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A7756 - Moraxella Dominates the Airway of Infants with Early Wheeze
Author Block: K. M. Kloepfer1, S. Ross1, C. Hemmerich2, J. Slaven3, D. Rusch2, S. D. Davis1; 1Pediatric Pulmonary, Allergy and Sleep Medicine, Indiana University School of Medicine, Indianapolis, IN, United States, 2Center of Genomics and Bioinformatics, Department of Biology, Indiana University, Bloomington, IN, United States, 3Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN, United States.
Rationale: Thirty percent of children born to asthmatic mothers develop recurrent wheeze. The presence of Streptococcus in the upper airway within the first few months of life is linked to recurrent wheezing in children. To determine if these findings are similar in an ethnically diverse urban population, we obtained nasopharyngeal (NP) samples from three month old infants born to mothers with asthma. We assessed the association of early microbiota findings to the presence of wheeze and/or infant lung function. Methods: Neonates (n=23) born to women with a physician diagnosis of asthma were recruited shortly after birth. At three months of age, NP swabs were obtained and sedated pulmonary function testing (PFT) was performed. Questionnaires regarding wheezing episodes and medication utilization were collected bi-monthly for the first 12 months of life. Bacterial DNA was extracted from samples; the V4 region of 16S rRNA gene was amplified and sequenced on the Illumina Miseq platform. Results: Median age at time of sample was 3.6 months. 39% had a physician diagnosis of wheeze within the first year of life. At three months of age, the microbiota was dominated by Moraxella in children who developed early wheeze (57% vs 31%, p=0.07). In contrast, Streptococcus was more abundant in the airway of those without early wheeze (1% vs. 18%, p=0.01). Infant PFTs differed between the wheeze vs. no wheeze group. Forced expiratory volume at 0.5 seconds was lower in infants who developed wheeze compared to those without wheeze in the first year of life (mean -0.57 ± 0.74 vs. 0.38 ± 0.83, p=0.009). This was also seen with forced expiratory flow (FEF) between 25 and 75% of forced vital capacity (-0.38 ± 1.01 vs. 0.99 ± 1.33, p=0.025) and FEF 75% (-1.09 ± 1.23 vs. 0.74 ± 1.33, p=0.004). Conclusion: Our findings support recent reports that the early upper airway microbiota differs in infants who develop early wheeze. However, our study reveals that infants with a high abundance of Streptococcus in their airway at three months of age are less likely to have early wheeze, while those with a high abundance of Moraxella are more likely to have early wheeze. The decrease in iPFT values in this population suggests a link may exist between the early airway microbiota and airway function. Ongoing analyses and a larger sample size are needed to confirm these preliminary findings and assess the association of microbiota findings to lung function.