Adherence properties of lactic acid bacteria isolated from breast milk.

Abstract

Probiotics are live microorganism that will exert beneficial effect to the host when ingested in sufficient amounts. The ability to adhere to intestinal epithelial cells is a prerequisite for probiotic action. The aim of this study was to identify the adherence properties of nine lactic acid bacteria isolated from breast milk which are potential as probiotic (L. rhamnosus A15, Lactobacillus A27, L. rhamnosus A29, L. rhamnosus R14, L. rhamnosus R21, L. rhamnosus R23, L. rhamnosus R26, L. rhamnosus B10, L. rhamnosus B13, dan L. rhamnosus B16). This study was conducted in three stages i.e. (1) the evaluation of adherence method on mucus of broiler and rat intestine (2) the evaluation of adherence properties that consist of hydrophobicity, autoaggregation, adhesion to rat intestinal cells, and adhesion to the surface of rat intestine and (3) the competition of adhesion between LAB and EPEC which included competition, exclusion, displacement, and observation of the bacteria adherence on the surface of rat intestine used SEM. The use of rat intestine gave better result in showing the adhesion ability of LAB tested than mucus of broiler. The exposure of rat intestine in suspension of LAB raised the total number of LAB which indicated the attachment of LAB isolates while reducing the total number of E. coli which indicated competition between LAB and indigenous E. coli on the surface of rat intestine. All of nine LAB isolates tested have low autoaggregation ability due to their hydrophobicity. There were only three LAB isolates that adhered to rat intestinal cells, they were A27, B16, and R23. However, all LAB isolates adhered to the surface of rat intestine. The most adhesive LAB was A27 followed by B16, R14, and R23. The degree of adherence of LAB was strain specific and affected by the type of adherence medium. The competition test showed that the LAB isolates tested were able to compete with EPEC. The adhesion of the LAB isolates affected by the number of LAB, the higher the number of LAB the higher the number of adhering bacteria. The exclusion and displacement test showed that the LAB isolates tested were likely able to attach well on the surface of rat intestine. R23 isolate was not able to be excluded by EPEC while B16 isolate was slightly excluded. Both LAB isolates were not able to displace EPEC. The observation of adherence using SEM showed bacilliform of bacteria on the surface of rat intestine that have been incubated with LAB R14, R23, B16, and A27.