Screening, Characterization and In Vitro Evaluation of Probiotic Properties Among Lactic Acid Bacteria Through Comparative Analysis.

The present work aimed to identify probiotic
bacteria from healthy human infant faecal and dairy samples.
Subsequently, an assay was developed to evaluate the
probiotic properties using comparative genetic approach
for marker genes involved in adhesion to the intestinal
epithelial layer. Several in vitro properties including tolerance
to biological barriers (such as acid and bile),
antimicrobial spectrum, resistance to simulated digestive
fluids and cellular hydrophobicity were assessed. The
potential probiotic cultures were rapidly characterized by
morphological, physiological and molecular-based methods
[such as RFLP, ITS, RAPD and (GTG)5]. Further
analysis by 16S rDNA sequencing revealed that the
selected isolates belong to Lactobacillus, Pediococcus and
Enterococcus species. Two cultures of non-lactic, nonpathogenic
Staphylococcus spp. were also isolated. The
native isolates were able to survive under acidic, bile and
simulated intestinal conditions. In addition, these cultures
inhibited the growth of tested bacterial pathogens. Further,
no correlation was observed between hydrophobicity and
adhesion ability. Sequencing of probiotic marker genes
such as bile salt hydrolase (bsh), fibronectin-binding protein
(fbp) and mucin-binding protein (mub) for selected
isolates revealed nucleotide variation. The probiotic binding
domains were detected by several bioinformatic tools.
The approach used in the study enabled the identification of
potential probiotic domains responsible for adhesion of
bacteria to intestinal epithelial layer, which may further
assist in screening of novel probiotic bacteria. The rapid
detection of binding domains will help in revealing the
beneficial properties of the probiotic cultures. Further,
studies will be performed to develop a novel probiotic
product which will contribute in food and feed industry.