In a culture from an intra-abdominal abscess producing orange-tan colonies, what is the most likely identification based on oxidase positive and DNase positive results?

The presence of orange-tan colonies in conjunction with oxidase positive and DNase positive results strongly suggests the identification of Shewanella putrefaciens. This organism is known for producing orange-tan colonies on specific culture media, which aligns with the observation from the intra-abdominal abscess.

Shewanella putrefaciens is primarily recognized for its versatility in various environments, which includes the ability to degrade organic matter and its frequent association with marine environments. The oxidase positive reaction indicates the presence of cytochrome c oxidase, a characteristic feature that helps distinguish Shewanella from many other potential bacterial pathogens. Additionally, the positive DNase test reflects its ability to degrade DNA, which is consistent with the enzymatic actions seen in this organism.

While Pseudomonas aeruginosa is oxidase positive and can also produce pigment, it typically results in greenish colonies rather than orange-tan. Acinetobacter spp. generally do not exhibit the same colony coloration and are more often found as non-pigmented or white colonies. Chryseobacterium spp. can produce yellow or orange colonies, but they do not fit the oxidase and DNase profile in conjunction with the characteristic colony coloration observed.

Overall, the orange-tan