TITLE:
Isolation and Screening of Lactic Acid Bacterial Strains with Antibacterial Properties from the Vaginas of Healthy Cows
AUTHORS:
Chao Cheng, Qiaozhen Tian, Shaofeng Su, Hui Zhang, Hongjie Guo, Pengfei Gao, Songhe Xu, Zhiguo Liu, Yanfen Ma, Zhenjun Li
KEYWORDS:
Antibacterial Properties, Cow, Lactic Acid Bacteria, SQ0048, Vagina
JOURNAL NAME:
Open Journal of Animal Sciences,
Vol.12 No.3,
June
29,
2022
ABSTRACT: In the present study, eight strains were isolated from 20 cow vagina samples and
identified using phenotype, biochemical analysis, sugar fermentation tests, and 16S rRNA sequence analysis. Among eight
strains, only SQ0048 was identified as Lactobacillus johnsonii based on a series of biochemical
testing (including the adhesion test, catalase test,
bacteriocin production test, antibacterial test, and pH value), suggesting that
its biological activity was superior to the other seven strains. Furthermore,
SQ0048 had the lowest pH value (4.32) and the shortest fermentation time (8 h)
compared with the other strains. The adhesion rate of SQ0048 was significantly
higher than that of Lactobacillus
delbrueckii, with an average adhesion number of 304 ± 2.67. The
hydrogen peroxide production testing in SQ0048 was positive; in addition,
bacteriocin gene of SQ0048, encoding an approximately 10-kDa product, was
successfully cloned, expressed, and detected using the SDS-PAGE method. Meanwhile, SQ0048 had a weak inhibitory
effect on Staphylococcus
aureus and Escherichia coli. However, the expression products
of the bacteriocin gene of SQ0048 had a very strong inhibitory effect on S. aureus and E. coli, with
inhibition zone sizes of 18 ± 0.45 mm and 15 ± 0.60 mm, respectively. These
data showed that SQ0048 has excellent antibacterial properties compared with
other isolated strains and is a potential probiotic candidate to improve the health
of the vaginas of cows by inhibiting pathogenic microorganisms.