In the described case, which medium and atmosphere supported growth of the organism?

In the described case, which medium and atmosphere supported growth of the organism?

• A. Chocolate agar incubated in CO2
• B. Sheep blood agar incubated in CO2
• C. MacConkey agar incubated in CO2
• D. Chocolate agar incubated in ambient air

Answer: (A)

Growth of many fastidious respiratory bacteria depends on special growth factors and a capnophilic atmosphere. Chocolate agar is made by lysing red blood cells, which releases X (hemin) and V (NAD) factors the organism needs. Incubating in a CO2-enriched environment further supports these organisms, helping them grow more robustly than in ambient air. Therefore, the combination of chocolate agar with CO2 provides both the necessary nutrients and the favorable atmosphere, making it the best choice for supporting growth in this scenario. The other options lack either the enriched X and V factors, or the CO2-rich environment needed by these capnophilic organisms.

Growth of many fastidious respiratory bacteria depends on special growth factors and a capnophilic atmosphere. Chocolate agar is made by lysing red blood cells, which releases X (hemin) and V (NAD) factors the organism needs. Incubating in a CO2-enriched environment further supports these organisms, helping them grow more robustly than in ambient air. Therefore, the combination of chocolate agar with CO2 provides both the necessary nutrients and the favorable atmosphere, making it the best choice for supporting growth in this scenario. The other options lack either the enriched X and V factors, or the CO2-rich environment needed by these capnophilic organisms.