Screening of Lactic acid bacteria isolated from piglet faeces for antimicrobial activity

摘要

Lactic acid bacteria (LAB) were isolated from 136 samples of pig faeces. The number of LAB varied from 8.03 to 8.97 log cfu/g faeces. A total of 317 lactic acid bacteria were isolated and tested for antimicrobial activities against 8 pathogenic bacterial strains using agar well diffusion technique. The inhibitory activity of most LAB was due to the production of organic acids except one isolate, WX153, which was found to produce bacteriocin-like substance. Strain WX153 was identified by using API50 CHL kit and 16S rDNA sequencing as Lactococcus lactis subsp. lactis. The production of antimicrobial substance by L. lactis subsp. lactis WX153 in MRS medium followed a growth-associated pattern. This study allowed the preliminary selection of LAB isolates with antimicrobial activity to be used as potential probiotic in pig. In addition, inhibitory compound produced by L. lactis subsp. lactis WX153 may have potential applications as bio-preservative in food industry.