Comparative studies on the use of 5-fluorouracil in two different media as a selective agent for isolation of Leptospira.

Incorporation of 5-fluorouracil at concentrations of 100-150 mug/ml in Korthof's medium was found to be effective in inhibiting staphylococci and Escherichia coli without adversely affecting leptospiral growth when cultures were incubated at 30 degrees C or at room temperature (15-22 degrees C). No growth was detected in cultures incubated at 37 degrees C. it was concluded that Korthof's medium containing 5-fluorouracil at these concentrations forms a useful selective medium for the isolation of leptospires when incubated at appropriate temperatures.