from indigenous fermented foods and human gut ... - Thapar University

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Chapter IV: Results
Fig. 4.5 Scoring system for the coaggregation assay. Organisms used to illustrate the
different scores were S. typhimurium ATCC 19585 together with L. casei LAM-1. (A): S.
typhimurium ATCC 19585 together with L. casei LAM-1, (B): L. casei LAM-1 together
with E. coli 0517: H7, (C): L. monocytogenes together with L. casei LAM-1 and (D): L.
casei LAM-1 together with S. aureus. Photographs were taken on a microscope (200 x
magnification).
In that way, L. casei LAM-1 reached the highest score (4) in co-aggregation with
these foodborne pathogen strains. L. fermentum co-aggregated with S. typhimurium with a
score of 3 (Table 4.20). After Gram staining, it was verified by light microscopy that
aggregates comprised of Gram-positive as well as Gram-negative bacteria.
4.8.4 Adhesion of Lactobacillus strains to Caco2 cells
The probiotic Lactobacillus strains were investigated for their ability to adhere to the
human intestinal epithelial CaCo2 cells. L. casei (LAM-1) posses high adhesion. Gram
staining of the slides enabled adherent bacterial strains to be clearly visible as dark purple
rods on a pale pink cell background (Fig. 4.6).
L. casei LAM-1 was characterised as non-adhesive wheras L. delbruckeii, showed moderate
adherence. Interestingly, the L. casei LAM-1 and LAM-2 isolated from mango pickle showed
a much higher adhesive index.