[Carbohydrate containing media for the detection of urease in "Klebsiella"].

Sone strains of Klebsiella pneumoniae and K. oxytoca grown on nutrient agar may appear "urease negative" in a Ferguson type reagent medium after a 24 h incubation at 37 degrees C. Amongst such 147 so called urease negative strains, urease has been detected within a few hours in 79 strains, when bacteria have grown on media containing carbohydrates (Kligler iron agar, Drigalski lactose agar, SS agar and Worfel-Ferguson sucrose medium). Acid production by carbohydrate fermentation increases urease production by Klebsiella: pH 4 is the most convenient pH for urease synthesis by these bacteria. The other 68 strains have been considered as urease-less Klebsiella. The best results are obtained from culture on Worfel-Ferguson sucrose medium: urea hydrolysis is positive--on an average-after 1 hour and 30 minutes when detected in a Ferguson type reagent medium, and after 2 hours and 35 minutes when detected in a Christensen reagent medium.