Multilocus sequence typing of Enterococcus faecalis from vegetable foods reveals two new sequence types

Area of Science:

• Food microbiology
• Bacterial genetics
• Molecular typing

Background:

• Enterococcus faecalis is a common bacterium found in various environments, including food.
• Understanding the genetic diversity of foodborne Enterococcus faecalis is crucial for food safety and public health.
• Multilocus sequence typing (MLST) is a powerful tool for bacterial strain characterization and epidemiological studies.

Purpose of the Study:

• To characterize the genetic diversity of Enterococcus faecalis isolates from vegetable foods using MLST.
• To identify novel sequence types (STs) within the Enterococcus faecalis population associated with vegetable products.
• To investigate the relationship between foodborne Enterococcus faecalis and strains from other environments, such as hospitals.

Main Methods:

• Isolation of Enterococcus faecalis from diverse vegetable food sources.
• Characterization of isolates using multilocus sequence typing (MLST) to determine sequence types (STs).
• Comparative analysis of identified STs with existing databases to assess genetic relatedness.

Main Results:

• Sixteen Enterococcus faecalis isolates from vegetable foods were analyzed.
• One isolate matched the known hospital-associated sequence type 9 (ST9).
• Two novel STs, ST168 and ST169, were identified. ST168, a predominant type in this study, comprised 14 isolates and was closely related to ST72. ST169 was a unique singleton.

Conclusions:

• Vegetable foods harbor diverse genetic lineages of Enterococcus faecalis, including novel types.
• The identification of ST168 as a predominant type suggests its successful adaptation to vegetable food environments.
• MLST provides valuable insights into the population structure and potential sources of foodborne Enterococcus faecalis.