Identification of clinically relevant viridans streptococci by an oligonucleotide array

Area of Science:

• Microbiology
• Molecular Biology
• Infectious Diseases

Background:

• Viridans streptococci (VS) are significant pathogens, frequently causing subacute infective endocarditis and other pyogenic infections.
• Phenotypic identification of many VS species is challenging, necessitating improved diagnostic methods.

Purpose of the Study:

• To develop and evaluate an oligonucleotide array for the accurate identification of 11 clinically relevant Viridans streptococci species.
• To provide a reliable molecular alternative for routine species identification of VS.

Main Methods:

• Development of an oligonucleotide array targeting the 16S-23S rRNA gene intergenic spacer (ITS) sequences.
• PCR amplification of ITS regions followed by hybridization to species-specific oligonucleotide probes immobilized on a nylon membrane.
• Testing of 120 VS strains and 91 other bacterial strains to assess array performance.

Main Results:

• The oligonucleotide array demonstrated 100% sensitivity and 95.6% specificity in identifying the 11 target VS species.
• Cross-hybridization was observed between S. pneumoniae and S. mitis probes, requiring complementary biochemical tests for differentiation.
• The method proved accurate for identifying VS species.

Conclusions:

• The developed oligonucleotide array is an accurate and reliable method for identifying 11 clinically relevant Viridans streptococci species.
• This molecular approach can serve as a valuable alternative to traditional methods for VS species identification.
• Further differentiation using biochemical tests is recommended for S. pneumoniae and S. mitis.