Characterization of Leuconostoc lactis strains from human sources

Area of Science:

• Microbiology
• Bacteriology
• Chemotaxonomy

Background:

• Vancomycin-resistant bacteria pose a significant clinical challenge.
• Streptococcus-like isolates with atypical biochemical profiles require accurate identification.
• Leuconostoc lactis is primarily associated with dairy products.

Purpose of the Study:

• To identify and characterize 23 vancomycin-resistant, Streptococcus-like clinical isolates.
• To determine the taxonomic relationship of these isolates using advanced methods.
• To assess the potential for non-dairy origins of Leuconostoc lactis.

Main Methods:

• Chemotaxonomic studies were performed on 23 clinical isolates.
• Thin-layer chromatography was used to analyze polar lipid patterns.
• Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was employed for whole-cell protein analysis.

Main Results:

• Fourteen of the 23 isolates showed relatedness to Leuconostoc lactis (CIP 102422).
• These isolates presented atypical results with classical biochemical tests.
• Chemotaxonomic analyses, particularly lipid and protein profiles, confirmed the identification.

Conclusions:

• Clinical isolates previously considered atypical Streptococcus-like bacteria can be identified as Leuconostoc lactis.
• Chemotaxonomic methods are crucial for accurate identification of bacteria with unusual profiles.
• The findings suggest Leuconostoc lactis may have broader ecological niches than previously assumed, including clinical environments.