Quorum Sensing and Production of Autoinducer-2 in Campylobacter spp., Escherichia coli O157:H7, and Salmonella enterica Serovar Typhimurium in Foods

Abstract

Autoinducer molecules are utilized by gram-negative and gram-positive bacteria to regulate density-dependent gene expression by a mechanism known as quorum sensing. PCR and DNA sequencing results showed that Campylobacter jejuni and Campylobacter coli possessed luxS, which is responsible for autoinducer-2 (AI-2) production. Using a Vibrio harveyi luminescence assay, the production of AI-2 was observed in milk, chicken broth, and brucella broth by C. coli, C. jejuni, Salmonella enterica serovar Typhimurium, and Escherichia coli O157:H7 under different conditions.

Critical Role of LuxS in the Virulence of Campylobacter jejuni in a Guinea Pig Model of Abortion

“…AI-2 is synthesized as a byproduct of the LuxS enzyme, a key enzyme in the activated methyl cycle of bacteria, where it is responsible for converting S-ribosylhomocysteine into homocysteine (36). It is known that C. jejuni produces functional AI-2 and that mutagenesis of the luxS gene results in decreases in motility, agglutination, cytolethal distending toxin production, and chicken colonization (10,13,26,27,39). Certain C. jejuni strains have a unique affinity for the uteroplacental unit in pregnant livestock and are known to be an important cause of abortions in ruminants (1,6,42).…”

Autoinducer-2 Production in Campylobacter jejuni Contributes to Chicken Colonization

“…AI-2 production was demonstrated to regulate swarming motility (8,12,15), autoagglutination (9,15), biofilm formation (29), sensitivity to hydrogen peroxide (12), and the transcription of the cytolethal distending toxin genes (cdtABC) (16). Recently, AI-2 was detected in chicken broth and milk, demonstrating the production of this molecule in the food environment (6). In the present study, a luxS mutation in C. jejuni strain 81-176 was characterized to further understand the contribution of AI-2 production on the colonization of the chicken host and interactions with chicken epithelial cells.…”

Quorum sensing dependent phenotypes and their molecular mechanisms inCampylobacterales

“…[31,33,34], but LuxS or AI-2 activity was not detectable in C. lari, C. peloridis and C. insulaenigrae strains [31,34]. For C. jejuni it has been demonstrated that the AI-2 level increases in the supernatant during late exponential growth phase and diminishes during entry into stationary phase Table 1.…”

“…For C. jejuni it has been demonstrated that the AI-2 level increases in the supernatant during late exponential growth phase and diminishes during entry into stationary phase Table 1. Continued [33,35]. AI-2 is produced by Campylobacter in different food matrices at various temperatures [33] and expression of luxS is up-regulated by cultivation in chicken juice at 5 °C [36].…”

“…Continued [33,35]. AI-2 is produced by Campylobacter in different food matrices at various temperatures [33] and expression of luxS is up-regulated by cultivation in chicken juice at 5 °C [36]. Furthermore, the expression of luxS is negatively regulated by CosR (the campylobacter oxidative stress regulator, cj.0355c) at 42 °C [37].…”