DOZ047.18: Diagnosing reflux aspiration in esophageal atresia: role of microbiome and pepsin

Background Children with esophageal atresia (EA) often suffer from gastroesophageal reflux disease (GERD) and it's complications, including reflux aspiration. Reflux aspiration can be difficult to diagnose in these patients who often have other causes for their respiratory symptoms. Tracheal pepsin has been studied as a marker of reflux aspiration in other conditions but not in EA. The role of the airway microbiome in the diagnosis of reflux aspiration has not been studied previously. Aims The aim of this study was to examine the composition of the airway (tracheal aspirate) microbiome of EA patients and correlate the results of the microbial analysis with the presence of gastric pepsin in the airways as a marker of reflux aspiration. Methods A cohort of children with EA was prospectively recruited at Sydney Children's Hospital in 2018. The EA group were subdivided into children with GERD, eosinophilic esophagitis (EoE), and those with no disease. Tracheal aspirates were collected. The bacterial component (16S rRNA gene) of the microbiome was amplified. Pepsin was assayed using a monoclonal antibody specific for pepsin A by the ELISA technique. Results There were 26 EA patients. The mean age was 6.96 years (0.7–18) and 15 (58%) were female. Eighteen (69%) children were on proton pump inhibitors for GERD and 8 (30%) were on swallowed steroids for EoE. GERD, defined as reflux esophagitis on biopsy and/or abnormal result on pH/impedance testing, was present in 7 (27%) and EoE defined as >15 eosinophils/HPF was seen in 5 (19%) children. Tracheal pepsin was detected in a significant proportion of EA patients and correlation between the pepsin results and the airway microbial analysis was seen in some of the EA patients who were pepsin positive. Conclusions This study is the first to examine the role of the microbiome and pepsin in tracheal aspirates as markers of reflux aspiration in children with EA. These results require validation in larger cohorts.

Detection of Gastric Pepsin in Middle Ear Fluid of Children with Otitis Media

OBJECTIVE: We sought to confirm the finding of pepsin/pepsinogen in the middle ear fluid of children with otitis media in a larger sample size using a sensitive and specific pepsin assay. STUDY DESIGN AND SETTING: We evaluated 152 children (225 ear samples) in a prospective study at a tertiary care children's hospital. The presence of pepsin in middle ear aspirates was determined using enzymatic assay. RESULTS: Of the patients, 14.4 percent (22 of 152) had detectable pepsin activity in one or both of the ear samples with no pepsin activity detected in control serum. Average pepsin concentration in the samples was 96.6 ± 170.8 ng/ml, ranging from 13 to 687 ng/ml. Pepsin concentration in the middle ear of children younger than 1.0 year was significantly higher than in older age groups. CONCLUSION AND SIGNIFICANCE: Results indicate that pepsin/pepsinogen is present in the middle ears of children with otitis media, although not at the high rate previously reported. Gastric reflux may be one causative factor in the pathogenesis of otitis media.