Which of the following best describes Gram-negative, coffee bean shaped diplococci with adjacent sides flatted?

The description of Gram-negative, coffee bean-shaped diplococci with adjacent sides flattened fits perfectly with Neisseria species, particularly Neisseria gonorrhoeae and Neisseria meningitidis. These bacteria exhibit a distinct morphological characteristic: they are often seen in pairs (diplococci) and their unique shape resembles that of a coffee bean. This configuration is a key identifying feature when working with these organisms in a laboratory setting.

Neisseria species are known for their role in causing diseases such as gonorrhea and meningitis, which further emphasizes their clinical relevance. The Gram-negative classification indicates that they have a thinner peptidoglycan layer and an outer membrane, characteristic of this type of bacteria.

In contrast, the other options provided do not share this specific morphology. Staphylococcus, for instance, refers to clusters of cocci and typically appears as grapelike clusters rather than in pairs. Listeria is rod-shaped, and Chlamydia, though it can appear in various forms, does not typically exhibit the distinctive flattened diplococci shape described in the question. Therefore, Neisseria stands out as the only option that accurately correlates with the morphology described in the question.