A microbiologist is looking at the blood culture plates taken from a woman who had ingested fresh, unpasteurized milk.The growth on the blood agar and chocolate agar showed small, circular, smooth, convex, nonpigmented, and nonhemolytic colonies.Gram stain revealed tiny gram-negative rods.The organism was catalase, oxidase, nitrate reduction, and urease positive, but showed a lack of motility.What is the most probable organism?
A)Francisella tularensis
B)Brucella abortus
C)Yersinia pestis
D)Burkholderia cepacia

Question

Quizplus · Accepted Answer

Brucella colonies are small, circular, smooth, and convex, nonpigmented and nonhemolytic.On Gram stain, brucellae reveal tiny gram-negative coccobacilli.Results for a presumptive identification of Brucella spp.include the characteristics mentioned earlier for an organism that was isolated from an appropriate specimen, along with catalase, oxidase, nitrate reduction, urease positivity, and lack of motility.

A Microbiologist Is Looking at the Blood Culture Plates Taken