A gram-negative, anaerobic coccus that produces red fluorescence under ultraviolet light is?

The organism in question is identified as a gram-negative, anaerobic coccus that exhibits red fluorescence under ultraviolet light. Veillonella is a genus of bacteria that fits all these criteria. In addition to being anaerobic and gram-negative, Veillonella is known to be a coccus-shaped bacteria that often resides in the oral cavity and gastrointestinal tract.

The characteristic of producing red fluorescence under ultraviolet light is particularly important for distinguishing Veillonella from other similar bacteria. This fluorescence is due to the presence of specific porphyrins produced by the bacteria during metabolic processes. These traits combined make Veillonella easily recognizable in a laboratory setting, particularly in clinical diagnostics.

Other genera listed do not share the same combination of traits. For instance, Peptococcus is also a gram-positive anaerobic coccus, which eliminates it from consideration. Neisseria, although a coccus, is primarily gram-negative but typically does not exhibit the characteristics of fluorescence and does not grow anaerobically as required in the question. Fusobacterium, on the other hand, is a gram-negative rod, not a coccus, which further confirms that it does not meet the criteria of the question.