Classification and identification of the viridans streptococci.

Area of Science:

• Microbiology
• Bacteriology
• Genetics

Background:

• Viridans streptococci are a group of bacteria historically difficult to classify.
• Previous taxonomic methods lacked precision in defining distinct species.
• Understanding their genetic relationships is crucial for accurate identification.

Purpose of the Study:

• To redefine the taxonomy of viridans streptococci.
• To establish species definitions based on genetic relatedness.
• To correlate genetic classifications with easily identifiable phenotypic characteristics.

Main Methods:

• Review of historical data on viridans streptococci.
• Analysis of biochemical profiles.
• Nucleic acid sequencing for genetic relationship assessment.

Main Results:

• Division of Streptococcus mutans into four species, with two prevalent in humans.
• Reclassification of S. constellatus, S. intermedius, and "S. milleri" under S. anginosus.
• Clarification of S. mitis and identification of genetic heterogeneity within S. sanguis and S. bovis.

Conclusions:

• Modern taxonomic approaches provide clearer species definitions for viridans streptococci.
• Accurate identification of these bacteria, including potential pathogens, is now more feasible.
• This improved classification aids in diagnosing and managing infections caused by these streptococci.