Microbiology of otitis media in Indigenous Australian children: review.

OBJECTIVES: To review research addressing the polymicrobial aetiology of otitis media in Indigenous Australian children in order to identify research gaps and inform best practice in effective prevention strategies and therapeutic interventions. METHODS: Literature review. RESULTS: Studies of aspirated middle-ear fluid represented a minor component of the literature reviewed. Most studies relied upon specimens from middle-ear discharge or the nasopharynx. Culture-based middle-ear discharge studies have found that non-typeable Haemophilus influenzae and Streptococcus pneumoniae predominate, with Moraxella catarrhalis, Staphylococcus aureus and Streptococcus pyogenes isolated in a lower proportion of samples. Alloiococcus otitidis was detected in a number of studies; however, its role in otitis media pathogenesis remains controversial. Nasopharyngeal colonisation is a risk factor for otitis media in Indigenous infants, and bacterial load of otopathogens in the nasopharynx can predict the ear state of Indigenous children. CONCLUSION: Most studies have used culture-based methods and specimens from middle-ear discharge or the nasopharynx. Findings from these studies are consistent with international literature, but reliance on culture may incorrectly characterise the microbiology of this condition. Advances in genomic technologies are now providing microbiologists with the ability to analyse the entire mixed bacterial communities ('microbiomes') of samples obtained from Indigenous children with otitis media.

Efficacy of low-dose intratympanic dexamethasone as a salvage treatment for idiopathic sudden sensorineural hearing loss: the Modbury Hospital experience.

OBJECTIVE: To evaluate the efficacy of low-dose intratympanic dexamethasone therapy in patients with idiopathic sudden sensorineural hearing loss whose hearing in the affected ear had failed to improve following a course of oral steroid therapy. METHODS: A prospective pilot study was undertaken of eight patients with idiopathic sudden sensorineural hearing loss whose hearing had failed to improve after a course of prednisolone. These patients subsequently received 8 mg intratympanic dexamethasone therapy, delivered via a ventilation tube on a weekly basis for 1 month. Clinical outcome was assessed weekly with pure tone audiography. RESULTS: At the end of the 1-month treatment period, no significant hearing improvement was observed on pure tone audiography in any of the patients (i.e. improvements were all less than 10 dB). CONCLUSION: The response to 8 mg of intratympanic dexamethasone used as a salvage therapy for idiopathic sudden sensorineural hearing loss was inadequate. A higher dosage of intratympanic dexamethasone might be required to achieve better outcomes.

Adaptive immune responses in Staphylococcus aureus biofilm-associated chronic rhinosinusitis.

BACKGROUND: The etiopathogenesis of chronic rhinosinusitis (CRS) is currently an area of intense debate. Recently, biofilms have been proposed as a potential environmental trigger in this disease. In particular, Staphylococcus aureus biofilms appear to be a predictor of severe disease recalcitrant to current treatment paradigms. However, direct causal links between biofilms and host immune activation are currently lacking. This study aimed to document both the adaptive immune responses that characterize S. aureus biofilm-associated CRS and the relative contributions of staphylococcal superantigens and S. aureus biofilms in the inflammatory make-up of this disease. METHODS: A total of 53 disease subjects and 15 controls were recruited. Sinonasal mucosa was collected for the determination of S. aureus and Haemophilus influenzae biofilms and presence of total and superantigen-specific IgE and for the measurement of cytokines that characterize the T-helper pathways. RESULTS: Staphylococcus aureus biofilms and superantigens are significantly associated in CRS patients, suggesting the biofilm may be a nidus for superantigen-eluting bacteria. The presence of S. aureus biofilms is associated with eosinophilic inflammation, across the spectrum of CRS, on the back of a T-helper(2) skewing of the host's adaptive immune response (elevated Eosinophilic Cationic Protein and IL-5). This can be distinguished from the superantigenic effect resulting in the induction of IgE. CONCLUSION: This study provides novel evidence of a link between S. aureus biofilms and skewing of the T-cell response toward the T-helper(2) pathway that is independent of superantigen activities. Further research is required to confirm the cause-effect relationship of this association.