04-16-2012, 01:00 AM
A 17-year-old girl with cystic fibrosis has a slight increase in her frequent cough and production of mucoid sputum. A sputum specimen is obtained and plated on routine culture media. The predominant growths are gram-negative bacilli that form very mucoid colonies after 48 hours of incubation. These bacilli are oxidase-positive, grow at 42°C, and have a grape-like odor.
The sputum also is plated on a colistin-containing agar. After 72 hours of incubation, the colistin-containing agar grows gram-negative bacilli that are oxidase-positive but are otherwise difficult to identify. This microorganism is of major concern. It is sent to a reference laboratory so that molecular methods can be used to identify or rule out which of the following?
A. Pseudomonas aeruginosa
B. Burkholderia cepacia
C. Haemophilus influenzae
D. Pseudomonas putida
E. Burkholderia pseudomallei
The sputum also is plated on a colistin-containing agar. After 72 hours of incubation, the colistin-containing agar grows gram-negative bacilli that are oxidase-positive but are otherwise difficult to identify. This microorganism is of major concern. It is sent to a reference laboratory so that molecular methods can be used to identify or rule out which of the following?
A. Pseudomonas aeruginosa
B. Burkholderia cepacia
C. Haemophilus influenzae
D. Pseudomonas putida
E. Burkholderia pseudomallei