Which organism is notably oxidase-positive and can be identified using the beta-lactamase test?

Moraxella catarrhalis is notably oxidase-positive, which is a key characteristic used in its identification. It is a gram-negative diplococcus that frequently causes respiratory tract infections, especially in individuals with underlying pulmonary conditions. The oxidase test is utilized to differentiate Moraxella catarrhalis from other organisms, particularly from species like Neisseria.

Furthermore, Moraxella catarrhalis produces beta-lactamases, which are enzymes that confer resistance to certain antibiotics, most notably penicillins. This characteristic is significant in clinical microbiology because it impacts treatment options for infections caused by this organism. The beta-lactamase test determines the presence of these enzymes, aiding in the identification of Moraxella catarrhalis and guiding appropriate therapy.

The other organisms listed do not align with the characteristics mentioned. Staphylococcus aureus is typically oxidase-negative and does not usually require a beta-lactamase test for identification, as it is primarily identified through gram staining and coagulase testing. Escherichia coli is also oxidase-negative and is identified using different biochemical tests, while Salmonella typhi is part of the Enterobacteriaceae family and is typically tested for other characteristics such as hydrogen