The correlations between the bacteriologic agent of lamb pneumonia and its pathologic characters were investigated in this study. Pneumonia was detected in 262 (35.41%) of 740 diseased or dead lambs. Pathogenic bacteria were isolated in 114 cases (14.96% of all lamb deaths and 43.51% of all pneumonias). Lung lesions were histopathologically described as acute-catarrhal (17.56%), catarrhal-purul...

Pasteurella haemolytica serotype 1 was transferred daily for 128 serial passages on both unsupplemented brain heart infusion agar and the same basal medium supplemented with bovine blood, horse serum, and yeast extract. Repeatedly transferred cultures were shown to retain the ability to produce both capsular material and leukotoxin. Furthermore, intact organisms were found to be as toxic in vit...

This paper reports an experiment designed to demonstrate that the calf lung can be sensitized to a specific respirable challenge following parenteral immunization with a nonliving antigen (human serum albumin). The possibility that immune-mediated injury could subsequently interfere with nonspecific mucosal defenses was also investigated by infecting calves with Pasteurella haemolytica after th...

By using well-defined techniques under optimum conditions it is possible adequately to define the biochemical characteristics of typical A. seminis strains. A. seminis can be distinguished from Histophilus ovis on the latter's distinctive colony morphology, but it cannot be distinguished from Actinobacillus actinomycetem-comitans. These organisms, however, can be differentiated from Pasteurella...

OBJECTIVES The aim of this study was to identify and analyse the first integrative and conjugative element (ICE) from Mannheimia haemolytica, the major bacterial component of the bovine respiratory disease (BRD) complex. METHODS The novel ICEMh1 was discovered in the whole-genome sequence of M. haemolytica 42548 by sequence analysis and comparative genomics. Transfer of ICEMh1 was confirmed b...

A 16-kbp DNA region that contains genes involved in the biosynthesis of the capsule of Mannheimia (Pasteurella) haemolytica A1 has been characterized. The gene cluster can be divided into three regions like those of the typical group II capsule biosynthetic clusters in gram-negative bacteria. Region 1 contains four genes (wzt, wzm, wzf, and wza) which code for an ATP-binding cassette transport ...

BACKGROUND Pasteurella multocida, Mannheimia haemolytica, Histophilus somni and Trueperella pyogenes are four bacterial agents commonly associated with bovine respiratory disease (BRD). In this study a bacterial multiplex real-time PCR (the RespoCheck PCR) was evaluated for the detection in bronchoalveolar lavage fluid (BALF) of these four bacterial agents. RESULTS The analytical sensitivity ...

The respiratory tract contains numerous antimicrobial factors necessary for normal innate pulmonary defense. Although many of these molecules reside in airway surface liquid (ASL) simultaneously, little information exists concerning antagonistic, additive, or synergistic interactions. Since both cationic lysozyme and anionic antimicrobial peptides (AP) are found in high concentrations in ASL, t...

Antigens associated with whole Pasteurella haemolytica biotype A serotype 1, a capsular carbohydrate-protein extract of the organism, and P. haemolytica leukotoxin were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Antigens of the electrophoresed preparations were detected by Western blotting (immunoblotting) with sera from cattle which were either nonvaccinated or vac...

OBJECTIVE To characterise eight isolates of a Gram-negative organism obtained from the upper respiratory tract of cattle showing evidence of mild upper respiratory tract disease. DESIGN The isolates were compared with the five recognised species within the genus Mannheimia - M haemolytica, M glucosida, M granulomatis, M ruminalis and M varigena--using a range of phenotypic and genotypic metho...