Isolation of Lactococcus lactis from Whole Crop Rice and Determining Its Probiotic and Antimicrobial Properties towards Gastrointestinal Associated Bacteria

Abstract

Antimicrobial resistance is an emerging condition that increases the risk of spreading and prolonging infectious diseases globally. Therefore, a new alternative strategy for antibiotics is required urgently to control pathogens spreading. Probiotics are considered as an alternative for antibiotics that inhibit pathogens. In the present study, potent lactic acid bacteria (LAB) were isolated and screened for their probiotic characteristics and antagonistic activity against intestinal pathogens by agar well diffusion, Time and Dose-dependent killing assay, minimum inhibitor, and minimum bactericidal concentration (MIC/MBC), and co-culture methods. The Lactococcus lactis RWP-3 and RWP-7 fermented the different carbohydrate substrates and produced different extracellular enzymes. Both isolates showed significant tolerant capability in the gastric, duodenal, and intestinal juices. In addition, RWP-3 and RWP-7 had hydrophobicity and aggregation properties in a time-dependent manner. Furthermore, the cell-free secondary metabolites (CFS) of RWP-3 and RWP-7 showed strong antibacterial activity against Escherichia coli,Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis. A co-culture study revealed that the RWP-3 and RWP-7 strongly compete with pathogen growths. RWP-3 and RWP-7 showed strong antagonistic activities against tested pathogens with significant probiotic characteristics, suggesting that these strains obtained could be used as an alternative strategy for the antibiotic to control infectious pathogens.

A Novel Strain of Probiotic Leuconostoc citreum Inhibits Infection-Causing Bacterial Pathogens

“…In general, bile salts have detrimental effects that limit microbial growth. Overall, these strains gained tolerance in their stomach juice and improved their ability in subsequent unfavorable conditions, referred to as the cross-protective stress response [ 45 ], before reaching the intestinal wall and re-establishing the gut microbiome and inhibiting undesirable microbial growth [ 23 ]. Leuconostoc sp.…”

“…The whole rice plant was collected from an agriculture field in Division of Grassland and Forage, Cheonan, South Korea. The LAB were isolated using De Man Rogosa and Sharpe agar (MRS) and the identity was confirmed by bromocresol purple agar medium (BCP) [ 23 , 24 ]. APICH50 and AbiZym detection kits (MarcyI Etoile, France) were used to measure carbohydrate fermentation and extracellular enzyme production by selected strains, respectively.…”

“…Active fresh cultures (24 h) of isolated strains were tested in simulated gastrointestinal juices (gastric, duodenal and intestinal) [ 23 , 25 ]. A hydrophobicity assay was conducted [ 26 ] and the aggregation properties [ 27 ] of selected isolates were determined.…”

“…The absorbance values were then normalized with blanks [ 28 ]. The MIC and MBC were also identified [ 23 , 29 ].…”

Deciphering Azadirachta indica (Neem) Gum Microbiome using Metagenomic Approaches

“…Earlier studies have shown that Lactococcus exerts antagonistic activity against many pathogens by producing secondary metabolites. [24][25][26] Lactococcus has a high tolerance to low pH and produces different exopolysaccharides with viscous physical properties. Exopolysaccharides are stabilizing, emulsifying, and antioxidant agents that enhance the antibacterial, anticoagulant, and antioxidant activities of microbes.…”