EVALUATION OF ADHESIVE AND AGGREGATION PROPERTIES OF LACTIC ACID BACTERIA ISOLATED FROM DIFFERENT BIOTOPES

Abstract

The objective of this study were fifty strains of seven lactic acid bacteria (LAB) species (L. paracasei, L. casei, L. rhamnosus, L. plantarum, L. fermentum, L. delbrueckii subsp. bulgaricus and L. koreensis), previously isolated from various biotopes (human breast milk, newborn feces, and fermented vegetables). As part of their probiotic potential, their ability for adhesion, biofilm / anti-biofilm formation, auto-aggregation and co-aggregation with different pathogenic species were evaluated.
Based on their capacity to form biofilm, strains were grouped as poor (34 %), moderate (33 %), and strong (33 %) biofilm forming bacteria (BFB). L. fermentum 18V, showed the strongest biofilm formation ability and 70 % anti-biofilm activity against P. aeruginosa. The auto-aggregation capability of LAB ranged from 12 % to 68 %. The highest auto-aggregation (85 %) was established for L. fermentum 12V and L. casei 8V (78 %). The best co-aggregation ability with all tested pathogenic species was demonstrate by L. casei 8V. The highest percentage (85 %) of co-aggregation was determined for L. paracasei strain 29V with L. innocua. The housekeeping genes (ef-Tu, eno, gap, groEl, and srtA) involved in binding mechanisms shown 100 % presence in all of the tested strains. The great ability to adhere to mucin was determined for L. koreensis 35V (1. 9 x 106 CFU mL-1). The degree of adhesion varies both between individual species and between strains belonging to the same species. The obtained results showed that the LAB possess strain- and species-specifically probiotic properties with potential  applications in the food industry.