Answer :
Based on the characteristics provided in the question, a gram-negative cocci that is oxidase-positive and isolated from a genitourinary swab is likely to be Neisseria. Here's a breakdown of why Neisseria is the most suitable choice:
1. Gram-Negative Cocci: Neisseria species are gram-negative cocci, which means they have a spherical shape and appear pink under a microscope when subjected to the Gram staining procedure.
2. Oxidase-Positive: Neisseria species are oxidase-positive, indicating that they possess the enzyme cytochrome c oxidase, which is involved in the electron transport chain in their metabolism.
3. Genitourinary Swab Source: Neisseria species, such as Neisseria gonorrhoeae and Neisseria meningitidis, are commonly associated with infections in the genitourinary tract, including sexually transmitted infections like gonorrhea.
In contrast, the other options provided do not fully match the characteristics mentioned in the question:
- Citrobacter is a gram-negative bacillus, not a cocci.
- Streptococcus is a gram-positive cocci.
- Proteus is a gram-negative bacillus.
- Staphylococcus is a gram-positive cocci.
Therefore, based on the given criteria, Neisseria is the most likely bacterium that fits the description of a gram-negative cocci, oxidase-positive, isolated from a genitourinary swab.
1. Gram-Negative Cocci: Neisseria species are gram-negative cocci, which means they have a spherical shape and appear pink under a microscope when subjected to the Gram staining procedure.
2. Oxidase-Positive: Neisseria species are oxidase-positive, indicating that they possess the enzyme cytochrome c oxidase, which is involved in the electron transport chain in their metabolism.
3. Genitourinary Swab Source: Neisseria species, such as Neisseria gonorrhoeae and Neisseria meningitidis, are commonly associated with infections in the genitourinary tract, including sexually transmitted infections like gonorrhea.
In contrast, the other options provided do not fully match the characteristics mentioned in the question:
- Citrobacter is a gram-negative bacillus, not a cocci.
- Streptococcus is a gram-positive cocci.
- Proteus is a gram-negative bacillus.
- Staphylococcus is a gram-positive cocci.
Therefore, based on the given criteria, Neisseria is the most likely bacterium that fits the description of a gram-negative cocci, oxidase-positive, isolated from a genitourinary swab.
