Technical Abstract Search Details

Technical Abstract Details

Title Trans -cinnamaldehyde and thymol down-regulate antibiotic resistance gene expression in multidrug resistant Salmonella Typhimurium DT104 and reduce bacterial invasion of porcine intestinal epithelial cells
Presenter Anup Kollanoor Johny , Kumar S. Venkitanarayanan, Univ. of Conn., Storrs, CT
Abstract Multidrug resistant Salmonella Typhimurium DT104 is a significant foodborne pathogen with swine serving as the major reservoir host. In swine, DT104 invades the intestinal epithelium resulting in infection. Interventions that reduce host invasion of DT104 would decrease its carriage in pigs. Additionally, reducing DT104's antibiotic resistance is critical for protecting public health. We previously reported that plant molecules, trans -cinnamaldehyde, and thymol increased DT104's sensitivity to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracyline. The current study investigated the molecular mechanism by which trans -cinnamaldehyde and thymol decreased antibiotic resistance in DT104. Moreover, we determined the efficacy of trans -cinnamaldehyde and thymol for reducing DT104 invasion of porcine intestinal epithelial cells (IPEC). DT104 (6.0 log CFU) was grown to midlog phase at 37 °C in Luria Bertani broth with or without sub-inhibitory concentrations (SICs, concentrations not inhibiting bacterial growth) of trans -cinnamaldehyde (1.5 mM) and thymol (0.7 mM), and mRNA extracted. Complementary DNA was synthesized and subjected to real-time quantitative PCR (RT-qPCR) to determine the expression of genes encoding resistance to ampicillin (blaPSE), chloramphenicol (floR), streptomycin (aadA2), sulfamethoxazole (sul1), and tetracyline (tetG). For determining the effect of plant molecules on DT104 invasion of intestinal cells, invasion assay was performed using IPEC lines with a multiplicity of infection of 1:50, and invaded bacteria enumerated. The effect of trans -cinnamaldehyde and thymol on DT104 invasion genes hilA, hilD, invF, fliZ, and ygiX was also investigated using RT-qPCR. Trans -cinnamaldehyde and thymol down-regulated expression of all antibiotic resistance genes (P < 0.05). Additionally, these molecules decreased (P < 0.05) DT104 invasion of IPEC. Trans -cinnamaldehyde and thymol also down-regulated all invasion genes (P < 0.05). Trans -cinnamaldehyde and thymol reduced antibiotic resistance and host invasion of DT104 by down-regulating gene expression. Trans -cinnamaldehyde and thymol could be used to control DT104 infection in pigs, but follow-up in vivo studies are necessary.
Year/Location2011 IFT Annual Meeting, June 11 - 14, New Orleans LA
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