Inhibiting bacterial colonization on catheters: Antibacterial and antibiofilm activities of bacteriocins from Lactobacillus plantarum SJ33.

BACKGROUND: Catheter-associated urinary tract infections are one of the most common types of hospital-acquired infections that start with bacterial adhesion and lead to biofilm formation. The antagonistic activity of lactic acid bacteria against pathogenic organisms makes them important for medical applications. OBJECTIVE: This study evaluated the precise method for purification of bacteriocin from Lactobacillus plantarum subsp. argentoratensis SJ33, and its characterization and effectiveness for biofilm inhibition on urinary catheters coated with bacteriocin. METHODS: Purification of bacteriocin was carried out using various methods such as cell adsorption-desorption, gel permeation chromatography, and hydrophobic interaction chromatography. Bacteriocin preparation was analysed using reverse-phase high-performance liquid chromatography (HPLC) and further characterised by Tricine SDS-PAGE and Q-TOF ESI MS. Antibacterial activity of bacteriocin was assessed against 16 different Gram-positive and Gram-negative bacterial strains, and their effect on morphology was observed under scanning electron microscopy (SEM). Biofilm adherence and inhibition were evaluated by crystal violet assay, fluorescence microscopy and SEM. RESULTS AND CONCLUSIONS: Bacteriocin preparation exhibited broad-spectrum activity against both Gram-positive and Gram-negative bacteria, and SEM analysis revealed membrane pore formation. On treating with various enzymes, bacteriocin was found to be sensitive to proteases, which confirmed its proteinaceous nature. Bacteriocin showed its applicability at acidic pH in the urinary tract. Antibiofilm activity of bacteriocin established its significance in catheter-associated biofilm inhibition against Pseudomonas aeruginosa and Staphylococcus aureus. Molecular weight of bacteriocins, namely Bac F1 and Bac F2 as resolved by RP-HPLC, was estimated to be 4039 Da and 1609 Da, respectively.

Molecular characterization of lactobacilli isolated from fermented idli batter

Lactic acid bacteria are non pathogenic organism widely distributed in nature typically involved in a large number of spontaneous food fermentation. The purpose of this study was to characterize the bacteriocinogenic lactobacilli from fermented idli batter which can find application in biopreservation and biomedicine. Eight most promising lactobacilli were chosen from twenty two isolates based on their spectrum of activity against other lactic acid bacteria and pathogens. The eight lactobacilli were characterized based on the various classical phenotypic tests, physiological tests and biochemical tests including various carbohydrate utilization profiles. All isolates were homo fermentative, catalase, and gelatin negative. Molecular characterization was performed by RAPD, 16S rRNA analysis, 16S ARDRA, and Multiplex PCR for species identification. RAPD was carried out using the primer R2 and M13. Five different clusters were obtained based on RAPD indicating strain level variation. 16S rRNA analysis showed 99 to 100% homology towards Lactobacillus plantarum. The restriction digestion pattern was similar for all the isolates with the restriction enzyme AluI. The subspecies were identified by performing Multiplex PCR using species specific primer. Among the five clusters, three clusters were clearly identified as Lactobacillus plantarum subsp. plantarum, Lactobacillus pentosus, and Lactobacillus plantarum subsp. argentoratensis.

Molecular characterization of lactobacilli isolated from fermented idli batter.

Lactic acid bacteria are non pathogenic organism widely distributed in nature typically involved in a large number of spontaneous food fermentation. The purpose of this study was to characterize the bacteriocinogenic lactobacilli from fermented idli batter which can find application in biopreservation and biomedicine. Eight most promising lactobacilli were chosen from twenty two isolates based on their spectrum of activity against other lactic acid bacteria and pathogens. The eight lactobacilli were characterized based on the various classical phenotypic tests, physiological tests and biochemical tests including various carbohydrate utilization profiles. All isolates were homo fermentative, catalase, and gelatin negative. Molecular characterization was performed by RAPD, 16S rRNA analysis, 16S ARDRA, and Multiplex PCR for species identification. RAPD was carried out using the primer R2 and M13. Five different clusters were obtained based on RAPD indicating strain level variation. 16S rRNA analysis showed 99 to 100% homology towards Lactobacillus plantarum. The restriction digestion pattern was similar for all the isolates with the restriction enzyme AluI. The subspecies were identified by performing Multiplex PCR using species specific primer. Among the five clusters, three clusters were clearly identified as Lactobacillus plantarum subsp. plantarum, Lactobacillus pentosus, and Lactobacillus plantarum subsp. argentoratensis.