Otopathogen interactions in the nasopharynx of children, and the predictive value of nasopharyngeal aspirate culture for the aetiology of upper respiratory infections.

Abstract

To evaluate nasopharyngeal aspirate cultures for screening otopathogen carriage in the adenoid in children 2-7 years of age. Thirty-seven children, 2-7 years of age, scheduled for adenoidectomy were enrolled into this prospective study at Rockhampton, Australia. Adenoid biopsy and nasopharyngeal aspirate bacteriology were assessed by conventional culture. Demographic and environmental data were collected by questionnaire. Statistical analyses for descriptive, comparison and logistic regression tests between microbial, demographic, environmental and clinical groups were applied. Streptococcus pneumoniae, Staphylococcus aureus, non-typeable Haemophilus influenzae and Moraxella catarrhalis were detected in 38, 38, 35 and 24% of cases, respectively. Streptococcus pneumoniae was an independent determinant for non-typeable H. influenzae and S. aureus colonisation, and S. aureus was an independent determinant for S. pneumoniae colonisation. The nasopharyngeal aspirate otopathogen cultures were strong predictors for otopathogens in the adenoid, with moderate-high test accuracy for all otopathogens (receiver operator characteristics area under the curve ranging from 71 to 97% for the otopathogens tested). Children with positive non-typeable H. influenzae, M. catarrhalis, S. pneumoniae and S. aureus nasopharyngeal aspirate cultures were more likely to have the equivalent species in adenoid cultures (positive likelihood ratios=undefined, 15.0, 9.09 and 5.85, respectively). This study provides evidence that nasopharyngeal aspirate cultures are an indicator of otopathogens in the adenoid. Nasopharyngeal aspirate cultures may provide clinicians with information that informs clinical management. Strategies for improved management to reduce otopathogen carriage could reduce the prevalence of chronic upper respiratory infections that contribute to adenoidectomy.