A 48-hour culture of a finger lesion biopsy from a veterinarian produced small, slightly alpha-hemolytic colonies on BAP. The Gram stain revealed short grampositive rods.
Biochemical reactions included:
$\begin{array}{lrr} \text {Catalase: no bubbles }& \text {Nonmotile}& \text { Vancomycin: resistant}\end{array}$
TSI: no change except for blackening along the line of inoculation
What is the most likely identification of this organism?

Question

Quizplus · Accepted Answer

The organism is most likely Erysipelothrix rhusiopathiae, as indicated by the characteristics of being a short, gram-positive rod, catalase-negative, nonmotile, vancomycin-resistant, and causing blackening along the line of inoculation in TSI, which are consistent with the known properties of Erysipelothrix rhusiopathiae.

A 48-Hour Culture of a Finger Lesion Biopsy from a Veterinarian