Pus collected from a draining axillary lymph node is sent to the laboratory. A gramnegative rod is observed on Gram stain. Twenty-four hours after incubation at 35°C in CO2, a poorly growing non-lactose fermenter is observed. After 48 hours, the colonies on BAP and MAC were slightly larger. The organism proved to be

$\begin{array}{ll} \text {Motility at $ 35^{\circ} \mathrm{C} $ : negative}& \text {Urea: no color change}\
\text {Motility at $ 25^{\circ} \mathrm{C} $ : negative}& \text {PAD: no color change}\
\text {VP: no color change}&\text {Lysine and Ornithine: no color change}\
\text {Indole: no color change}&\text {TSI: red slant and yellow butt}\\end{array}$

Citrate: green
This organism is the causative agent of

Question

Pus collected from a draining axillary lymph node is sent to the laboratory. A gramnegative rod is observed on Gram stain. Twenty-four hours after incubation at 35°C in CO2, a poorly growing non-lactose fermenter is observed. After 48 hours, the colonies on BAP and MAC were slightly larger. The organism proved to be

$\begin{array}{ll}  \text {Motility at $ 35^{\circ} \mathrm{C} $ : negative}&  \text {Urea: no color change}\
  \text {Motility at $ 25^{\circ} \mathrm{C} $ : negative}& \text {PAD: no color change}\
  \text {VP: no color change}&\text {Lysine and Ornithine: no color change}\
  \text {Indole: no color change}&\text {TSI: red slant and yellow butt}\\end{array}$

Citrate: green
This organism is the causative agent of

Quizplus · Accepted Answer

The organism's characteristics, including being a gram-negative rod, non-lactose fermenter, and the TSI results of a red slant and yellow butt, along with the clinical presentation of a draining axillary lymph node, are consistent with Yersinia pestis, the causative agent of plague.

Pus Collected from a Draining Axillary Lymph Node Is Sent