Which organism likely caused the 'bulls-eye' colonies observed in a stool culture from a patient with enterocolitis?

The organism associated with 'bulls-eye' colonies observed in a stool culture from a patient with enterocolitis is Yersinia enterocolitica. This pathogen is known to cause enterocolitis, especially in children, and is frequently linked to undercooked pork or contaminated food and water.

Yersinia enterocolitica can appear as colonies with a distinctive morphology on certain types of selective media, often resembling a 'bulls-eye' due to their unique growth patterns. This characteristic morphology is indicative of the organism and aids microbiologists in identifying it during stool culture examinations.

Understanding the context in which Yersinia enterocolitica is detected is crucial; patients typically present with gastrointestinal symptoms like diarrhea, abdominal pain, and fever. The correlation of the 'bulls-eye' colony appearance with the clinical data points toward this organism as the causative agent of enterocolitis in this scenario.