Aim/goal of project

Primary:
“Amongst 200 hospitalised Indigenous children with bronchiolitis does azithromycin (compared to placebo) 30mg/kg per dose given in three doses 7 days apart improve clinical outcomes (length of stay in hospital and duration of oxygen supplementation)?”

Secondary:
Our secondary aims are designed to evaluate other important questions related to ALRTIs in Indigenous children, including potential adverse outcomes from widespread use of macrolides in Indigenous communities.

1.  To determine the effect of treatment on readmissions into hospital within 6 months;

2. To examine whether macrolide-resistant respiratory pathogens present in nasopharyngeal swabs (NPS) influence clinical severity;

3. To assess the short-term impact of azithromycin on macrolide resistance patterns of respiratory pathogens in the nasopharynx;

4. To describe the point prevalence and diversity of respiratory viruses, Mycoplasma pneumoniae and Chlamydia species (C. pneumoniae, C. trachomatis, Simkania negevensis) using sensitive molecular diagnostic techniques.

Background
Bronchiolitis remains the most common acute lower respiratory tract infection (ALRTI) in infants. It is primarily caused by a viral infection called Respiratory Syncytial Virus (RSV) although other viruses may also contribute. Bronchiolitis is characterised by inflammation of the airways, increased mucous production and necrosis of epithelial tissue. In paediatrics, bronchiolitis is a clinical diagnosis characterised by tachypnoea, wheeze and/or crepitations in infants following a preceding upper respiratory illness. Most cases can be treated at home; however in some cases hospitalisation may be required for supportive therapy (such as oxygen and fluid therapy).

We have found that Northern Territory (NT) Indigenous infants present to hospital more often and with more severe bronchiolitis than non Indigenous infants. These infants are at greater risk of developing longer term respiratory problems including chronic suppurative lung disease or bronchiectasis. Bronchiolitis in NT Indigenous children is complicated by the known early colonisation of the nasopharynx by bacterial pathogens, notably Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae.

A class of antibiotics called the macrolides like Azithromycin have been widely used in the Northern Territory for bronchiectasis, trachoma and sexually transmitted diseases. Azithromycin has anti inflammatory and bacterial properties. It has a longer half life and better tissue penetration than other macrolides thus requiring a much shorter treatment regime. Once weekly dosing has been shown to be sufficient for tissue effects lasting over a week. Any intervention that is efficacious in reducing the severity of bronchiolitis and or readmission for bronchiolitis in particular for Indigenous children would be beneficial in both short and long term outcomes

Interesting information
We have enrolled 71 of the 200 required from both Royal Darwin Hospital and The Townsville Hospital.

Links/newsletters

Bronchiolitis Flip Chart-Citation

www.LungInfoNet.org.au