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Characterization of Pasteurella species isolated from lungs of calves with pneumonia
Abstract:
During routine bacteriological examination of pneumonic calf lungs it was experienced that many Pasteurella multocida-like isolates had a fermentation pattern different from what is generally accepted for P. multocida sensu stricto. Forty-one out of 50 strains selected for further investigation were phenotypically related and formed a group of indole-, mannitol-and sorbitol-negative P. multocida-like strains, which was tentatively designated taxon 13. Deoxyribonucleic acid/deoxyribonucleic acid hybridizations including both ornithine positive and ornithine negative strains of taxon 13 allowed the classification of the former as P. multocida biovar 6 and the latter as V factor independent strains of Haemophilus avium.
Insights
Bacteriological examination revealed Pasteurella multocida-like strains with unusual fermentation patterns. DNA hybridizations reclassified these as P. multocida biovar 6 and Haemophilus avium.
Area of Science:
- Veterinary microbiology
- Bacteriology
- Molecular biology
Background:
- Routine examination of pneumonic calf lungs identified Pasteurella multocida-like isolates with atypical fermentation profiles.
- Standard identification criteria for P. multocida sensu stricto did not align with observed phenotypic characteristics.
Purpose of the Study:
- To investigate and classify Pasteurella multocida-like strains exhibiting divergent biochemical properties.
- To accurately identify and categorize these isolates using molecular and phenotypic methods.
Main Methods:
- Phenotypic characterization, including fermentation tests for indole, mannitol, and sorbitol.
- Deoxyribonucleic acid/deoxyribonucleic acid (DNA/DNA) hybridization assays.
- Ornithine utilization tests for strain differentiation.
Main Results:
- Forty-one of 50 examined strains formed a distinct group, negative for indole, mannitol, and sorbitol fermentation, designated taxon 13.
- DNA/DNA hybridizations classified ornithine-positive strains of taxon 13 as P. multocida biovar 6.
- Ornithine-negative strains of taxon 13 were identified as V factor-independent Haemophilus avium.
Conclusions:
- The study reclassifies atypical P. multocida-like isolates, highlighting the importance of comprehensive phenotypic and genotypic analysis.
- Taxon 13 represents two distinct bacterial species: P. multocida biovar 6 and V factor-independent H. avium, necessitating revised diagnostic approaches.