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A hemagglutinating variant of Prevotella melaninogenica isolated from the oral cavity
1University of Iceland, Faculty of Odontology, Reykjavik.
Abstract:
Strains resembling Prevotella melaninogenica were isolated from healthy subjects and patients with periodontal disease and were identified using: a 5-test phenotypic screen; commercial identification kits; and a 16S rRNA-based polymerase chain reaction (PCR) method. Eleven clinical isolates closely resembling P. melaninogenica, and all from patients with periodontitis, were able to agglutinate erythrocytes. In the electron microscope, hemagglutinating isolates showed fimbria-like structures, that were not seen on non-hemagglutinating isolates. Some strains were further classified with PCR-restriction fragment-length polymorphism (RFLP) of 16S rRNA genes. Amplified 16S rDNA was digested using five different endonucleases, separated with agarose gel electrophoresis, stained and photographed. Photographs were then scanned, digitized and a distance matrix calculated using Dice coefficient, where the presence or absence of a band was used as a character. The distance matrix was plotted as a phenogram. At 70% similarity six clusters were seen. Type strains of separate Prevotella species did not fall into any cluster. Hemagglutinating isolates fell into three clusters: four clustered with the type strains of P. melaninogenica and Prevotella veroralis; four with other P. melaninogenica isolates and two hemagglutinating isolates clustered together Prevotella loescheii. The PCR-RFLP results showed that the hemagglutinating strains did not form a homogenous group inside the Prevotella genus.
Insights
Prevotella melaninogenica strains from periodontitis patients showed hemagglutination, linked to fimbriae. Molecular analysis revealed these hemagglutinating strains were not a uniform group within the Prevotella genus.
Area of Science:
- Microbiology
- Periodontology
- Molecular Biology
Background:
- Prevotella melaninogenica is associated with periodontal disease.
- Hemagglutination is a potential virulence factor in oral bacteria.
- Accurate identification of Prevotella species is crucial for understanding their role in disease.
Purpose of the Study:
- To identify and characterize Prevotella melaninogenica strains isolated from healthy and periodontitis patients.
- To investigate the relationship between hemagglutination, fimbriae, and Prevotella species identification.
- To assess the genetic diversity of hemagglutinating Prevotella isolates using PCR-restriction fragment-length polymorphism (PCR-RFLP).
Main Methods:
- Bacterial isolation and identification using phenotypic screening, commercial kits, and 16S rRNA gene sequencing.
- Hemagglutination assays using erythrocytes.
- Electron microscopy to visualize fimbriae.
- PCR-RFLP analysis of 16S rRNA genes, including endonuclease digestion, gel electrophoresis, and phenogram construction.
Main Results:
- Eleven clinical isolates resembling P. melaninogenica from periodontitis patients exhibited hemagglutination.
- Hemagglutinating isolates possessed fimbria-like structures, absent in non-hemagglutinating strains.
- PCR-RFLP analysis showed hemagglutinating isolates did not form a single, homogenous group, clustering with P. melaninogenica, P. veroralis, and P. loescheii.
Conclusions:
- Hemagglutination in Prevotella isolates may be associated with fimbriae and periodontitis.
- The genetic diversity of hemagglutinating Prevotella strains is significant.
- 16S rRNA gene PCR-RFLP is a valuable tool for differentiating Prevotella species and understanding their heterogeneity.
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