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Title 204-116 Effect of Probiotic Supernatants on Adhesion to and Invasion of <i>Salmonella</i> Heidelberg Isolates on Avian Abdominal Epithelial Cells, and Virulence and Antibiotic Resistance Genes
Presenter Anup Kollanoor Johny, Meera Surendran Nair, Kumar Venkitanarayanan, University of Connecticut, Storrs, CT
Abstract <i>Salmonella</i> Heidelberg (SH) is one of the top five <i>Salmonella</i> serotypes associated with human Salmonellosis. Recent reports suggest that the pathogen is frequently isolated from poultry, including turkey, thereby resulting in foodborne disease outbreaks. Apart from its reported virulence, resistance to multiple antibiotics has been increasingly observed in SH. The current study investigated the potential of supernatant derived from two probiotic bacterial strains, namely <i>Lactobacillus reuteri</i> B14172 (LRsn) and <i>Lactococcus lactis</i> B633 (LLsn), on SH adhesion to and invasion of avian abdominal epithelial cells. Further, the effect of supernatants on the expression of virulence and antibiotic resistance genes was determined. Three different SH isolates (ATCC, Egg and turkey outbreak isolates) were used in the study. A confluent monolayer of BAT (budgerigar avian abdominal tumor) cells grown in 24-well tissue culture plates (~10<sup>6</sup> cells/well) were inoculated with each SH isolate (multiplicity of infection of 1:50), followed by the addition of 2 ml of LRsn or LLsn. The samples were incubated at 37 &#176;C with 5% CO<sub>2</sub> for 2 h. SH population that attached and invaded BAT was enumerated using gentamicin protection assay. Additionally, the effect of LRsn and LLsn on the expression of SH virulence genes <i>hilA</i>, and <i>fliZ</i>, and antibiotic resistance genes, <i>blap</i>, <i>floR</i>, and <i>aadA2</i> was investigated using real-time quantitative PCR. The supernatant from LBsn and LLsn significantly reduced SH adhesion to and invasion of BAT cells (P < 0.05). Moreover, the culture supernatants down-regulated the expression of antibiotic resistance and virulence genes in SH. Results of this study suggest that LBsn and LLsn could potentially be used to control SH, but follow up <i>in vivo</i> studies are necessary. Mechanistic studies for identifying the anti-<i>Salmonella</i> factor in the probiotic culture supernatants are currently underway in our laboratory.
Year/Location2013 IFT Annual Meeting, July 13 – 16, 2013, Chicago Illinois
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