“…The prevalence of these pathogens varies between populations, but most children are colonized by at least one of these species in the first year of life. 5,8,[33][34][35][36][37] Positive correlations between S. pneumoniae, M. catarrhalis and H. influenza, and negative correlations between H. influenza and S. aureus have been reported in epidemiological studies 5,7,8,38,39 as well as infection models. 40,25,41 Pettigrew et al showed that colonization with M. catarrhalis and H. influenza together doubled the likelihood of co-colonization with S. pneumoniae.…”