Sequencing of amplified 16S rRNA
The amplified 16S rRNA were purified by using a QIAquick
PCR purification kit (Qiagen, Hilden, Germany) according
to the manufacturer’s instructions and then sequenced by
a Korean sequencing company (Macrogene). The isolates
were then identified and discriminated by blasting their
sequences with BLAST software (http://blast.ncbi.nlm.
nih.gov/Blast.cgi). The strains were then compared with the
sequences deposited in NCBI and GenBank.
Low pH and high concentrations of bile salts
tolerance tests
Bacterial stocks were incubated in 5 mL of MRS growth
medium at 37°C for 24 h. Then, 200 lL of bacterial
media were incubated in 5 mL of fresh medium for
another 24 h. Bacterial cells were suspended by centrifuging
at 2000g for 15 min and then washed twice with PBS
(Phosphate-buffered saline). Thereafter, the cells were resuspended
in adjusted PBS (1 mL) with pH 2.5 or mediaTHIO
(thioglycollate media) broth (37°C) for 3 h. The
media-THIO broth was prepared by mixing MRS broth
with 0.3% (w/v) oxgall and 0.2% (w/v) sodium thioglycollate
(Sigma, St. Louis, MO, USA). The resistant cells
were isolated, and their survival rates were calculated by
using the pour plate technique in agar media; the