Influence of Urinary Urea Concentration on Hemolytic Activity and Cytotoxicity of Uropathogenic Morganella morganii Strain

We studied the effect of urinary urea concentration on the hemolysin production and cytotoxicity of the uropathogenic Morganella morganii strain MM 190. The highest hemolytic activity of M. morganii cultivated in urine with low urea concentration (23 and 82 mmol/liter) was observed between 3rd and 4th hours of post-inoculation, while in urine with standard urea level (117 mmol/liter), the activity was observed at 5th hour of post-inoculation. Our findings indicate a correlation between this activity and the expression of the hlyA gene. Bacterial culture fluid containing hemolysin caused the death of up to 40% of urothelial cells; cytotoxicity was more pronounced against OKP-GS kidney carcinoma cells compared to T-24 bladder carcinoma cells. Hence, in urine with higher urea concentrations, hemolytic activity of bacteria was observed at later stages of growth, and this culture fluid exhibited higher cytotoxicity.