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Technical Abstract Details

Title 204-120 Effect of <i>Lactococcus lactis</i> B633 Supernatant on Adhesion to and Invasion of Multidrug-Resistant <i>Salmonella</i> Typhimurium DT104 on Human Intestinal Epithelial Cells, and Its Antibiotic Resistance Genes
Presenter Anup Kollanoor Johny, Meera Surendran Nair, Kumar Venkitanarayanan, University of Connecticut, Storrs, CT
Abstract <i>Salmonella</i> Typhimurium DT104 (DT104) is a multidrug-resistant (MDR) foodborne pathogen. DT104 possesses resistance to at least 5 antibiotics (ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracylines), which is encoded by <i>blaP</i>, <i>floR</i>, <i>aadA2</i>, <i>sul1</i>, and <i>tetG</i> genes, respectively. DT104 could be transferred to humans through consumption or handling of contaminated foods, resulting in infections difficult to treat with antibiotics. Thus, there is a need for effective interventions to control DT104, especially its antibiotic resistance. The current study investigated the potential of culture supernatant derived from <i>Lactococcus lactis</i> B633 (LLsn) on DT104 adhesion and invasion of human intestinal epithelial cells. Further, the effect of supernatant on DT104 antibiotic resistance genes was determined. A confluent monolayer of HCT 116 (human colon carcinoma) cells grown in 24-well tissue culture plates (~106 cells/well) was inoculated with DT104 H3380 (human strain, CDC) (multiplicity of infection of 1:10), followed by the addition of 2 ml of LLsn. The samples were incubated at 37 &#176;C with 5% CO<sub>2</sub> for 2 h. DT104 populations that attached and invaded HCT 116 were enumerated. Additionally, the effect of LLsn on the expression of antibiotic resistance genes, <i>blap</i>, <i>floR</i>, <i>aadA2</i>, <i>sul1</i>, and <i>tetG</i> was investigated, using real-time quantitative PCR. LLsn significantly reduced DT104 adhesion and invasion of HCT 116 cells (P < 0.05). Moreover, it significantly down-regulated expression of all antibiotic resistance genes tested. Results suggest that <i>Lactococcus lactis</i> B633 could potentially be used to control DT104, but followup <i>in vivo</i> studies validating these results are necessary. Additional studies for identifying the anti-DT104 factor in the culture supernatant are currently underway.
Year/Location2013 IFT Annual Meeting, July 13 – 16, 2013, Chicago Illinois
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