Lactobacillus is a genus of gram-positive bacteria commonly used in the cosmetic and personal care industry for its probiotic, skin-conditioning, and antimicrobial properties. These beneficial bacteria are known for their ability to promote healthy skin microbiota and enhance the skin's natural defense mechanisms.

Chemical Composition and Structure

Lactobacillus bacteria have a simple, rod-shaped structure and are composed of:

• Peptidoglycan Cell Wall: Provides structural support and protection.
• Cytoplasmic Membrane: Encloses the cell's internal contents.
• Cytoplasm: Contains enzymes, ribosomes, and other essential cellular components.
• Genetic Material: Circular DNA that contains the bacterial genome.
• Metabolites: Produce beneficial compounds such as lactic acid, which contribute to their probiotic effects.

Physical Properties

Lactobacillus bacteria are typically found in a lyophilized (freeze-dried) powder form for cosmetic use. They are reactivated when incorporated into aqueous cosmetic formulations, ensuring their viability and efficacy.

Cosmetic and Personal Care Applications

• Probiotic: Helps to balance and maintain a healthy skin microbiome, promoting overall skin health.
• Skin Conditioning: Improves the texture and appearance of the skin, making it smoother and healthier.
• Antimicrobial: Inhibits the growth of harmful bacteria, helping to prevent skin infections and maintain clear skin.
• Anti-inflammatory: Reduces redness, swelling, and irritation associated with various skin conditions.
• Moisturizing: Enhances the skin's ability to retain moisture, preventing dryness and promoting softness.

Environmental and Safety Considerations

Lactobacillus is generally considered safe for use in cosmetic and personal care products when used within recommended concentrations. It is derived from natural sources and is biodegradable, making it an environmentally friendly choice. Proper formulation and testing ensure the safety and efficacy of products containing Lactobacillus.

Cosmetics - INCI Functions

• Skin conditioning agent. It is the mainstay of topical skin treatment as it has the function of restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants that can be added in the formulation.

Conclusion

Benefits:

• Helps maintain gut microbiota balance.
• Aids in lactose digestion for those with intolerance.
• Strengthens the immune system.
• Contributes to preventing intestinal and urinary infections.
• Supports skin health, useful for acne and dermatitis.

Contraindications:

• May cause bloating or gas in some individuals.
• Not suitable for immunocompromised people without medical supervision.
• Possible interactions with antibiotic treatments.
• Rare risk of systemic infections in vulnerable individuals.
• Avoid if allergic to specific probiotics.

References__________________________________________________________________________

O'Callaghan J, O'Toole PW. Lactobacillus: host-microbe relationships. Curr Top Microbiol Immunol. 2013;358:119-54. doi: 10.1007/82_2011_187. 

Abstract. Lactobacilli are a subdominant component of the human intestinal microbiota that are also found in other body sites, certain foods, and nutrient-rich niches in the free environment. They represent the types of microorganisms that mammalian immune systems have learned not to react to, which is recognized as a potential driving force in the evolution of the human immune system. Co-evolution of lactobacilli and animals provides a rational basis to postulate an association with health benefits. To further complicate a description of their host interactions, lactobacilli may rarely cause opportunistic infections in compromised subjects. In this review, we focus primarily on human-Lactobacillus interactions. We overview the microbiological complexity of this extraordinarily diverse genus, we describe where lactobacilli are found in or on humans, what responses their presence elicits, and what microbial interaction and effector molecules have been identified. The rare cases of Lactobacillus septicaemia are explained in terms of the host impairment required for such an outcome. We discuss possibilities for exploitation of lactobacilli for therapeutic delivery and mucosal vaccination.

Slattery C, Cotter PD, O'Toole PW. Analysis of Health Benefits Conferred by Lactobacillus Species from Kefir. Nutrients. 2019 Jun 1;11(6):1252. doi: 10.3390/nu11061252. 

Abstract. Lactobacilli are among the most common microorganisms found in kefir; a traditional fermented milk beverage produced locally in many locations around the world. Kefir has been associated with a wide range of purported health benefits; such as antimicrobial activity; cholesterol metabolism; immunomodulation; anti-oxidative effects; anti-diabetic effects; anti-allergenic effects; and tumor suppression. This review critically examines and assesses these claimed benefits and mechanisms with regard to particular Lactobacillus species and/or strains that have been derived from kefir; as well as detailing further potential avenues for experimentation.

Claesson MJ, van Sinderen D, O'Toole PW. The genus Lactobacillus--a genomic basis for understanding its diversity. FEMS Microbiol Lett. 2007 Apr;269(1):22-8. doi: 10.1111/j.1574-6968.2006.00596.x.

Abstract. The genus Lactobacillus is a diverse group that includes many species used in food production and preservation. Some lactobacilli are considered probiotic, conferring health benefits upon the host. The heterogeneity of this genus poses challenges and opportunities when characterizing or exploiting individual strains. To date, 10 Lactobacillus genome sequences have been published, and at least 11 more sequencing projects are ongoing. These studies will dramatically improve one's understanding of metabolic processes, bioprocessing capabilities and potential roles in health and well-being of the Lactobacilli. This review describes the current status of Lactobacillus genome sequence projects, highlights the major findings and summarizes functional genomics or comparative genomics studies. The genomic basis for the unusual diversity of this genus is discussed, and the potential for comparative genomics to rigorously extend phylogenetic analysis of the Lactobacilli is described.

Lentsner AA, Lentsner KhP, Mikel'saar ME, Tiuri ME, Brilene TA. Lactobacillus flora and colonization resistance. Antibiot Med Biotekhnol. 1987 Mar;32(3):173-9.

Abstract. Lactobacillus flora of healthy persons and the properties influencing the protective function of lactobacilli are described. It was shown that the species and quantitative composition of the Lactobacillus flora in healthy persons was characterized by individual features and the Lactobacillus flora of separate microbiotopes was different. Furthermore, the properties defining the protective function of lactobacilli in the host: colonization capacity, direct antimicrobial activity and interference with other protective mechanisms were also different in separate species and even strains.