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Identification of the psaA gene, coding for pneumococcal surface adhesin A, in viridans group streptococci other than
1Laboratorio de Referencia de Neumococos, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda E-28220, Madrid, Spain.
Abstract:
The gene encoding the pneumococcal surface adhesin A (PsaA) protein has been identified in three different viridans group streptococcal species. Comparative studies of the psaA gene identified in different pneumococcal isolates by sequencing PCR products showed a high degree of conservation among these strains. PsaA is encoded by an open reading frame of 930 bp. The analysis of this fragment in Streptococcus mitis, Streptococcus oralis, and Streptococcus anginosus strains revealed a sequence identity of 95, 94, and 90%, respectively, to the corresponding open reading frame of the previously reported Streptococcus pneumoniae serotype 6B strain. Our results confirm that psaA is present and detectable in heterologous bacterial species. The possible implications of these results for the suitability and potential use of PsaA in the identification and diagnosis of pneumococcal diseases are discussed.
Insights
The pneumococcal surface adhesin A (PsaA) gene is highly conserved and found in other streptococcal species. This suggests PsaA
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- The pneumococcal surface adhesin A (PsaA) protein is crucial for Streptococcus pneumoniae virulence.
- Understanding the genetic conservation of PsaA across different streptococcal species is important for diagnostics.
Purpose of the Study:
- To investigate the presence and conservation of the psaA gene in various viridans group streptococci.
- To assess the potential of PsaA as a target for identifying and diagnosing pneumococcal infections.
Main Methods:
- Polymerase Chain Reaction (PCR) amplification of the psaA gene from different streptococcal species.
- DNA sequencing of the PCR products to analyze gene conservation.
- Comparative sequence analysis against the Streptococcus pneumoniae psaA gene.
Main Results:
- The psaA gene was identified in three viridans group streptococcal species: Streptococcus mitis, Streptococcus oralis, and Streptococcus anginosus.
- High sequence identity was observed between the psaA genes of these species and Streptococcus pneumoniae (90-95%).
- The psaA gene is a 930 bp open reading frame, showing significant conservation.
Conclusions:
- The psaA gene is present and detectable in heterologous bacterial species beyond Streptococcus pneumoniae.
- The high conservation of psaA suggests its potential utility as a biomarker for pneumococcal identification and diagnosis.