**4. Symbioflor-2**

Symbioflor-2 is a commercial product containing six *E. coli* strains, which brings about an increase in β-defensin-2 and reduces mast cell activation [19]. Symbioflor-2 is effective in reducing symptoms of irritable bowel syndrome [34]. Microcin S is produced by Symbioflor G3/10 strain. Surprisingly, virulence genes have also been detected in Symbioflor-2 genomes suggesting that the presence of virulence genes does not imply pathogenicity [2]. Transcriptomic analysis of ileum and colon upon inoculation with Symbioflor-2 strains indicated the increase in defense responses involving dual oxidase/nitric oxide pathway mediated reactive oxygen species generation along with β-defensin-2 activity [35]. Transcription profiles were distinct with EcN and Symbioflor-2.
