Inhibitory effects of lactic and malic organic acids on autoinducer type 2 (AI-2) quorum sensing of Escherichia coli O157:H7 and Salmonella Typhimurium

Abstract

Several organic acid based antimicrobials are reported to reduce bacterial populations but studies showing inhibition of autoinducer-2 (AI-2) activity or quorum sensing are limited. The effect of lactic and malic acids on autoinducer activity of selected strains of E. coli O157:H7 and Salmonella Typhimurium is tested in this study. The strains were screened for AI-2 like activity on spinach and cantaloupe homogenates using autoinducer sensing V. harveyi biosensor strains. The ED 14 strain of E. coli O157:H7 and the SD 10 strain of Salmonella showed highest AI-2 like activity of 55 and 53 Relative Light Units respectively. These two strains were used to evaluate the AI-2 inhibitory activities of lactic and malic acids at 1 to 4% concentrations (alone or in combinations). Lactic acid at 4.0% had the highest inhibition of 80% on ED 14 E. coli strain while the combination treatment of lactic acid + malic acid at 4.0% each had the highest inhibition of 80% on SD 10 Salmonella strain. Results from the study indicate that the quorum sensing ability of the E. coli O157:H7 and Salmonella Typhimurium strains can be effectively inhibited by antimicrobial organic acids.

Antiquorum sensing, antibiofilm formation and cytotoxicity activity of commonly used medicinal plants by inhabitants of Borabu sub-county, Nyamira County, Kenya

“…g ., acylated homoserine lactones and furanosyl borate diester) [ 9 , 10 ]. Marine bacterium Vibrio harveyi is commonly utilized as a bioluminescent reporter strain to detect the presence of autoinducer molecules at extremely low concentrations (< 1 nM) [ 11 ]. Multiple QS systems that impinge on the activity of a shared transcriptional regulator have also been reported in many bacterial species.…”

Quorum Sensing and the Use of Quorum Quenchers as Natural Biocides to Inhibit Sulfate-Reducing Bacteria

“…Alternatively, quorum-sensing antagonists of either natural or synthetic origin (e.g., vanillin [89], malic and lactic acids [90], or numerous biosurfactants [91]) are able to interfere with the receptor-binding process. Some of these compounds are produced by thermophiles and halophiles and hence make them suitable for application in seawater cooling tower systems and seawater injection systems.…”

Ethanol Extract of Campsis grandiflora Flower and Its Organic Acid Components Have Inhibitory Effects on Autoinducer Type 1 Quorum Sensing

“…UPLC-MS/MS results in this study revealed that organic acids are one of the principal components of CFEE. None of these organic acids have been reported to have QSI activity, except malic acid which has been reported to have inhibitory effect on AI-2 QS system of E. coli O157:H7 and S. typhimurium [ 33 ]. Our results demonstrate for the first time that malic acid and succinic acid have inhibitory effects on the AI-1 QS system of C. violaceum 026.…”