What is the most likely pathogen responsible for a cat scratch fever following a kitten bite with signs of lymphadenopathy?

The most likely pathogen responsible for cat scratch fever following a kitten bite, particularly when accompanied by signs of lymphadenopathy, is Bartonella henselae. This bacterium is well-known for causing cat scratch disease, which is typically transmitted through scratches or bites from an infected cat, often a young kitten. The hallmark symptoms of this infection include swollen lymph nodes, which develop in response to the local infection as the body's immune system reacts to the pathogen.

Bartonella henselae specifically targets lymphatic tissues, leading to the characteristic lymphadenopathy observed in affected individuals. This condition can also present with fever and other systemic symptoms, but the lymph node enlargement is a key diagnostic feature that differentiates it from other possible infections.

In contrast, the other pathogens listed are associated with different diseases or transmission modes. For instance, Yersinia pestis is primarily associated with plague, and Francisella tularensis is linked to tularemia, both of which do not typically present with the classic symptoms of cat scratch disease. Pasteurella multocida is often implicated in infections resulting from animal bites but usually causes localized skin infections rather than the systemic lymphadenopathy seen with Bartonella henselae. Thus, the presence of lymphadenopathy following a