Molecular identification and typing of streptococcus isolates from sore throat patients using 16S rRNA sequencing

Abstract

Background: Streptococcus species are widely known as human pathogens targeting a variety of infections such as throat diseases as well as severe infections such as pneumonia and bacteremia. Classical methods used to culture bacteria can be labor-intensive and are not always successful in identifying some species. The aim of the current study was to genetically characterize Streptococcus spp. isolated from throat swabs from patients with throat infections using 16S rRNA sequencing and Vitek2 System.

Methods: An experimental study was designed to collect throat swabs from one hundred patients with clinical features and suspicion of streptococcal pharyngitis. Specimens were inoculated on blood and Azide blood agar plates to isolate Streptococcus species, and the isolates were confirmed with Vitek2 System. The entire genomic DNA was obtained straight from the colonies of bacteria, the 16S rRNA gene, Polymerase Chain Reaction (PCR) and sequencing was done for a bacterial species confirmation.

Results: Of the 100 samples analyzed, 89% exhibited bacterial growth on culture media, with 35% of the isolates identified as belonging to the genus Streptococcus. Among these, S. pyogenes was detected in 28.6% of cases using the Vitek2 system, followed by S. pneumoniae and S. viridans, each accounting for 20%. The identification of bacterial species using conventional techniques, such as culture, showed 100% agreement with modern molecular methods, including 16S rRNA gene sequencing.

Conclusions: The use of molecular techniques such as 16S rRNA sequencing with traditional culture methods enhances the validity and accuracy of identifying Streptococcus species. This approach stands to enhance the diagnostic accuracy in a large way, and thus warrant more focused treatment and better clinical results.