Cell-Free Preparations of Lactobacillus acidophilus Strain La-5 and Bifidobacterium longum Strain NCC2705 Affect Virulence Gene Expression in Campylobacter jejuni

Abstract

Campylobacter spp. are among the most commonly reported bacterial causes of acute diarrheal disease in humans worldwide. Potential virulence factors include motility, chemotaxis, colonization ability, adhesion to intestinal cells, invasion and epithelial translocation, intracellular survival, and formation of toxins. Probiotic Lactobacillus and Bifidobacterium strains are known to have an inhibitory effect against the growth of various foodborne pathogens. The objective of this study was to investigate the effect of Lactobacillus acidophilus strain La-5 and Bifidobacterium longum strain NCC2705 cell-free spent media (CFSM) on the expression of virulence genes (cadF, cdtB, flaA, and ciaB) of Campylobacter jejuni strain 81-176 and a luxS mutant, using real-time PCR. Our results demonstrated that the CFSM of both probiotic strains were able to down-regulate the expression of ciaB (ratio of -2.80 and -5.51, respectively) and flaA (ratio of -7.00 and -5.13, respectively) in the wild-type Campylobacter strain. In the luxS mutant, where the activated methyl cycle is disrupted, only the ciaB gene (ratio -7.21) was repressed in the presence of La-5 CFSM. A supplementation of homocysteine to restore the disrupted cycle was able to partially reestablish the probiotic effect of both strains. luxS and the activated methyl cycle might play an active role in the modulation of virulence of C. jejuni by probiotic extracts.

The Microbial Lipopeptide Paenibacterin Disrupts Desiccation Resistance in Salmonella enterica Serovars Tennessee and Eimsbuettel

“…RNA was extracted using a commercial kit (RNeasy minikit; Qiagen) according to the manufacturer's instructions. After RNA extraction, residual DNA elimination and RNA cleanup were performed using DNase enzyme (DNase I; Roche Applied Science, Indianapolis, IN, USA) and a cleanup kit (Qiagen) as described previously (31). The purified RNA was used immediately for reverse transcription using a reverse transcription kit (High-Capacity cDNA; Applied Biosystems, Grand Island, NY, USA) in a thermocycler (GeneAmp 2400 PCR; Applied Biosystems) according to the manufacturer's instructions.…”

Lactobacillus acidophilus modulates the virulence of Clostridium difficile

“…In addition, single and combinations of probiotics have been shown to effectively inhibit pathogens (Chapman et al, 2012). It has been reported by other workers that L. acidophilus strains inhibit QS and thereby affect virulence of E. coli O157:H7 (Medellin-Peña et al, 2007;Kim et al, 2012;Zeinhom et al, 2012) and Campylobacter (Mundi et al, 2013). Epigallocatechin gallate, a major catechin compound found in tea extracts, attenuates the virulence phenotypes and the gene expression regulated by QS in E. coli O157:H7 (Lee et al, 2009).…”

“…Some evidence exists that the expression of the locus of the enterocyte effacement (LEE) pathogenicity island in E. coli O157:H7 is downregulated by probiotics, and this may be mediated by the interference of the AI-2 autoinducer signaling system (Medellin-Peña et al, 2007). Lactobacillus acidophilus and bifidobacteria also exert antagonistic effects on the growth of pathogens such as Staphylococcus aureus, Salmonella Typhimurium, Yersinia enterocolitica, C. perfringens, E. coli O157:H7, and Campylobacter (Zeinhom et al, 2012;Mundi et al, 2013). Lactobacillus acidophilus GP1B stain is an intestinal isolate from swine and known to tolerate acid, assimilate cholesterol, and produce a thermostable bacteriocin (Han et al, 2007).…”

Research Progress of Gamma-Aminobutyric Acid(GABA)

“…It can effectively remove aflatoxins in dairy products [31]. LAB application technology to become the focus, such as genetic engineering lactic acid bacteria, lactic acid bacteria production enzyme, lactic acid bacteria preparation, starch embedding preparation of microcapsule lactic acid bacteria, selenium-enriched lactic acid bacteria and so on [32][33][34][35][36].Tamura [37] screened a lactic acid bacteria(Enterococcus avium G-15) has a high GABA conversion capability, the conversion rate reached (86.0 ± 5.0)%. Liang [1] isolated the strain from pickled cabbage juice using lactic acid bacteria isolation medium, he obtained strain (Lp-Lw-131) after re-screening and it had better ability to produce GABA.…”