Modulation of anti-pathogenic activity in canine-derived Lactobacillus species by carbohydrate growth substrate

Abstract

Aims:To investigate the effect of various carbon sources on the production of extracellular antagonistic compounds against two Escherichia coli strains and Salmonella enterica serotype Typhimurium by three caninederived lactobacilli strains. Methods and Materials: Cell-free preparations, pH neutralized, were used in antibiotic disc experiments as an initial screening. The bacteria/carbohydrate combinations that showed inhibition of the growth of those pathogens, were further investigated in batch co-culture experiments. The cell-free supernatants of the cultures, that decreased the population number of the pathogens in the co-culture experiments to log CFU ml )1 £ 4, were tested for inhibition of the pathogens in pure cultures at neutral and acidic pH. Conclusions:The results showed that the substrate seems to affect the production of antimicrobial compounds and this effect could not just be ascribed to the ability of the bacteria to grow in the various carbon sources. L. mucosae, L. acidophilus and L. reuteri, when grown in sugar mixtures consisting of a-glucosides (Degree of Polymerization (DP) 1-4) could produce antimicrobial compounds active against all three pathogens in vitro. This effect could not be attributed to a single ingredient of those sugar mixtures and was synergistic. This inhibition had a dose-response characteristic and was more active at acidic pH. Significance and Impact of the Study: Knowledge of the effect that the carbon source has on the production of antimicrobial compounds by gut-associated lactobacilli allows the rational design of prebiotic/probiotic combinations to combat gastrointestinal pathogens.

The effect of prebiotics on production of antimicrobial compounds, resistance to growth at low pH and in the presence of bile, and adhesion of probiotic cells to intestinal mucus

“…Increased antimicrobial activity was recorded in MRS‐D broth supplemented with 1% Raftilose ® Synergy1, which is a combination of inulin and fructo‐oligosaccharides. Similar results have been reported by Tzortzis et al. (2004).…”

“…Increased antimicrobial activity was recorded in MRS-D broth supplemented with 1% Raftilose Ò Synergy1, which is a combination of inulin and fructo-oligosaccharides. Similar results have been reported by Tzortzis et al (2004). In the latter study, an increase in antimicrobial activity was recorded when Lactobacillus mucosae, Lactobacillus acidophilus and Lactobacillus reuteri were grown in the presence of malto-oligosaccharides.…”

The Utilisation of Prebiotics and Synbiotics in Dogs

“…Furthermore, the increase in the counts of bifidobacteria was highest for the combination of GMM and L. reuteri (compared with inoculum at start, +1.3 log10 CFU/mL). During another in vitro study, Tzortzis et al (2004a) production of antimicrobial compounds by lactobacilli strains was influenced by substrate in a synergistic mode of action.…”

Effects of dietary scFOS on immunoglobulins in colostrums and milk of bitches

“…In some studies using cultural methods, faecal Bifidobacteria were reported to average 9–10 log CFU/ml (Beynen et al., 2002; Swanson et al., 2002a,b; Flickinger et al., 2003), whereas some other studies using biomolecular tools could not detect any Bifidobacteria (Greetham et al., 2002; Vanhoutte et al., 2005). In vitro , scFOS particularly stimulate the growth of Lactobacillus reuteri from canine origin and improve the antimicrobial activity of this probiotic against Escherichia coli (Tzortzis et al., 2004). Furthermore, there is increasing evidence that fermentable fibres can alter the function and the structure of the gastrointestinal tract in different species, e.g.…”