Lactic acid bacteria: prominent player in the fight against human pathogens

ABSTRACT

Introduction

The human microbiome is a unique repository of diverse bacteria. Over 1000 microbial species reside in the human gut, which predominantly influences the host’s internal environment and plays a significant role in host health. Lactic acid bacteria have long been employed for multiple purposes, ranging from food to medicines. Lactobacilli, which are often used in commercial food fermentation, have improved to the point that they might be helpful in medical applications.

Areas covered

This review summarises various clinical and experimental evidence on efficacy of lactobacilli in treating a wide range of infections. Both laboratory based and clinical studies have been discussed.

Expert opinion

Lactobacilli are widely accepted as safe biological treatments and host immune modulators (GRAS- Generally regarded as safe) by the US Food and Drug Administration and Qualified Presumption of Safety. Understanding the molecular mechanisms of lactobacilli in the treatment and pathogenicity of bacterial infections can help with the prediction and development of innovative therapeutics aimed at pathogens which have gained resistance to antimicrobials. To formulate effective lactobacilli based therapy significant research on the effectiveness of different lactobacilli strains and its association with demographic distribution is required. Also, the side effects of such therapy needs to be evaluated.

KEYWORDS:

• Lactobacilli
• lactic acid bacteria
• gastrointestinal infections
• respiratory infections
• uropathogenic infections
• skin infections
• probiotics

Article highlights

• The normal microbiota of the human mouth, digestive tract, and female genital tract include Lactobacillus species, which produce lactic acid (which lowers the pH of the vagina) and outcompete pathogenic organisms.

• A number of antimicrobial strategies, including nutritional competition, the production of inhibitory substances, immunological activation, and competition for binding sites, have been shown to be used by lactobacilli strains.

• Understanding the varied ways utilised to combat various bacterial illnesses using diverse lactobacilli strains may aid in the development of cutting-edge and therapeutic methods to treat infections.

Acknowledgments

US is supported by the junior research fellowship program of the Symbiosis International (Deemed University).

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or material discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or mending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

The work was supported by the Ramalingaswami fellowship program of Department of Biotechnology, India under grant BT/RLF/Re-entry/41/2015; ERASMUS+ under grant 598515-EPP-1-2018-1-IN-EPPKA2- CBHE-JP