Which organisms are classified as oxidase-negative?

The classification of organisms as oxidase-negative is significant in microbiology, particularly in differentiating among various bacterial groups. In this context, Enterobacteriaceae and Haemophilus are indeed known for being oxidase-negative.

Enterobacteriaceae, which includes members such as Escherichia coli and Salmonella, are characterized by their inability to produce the enzyme cytochrome c oxidase, which is evident in their negative reaction to oxidase testing. This feature helps laboratory personnel quickly identify and differentiate this family from other gram-negative bacteria that might be oxidase-positive.

Haemophilus species, including Haemophilus influenzae, are also oxidase-negative. Their classification aids in the identification process during the diagnosis of infections, as distinguishing these organisms from potential pathogens that may yield a positive oxidase reaction is crucial for accurate diagnosis and treatment planning.

In contrast, the other groups mentioned such as Neisseria and Moraxella are typically oxidase-positive, and organisms like H. pylori and V. cholera, as well as Vibrio and Aeromonas, have varying oxidase reactions, predominantly showing positive results. Understanding these characteristics enables medical technologists to effectively isolate and identify pathogens in clinical specimens.