Isolation of enteric pathogens from stool using selective media

Selective media used in the isolation of enteric pathogens from stool. On each plate, Shigella is indicated by the arrowhead and Escherichia coli by the arrow; all three media differentiate lactose fermenting from nonlactose fermenting organisms by pH sensitive dyes. Panel A: MacConkey agar; panel B: Hektoen enteric agar; and panel C: Xylose lysine deoxycholate agar.