I had a similar problem like this last year ! an oldish couple had hired a rug docter to clean there very dirty nylon carpet, as you can imagne they diddn't pre vac at all and after running the rug doctor over it they were not too pleased with the results! so they cleaned it again and again and again realy over wetting the carpet, a couple of days later there was quite a bad stensh comming from the carpet and so they asked us if we could rectify the situation ! we prevacked thoroughly, pre sprayed with an enzyme then rinsed with chemspecs one clean and for good measure we sprayed on chemspecs Antimicrobial treatment Ultrafresh, I telephoned the custy the next day and they said the foul smelling odour had completely vanished