Airway Microbiota Based Treatment of Asthma in Preschool Children (AMBT)

Effects of Airway Microbiota and Blood Eosinophils Based Therapy or Treatment Using Current Clinical Guidelines in Recurrent Preschool Wheeze

Airway microbiota pattern may related the preschool asthma exacerbation. This is a single-center, randomized-controlled trial, the study will compare the management of preschool wheeze determined by airway microbiota phenotype and blood eosinophils level to the management using current clinical guidelines.

In this study, participants will be children aged 1-5 years who have recurrent wheezing and will be allocated to one of two treatment groups, either current clinical care or airway microbiota and blood eosinophils phenotype based management for 3 months.They will be followed up for one year after the intervention. The primary outcome is the frequency of unscheduled healthcare visit for wheezing, the secondary outcome parameters are events of severe wheezing requiring oral or intravenous steroids, events of emergency department visit and hospital admissions, the changes of Test for Respiratory and Asthma Control in Kids (TRACK) score and Paediatric Asthma Caregiver's Quality of Life Questionnaire (PACQLQ) score.

The children will be treated with different protocol(Fluticasone propionate (FP),Azithromycin,or FP+Azithromycin) according to their Blood eosinophils level and airway microbiota pattern for 3 months and follow up for 1 year.

The children will be treated as directed by their paediatrician, the clinical practice is based on the guideline for the diagnosis and optimal management of asthma in children of China 2016 (FP or montelukast for 3 months，or intermittent budesonide inhalation suspension during wheezing episode) and follow up for 1 year.

Blood eosinophils ≥3%+ mixed airway microbiota: 3 month course of FP 50 ug twice daily via spacer Blood eosinophils<3%+ Moraxella species>40% in airway microbiota: Azithromycin 10mg/kg per day for 3 consecutive days a week for 4 weeks; Blood eosinophils ≥3%+ Moraxella species>40% in airway microbiota: 3 month course of FP 50 ug twice daily via spacer and Azithromycin 10mg/kg per day for 3 consecutive days a week for 4 weeks; Blood eosinophils<3%+ mixed airway microbiota: intermittent budesonide inhalation suspension (1mg twice daily) and terbutaline inhalation suspension for 7 days during wheeze episode. The participants will be followed up for one year after the intervention.

The children will be treated as directed by their paediatrician ( The clinical practice is based on the guideline for the diagnosis and optimal management of asthma in children of China 2016).The treatment protocols include: regular inhaled FP 50 ug twice daily via spacer for 3 months; montelukast(4mg od for 3 months) intermittent budesonide inhalation suspension (1mg twice daily for 7 days during wheeze episode). The participants will be followed up for one year after the intervention.

the number of courses of an oral prednisolone or intravenous methylprednisolone started for acute wheezing after consultation with a physician, and is recorded by the physician or confirmed by the medical records

Inclusion Criteria: physician diagnosed recurrent wheeze（at least 3 episodes of wheezing or at least one course of oral steroids in the last 6 months） Exclusion Criteria: Any congenital heart disease diagnosed by a physician Any chronic respiratory condition other than preschool wheeze (bronchopulmonary dysplasia, bronchiolitis obliteran, congenital airway and lung malformations, bronchomalacia, chronic aspiration) diagnosed by a physician Received antibiotic last 6 weeks