# Necrotizing Pneumonia Complicated by Bartonella-Associated Culture-Negative Endocarditis in an Immunocompetent Adult

## TL;DR

A healthy adult developed severe lung infection and endocarditis caused by Bartonella, a hard-to-detect bacteria, highlighting the need for better diagnostic approaches.

## Contribution

This case highlights the importance of considering zoonotic pathogens like Bartonella in culture-negative endocarditis.

## Key findings

- Bartonella was diagnosed using serologic testing and echocardiography despite negative blood cultures.
- The patient had necrotizing pneumonia and complications like empyema and bronchopleural fistula.
- Early recognition of zoonotic pathogens is critical for effective treatment and avoiding complications.

## Abstract

Bartonella-related culture-negative endocarditis (CNE) is an infrequent and difficult diagnosis, due to the organism’s unique growth characteristics and frequent negative cultures. We describe a case of a 42-year-old previously healthy male with necrotizing pneumonia complicated by empyema and bronchopleural fistula. Despite signs of systemic inflammation and infection, multiple blood cultures remained negative. Our diagnosis was made with serologic testing, which revealed elevated Bartonella antibody levels, and echocardiographic findings of endocarditis. Bartonella species are zoonotic, time-dependent, Gram-negative bacteria most often transmitted by arthropod vectors. Cats often serve as reservoirs of the organism. Because of ambiguous clinical manifestations, early recognition is challenging unless there is initial suspicion of a zoonotic etiology. We hope this case emphasizes thinking of Bartonella and other zoonotic pathogens in CNE when routine cultures do not provide a diagnosis. Serologic testing and imaging studies are invaluable in the diagnostic process. Rapid identification and the use of appropriate antimicrobial therapy are essential to avoid significant complications and improve patient care.