Indigenous Probiotic Lactobacillus Isolates Presenting Antibiotic like Activity against Human Pathogenic Bacteria

Area of Science:

• Microbiology
• Probiotics Research
• Food Science

Background:

• Indigenous lactic acid bacteria (LAB) are recognized for their probiotic properties and antibacterial effects.
• This study focuses on characterizing LAB isolated from curd for probiotic potential and antagonistic activity against clinical pathogens.

Purpose of the Study:

• To isolate and identify lactic acid bacteria (LAB) from curd samples.
• To evaluate the probiotic characteristics of isolated LAB, including tolerance to low pH, bile salt, and sodium chloride.
• To assess the antagonistic activity of LAB against key human pathogenic bacteria.

Main Methods:

• Isolation and identification of LAB using conventional microbiological and biochemical tests.
• Probiotic potential assessed through tolerance assays (low pH, bile salt, NaCl).
• Antimicrobial activity determined via agar-well and agar overlay methods against *Escherichia coli*, *Proteus vulgaris*, *Acinetobacter baumannii*, and *Salmonella enterica*.

Main Results:

• Four LAB isolates (*L. animalis* LMEM6, *L. plantarum* LMEM7, *L. acidophilus* LMEM8, *L. rhamnosus* LMEM9) demonstrated tolerance to low pH and bile salt.
• Significant growth inhibition zones observed against pathogenic bacteria, with average inhibitory activity ranging from 233.34 to 280.56 AU/mL.
• All isolates were non-hemolytic, antibiotic-sensitive, and exhibited cumulative probiotic potential (CPP) values of 80-100%.

Conclusions:

• Curd-derived lactobacilli are promising candidates for probiotic applications.
• These LAB demonstrate potential as bio-therapeutics to combat bacterial infections in humans.