Tarnhathai Malawach, Duangporn Kantachote and Wilawan Charernjiratrakul

pp. 269 - 279

Abstract

A total of 306 isolates of lactic acid bacteria were isolated from 250 samples of piglet faeces. The strains were investigated for preliminary probiotic properties based on their stability in bile salts (0.30%) and high acidity (pH 3.0). Ability to utilize protein, fat and starch, growth in the absence of vitamin B12 and
growth with both aerobic and anaerobic conditions were also considered. As a result of above criteria, 20 isolates were selected. Using an agar spot method, all isolates were able to inhibit β-hemolytic Escherichia coli 240/2 under aerobic and anaerobic condition. A further investigation using a co-culture technique
showed that only six isolates inhibited β-hemolytic E. coli 240/2, E. coli K88 and E. coli K 99 by more than 90 percent. The selected isolates were resistant to the following antibiotics: amikacin, polymyxin B and nalidixic acid; however the strains were susceptible to erythromycin and chloramphenicol. All six active
isolates were identified as Lactobacillus plantarum by API 50 CH system.

Keywords

• lactic acid bacteria
• probiotic
• Escherichia coli