Screening and characterization of probiotic lactic acid bacteria isolated from Korean fermented foods

Abstract

To examine their potential as probiotics, acid and bile tolerance, antibiotics resistance, adhesion capacity to Caco- 2 and HT-29, and antibacterial activity, of LAB isolated from Korean fermented foods such as dongchimi, kimchi, Meju, and doenjang were assayed against foodborne pathogenic bacteria. DC 55, DC 136, DC 222, KC 117, KC 21, KC 24, KC 34, KC 43, MJ 301, MJ 54, SP 170, and SP 33 strains were resistant to acid and bile conditions. In particular, DC 55, DC 136, KC 24, KC 43, and MJ 301 strains were highly resistant to higher than 20 microg/ml concentrations of vancomycin, streptomycin sulfate, or amoxicillin, whereas, DC 222, KC 117, KC 21, KC 34, MJ 54, and SP 33 strains were susceptible to lower than 2microg/ ml concentrations of those antibiotics. The adhesion to HT-29 and Caco-2 cells varied with the strains tested in a strain-dependent manner. The highest level of adhesion was observed with DC 55, KC 21, KC 24, and MJ 301 strains, having higher than 50% of adhesion to HT-29 or Caco-2 cells. In addition, Staphylococcus aureus was the most sensitive to KC 21, showing an inhibition of about 70%, and the antibacterial activity of KC 21 against S. aureus resulted most likely from both organic acids and bacteriocin. Based on its phenotypic characteristics and utilization of various sugars, the KC 21 strain was identified as Lactobacillus plantarum.