Which organism is usually transmitted from pet feces (e.g., puppies), contaminated milk, or pork and can cause enterocolitis with pseudoappendicitis right-lower-quadrant pain in children?

• A. Yersinia enterocolitica
• B. Salmonella enterica
• C. Campylobacter jejuni
• D. Shigella dysenteriae

Answer: (A)

This question tests recognizing Yersinia enterocolitica as a cause of enterocolitis that can mimic appendicitis in children. The illness often presents with fever and abdominal pain in the right lower quadrant due to mesenteric lymphadenitis, which can create a pseudoappendicitis picture. The key clue is the exposure pattern: transmission can occur from pet feces (for example puppies), contaminated milk, or pork. This combination of nonbloody diarrhea less central here, fever, RLQ pain, and these specific sources points to Yersinia.

Other bacteria can cause intestinal infections with abdominal pain, but their typical exposures or presentations don’t fit as neatly. For instance, Campylobacter and Salmonella are often linked to poultry or eggs and dairy, and Shigella to person-to-person spread with dysentery; their patterns don’t align as cleanly with the pet-feces, milk, and pork exposures that strongly suggest Yersinia.