Polymicrobial colonisation associated with chronic otitis media correlates with microbial conditions in vitro that increase adherence, biofilm formation and reduced pro-inflammatory responses with respiratory epithelial cells
Kyd, JM, Browne, J, Krishnamurthy, A & Matthews, E 2015, 'Polymicrobial colonisation associated with chronic otitis media correlates with microbial conditions in vitro that increase adherence, biofilm formation and reduced pro-inflammatory responses with respiratory epithelial cells', abstract presented to the 18th International symposium on recent advances in otitis media, Maryland, USA, 26-27 November.
Objective: Polymicrobial colonisation load has been identified as a significant risk factor for AOM and particularly recurrent and chronic OM. This study aimed to investigate the bacterial factors that contribute to increased biofilm, adherence and modification of inflammation in vitro using respiratory epithelial cells and compare to adenoidal and nasopharyngeal colonisation patterns in OM and non-OM children to understand the significance of the colonisation patterns to clinical condition.
Method: Human respiratory epithelial cell lines were used to study single and multiple combinations of Streptococcus pneumonia, Moraxella catarrhalis and nontypable Haemophilus influenzae inoculation conditions with and without viral infection. Adherence, biofilm formation and Interleukin-6 and IL-8 responses were measured. Clinical microbiology was measured on adenoid biopsies and nasopharyngeal aspirates from children 2 to 7 years of age, with or without chronic otitis media.
Results: Polymicrobial combinations in vitro and particularly a pre-viral infection significantly increased S. pneumoniae, M. catarrhalis and NTHi adherence and biofilm formation in specific combinations of co-culture and epithelial cell type (p<0.05) and reduction in the production of IL-6 and IL-8. Epithelial cell contact was a significant contributor to rapid upregulation of biofilm formation. M. catarrhalis positive adenoid biopsies and nasopharyngeal aspirates positively correlated with presence of S. pneumoniae cultures (p<0.05); and S. pneumoniae positively correlated with NTHi (p<0.005).
Conclusion: Certain polymicrobial infections conditions are associated with chronic OM and in vitro, specific conditions can be shown to augment bacterial adherence and biofilm formation as well as reduce the pro-inflammatory cytokine responses by epithelial cells.