Which organism's isolation is enhanced by incubation in increased CO2?

Which organism's isolation is enhanced by incubation in increased CO2?

• A. Neisseria gonorrhoeae
• B. Escherichia coli
• C. Klebsiella pneumoniae
• D. Staphylococcus aureus

Answer: (A)

The main concept here is capnophilic growth—some bacteria need higher levels of carbon dioxide for optimal growth. Neisseria gonorrhoeae is a classic capnophile; in the lab it’s routinely incubated in a CO2-enriched atmosphere (about 5–10% CO2) on chocolate or selective media to boost isolation and colony yield. The elevated CO2 supports its metabolism and helps it grow more robustly than in ambient air. In contrast, the other organisms listed grow well in standard atmospheric conditions and don’t require or gain a notable advantage from increased CO2, so their isolation isn’t enhanced by CO2-enriched incubation. Therefore, the organism whose isolation is enhanced by incubation in increased CO2 is Neisseria gonorrhoeae.

The main concept here is capnophilic growth—some bacteria need higher levels of carbon dioxide for optimal growth. Neisseria gonorrhoeae is a classic capnophile; in the lab it’s routinely incubated in a CO2-enriched atmosphere (about 5–10% CO2) on chocolate or selective media to boost isolation and colony yield. The elevated CO2 supports its metabolism and helps it grow more robustly than in ambient air. In contrast, the other organisms listed grow well in standard atmospheric conditions and don’t require or gain a notable advantage from increased CO2, so their isolation isn’t enhanced by CO2-enriched incubation. Therefore, the organism whose isolation is enhanced by incubation in increased CO2 is Neisseria gonorrhoeae.