Evaluation of lactic acid bacteria from kefir, molasses and olive brine as possible probiotics based on physiological properties
A combination of eight strains comprising of Lactobacillus plantarum, Enterococcus faecium and Leuconostoc mesenteroides subsp. mesenteroides isolated from molasses, olives, beer and kefir were studied for growth at low pH and ox-bile resistance. pH neutralised cell-free supernatants from 24-h-old cultures inhibited the growth of Enterococcus faecium, Lactobacillus sakei, Lactococcus lactis subsp. lactis, Listeria innocua and Listeria ivanovii subsp. ivanovii. Good growth was recorded in MRS broth supplemented with 0.3% (w/v) ox-bile. Lactobacillus plantarum ST28MS and ST26MS, Enterococcus faecium ST311LD and Leuconostoc mesenteroides subsp. mesenteroides ST33LD grew well in the presence of 0.6% (w/v) ox-bile. All eight strains grew well in MRS broth adjusted to pH 7.0. Good growth of Enterococcus faecium ST311LD, Leuconostoc mesenteroides subsp. mesenteroides ST33LD and Lactobacillus plantarum 423 was recorded in MRS broth with an initial pH of 4.0. Auto cell-aggregation ranged from 74.3% for Lactobacillus plantarum ST23LD to 95.4% for Lactobacillus plantarum ST28MS. Different levels of co-aggregation were recorded between the eight strains and Enterococcus faecium HKLHS, Lactobacillus sakei DSM 20017, Lactococcus lactis subsp. lactis HV219, Listeria innocua LMG 13568 and UWC N27, and Listeria ivanovii subsp. ivanovii ATCC 19119. Growth of the eight strains was inhibited by several antibiotics and anti-inflammatory medicaments containing ibuprofen, hydrochlorothiaziden and thioridazine hydrochlorid. Sodium diclofenac inhibited the growth of Lactobacillus plantarum ST8KF and ST341LD, Enterococcus faecium ST311LD and Leuconostoc mesenteroides subsp. mesenteroides ST33LD. Dimenhydrinate inhibited the growth of only Lactobacillus plantarum ST8KF. Adherence to Caco-2 cells ranged from 8.0 to 1.3%. All eight strains contain the Mub, MapA and EF-Tu genes, as determined by amplification with gene-specific primers.