The effect of sodium azide concentration on the recovery of enterococci from water

The ability of Slanetz and Bartley medium to recover chlorine-stressed enterococci has been studied. Results showed that chlorine injury significantly affected the ability of Slanetz and Bartley medium to recover enterococci while lower concentrations of sodium azide in the same basal medium allowed their recovery. However, reducing the concentration of sodium azide considerably reduced the specificity making it unsuitable for use in the routine examination of water. A non-azide-containing medium, Enterolert(®)-DW appeared to be able to recover injured and non-injured enterococci with similar efficiency. The data presented here suggest that further work is required to improve the recovery of chlorine-injured enterococci by Slanetz and Bartley medium.