cell growth and colorimetric assay - (Feb/13/2007 )

Hi,

I realise some infection and I want to see the effect of the infection on cell growth. I can't use MTT assay because my bacteria react also with MTT. I try also neutral red and crystal violet.
Is anyone know an other colorimetric assay to observe the cell growth but who can't interact with bacteria gram+???

Thanks for your help

biofred