Infective endocarditis: prevention strategy and risk factors in an animal model

Abstract

Introduction: Infective endocarditis is a serious infection of the endocardium, especially the heart valves, which is associated with a high mortality rate. It generally occurs in patients with altered and abnormal cardiac architecture combined with exposure to bacteria from trauma and other potentially high-risk activities with transient bacteremia. Aim: The aim of the study was to develop a reproducible periodontitis-endocarditis model in a rat that can be used to answer the question of how the administration of antibiotic prophylaxis before tooth extraction affects the prevalence of bacteremia and the incidence of endocarditis. Materials and methods: Thirty-five female Wistar rats were divided into three groups: periodontitis group (PG): ligatures were placed bilaterally on maxillary first molars, and the maxillary molars were extracted after 30 T; endocarditis group (EG): in addition to PG, aortic valve injury was performed with simulated prosthetic material before extraction; antibiotic prophylaxis group (AG): in addition to EG, a single-shot antibiotic administration was performed 30–60 minutes before extraction. Periodontal indices were collected, blood samples were microbiologically analyzed. Hearts were examined histologically after euthanasia. Results: On the day of extraction, 93% of the ligatures were still in situ. The average approximal plaque index of maxillary first molars was 92%. The average papilla bleeding index according to Saxer and Mühlemann of the first molar in the first quadrant was grade 3, in the second quadrant – grade 2. The average probing depth of the first molar in the first quadrant was 3 mm, in the second – 2 mm. Endocarditic changes were identified in 20% in the AG group, 60% in the EG, and 0% in the PG control group. A successful model was developed by reliably developing endocarditis and periodontitis. Specific marker germs for periodontitis could be detected in blood cultures. The effectiveness of antibiotic prophylaxis prior to tooth extraction in groups at risk of endocarditis has been demonstrated in animal models. Conclusions: In the present experimental animal study, a reproducible model could be developed by creating a manifest periodontal lesion, which, in connection with an aortic valve lesion and a tooth extraction, triggers bacteremia. Clinical relevance The model could act as a basis for further studies on the topic to answer remaining questions related to oral pathogens and IE.