Investigators: Deborah Lehmann
Otitis media (OM, middle ear infection) can seriously affect childhood development, school performance and subsequent social and economic well-being. The Kalgoorlie Otitis Media Research Project was established in 1999 to investigate the causal pathways to OM and, specifically, to identify demographic, socio-economic, environmental, microbiological and immunological risk factors for OM in Aboriginal and non-Aboriginal children in order to develop appropriate interventions. We followed 100 Aboriginal and 180 non-Aboriginal children from birth to age two years. Field work was completed in 2004 and data cleaning completed in April 2005. Analysis of association between bacterial carriage and mucosal immunity is ongoing.
Major findings:
- The peak prevalence of OM in the Kalgoorlie-Boulder area was 72% in Aboriginal children aged 5-9 months and 40% in non-Aboriginal children aged 10-14 months.
- Almost one-third of Aboriginal children and 5% of non-Aboriginal children had a perforated ear drum at least once by age 2 years.
- 65% of Aboriginal children and 23% of non-Aboriginal children have some degree of hearing loss at age 12-17 months.
- Measurement of otoacoustic emissions in early infancy can identify children at subsequent risk of OM.
- Exposure to environmental tobacco smoke is an important risk factor for OM.
- Crowding is the strongest and most consistent predictor of carriage of OM-associated bacteria (pneumococcus, nontypeable Haemophilus influenzae, Moraxella catarrhalis) in the URT, but living in a larger house attenuates this effect in Aboriginal children.
- Daycare attendance predicts carriage of OM-associated bacteria in non-Aboriginal children while exclusive breastfeeding for the first 6-8 weeks of life protects children from carriage of Staphylococcus aureus.
- Rhinoviruses (HRV) and adenoviruses were commonly identified in asymptomatic children, more commonly in Aboriginal than non-Aboriginal children and are frequently associated with bacterial carriage.
- Human rhinovirus A is the most common virus type identified in healthy children and HRV C is associated with presence of upper respiratory symptoms and carriage of bacteria associated with OM.
- Early carriage of non-typeable H. influenzae increases risk of OM in Aboriginal children, while early carriage of M. catarrhalis increased risk of OM in non-Aboriginal children.
- A large proportion of M. catarrhalis strains were resistant to ampicillin and/or co-trimoxazole. Therefore, current therapeutic guidelines, which recommend amoxycillin for treatment of OM, may need to be revised. We have also documented for the first time simultaneous carriage of multiple strains of M. catarrhalis.
- A broader range of pneumococcal serotypes is seen in the upper respiratory tract of Aboriginal than non-Aboriginal children, reducing coverage afforded by pneumococcal conjugate vaccines.
- Different antimicrobial susceptibility patterns of carriage strains of pneumococci are seen in Aboriginal than non-Aboriginal children with a multiresistant serotype 6B clone only identified in non-Aboriginal children."