Antibacterial and antibiofilm potential of Lacticaseibacillus rhamnosus YT and its cell-surface extract.

Foodborne pathogens and spoilage bacteria survived in the biofilm pose a serious threat to food safety and human health. It is urgent to find safe and effective methods to control the planktonic bacteria as well as the biofilm formation. Substances with antibacterial and antibiofilm activity found in lactic acid bacteria were mainly metabolites secreted in the cell-free supernatant. Previously, Lacticaseibacillus rhamnosus YT was isolated because its cell pellets displayed distinguished antibacterial activity under neutral conditions. This study aimed to investigate the antibacterial and antibiofilm properties of the L. rhamnosus YT cells and its crude cell-surface extract. The antibacterial activity of the L. rhamnosus YT cells constantly increased with cells growth and reached the peak value after the cells grew into stationary phase. After cocultivation with the L. rhamnosus YT cells, the biofilm formation of B. subtilis and S. enterica was reduced. The antibacterial activity of the L. rhamnosus YT cells was varied along with various culture conditions (carbon sources, nitrogen sources, medium pH and cultural temperatures) and the antibacterial intensity (antibacterial activity per cell) was disproportional to the biomass. Furthermore, the cell-surface extract was isolated and displayed broad antimicrobial spectrum with a bacteriostatic mode of action. The antibiofilm activity of the extract was concentration-dependent. In addition, the extract was stable to physicochemical treatments (heat, pH and protease). The extract performed favorable emulsifying property which could reduce the water surface tension from 72.708 mN/m to 51.011 mN/m and the critical micelle concentration (CMC) value was 6.88 mg/mL. Besides, the extract was also able to emulsify hydrocarbon substrates with the emulsification, index (E24) ranged from 38.55% (for n-hexane) to 53.78% (for xylene). The E24 for xylene/extract emulsion was merely decreased by 5.77% after standing for 120 h. The main components of the extract were polysaccharide (684.63 μg/mL) and protein (120.79 μg/mL). The properties of the extract indicated that it might be a kind of biosurfactant. These data suggested that L. rhamnosus YT and the cell-surface extract could be used as an alternative antimicrobial and antibiofilm agent against foodborne pathogens and spoilage bacteria in food industry.

Guan C ，Zhang W ，Su J ，Li F ，Chen D ，Chen X ，Huang Y ，Gu R ，Zhang C ... -  《BMC MICROBIOLOGY》

Isolation, Identification and Antibacterial Characteristics of Lacticaseibacillus rhamnosus YT.

Guan C ，Li F ，Yu P ，Chen X ，Yin Y ，Chen D ，Gu R ，Zhang C ，Pang B ... -  《Foods》

Inhibition of Bacterial Adhesion and Antibiofilm Activities of a Glycolipid Biosurfactant from Lactobacillus rhamnosus with Its Physicochemical and Functional Properties.

Patel M ，Siddiqui AJ ，Hamadou WS ，Surti M ，Awadelkareem AM ，Ashraf SA ，Alreshidi M ，Snoussi M ，Rizvi SMD ，Bardakci F ，Jamal A ，Sachidanandan M ，Adnan M ... -  《Antibiotics-Basel》

Strong Activity and No Resistance Induction Exerted by Cell-Free Supernatants from Lacticaseibacillus rhamnosus against Mono-Species and Dual-Species Biofilms of Wound Pathogens in In Vivo-like Conditions.

Kaya E ，Bianchi M ，Maisetta G ，Esin S ，Batoni G ... -  《-》

Polysaccharides of Weissella cibaria Act as a Prebiotic to Enhance the Probiotic Potential of Lactobacillus rhamnosus.

This work aimed to investigate the effect of EPS (extracellular polysaccharide) of Weissella cibaria as a prebiotic to promote the growth and antibacterial properties of Lactobacillus rhamnosus. The morphological, growth behavior, and antibacterial properties of L. rhamnosus were determined in MRSB (de Man Rogosa Sharpe broth) supplemented with different concentrations of EPS (0.1-2%). The results revealed that the incorporation of the EPS (2%) in MRSA improved the bacterial growth in terms of colony-forming unit (CFU, 0.7 × 105 CFU/mL) compared to L. rhamnosus grown in bare MRSA. The SEM observation revealed that EPS incorporation in the MRSB culture media does not affect the morphological properties of L. rhamnosus. Moreover, it was confirmed that the extract of probiotics cultured in MRSA supplemented with EPS (2%) was exhibited strong antibacterial and antibiofilm activity against targeted pathogens. This L. rhamnosus extract was found to be biocompatible evidanced by erythrocyte hemolysis assay. These results confirmed that EPS regulates the growth of probiotics, resists pathogen infection, and biocompatibility.

Park S ，Saravanakumar K ，Sathiyaseelan A ，Han KS ，Lee J ，Wang MH ... -  《-》