Which bacteria is known for being indole positive?

Escherichia coli is recognized for being indole positive. Indole production is a characteristic trait used in microbiological identification tests. When E. coli is grown in a medium containing tryptophan, it can metabolize tryptophan to produce indole, which can then be detected using specific reagents, typically resulting in a color change.

In contrast, while some of the other bacteria listed may have their own unique properties, they do not share the indole positive characteristic as prominently as E. coli does. For instance, Pseudomonas aeruginosa and Chryseobacterium spp. may show variable indole production, but these results are not as reliable or consistent. Staphylococcus aureus is typically known to be indole negative. Hence, the key role E. coli plays in demonstrating indole positivity makes it an important bacterium in microbiology, particularly in clinical diagnostics.