Lactiplantibacillus plantarum strains isolated from spontaneously fermented cocoa exhibit potential probiotic properties against Gardnerella vaginalis and Neisseria gonorrhoeae

Abstract

Background Probiotics are important tools in therapies against vaginal infections and can assist traditional antibiotic therapies in restoring healthy microbiota. Recent research has shown that microorganisms belonging to the genus Lactobacillus have probiotic potential. Thus, this study evaluated the potential in vitro probiotic properties of three strains of Lactiplantibacillus plantarum, isolated during the fermentation of high-quality cocoa, against Gardnerella vaginalis and Neisseria gonorrhoeae. Strains were evaluated for their physiological, safety, and antimicrobial characteristics. Results The hydrophobicity of L. plantarum strains varied from 26.67 to 91.67%, and their autoaggregation varied from 18.10 to 30.64%. The co-aggregation of L. plantarum strains with G. vaginalis ranged from 14.73 to 16.31%, and from 29.14 to 45.76% with N. gonorrhoeae. All L. plantarum strains could moderately or strongly produce biofilms. L. plantarum strains did not show haemolytic activity and were generally sensitive to the tested antimicrobials. All lactobacillus strains were tolerant to heat and pH resistance tests. All three strains of L. plantarum showed antimicrobial activity against the tested pathogens. The coincubation of L. plantarum strains with pathogens showed that the culture pH remained below 4.5 after 24 h. All cell-free culture supernatants (CFCS) demonstrated activity against the two pathogens tested, and all L. plantarum strains produced hydrogen peroxide. CFCS characterisation in conjunction with gas chromatography revealed that organic acids, especially lactic acid, were responsible for the antimicrobial activity against the pathogens evaluated. Conclusion The three strains of L. plantarum presented significant probiotic characteristics against the two pathogens of clinical importance. In vitro screening identified strong probiotic candidates for in vivo studies for the treatment of vaginal infections.

Evaluation of IR Biotyper for Lactiplantibacillus plantarum Typing and Its Application Potential in Probiotic Preliminary Screening

“…Lactiplantibacillus plantarum (formerly Lactobacillus plantarum ), which is a homofermentative lactic acid bacterium (LAB), has been widely applied as a model species for ecological, metabolic, and genetic studies in lactobacilli ( Zheng et al, 2020 ). In addition, L. plantarum is used as a starter culture in multiple food and beverage fermentations and as a probiotic for both animals and humans, making it of considerable academic and economic importance ( das Neves Selis et al, 2021 ). L. plantarum has been classified as a “nomadic” or “generalist” bacterium because of its diverse habitats ( Martino et al, 2016 ; Choi et al, 2018 ; Yu et al, 2020 , 2021 ).…”

In Silico and In Vitro Evaluation of the Antimicrobial Potential of Bacillus cereus Isolated from Apis dorsata Gut against Neisseria gonorrhoeae

“…Because the supernatant in treatment 1 was heated, it was assumed that any antimicrobial peptides present would become inactive [53], leaving organic acids, hydrogen peroxide (H 2 O 2 ), and alcohol as the bioactive components that inhibited N. gonorrhoeae. A recent study demonstrated that probiotic Lactiplantibacillus plantarum strains isolated from spontaneously fermented cocoa may possess antimicrobial activity against N. gonorrhoeae [54]. Additionally, this probiotic was discovered to produce H 2 O 2 .…”

Bioprospecting Antimicrobials from Lactiplantibacillus plantarum: Key Factors Underlying Its Probiotic Action

“…The antimicrobials produced by lactobacilli are quite diverse and fall within two main chemical categories, proteinaceous and non-proteinaceous substances. Data reported in Table 1 and Table 2 show that the antimicrobial activity of L. plantarum is mainly exerted by bacteriocins (~60% of the reported strains) or partially characterised proteinaceous compounds, followed by organic acids or acidic conditions (i.e., acid CFS [ 25 ]), and biosurfactants (BS) such as glycoproteins and EPS.…”

“…Since the growth of important food-spoilage and food-poisoning microorganisms is inhibited at low pH (<4), L. plantarum , which is one of the lactobacilli with the highest lactic acid production rate [ 25 , 68 ], can be added to many fermented foods as a natural preservative [ 69 , 70 ]. LAB, including L. plantarum , may be homofermentative or heterofermentative depending on the pathway used for glucose fermentation.…”

“…The main antimicrobial chemicals produced by lactobacilli comprise ( i ) ribosomally synthesised peptides, i.e., bacteriocins [ 23 ] and ( ii ) metabolic by-products of various chemical nature, such as hydrogen peroxide (H 2 O 2 ) [ 24 ], lactic acid and other organic acids [ 25 ], phenolic compounds [ 26 , 27 ], etc. While bacteriocins typically exhibit selective and target-specific antagonistic activity [ 23 ], the latter group comprise molecules that generally act rather aspecifically in inhibiting the growth of competitor species ( Figure 1 ).…”