The effect of Lactobacillus spp. on the attachment of enterotoxigenic Escherichia coli to isolated porcine enterocytes

Abstract

A total of 43 strains of lactobacilli were isolated from the gastrointestinal tract of piglets at the time of weaning. Isolates, grown on solid media, were allocated to strongly adherent or non/weakly adherent groups on the basis of numbers attaching to isolated porcine enterocytes. Strains of Lactobacillus fermentum were disproportionally represented amongst the strongly-adherent strains and Lact. acidophilus and Lact. salivarius amongst the non/weakly-adherent group. Lactobacilli showed significantly better attachment ability when grown on agar than when grown in broth culture. Strongly adherent strains were not found to effect the attachment of enterotoxigenic Escherichia coli to porcine enterocytes, tested under the conditions of exclusion (lactobacilli added to the enterocytes before E. coli), competition (lactobacilli and E. coli added simultaneously) and displacement (E. coli added before lactobacilli). Tests were made with [14C]-labelled E. coli. Suspensions of bacteria and enterocytes were passed through a filter selected to retain enterocytes but pass free bacterial cells. Counts (dpm) obtained from filters after solubilization were taken as a measure of E. coli attachment. Some strains of lactobacilli coaggregated with enterotoxigenic E. coli with K88 fimbriae, but not with a K88-negative mutants strain. These were excluded from the competitive exclusion experiments. In the apparent absence of a direct effect on the association of E. coli with host tissue, removal of potential gut pathogens by aggregation could contribute to the probiotic properties ascribed to lactic acid bacteria.

Alternative for improving gut microbiota: use of Jerusalem artichoke and probiotics in diet of weaned piglets

“…The results have shown that such combination could reduce levels of enteric pathogens in fecal samples compared with the control group, because Jerusalem artichoke with probiotics supplementation has successfully increased the population of LAB and decreased the counts of Enterobacteriacea and, ecpecially, the number of E.coli in fecal samples of pigs. Several studies in vitro in pigs found that Lactobacilli can compete with pathogens for adhesion sites in the gut (Spenser and Chesson 1994), however in our study difference of microbial counts between groups fed Lactobacillus and Pediococcus were not seen. The most signifficant reduction of enteric bacteria was observed in T3 group piglets, that indicated the synergistic effect of probiotics.…”

In vitro evaluation of adhesion and aggregation abilities of four potential probiotic strains isolated from guppy (Poecilia reticulata)

“…Coaggregation between the native bacteria and pathogens has been considered as a way to exclude thepathogenic bacteria from their hosts (Spencer and Chesson 1994). It has been suggested that inhibitor producing LAB, which coaggregate with pathogens, may constitute an important host defence mechanism against infection in the urogenital tract (Reid et al 1988) and in gastrointestinal tract (Spencer and Chesson 1994). Coaggregation with potentially gut pathogens could, therefore, contribute to the probiotic properties ascribed to LAB.…”

“…To quantify interbacterial adherence, a coaggregation assay was developed, which established coaggregation between the selected probiotic strains and five indicator strains. Coaggregation between the native bacteria and pathogens has been considered as a way to exclude thepathogenic bacteria from their hosts (Spencer and Chesson 1994). It has been suggested that inhibitor producing LAB, which coaggregate with pathogens, may constitute an important host defence mechanism against infection in the urogenital tract (Reid et al 1988) and in gastrointestinal tract (Spencer and Chesson 1994).…”

Potencial bioterapêutico dos probióticos nas parasitoses intestinais

“…Dessa forma, há relatos de que algumas cepas de Lactobacillus são capazes de inibir in vitro a adesão de Escherichia coli enteropatogênica aos enterócitos de suínos (SPENCER & CHESSON, 1994) e de Clostridium perfringens e de Campylobacter jejuni ao muco intestinal de cães (RINKINEN et al, 2003).…”

“…Pesquisas realizadas no Brasil (BARRETO et al, 2000) e em outros países (LIPNER et al, 2006) revelam que a incidência, prevalência e intensidade de infecção por ancilostomídeos são menores em crianças vacinadas com BCG (Bacilo-Calmette-Guerin) que nas não-vacinadas. Corroborando essas observações, ensaios in vivo realizados com camundongos experimentalmente infectados com Schistosoma mansoni (TEIXEIRA et al, 1996) mostraram que o número de vermes adultos recuperados de animais previamente inoculados com Corynebacteriun parvum era menor que o dos animais controles e também dos que foram inoculados com a bactéria após a infecção pelo verme.…”