A cluster of cases of legionellosis have occurred in your neighborhood. People with the illness have cough, fever, shortness of breath, chest pain and sometimes diarrhea. The illness is caused by the bacterium Legionella pneumophila, a facultative intracellular parasite that survives in certain ameba. The organism has an absolute requirement for L-cysteine.
-Diagnosis of legionellosis depends partly on culture of the causative agent from medical samples. Typically, the organism is grown on buffered charcoal yeast extract (BCYE) agar. What essential component must this medium have to ensure growth of L. pneumophila?
A) red blood cells
B) chlorine
C) NaCl
D) cysteine
E) All of the answer choices are correct.

Question

Quizplus · Accepted Answer

L. pneumophila has an absolute requirement for L-cysteine, which is an important component for its growth on BCYE agar. Therefore, the essential component that this medium must have to ensure the growth of L. pneumophila is cysteine. Red blood cells, chlorine, and NaCl are not essential components for the growth of L. pneumophila.

A Cluster of Cases of Legionellosis Have Occurred in Your