的M.dispar与殊异支原体聚为一支。结果表明,青海刚察地区牦牛存在感染多杀性巴氏杆菌和殊异支原体的潜在风险,该研究为牦牛呼吸道疾病与肺炎的病原学调查和病原的流行病学调查提供了参考数据。     

Production and application of a live Salmonella gallinarum vaccine

The production and application of a freeze-dried Salmonella gallinarum vaccine are described in this report. The vaccine is stable when kept at 4 degrees C and a single injection elicits a good immunity for 2 months, though its effect gradually diminishes. Immunity is neither enhanced nor depressed by repeated injections of the live vaccine, and no interference effect was observed in experimentally infected chickens. Furazolidone therapy jeopardizes the immunogenicity of a live vaccine, but its effect can be countered by the administration of either an inactivated or a live vaccine when medication is commenced and this is followed by the application of live vaccine 6 days after cessation of medication.     

Pathogenicity of Tetratrichomonas gallinarum]

Eight axenic strains of Tetratrichomonas gallinarum were isolated from the caeca or cloacae of ducks and geese. Different growth curves were determined for each of the strains and the generation times were calculated, ranging from 2 h 36 min to 4 h 44 min. The axenic cultures of seven T. gallinarium strains were subjected to the Honigberg test on inbred mice. The average volumes of the six-day-old subcutaneous abscesses ranged from 129.98 to 185.63 mm3. Selected strains of trichomonads were used for experimental infection of ducks and geese. Neither the macroscopis examination nor the microscopic analysis did find any greater pathological changes in the mucosa of the caecum of the birds, though the Trichomonas organisms were observed in large quantities among the villi in the crypts. It is believed on the basis of the results that the species T. gallinarium carries no primary pathogenicity to the specific hosts.     

Salmonella gallinarum biovar gallinarum as the cause of a highly acute septicemic disease in adult laying hens kept in battery cages

Early in the summer of 1988 two flocks each of them consisted of about 7500 brown laying hens of a heavy hybrid line were affected by fowl typhoid. The birds have been bought at the age of 20 weeks and housed in two buildings placed close together in one farm. The disease started in flock I at the age of 26 weeks and in flock II at the age of 36 weeks. In repeated trials amoxicillin was effective in the treatment of fowl typhoid when given in the drinking water for ad libitum consumption over a 4-7 days period; however relapse occurred 3-4 days after withdrawal of the drug. All the hens were slaughtered 5 days after termination of the last therapy. In spite of the treatment 18.3% of the hens in flock I and 14.3% of those in flock II died within the observation period of 47 days and 22 days respectively. Egg production was not affected. The source of the fowl typhoid producing organisms could be not elucidated.     

Investigation of outer membrane proteins of Pasteurella. 2: Iron-regulated outer membrane proteins of Pasteurella multocida and Pasteurella haemolytica

Pasteurella multocida and Pasteurella haemolytica produce specific proteins in the outer membrane under iron-depleted conditions. Pasteurella multocida serovar A expresses these proteins of molecular masses of 76 and 96 kDa as determined by electrophoresis. The analogous serovar D produces a further iron-regulated protein of 85 kDa. The Pasteurella haemolytica strains of serovar A1, A6 and T contain iron-regulated outer membrane proteins of molecular masses of 71, 77 and 100 kDa. These proteins possess binding positions for iron ions. Both Pasteurella multocida and Pasteurella haemolytica strains utilize iron from porcine and bovine transferrin, but not from haemin and haemoglobin.     

Brucella: a pathogen without classic virulence genes

The first species of Brucella was isolated and characterized almost 120 years ago and recently the complete nucleotide sequences of the genomes of a number of well-characterized Brucella strains have been determined. However, compared to other bacterial pathogens relatively little is known about the factors contributing to its persistence in the host and multiplication within phagocytic cells. Also, many aspects of interaction between Brucella and their host remain unclear. Molecular characterization of intracellular survival process of Brucella is important as it will provide guidance for prevention and control. One of the features that distinguish Brucella is that they do not express classical virulence factors. Thus identification of virulence factors has been elusive and some of the identifications are putative. Disruption of putative virulence genes and studying their effect on attenuation in cell lines or mouse models is a widely used method. However, in most cases it is not apparent whether the mutated genes encode virulence factors or merely affect metabolic pathways of the pathogen. In addition, some mutations in Brucella can be compensated by redundancy or backup mechanisms. This review will examine known virulence genes (real and putative) identified to date and the mechanisms that contribute to the intracellular survival of Brucella and its ability to establish chronic infection.     

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.     

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.     

Atypical Pasteurella strains producing a toxin similar to the dermonecrotic toxin of Pasteurella multocida subspecies multocida

This paper is the first report of the production of a dermonecrotic toxin by pasteurella strains that do not belong to the species Pasteurella multocida subspecies multocida. Four strains, isolated from cattle with atrophic rhinitis, were characterised phenotypically. The strains were related to pasteurellaceae, but their taxonomic position remained unclear. The strains produced a toxin that caused a haemorrhagic dermonecrosis in guinea pigs and was lethal to mice. Both effects were neutralised by an antiserum against the purified dermonecrotic toxin of P multocida subspecies multocida. Western blot analysis of culture filtrates of the bovine strains revealed a protein, with the same molecular weight as dermonecrotic toxin, which reacted with both polyclonal and monoclonal antibodies against the toxin. In an immunodiffusion test, anti-dermonecrotic toxin serum did not discriminate between the toxin of the bovine strains and the toxin of P multocida subspecies multocida. It is concluded that these atypical pasteurella strains produce a toxin that is closely related to the dermonecrotic toxin of P multocida subspecies multocida.     

Bovine pneumonic pasteurellosis: model for Pasteurella haemolytica- and Pasteurella multocida-induced pneumonia in cattle

Pneumonic lesions in calves were induced with Pasteurella haemolytica or P multocida. The inoculum, consisting of a suspension of either organism, was administered by transthoracic intrapulmonic injection to 23 calves. Three died of septicemia; the 20 remaining, killed 96 hours after inoculation, had an expanding unifocal pneumonia qualitatively comparable with that of acute pneumonic pasteurellosis (shipping fever). The concentration of bacteria that consistently produced a lesion was a 5-ml volume containing 10(9) colony-forming units of bacteria; a concentration of 10(6) colony-forming units inconsistently produced lesions. Bacteria, except in calves that developed septicemia and died, remained localized at the injection site. The inflammatory process spread within the lungs, not only through airways, but through the interlobular and interalveolar septa as well.     

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)