The virulence of Enterobacter cloacae and Serratia marcescens in experimental bladder infection in diabetic mice

Diabetic mice were significantly more susceptible than normal mice to bladder infection with Enterobacter cloacae or Serratia marcescens but not to intraperitoneal infection. Normal urine inhibited the growth of E. cloacae and S. marcescens, whereas urine from diabetic mice permitted multiplication. The addition of urea to urine from diabetic mice restored its antibacterial properties for E. cloacae and S. marcescens. We consider that the decreased urea content of the urine of diabetic mice was responsible for their increased susceptibility to bacterial infection of the bladder.