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Serotype variation in Streptococcus anginosus, S. constellatus and S. intermedius
M Inoue1, H Eifuku-Koreeda, K Kitada
1Department of Preventive Dentistry, Kagoshima University Dental School, Japan.
Abstract:
Various serotypes reported in three serotyping systems for the 'Streptococcus milleri' group, i.e., Ottens I-IV, Osano I-IV and serotypes a-k, were compared with each other in a capillary precipitation test and by the double immunodiffusion test. Only two of the 19 serotypes, f and Ottens-III, were identical, and the other 17 serotypes were independent. Thus, 18 serotypes and another three candidates (a-, b- and g-cross-reactive) were found in the 'S. milleri' group. Of the 248 strains tested, 197 were serotypable, and 23 strains carried two type antigens. Generally, the Ottens I, II, III (serotype f), IV and Osano IV antigens, often together with the Lancefield group F antigen, were found in S. anginosus and S. constellatus. In addition, the serotype a, c, d, e and k antigens with the group A, C or G antigen were distributed in S. anginosus, the serotype b antigen in S. constellatus and the g, h, i, j, Osano I, II and III antigens in S. intermedius. Twenty-five of the untypable strains were Lancefield groupable (mostly F).
Insights
The Streptococcus milleri group has 18 distinct serotypes, with only two previously identified types being identical. This clarifies the serological classification of these medically important bacteria.
Area of Science:
- Microbiology
- Bacteriology
- Immunology
Background:
- The Streptococcus milleri group comprises several species, including Streptococcus anginosus, Streptococcus constellatus, and Streptococcus intermedius.
- Accurate serological classification is crucial for understanding the epidemiology and pathogenicity of these bacteria.
- Previous serotyping systems for the Streptococcus milleri group lacked standardization, leading to confusion.
Purpose of the Study:
- To compare and reconcile existing serotyping systems for the Streptococcus milleri group.
- To establish a clearer and more accurate serological classification for these bacteria.
- To investigate the distribution of serotypes among different species within the group.
Main Methods:
- Comparative analysis of three serotyping systems: Ottens I-IV, Osano I-IV, and serotypes a-k.
- Utilized capillary precipitation tests and double immunodiffusion assays for serological comparisons.
- Tested 248 strains of the Streptococcus milleri group.
Main Results:
- Identified 18 distinct serotypes within the Streptococcus milleri group, with only two previously designated types (f and Ottens-III) being identical.
- Found 17 independent serotypes, indicating significant divergence among existing classifications.
- Determined the association of specific serotypes with bacterial species: Ottens I-IV and Osano IV antigens (often with Lancefield group F) in S. anginosus and S. constellatus; serotypes a, c, d, e, k (with groups A, C, or G) in S. anginosus; serotype b in S. constellatus; and serotypes g, h, i, j, Osano I-III in S. intermedius.
- 197 out of 248 strains were serotypable, with 23 strains exhibiting dual type antigens.
Conclusions:
- The study establishes a more defined serological landscape for the Streptococcus milleri group, resolving ambiguities from previous systems.
- The findings provide a foundation for improved diagnostic and epidemiological studies involving these bacteria.
- Clarified serotype distribution aids in differentiating species within the Streptococcus milleri group.