[Report of three cases of purple urine bag syndrome which occurred with a combination of both E. coli and M. morganii].

Purple urine bag syndrome is a rare phenomenon in which bags turns purple or blue following catheterization. This phenomenon was reported to occur by Providencia stuartii in the presence of indicanuria. We reported herein three females above 75 years of age having a similar phenomenon. All were bedridden chronically and constipated. In these cases, no growth of P. stuartii was found on repeated urine culture, but Escherichia coli and Morganella morganii were concomitantly isolated during the blue bags. It is suggested that purple urine bag syndrome develops in a combination of E. coli and M. morganii besides P. stuartii.