The direct Gram stain of an anaerobic wound culture reveals gram-positive cocci in clusters. The aerobic agar plates show no growth, while a small white colony grows on the reducible blood agar plate. The organism provides the following reactions:
$\begin{array}{lrr}\text {Vancomycin $ (5 \mu \mathrm{g}): 15 \mathrm{~mm} $ }&\text {Indole: no color change}\
\text {Colisitin $ (10 \mu \mathrm{g}): 2 \mathrm{~mm} $}&\text { Nitrate: red after zinc}\
\text {$ 15 \% $ Catalase: no bubbles}&\text { Esculin: negative}\end{array}$

SPS disk: 3 mm
The organism is

Question

The direct Gram stain of an anaerobic wound culture reveals gram-positive cocci in clusters. The aerobic agar plates show no growth, while a small white colony grows on the reducible blood agar plate. The organism provides the following reactions:
$\begin{array}{lrr}\text {Vancomycin $ (5 \mu \mathrm{g}): 15 \mathrm{~mm} $ }&\text {Indole: no color change}\
\text {Colisitin $ (10 \mu \mathrm{g}): 2 \mathrm{~mm}  $}&\text { Nitrate: red after zinc}\
\text {$ 15 \% $ Catalase: no bubbles}&\text { Esculin: negative}\end{array}$

SPS disk: 3 mm
The organism is

Quizplus · Accepted Answer

The organism is likely Fingoldia magna, which is a gram-positive anaerobic cocci that grows in clusters and is resistant to colistin and sensitive to vancomycin. The small white colony on reducible blood agar and the biochemical reactions match this organism.

The Direct Gram Stain of an Anaerobic Wound Culture Reveals