Increase in Oral Streptococcal Endocarditis Among Moderate-Risk Patients: Impact of Guideline Changes on Endocarditis Prevention

Abstract

Background: The well-established connection between oral bacteria and infective endocarditis (IE) has prompted discussions about using antibiotic prophylaxis (AP) before invasive dental procedures. In 2007/2008, guidelines restricted AP from moderate and high-risk to exclusively high-risk patients.

Objectives: The authors aimed to assess whether the proportion of oral streptococcal IE increased in moderate-risk patients using University Hospital Zurich data from 2000 to 2022.

Methods: Adult IE patients were categorized into risk groups based on European Society of Cardiology and Swiss guidelines. The investigation focused on analyzing the proportion of oral streptococcal IE across different risk groups in two distinct periods (1: 2000-2008; 2: 2009-2022). Logistic regression models, adjusted for various factors, were employed.

Results: Of 752 IE cases, 163 occurred in period 1, and 589 in period 2. Oral streptococci caused 22% of cases. Proportions of streptococcal IE in period 1 versus period 2 were 24% versus 16% in high-risk, 24% versus 39% in moderate-risk, 33% versus 7% in low-/unknown-risk, and 18% versus 14% in no-risk patients. Compared to the other risk groups, the moderate-risk group had a 22% higher chance of oral streptococcal IE in period 2. After multivariable adjustment, moderate-risk patients had twice the risk of oral streptococcal IE compared to period 1 (OR: 2.59 [95% CI: 1.16-5.81]). Among moderate-risk conditions, congenital valve anomalies were associated with oral streptococcal IE (unadjusted OR: 2.52 [95% CI: 1.71-3.71]).

Conclusions: Oral streptococcal IEs increased in the moderate-risk group of patients after the AP guideline change. Exploring the potential necessity for expanding AP indications to certain patient groups with congenital valve anomalies may be warranted.

Keywords: antibiotic prophylaxis; bicuspid aortic valve; invasive dental procedures; mitral valve prolapse; oral streptococci.

Graphical abstract

Central Illustration

Increase in Oral Streptococcal Endocarditis Among Moderate-Risk Patients: Impact of Guideline Changes on Endocarditis Prevention Infective Endocarditis (IE) risk stratification and corresponding Antibiotic Prophylaxis (AP) Indications for invasive dental procedures before and after the guideline change are shown in the upper part of the illustration. Below, the proportion of IE episodes attributed to oral Streptococci is presented for the periods before and after the change in AP guidelines, both overall and stratified by IE risk groups. While we observed no change in the overall proportion, there was a notable increasing trend in the moderate-risk group and a corresponding decreasing trend in the high-, low-, and no-risk groups. ^aAP recommended in the American and Swiss guidelines.^, However, the 2009 ESC guidelines did not recommend AP for this group of patients. ∗Please note unequal distribution of patients in the low-risk group, period 1: 3 patients, period 2: 57 patients. CHD = congenital heart disease; ESC = European Society of Cardiology; HOCM = hypertrophic obstructive cardiomyopathy; ICD = implantable cardioverter defibrillator; LVAD = left ventricular assist device; PDA = persistent ductus arteriosus; PM = pacemaker; VSD = ventricular septal defect; other abbreviation as in Figure 1.

Figure 1

Study Flowchart Suspected episodes of infective endocarditis were retrospectively screened from 2000 to 2017 and prospectively from 2018 to 2022. The flowchart illustrates the reasons for exclusion. In total, 752 episodes were included in the analysis. IE = infective endocarditis.

Figure 2

Change in Proportion of IE Due to Different Pathogens Among the Moderate-Risk Group vs All Other Patients Before and After Change of AP Recommendations The proportion of IE episodes due to different pathogens before and after the change in AP guidelines for moderate-risk patients versus all other patients as a baseline are displayed. Notably, the proportion of IE attributed to oral streptococci increased by 22.5% (95% CI: 5.9%-39.1%) in the moderate-risk group compared to the other patients following the guideline change. P values shown are for difference between means of change in proportion over time between moderate-risk and all other patients. AP = antibiotic prophylaxis; CoNS = coagulase-negative staphylococci; and other abbreviation as in Figure 1.

Figure 3

Univariable and Multivariable Logistic Regression Model for OR of IE Due to Oral Streptococci The results of univariable and multivariable logistic regression analyses assessing the risk of Infective Endocarditis (IE) caused by oral streptococci are presented. Following comprehensive adjustments for all variables listed, noteworthy positive associations were observed in individuals at moderate IE risk during period 2 compared to period 1, as well as those who underwent recent high-risk dental procedures. Conversely, negative associations were identified for intravenous drug users (IVDU) and individuals of higher age. MV = multivariable; UV = univariable.