Does E.coli affect the growth of Enterobacter aerogenes

[MARK GRAHAM]

Hi there,
            can anyone help?  I am after any information in regards to
the effects that E.coli has on the growth of Enterobacter aerogenes. 
Why?  Because in a recent experiment I found that plateing a mixed
culture of E.coli and aerogenes, using Milk Plate Count Agar and Violet
Red Bile Agar, showed that aerogenes grew in more numbers than the
E.coli, and in more numbers than if plated seperatly, without E.coli
Why?  Does aerogens inhibit the growth of E.coli?  Does E.coli secrete
something that encourages aerogenes to grow?  I hope someone out there
knows and will reply.

Thank you 
            Mark