The adhesion of putative probiotic lactobacilli to cultured epithelial cells and porcine intestinal mucus

Abstract

Aims: To investigate the adhesion of lactobacilli and their subsequent competitive exclusion ability against pathogens. Methods and Results: Four species of putative probiotic lactobacilli were studied for their adhesion abilities. First, the adhesion to Caco‐2 cells was examined by light and electron microscopy. The four species were then labelled by [methyl‐3H] thymidine and their adhesion to porcine intestinal mucus was determined by radioactivity. The tested lactobacilli showed best adhesion on ileal mucus compared with duodenal and jujenal mucus. Oxidative compound pre‐treatment (NaIO3 and NaIO4) dramatically decreased the adhesion of the lactobacilli to mucus. Pre‐treating mucus with proteolytic enzymes (proteinase K and trypsin) resulted in the increase of adhesion in Lactobacillus serotype Reuteri I2021, but the results in the other species were variable. Lactobacillus serotype Fermentum I5007 showed greatest adhesion potential and exerted the best competitive exclusion against Salmonella and Escherichia. Conclusions: Adhesion ability in lactobacilli is species‐specific. Lactobacilli with higher adhesion index have better competitive exclusion ability. Significance and Impact of the Study: This study suggests that there is a positive correlation between adhesion and competitive exclusion ability of lactobacilli. Additionally, the in vitro adhesion assay is a feasible way to screen unknown lactobacilli, potentially for future industrial applications.

Salmonella biofilms: An overview on occurrence, structure, regulation and eradication

“…Remarkably, SL1344 was also the strain used by Brown et al to initially determine the role of mlrA and they did not notice any matrix production defects in wild-type SL1344 cells. This discrepancy can be explained by the fact that strain isolates from different laboratories might show different stages of domestication (Davidson et al, 2008;Li, Yue, Guan, & Qiao, 2008). In this context, White and Surette hypothesized that the high prevalence of trans-regulatory mutations in the SARC16 isolates might also be the result of domestication .…”

Analysis of biofilm formation by intestinal lactobacilli

“…To study the process of adhesion, a variety of methods for the quantitative measurement of adhesion, such as quantitative culturing, radioactive labelling, fluorescence in situ hybridization (FISH) (Bernet et al 1993;Mack et al 1999;Mare et al 2006), or in vitro model systems, e.g., immobilized mucus models and cell-culture models (Tuomola and Salminen 1998;Jonsson et al 2001;Li et al 2008), have been developed. However, most studies show that probiotic lactobacilli do not permanently colonize the GIT and are beneficial to the hosts only for a brief period after they have stopped being administered (Tannock et al 2000;Garrido et al 2005).…”

Crystal Structure of a Mucus-binding Protein Repeat Reveals an Unexpected Functional Immunoglobulin Binding Activity

“…They are commonly used as probiotics, which are defined by the Food and Agriculture Organization/World Health Organization as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host (9). As probiotic agents, lactobacilli can prevent or alleviate infectious diarrhea through their effects on the immune system and promote host resistance to colonization by pathogens (10,11), and many have been shown to adhere to intestinal mucus (12)(13)(14)(15)(16)(17)(18)(19). Confirmation of this lactobacillus-mucus association has not only been observed in vitro, but has also been validated by ex vivo/in vivo microscopic analysis of biopsy samples (20,21).…”