A prospective evaluation of the serotypes and antibiotic susceptibility of pneumococci colonizing the nasopharynx and causing acute otitis media in the years 2015-2019. The goal will be to recruit children into a prospective group beginning at 6 months of age and followed to 36 months of age in suburban Rochester, New York. Nasopharyngeal and oropharyngeal swabs will be obtained at each well child visit and at acute otitis media episodes. Middle ear fluid will be obtained from every child with every acute otitis media episode. Children who are otitis prone will be invited to join the prospective group thereafter (our experience to date suggests about 60% will continue in the prospective follow up). All of the nasopharyngeal and middle ear fluid samples collected will be tested by standard microbiologic techniques to identify the presence of 5 potential otopathogens (S. pneumoniae, nontypeable Haemophilus influenzae, M. catarrhalis, and Alloiococcus otitidis. All S. pneumoniae will undergo antibiotic susceptibility testing. All samples that are culture negative will be evaluated with a multi-locus PCR test to examine for presence of the 5 potential otopathogens.