AUTHOR=Zhang Guojian , Lu Miao , Liu Rongmei , Tian Yuanyuan , Vu Viet Ha , Li Yang , Liu Bao , Kushmaro Ariel , Li Yuqing , Sun Qun 

TITLE=Inhibition of Streptococcus mutans Biofilm Formation and Virulence by Lactobacillus plantarum K41 Isolated From Traditional Sichuan Pickles

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00774

DOI=10.3389/fmicb.2020.00774

ISSN=1664-302X

ABSTRACT=<p>Among cariogenic microbes, <italic>Streptococcus mutans</italic> is considered a major etiological pathogen of dental caries. <italic>Lactobacilli</italic> strains have been promoted as possible probiotic agents against <italic>S. mutans</italic>, although the inhibitory effect of <italic>Lactobacilli</italic> on caries has not yet been properly addressed. The objective of this study was to screen <italic>Lactobacillus</italic> strains found in traditional Sichuan pickles and to evaluate their antagonistic properties against <italic>S. mutans in vitro</italic> and <italic>in vivo</italic>. In the current study, we analyzed 54 <italic>Lactobacillus</italic> strains isolated from pickles and found that strain <italic>L. plantarum</italic> K41 showed the highest inhibitory effect on <italic>S. mutans</italic> growth as well as on the formation of exopolysaccharides (EPS) and biofilm <italic>in vitro</italic>. Scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM) revealed the reduction of both EPS and of the network-like structure in <italic>S. mutans</italic> biofilm when these bacteria were co-cultured with strain <italic>L. plantarum</italic> K41. Furthermore, when rats were treated with strain <italic>L. plantarum</italic> K41, there was a significant reduction in the incidence and severity of dental caries. Due to K41’s origin in a high salinity environment, it showed a high tolerance to acids and salts. This may give this strain an advantage in harsh oral conditions. Results showed that <italic>L. plantarum</italic> K41 isolated from traditional Sichuan pickles effectively inhibited <italic>S. mutans</italic> biofilm formation and thus possesses a potential inhibitory effect on dental caries <italic>in vivo</italic>.</p>