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

• Published in: Biomedicines Vol. 5; no. 2; p. 31
• Main Authors: Halder, Debashis, Mandal, Manisha, Chatterjee, Shiv Sekhar, Pal, Nishith Kumar, Mandal, Shyamapada
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 16-06-2017; MDPI
• Subjects: Agar; Antibacterial activity; Antibiotics; Bacteria; Bacterial infections; Bile; Cultural factors; Curd; Fermentation; Lactic acid; Lactic acid bacteria; Lactobacilli; pH effects; Probiotics; Salmonella; Salts; Sodium; Sodium chloride; Sugar; Yogurt; γ-hemolytic activity; indicator bacterial pathogens; lactobacilli; cumulative probiotic potential; antibiotic susceptibility; antagonistic activity; probiotics
• ISSN: 2227-9059; 2227-9059
• DOI: 10.3390/biomedicines5020031

Indigenous lactic acid bacteria are well known probiotics having antibacterial activity against potentially pathogenic bacteria. This study aims to characterize the curd lactobacilli for their probiotic potentiality and antagonistic activity against clinical bacteria.
Four curd samples were processed microbiologically for the isolation of lactic acid bacteria (LAB). The LAB strains obtained were identified by conventional methods: cultural aspect, gram-staining, biochemical and sugar fermentation tests. The probiotic properties were justified with tolerance to low-pH, bile salt and sodium chloride, and the antagonistic activity of the lactobacilli against human pathogenic bacteria (
,
,
and
serovar Typhi) was assessed. Hemolytic activity and antibiotic susceptibility were determined for the lactobacilli isolates, and the cumulative probiotic potential (CPP) values were recorded.
Four lactobacilli isolates,
LMEM6,
LMEM7,
LMEM8 and
LMEM9, procured from the curd samples, survived in low-pH and high bile salt conditions, and showed growth inhibitory activity against the indicator bacteria by agar-well (zone diameter of inhibition; ZDIs: 13.67 ± 0.58-29.50 ± 2.10 mm) and agar overlay (ZDIs: 11.33 ± 0.58-35.67 ± 2.52 mm) methods; the average growth inhibitory activity of lactobacilli ranged 233.34 ± 45.54-280.56 ± 83.67 AU/mL, against the test bacterial pathogens. All the lactobacilli were non-hemolytic and sensitive to most of the test antibiotics. The CPP values of the isolated LAB were recorded as 80-100%.
The curd lactobacilli procured might be used as the valid candidates of probiotics, and bio-therapeutics against bacterial infection to humans.