Competition of Lactobacillus paracasei with Salmonella enterica for Adhesion to Caco‐2 Cells

Abstract

Competition of commensal and probiotic bacteria with pathogens for adhesion and colonization is one of the important protective mechanisms of gastrointestinal tract. In this study, we examined the ability of Lactobacillus paracasei to inhibit the adhesion of pathogenic Salmonella enterica to human colon adenocarcinoma Caco-2 cells. Caco-2 cells were grown for 6 or 21 days to obtain nondifferentiated or well-differentiated cells, respectively. In adhesion experiments, bacteria were added to the cells for 2 or 4 hours. The number of attached bacteria was expressed as colony-forming units (CFUs), Caco-2 cells were counted in hematocytometer. Both bacterial strains used adhered better to well-differentiated than to nondifferentiated Caco-2 cells, however, the amount of Salmonella adhered to Caco-2 after 2 hours of contact was 12-fold higher in comparison to L. paracasei and almost 27-fold higher after 4 hours of contact. Two types of experiments were done: coincubation (both bacteria were added to Caco-2 cells simultaneously), and preincubation (L. paracasei was incubated with Caco-2 cells first, and then S. enterica was added). In coincubation experiment, the presence of L. paracasei decreased S. enterica adhesion by 4-fold and in preincubation experiment even 7-fold. Generally, Lactobacillus spent culture supernatants (SCSs) acted weaker as inhibitors of Salmonella adhesion in comparison to the whole L. paracasei culture in coincubation experiment. In conclusion, the displacement of pathogens by lactic acid bacteria and its secretions showed here depends on the time of bacteria-epithelial cell contact, and also on the stage of Caco-2 differentiation.

Three New Lactobacillus plantarum Strains in the Probiotic Toolbox against Gut Pathogen Salmonella enterica Serotype Typhimurium

“…10 3 CFU/ well) than the number of Salmonella alone (approx. 10 5 CFU per well) Jankowska et al (43) have shown that the presence of L. paracasei aff ected S. enterica adhesion to Caco-2 cells (4--fold reduction), but the anti-adhesion activity was even more pronounced (8-fold) when L. paracasei was preincubated with Caco-2 cells prior to Salmonella addition. In the same study, Lactobacillus spent culture supernatants (SCS) acted as weaker inhibitors of Salmonella adhesion.…”

Isolation of Endohyphal Bacteria from Foliar Ascomycota and In Vitro Establishment of Their Symbiotic Associations

“…Each plug was separately blended in three 5-s, high-speed pulses in a sterile blender (Waring 51BL31) in 100 ml of 1ϫ potato dextrose broth (PDB) and then transferred to a sterile flask and incubated on a rotary shaker at 27°C and 100 rpm for 7 days. Mycelium was collected via vacuum filtration onto sterile 8-m Whatman filter papers, washed twice with sterile 10 mM MgCl 2 (32,33), removed from the filter papers with forceps under sterile conditions, resuspended in 100 ml of 1ϫ PDB, and blended as before.…”

In vitro inhibition of Pseudomonas aeruginosa adhesion by Xylitol

“…Currently, xylitol's application has increased in the pharmaceutical, food industries, dental and clinical areas, being used as sweetener, excipient to pharmaceutical production, anticariogenic substance, osteoporosis combatant , acute otitis media and other pathologies (Mussatto and Roberto, 2002;Berlinck and Lima, 2003;Pereira et al, 2009;Silva, 2010). The pathogenic bacteria adherence hosting tissue is an essential process for these microorganisms' survival and colonization; it also represents a fundamental important stage in most infectious processes (Jankowska et al, 2008;Silva, 2010). In several cases, pathogenic bacteria adhesion is mediated by fimbriae which are present on the microorganism's surface and bind to carbohydrates on the host tissue surface (Sharon, 2006).…”