This photograph depicts the colonial growth pattern displayed by the Gram-negative enteric bacterium Yersinia enterocolitica cultivated on this triple sugar iron agar (TSI) medium.
TSI is used when differentiating bacteria, primarily from the family Enterobacteriaceae, according to their ability to ferment glucose, lactose or sucrose, as well as produce hydrogen sulfide, (H2S). If a yellow coloration results (Rt), it means that there was ongoing fermentation while if a reddish color results (Lt), it means that there was no fermentation taking place.
Quelle: CDC
