A microbiologist is reading the plates from a sputum culture.On the sheep blood agar (SBA),she sees flat spreading colonies with a metallic sheen.On cetrimide agar,she sees a fluorescent green color in the media with clear colonies.On MacConkey,she sees medium clear colonies that have a fruity or grape-like odor.What is the most likely organism?
A) Pseudomonas fluorescens
B) P. aeruginosa
C) P. putida
D) P. stutzeri

Question

Quizplus · Accepted Answer

Members of the Pseudomonas fluorescent group-which includes P.aeruginosa,P.fluorescens,P.putida,P.veronii,and P.monteilii-produce pyoverdin,a yellow-green or yellow-brown pigment.Many strains of P.aeruginosa will also produce the blue,water-soluble pigment pyocyanin.When pyocyanin combines with pyoverdin,the green color characteristic of P.aeruginosa is produced.Most isolates of P.aeruginosa are b-hemolytic on SBA and will produce flat spreading colonies with a characteristic metallic sheen.

A Microbiologist Is Reading the Plates from a Sputum Culture