Introduction

Infective endocarditis (IE) remains a life-threatening disease associated with substantial morbidity and mortality despite advances in antimicrobial therapy, multimodality imaging, and cardiac surgery. The epidemiology of IE has changed substantially over recent decades. In England, the incidence remained relatively stable at approximately 27 cases per million population per year until 2009 but subsequently increased to around 50 cases per million population per year by 2018, representing an 86% rise. Despite advances in diagnosis and treatment, one-year mortality continues to exceed 30%, highlighting the persistent burden of this disease [1-6].

Transoesophageal echocardiography (TOE) is a cornerstone of the diagnostic evaluation of suspected IE and constitutes a major imaging component of the modified Duke criteria. Compared with transthoracic echocardiography, TOE provides superior sensitivity for detecting valvular vegetations, peri-annular abscesses, prosthetic valve infection, leaflet perforation, and cardiac implantable electronic device (CIED)-related infection. Consequently, current European and American guidelines recommend TOE in patients with suspected IE when clinical suspicion remains high, particularly in the presence of prosthetic valves, intracardiac devices, or inconclusive transthoracic echocardiographic findings [1,3,7-9].

The microbiological profile of IE has also evolved, with Staphylococcus aureus emerging as the predominant pathogen in many contemporary cohorts, while viridans group streptococci and enterococci continue to account for a substantial proportion of cases. Oral microorganisms remain important causative pathogens, particularly in patients with underlying structural heart disease or prosthetic valves. Good oral hygiene and appropriate dental care are therefore recognised as important preventive measures. Current international guidelines recommend antibiotic prophylaxis only for patients at the highest risk of adverse outcomes who are undergoing selected invasive dental procedures [1-6,10-15].

Although several studies have described the microbiological and echocardiographic characteristics of IE, relatively few have specifically evaluated the relationship between documented dental exposure and oral flora-associated IE in routine clinical practice. Furthermore, data from UK teaching district general hospitals (DGHs) remain limited, particularly regarding the documentation of antibiotic prophylaxis administration and recent dental procedures. A better understanding of these associations may help improve risk assessment, reinforce collaboration between cardiology and dental services, and identify opportunities to strengthen preventive strategies for patients at increased risk of IE [14,15].

The primary aim of this retrospective observational study was to evaluate the association between documented dental procedures and oral flora-associated IE among patients with confirmed IE who underwent TOE at a UK teaching DGH. The secondary objectives were to describe the clinical, microbiological, and echocardiographic characteristics of the cohort, evaluate surgical intervention and in-hospital mortality, and assess the documentation of antibiotic prophylaxis in patients with recent dental procedures. This study was conducted within the UK clinical context, where National Institute for Health and Care Excellence (NICE) guidance (CG64) states that antibiotic prophylaxis is not routinely recommended for patients undergoing dental procedures.