Which organism is characterized as an oxidase-positive, nonmotile gram-negative coccobacillus?

Which organism is characterized as an oxidase-positive, nonmotile gram-negative coccobacillus?

• A. Bordetella pertussis
• B. Brucella spp.
• C. Haemophilus spp.
• D. Legionella pneumophila

Answer: (A)

The organism characterized as an oxidase-positive, nonmotile gram-negative coccobacillus is Bordetella pertussis. This bacterium is well-known as the causative agent of whooping cough (pertussis) and is typically identified through its morphology, which is that of a small, nonmotile coccobacillus under the microscope. In addition to its morphology, Bordetella pertussis is oxidase-positive, which is a key biochemical characteristic that helps differentiate it from other organisms in the same category. This oxidase test determines the presence of cytochrome c oxidase in the organism, a feature that is significant for identification in microbiological laboratories. While Brucella spp. and Haemophilus spp. are also nonmotile and can appear as coccobacilli, they differ in their oxidase reactions and other key biochemical and pathogenic characteristics. Specifically, Brucella is known for being non-fermentative and can be facultatively aerobic, while Haemophilus spp., particularly Haemophilus influenzae, are typically classified as bacilli rather than coccobacilli. Legionella pneumophila is a completely different organism, classified as a bacillus rather than

The organism characterized as an oxidase-positive, nonmotile gram-negative coccobacillus is Bordetella pertussis. This bacterium is well-known as the causative agent of whooping cough (pertussis) and is typically identified through its morphology, which is that of a small, nonmotile coccobacillus under the microscope.

In addition to its morphology, Bordetella pertussis is oxidase-positive, which is a key biochemical characteristic that helps differentiate it from other organisms in the same category. This oxidase test determines the presence of cytochrome c oxidase in the organism, a feature that is significant for identification in microbiological laboratories.

While Brucella spp. and Haemophilus spp. are also nonmotile and can appear as coccobacilli, they differ in their oxidase reactions and other key biochemical and pathogenic characteristics. Specifically, Brucella is known for being non-fermentative and can be facultatively aerobic, while Haemophilus spp., particularly Haemophilus influenzae, are typically classified as bacilli rather than coccobacilli. Legionella pneumophila is a completely different organism, classified as a bacillus rather than