Experimental endocarditis in calf after tricuspid valve replacement

Area of Science:

• Cardiovascular Research
• Infectious Diseases
• Surgical Innovation

Background:

• Prosthetic valve endocarditis (PVE) is a severe complication following cardiac surgery.
• Staphylococcus aureus is a common pathogen causing PVE.
• Developing reliable animal models is crucial for studying PVE pathogenesis and treatment.

Purpose of the Study:

• To establish a calf model for reproducible prosthetic tricuspid valve endocarditis (PVE) using Staphylococcus aureus.
• To characterize the clinical and bacteriological course of untreated PVE.
• To evaluate the efficacy of silver-allantoin-heparin (SAH) treatment in this model.

Main Methods:

• A calf model was developed using Staphylococcus aureus to induce prosthetic tricuspid valve endocarditis.
• Body temperature and blood cultures were monitored to assess disease progression.
• Bacterial titers were measured from various blood sampling sites, including peripheral veins, right atrium, right ventricle, and aorta.
• The protective effect of silver-allantoin-heparin (SAH) treatment was evaluated.

Main Results:

• The calf model demonstrated reproducible prosthetic tricuspid valve endocarditis with Staphylococcus aureus.
• Elevated body temperature and positive blood cultures were early indicators of valve colonization.
• A dose of 10(7) to 10(8) S. aureus organisms was required to colonize the prosthetic valve.
• SAH treatment did not protect against late-stage PVE with high bacterial inoculums.
• Peripheral venous blood cultures showed a 46% false-negative rate and significantly lower bacterial titers compared to central samples.

Conclusions:

• The calf model effectively replicates prosthetic tricuspid valve endocarditis.
• Untreated PVE progresses rapidly, with early signs including fever and positive blood cultures.
• Peripheral venous blood sampling is unreliable for diagnosing right heart endocarditis due to low bacterial detection rates.