How are Cedecea and Serratia spp. differentiated?

How are Cedecea and Serratia spp. differentiated?

• A. Positive motility
• B. Positive urease
• C. Positive phenylalanine deaminase
• D. Negative DNase

Answer: (D)

Cedecea and Serratia spp. can be differentiated based on their ability to produce DNase. Specifically, Serratia spp. are known to be DNase positive, whereas Cedecea spp. do not produce this enzyme and are thus DNase negative. This distinction is crucial in microbiological diagnostics, as it helps in correctly identifying and differentiating these genera within the Enterobacteriaceae family. The ability to produce or not produce DNase serves as an important biochemical marker. In clinical laboratories, this test can be performed as part of a series of biochemical tests to ascertain the identity of an isolate. Identifying the specific characteristics of a bacterium not only aids in taxonomy but also informs potential treatment strategies by giving clues about the pathogenicity of the organism. In contrast, other biochemical tests mentioned, such as motility, urease activity, and phenylalanine deaminase production, do not provide the same degree of differentiation between Cedecea and Serratia spp. These properties may overlap and can be present in both genera, making them less reliable for distinguishing between them. Thus, the negative DNase result is a clear marker for Cedecea spp. in this context.

Cedecea and Serratia spp. can be differentiated based on their ability to produce DNase. Specifically, Serratia spp. are known to be DNase positive, whereas Cedecea spp. do not produce this enzyme and are thus DNase negative. This distinction is crucial in microbiological diagnostics, as it helps in correctly identifying and differentiating these genera within the Enterobacteriaceae family.

The ability to produce or not produce DNase serves as an important biochemical marker. In clinical laboratories, this test can be performed as part of a series of biochemical tests to ascertain the identity of an isolate. Identifying the specific characteristics of a bacterium not only aids in taxonomy but also informs potential treatment strategies by giving clues about the pathogenicity of the organism.

In contrast, other biochemical tests mentioned, such as motility, urease activity, and phenylalanine deaminase production, do not provide the same degree of differentiation between Cedecea and Serratia spp. These properties may overlap and can be present in both genera, making them less reliable for distinguishing between them. Thus, the negative DNase result is a clear marker for Cedecea spp. in this context.