Multivariate chemosystematics demonstrate two groups of Actinobacillus actinomycetemcomitans strains

Area of Science:

• Microbiology
• Bacteriology
• Chemotaxonomy

Background:

• Actinobacillus actinomycetemcomitans is a bacterium implicated in various human infections.
• Previous chemical analyses suggested A. actinomycetemcomitans may not be a homogeneous species.
• Further investigation into its heterogeneity is crucial for accurate classification and understanding.

Purpose of the Study:

• To further investigate the heterogeneity of Actinobacillus actinomycetemcomitans using chemometric methods.
• To differentiate strains of A. actinomycetemcomitans based on a comprehensive set of chemical characteristics.
• To compare A. actinomycetemcomitans strains with members of the Haemophilus and Pasteurella genera.

Main Methods:

• Characterization of 9 A. actinomycetemcomitans strains using multiple chemical variables.
• Analysis included cell sugar and fatty acid content, lysis kinetics, methylene blue reduction, and API ZYM enzyme profiles.
• Chemometric techniques, principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA), were applied.

Main Results:

• Chemometric analysis successfully divided the 9 A. actinomycetemcomitans strains into two distinct groups.
• The two identified groups were statistically distinguishable (F-test, 95% confidence limits).
• Both A. actinomycetemcomitans groups were clearly differentiated from Haemophilus and Pasteurella species.

Conclusions:

• Actinobacillus actinomycetemcomitans comprises at least two distinct chemovar groups.
• These findings support the non-homogeneous nature of A. actinomycetemcomitans.
• The study provides a robust chemical basis for differentiating A. actinomycetemcomitans strains and related genera.