Effect of co-culture with enterocinogenic E. faecium on L. monocytogenes key virulence gene expression
2016
Eleftherios H. Drosinos | Konstantinos Nikolidakis | Spiros Paramithiotis | Agni Hadjilouka
The aim of the present study was to assess the expression of key virulence genes during co-culture of <em>L. monocytogenes</em> with a bacteriocinogenic <em>E. faecium</em> strain in liquid growth medium. For that purpose, BHI broth was inoculated with 7 log CFU·mL<sup>–1</sup> <em>L. monocytogenes</em> and 4, 5 or 6 log CFU·mL<sup>–1 </sup><em>E. faecium</em>. Sampling took place after 8 and 24 h of incubation, corresponding to the maximum and minimum of enterocin production, respectively. The RNA was extracted, stabilized and expression of <em>prfA</em>, <em>sigB</em>, <em>hly</em>, <em>plcA</em>, <em>plcB</em>, <em>inlA</em>, <em>inlB</em>, <em>inlC</em> and <em>inlJ</em>, was assessed by RT-qPCR. Most of the genes were downregulated during co-culture at 5 °C. Moreover, a statistically significant effect of the inoculum level was evident in most of the cases. On the contrary, no effect on the transcription level of most of the genes was observed during co-culture at 37 °C.
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