Although Lactobacillus species are not part of the “core” bacteriome of the human breast milk microbiome, they carry notable promise as probiotics.

Lactiplantibacillus plantarum (L. plantarum), for instance, formerly known as Lactobacillus plantarum1, is a Gram-positive lactic acid bacterium2 commonly found in fermented foods and in our own gastrointestinal tract. 

• Lactobacillus plantarum was renamed to Lactiplantibacillus plantarum in 2020 because advanced genetic sequencing revealed that the Lactobacillus genus was too diverse to be classified under a single group. 
• The genus was officially split into 25 new, smaller genera to reflect more accurate evolutionary, genetic, and metabolic relationships. 

• Lactic acid bacteria are a group of Gram-positive microorganisms characterized by their thick peptidoglycan cell wall, which retains the crystal violet dye used in Gram staining. 
• They are non-spore-forming and acid-tolerant, and can appear as either rod-shaped or cocci. 
• Their defining feature is that they produce lactic acid as the main end product of carbohydrate fermentation.

Research has linked L. plantarum to antioxidant, anticancer, anti-inflammatory, antiproliferative, anti-obesity, and anti-diabetic effects.

Even more inspiring, emerging studies suggest that it may help enhance cognitive function in individuals with major depression and may ease stress and anxiety in adults. 

The Lactiplantibacillus plantarum Probio87 strain (Probio87)

The Lactiplantibacillus plantarum Probio87 strain (Probio87) was discovered in the nurturing environment of human breast milk.

Motivated by its natural origin, the research team set out to explore Probio87 in vitro probiotic potential in depth. 

They examined its physiological resilience, ensured its safety, and studied its antimicrobial and anticancer properties, with a special focus on supporting vaginal and cervical health.

Result

Probio87 demonstrated several promising functional and safety characteristics:

A. Probio87 showed strong tolerance to acidic conditions and bile, efficient adhesion to mucin, and broad carbohydrate utilization. It preferentially utilized short-chain prebiotics such as fructooligosaccharides (FOS) and galactooligosaccharides (GOS) over inulin.

Probio87 is able to survive the highly acidic conditions of the stomach (pH 1.5–3.5) and withstand the bile salts present in the small intestine. 

It adheres strongly to mucin, the main protein in the mucus layer that coats the gut wall. This strong adhesion allows the strain to anchor itself to the gut lining, forming a physical barrier that helps crowd out and block harmful pathogens from attaching and causing infection.

In addition, Probio87 produces a wide range of enzymes that can break down different sugars and complex fibers. This enables the strain to access many energy sources and effectively compete with harmful bacteria for nutrients in the diverse environment of the human gut.

Probio87 also works particularly well with the short-chain prebiotics FOS and GOS, forming a potent synbiotic combination. 

Because FOS and GOS have smaller molecular structures than inulin (a long-chain prebiotic), Probio87 can ferment them quickly and efficiently, supporting rapid bacterial growth and colonization in the gut.

B. Probio87 complied with the European Food Safety Authority (EFSA) antibiotic safety criteria, indicating an acceptable safety profile with respect to antibiotic resistance.

When a probiotic strain meets the EFSA antibiotic safety criteria, it has been carefully evaluated to ensure it cannot transfer harmful antibiotic-resistance genes to other bacteria in your gut. 

This helps prevent the accidental creation of “superbugs”3 and protects the effectiveness of antibiotics you may need in the future.

• A superbug (or multidrug-resistant microbe) is any kind of infection that is hard to get rid of because it is resistant to (unable to be destroyed with) available treatment. 

• Most superbugs are bacteria that have developed antibiotic resistance, especially to multiple antibiotics. There are also fungal superbugs that are resistant to antifungal medications. 

There are two main requirements for EFSA compliance:

I. No acquired or transferable resistance (genotypic testing)

The strain’s entire DNA is analyzed using Whole Genome Sequencing (WGS). This confirms that it does not carry antibiotic-resistance genes4 on mobile genetic elements5 such as plasmids. 

Without these mobile genes, the probiotic cannot pass resistance traits6 to harmful bacteria like E. coli or Salmonella.

• Antibiotic resistance genes (ARGs) are DNA segments allowing bacteria to survive antibiotic treatment by degrading drugs, modifying targets, or pumping antibiotics out. 
• Located on chromosomes or mobile plasmids, these genes spread rapidly between bacteria—even across species—via horizontal gene transfer. 
• They pose a major global health threat, reducing treatment efficacy for infections.  

• Mobile genetic elements are sequences of genetic material that can change positions on chromosomes and be exchanged between bacteria and species, influencing microbial evolution and the spread of antibiotic resistance. 

• Pass resistance traits refer to the biological mechanism by which bacteria, fungi, or pests transfer their ability to survive exposure to antibiotics, antifungals, or pesticides to their offspring or to other neighboring microbes. 
• These traits—encoded in DNA—allow the organism to withstand treatments designed to kill them, leading to the rapid spread of resistance within a population. 

II. Susceptibility to key antibiotics (phenotypic testing)

The strain is grown in the presence of important antibiotics (i.e., ampicillin, tetracycline, and erythromycin). 

Scientists then determine the Minimum Inhibitory Concentration (MIC), which is the lowest antibiotic dose that stops the strain from growing. 

For EFSA compliance, these MIC values must be below specific microbiological cut-off levels, showing that the bacterium remains naturally sensitive to standard medical antibiotics.

C. Its cell-free supernatant (CFS) displayed potent antimicrobial activity, including complete inhibition of the fungal pathogen Candida albicans.

CFS is the liquid byproduct that remains after probiotic bacteria are grown in a laboratory and then removed using centrifugation. 

Because all live bacteria are spun out, this liquid contains no living microbes; instead, it retains the active therapeutic compounds produced by the bacteria during growth.

CFS is rich in bioactive substances (often referred to as “biotics”) that can effectively kill or inhibit the growth of bacteria, molds, and fungi. 

In other words, Probio87 produces a fluid filled with natural antimicrobial agents that remain active even after the bacteria themselves are gone.

Research shows that these secretions can completely halt the growth of Candida albicans, an opportunistic yeast responsible for common conditions such as thrush, vaginal yeast infections, and oral fungal overgrowth.