A black colony on HE and XLD agars, isolated from a stool culture, produces the following biochemical reactions:
$\begin{array}{ll} \text {Motility at $ 25^{\circ} \mathrm{C} $ : positive}& \text {PAD: no color change}\
\text {Motility at $ 35^{\circ} \mathrm{C} $ : positive}& \text {Indole: no color change}\
\text {Urea: no color change}&\text {VP: no color change}\
\end{array}$

If this organism is a strict pathogen, you expect it to also be

Question

A black colony on HE and XLD agars, isolated from a stool culture, produces the following biochemical reactions:
$\begin{array}{ll}  \text {Motility at $ 25^{\circ} \mathrm{C} $ : positive}&  \text {PAD: no color change}\
  \text {Motility at $ 35^{\circ} \mathrm{C} $ : positive}& \text {Indole: no color change}\
  \text {Urea: no color change}&\text {VP: no color change}\
  \end{array}$

If this organism is a strict pathogen, you expect it to also be

Quizplus · Accepted Answer

Citrate utilization and lysine decarboxylation are two biochemical reactions that are often used to differentiate between different species of Enterobacteriaceae. Strict pathogens, such as Salmonella and Shigella, are typically citrate negative and lysine negative.

A Black Colony on HE and XLD Agars, Isolated from a Stool