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Use of Molecular Pathogenicity Indices to Identify Pathogenic Strains of Pasteurella multocida
Thales Quedi Furian1, Karen Apellanis Borges1, Roberta Marmitt Pilatti1
1A Centro de Diagnóstico e Pesquisa em Patologia Aviária-CDPA, Faculdade de Medicina Veterinária, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, 90460-001, Rio Grande do Sul, Brazil.
Abstract:
In addition to being the causative agent of fowl cholera (FC), Pasteurella multocida is also one of the most prevalent opportunistic pathogens associated with respiratory diseases in various hosts. However, understanding of the traits that distinguish the virulent isolates that cause FC is still limited. The objective of this study was to characterize P. multocida isolates of Brazil by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis in order to determine if strain-type correlates with virulence or with 22 previously studied virulence genes. The PCR-RFLP was used to classify the isolates into seven strain types, and the isolates in Profile II had a higher pathogenicity index (P < 0.05) than did those in Profiles I, V, and VI. The overall identity among the nucleotide sequences of the ompH was 89.8%. Furthermore, strains available in GenBank showed a high level of homology of the different bacterial serotypes with the groupings resulting from the PCR-RFLP. Strain Types I and II showed the highest identity with Serotypes 3 (100%) and 3-4 (99.1%), respectively. Detection of the pfhA gene indicated the presence of strains that are highly pathogenic. The screening detection of 22 virulence genes and inference through the decision tree models comparing the results of pathogenicity indices permitted the identification of the most highly pathogenic strains of P. multocida .
Insights
This study characterized Pasteurella multocida strains using PCR-RFLP, identifying specific strain types linked to higher virulence and pathogenicity. These findings aid in distinguishing highly pathogenic fowl cholera (FC) agents.
Area of Science:
- Veterinary Microbiology
- Bacterial Pathogenesis
- Molecular Epidemiology
Background:
- Pasteurella multocida is a significant opportunistic pathogen causing fowl cholera (FC) and respiratory diseases.
- Limited understanding exists regarding the specific traits differentiating virulent FC-causing P. multocida isolates.
- Characterizing Brazilian P. multocida isolates is crucial for understanding virulence factors.
Purpose of the Study:
- To characterize P. multocida isolates from Brazil using PCR-restriction fragment length polymorphism (PCR-RFLP).
- To determine the correlation between P. multocida strain types and virulence or specific virulence genes.
- To identify highly pathogenic P. multocida strains through pathogenicity indices and virulence gene screening.
Main Methods:
- PCR-restriction fragment length polymorphism (PCR-RFLP) was employed to classify P. multocida isolates into distinct strain types.
- Pathogenicity indices were assessed for different strain types, with statistical analysis (P < 0.05).
- Nucleotide sequences of the ompH gene were analyzed, and 22 virulence genes were screened, including pfhA.
Main Results:
- Seven distinct strain types were identified among the Brazilian P. multocida isolates.
- Isolates classified under Profile II exhibited significantly higher pathogenicity indices compared to Profiles I, V, and VI.
- High homology was observed between bacterial serotypes and PCR-RFLP groupings, with Strain Types I and II showing strong identity with Serotypes 3 and 3-4, respectively. The pfhA gene was detected in highly pathogenic strains.
Conclusions:
- PCR-RFLP is effective in classifying P. multocida isolates and correlating strain types with pathogenicity.
- Specific strain types, particularly Profile II, are associated with increased virulence in P. multocida.
- The identification of virulence genes like pfhA and the use of decision tree models aid in pinpointing highly pathogenic P. multocida strains.
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