Bioprotective potential of lactic acid bacteria isolated from the
fermentation of fine cocoa (Theobroma cacao) and their metabolites
against enterotoxigenic Escherichia coli
Escherichia coli is one of the main pathogens that impacts swine
production. Given the need for methods for its control, the in vitro
effect of lactic acid bacteria (LAB) and their metabolites against E.
coli F4 was evaluated through cell culture and microbiological analysis.
The strains Limosilactobacillus fermentum 5.2, Lactiplantibacillus
plantarum 6.2, and L. plantarum 7.1 were selected. To evaluate the
action of their metabolites, lyophilized cell-free supernatants (CFS)
were used. The effect of CFS was evaluated in HT-29 intestinal lineage
cells; in inhibiting the growth of the pathogen in agar; and in
inhibiting the formation of biofilms. The bioprotective activity of LAB
was evaluated via their potential for autoaggregation and coaggregation
with E. coli. The CFS did not show cytotoxicity at lower concentrations,
except for L. fermentum 5.2 CFS, which is responsible for cell
proliferation at doses lower than 10 mg/mL. The CFS were also not able
to inhibit the growth of E. coli F4 in agar; however, the CFS of L.
plantarum 7.1 resulted in a significant decrease in biofilm formation at
a dose of 40 mg/mL. Regarding LAB, their direct use showed great
potential for autoaggregation and coaggregation in vitro, thus
suggesting possible effectiveness in animal organisms, preventing E.
coli fixation and proliferation. New in vitro tests are needed to
evaluate lower doses of CFS to control biofilms and confirm the
bioprotective potential of LAB, and in vivo tests to assess the effect
of LAB and their metabolites interacting with animal physiology.