How can Enterobacter aerogenes be differentiated from Edwardsiella tarda?

How can Enterobacter aerogenes be differentiated from Edwardsiella tarda?

• A. Motility, citrate, and urease
• B. Hydrogen sulfide (H2S) production, sucrose fermentation, indole, and VP
• C. Lysine decarboxylase, urease, and arginine dihydrolase
• D. Motility, H2S production, and DNase

Answer: (B)

The differentiation of Enterobacter aerogenes from Edwardsiella tarda is accurately conducted through the examination of hydrogen sulfide (H2S) production, sucrose fermentation, indole production, and the Voges-Proskauer (VP) reaction. Enterobacter aerogenes typically does not produce hydrogen sulfide, while Edwardsiella tarda does, which helps in identifying the latter. Additionally, Edwardsiella tarda is known for its ability to ferment sucrose, whereas Enterobacter aerogenes may display less ability or variability in fermentation patterns. The indole test provides further distinction, as Edwardsiella tarda is generally indole-positive, whereas Enterobacter aerogenes is indole-negative. Lastly, the Voges-Proskauer test assesses the production of acetoin, which is positive for Enterobacter aerogenes and negative for Edwardsiella tarda. This combination of biochemical tests effectively highlights the metabolic differences between the two organisms, enabling laboratory identification. The other options include tests that may not reliably distinguish these species in a clinical microbiology setting.

The differentiation of Enterobacter aerogenes from Edwardsiella tarda is accurately conducted through the examination of hydrogen sulfide (H2S) production, sucrose fermentation, indole production, and the Voges-Proskauer (VP) reaction.

Enterobacter aerogenes typically does not produce hydrogen sulfide, while Edwardsiella tarda does, which helps in identifying the latter. Additionally, Edwardsiella tarda is known for its ability to ferment sucrose, whereas Enterobacter aerogenes may display less ability or variability in fermentation patterns. The indole test provides further distinction, as Edwardsiella tarda is generally indole-positive, whereas Enterobacter aerogenes is indole-negative. Lastly, the Voges-Proskauer test assesses the production of acetoin, which is positive for Enterobacter aerogenes and negative for Edwardsiella tarda.

This combination of biochemical tests effectively highlights the metabolic differences between the two organisms, enabling laboratory identification. The other options include tests that may not reliably distinguish these species in a clinical microbiology setting.