Identification of vancomycin-resistant lactic bacteria isolated from humans

Area of Science:

• Microbiology
• Bacteriology
• Food Science

Background:

• Vancomycin-resistant lactic acid bacteria (VRLAB) are increasingly recognized in human samples.
• Accurate identification of VRLAB is crucial for understanding their role in human health and food safety.
• Existing identification methods can be complex and time-consuming.

Purpose of the Study:

• To develop and validate a rapid method for profiling vancomycin-resistant lactic acid bacteria from human sources.
• To differentiate key genera including Pediococcus, Lactobacillus, and Leuconostoc.
• To assess the utility of specific biochemical tests and commercial panels for VRLAB identification.

Main Methods:

• Utilized cell morphology, arginine dihydrolase activity, and gas production in de Man, Sharp, Rogosa broth for 122 VRLAB isolates.
• Employed spectrophotometry to detect the absence of L-(+)-lactic acid.
• Applied API 50 CHL panels for species-level identification, particularly for Lactobacillus.

Main Results:

• Successfully assigned 122 VRLAB isolates into five distinct profiles.
• Differentiated between Pediococcus, homofermentative and heterofermentative Lactobacillus, and Leuconostoc species.
• Confirmed Leuconostoc species by the absence of L-(+)-lactic acid and found API 50 CHL panels effective for Lactobacillus identification.

Conclusions:

• A combination of simple phenotypic tests provides a reliable method for profiling VRLAB from human origins.
• This approach facilitates the differentiation of important lactic acid bacterial genera.
• The findings support the use of these methods for routine laboratory identification of VRLAB.