P3.T389: The Unique Microbiology and Epidemiology of Pediatric Infective Endocarditis

Background: Pediatric infective endocarditis (IE) is a rare, highly morbid infection with complex diagnostic criteria that combine clinical suspicion with microbiologic and radiographic data. IE in the pediatric population is overall understudied, with many recommendations coming from generalizations of adult studies, despite pediatric patients often having different presentations, common pathogens, and risk factors. We aimed to better characterize the population at risk and update the microbiology of pediatric IE using the large and diverse U.S. Military Health System database.

Methods: Department of Defense beneficiaries less than 22 years-of-age admitted to a military treatment facility with an ICD-9/10 code for IE between October 2008 and September 2019 were included. Congenital heart disease (CHD) was also identified using ICD-9/10 codes. Demographic data including age, sex, geographic region, and year of admission were collected for each patient. Microbiologic culture data were collected for each patient, as well as echocardiographic data.

Results: 105 patients with IE were identified over the 11-year study period. IE cases were clustered among those less than 1 year of age and 18-21 years of age. Seventeen (16.2%) of patients had underlying CHD, with ventricular septal defect (41.2%), tetralogy of Fallot (29.4%), and aortic and mitral valve defects (11.8%) being the most common types of CHD identified. Only 28 (26.7%) IE patients had positive blood cultures: 8 (28.6%) Staphylococcus epidermidis, 7 (25%) methicillin-sensitive Staphylococcus aureus, 4 (14.3%) Streptococcal species, 4 (14.3%) Pseudomonas, 2 (7.1%) methicillin-resistant Staphylococcus aureus, 2 (7.1%) Escherichia coli, and 1 (3.6%) Bacillus cereus. Only 3 (2.8%) had echocardiographic data confirming a vegetation.

Conclusion: Only 17/105 (16.2%) of pediatric patients with ICD 9/10 codes for IE met 2023 Duke Microbiologic Major Criteria for multiple positive blood cultures (12 with typical IE microorganisms and 5 with nontypical microorganisms). Seventeen (16.2%) met Minor Duke Criteria for a predisposing congenital heart condition. Another 12 (11.4%) met Minor Duke Criteria for an isolated positive blood culture or a positive culture from a sterile body site with a typical IE microorganism. Pediatric IE is mostly caused by typical IE pathogens such as Staphylococcus aureus, CoNS, and Streptococcal species; however, we found that gram-negative pathogens such as E. coli and Pseudomonas are also contributors to IE in children. Children with CHD (repaired and unrepaired) should be targeted for efforts to prevent IE such as maintaining optimal oral health, timely surgical closure, and in certain cases antibiotic prophylaxis before invasive oral procedures. ICD diagnosis codes for infectious endocarditis in children correlate poorly with the 2023 Duke Criteria. This indicates either a large degree of IE misclassification or the reality that providers clinically suspect and treat IE in many children who do not meet Duke Criteria.