Which of the following indicates a positive reaction for the beta-lactamase chromogenic cephalosporin method?

Study for the Apollon Bacteriology Test. Improve your knowledge with flashcards and multiple choice questions, each with hints and explanations. Get ready to excel on your exam!

The beta-lactamase chromogenic cephalosporin method is a specific biochemical test used to detect the presence of beta-lactamase enzymes produced by certain bacteria. These enzymes confer resistance to beta-lactam antibiotics, including penicillins and cephalosporins. The method involves the use of chromogenic cephalosporin substrates, which, upon hydrolysis by the beta-lactamase enzyme, lead to a color change in the medium.

A positive reaction, indicated by a color change, occurs when the substrate is cleaved by the beta-lactamase enzyme, resulting in the release of a chromogenic product that alters the color of the medium. This visual cue allows for the easy identification of beta-lactamase-producing organisms in a laboratory setting.

Other potential indicators, such as the production of acid, reduction of nitrates, or decolorization of a starch-iodine mixture, are not relevant to this specific test. Acid production and nitrate reduction pertain to different metabolic pathways and tests, while the starch-iodine test assesses the presence of starch breakdown, unrelated to beta-lactamase activity. Thus, the observation of a color change is the definitive indicator of a positive result

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