Effect of adenovirus type 1 and influenza A virus on Streptococcus pneumoniae nasopharyngeal colonization and otitis media in the chinchilla

Considerable evidence has implicated respiratory tract virus potentiation o f bacterial adherence, colonization, and superinfection as a significant fa ctor contributing to the pathogenesis of otitis media (OM). influenza A and B viruses, adenovirus, and respiratory syncytial virus are the primary res piratory tract viruses associated with this disease. Investigations have es tablished a dramatic increase in the development of experimental OM in chin chillas co-inoculated with influenza A virus and Streptococcus pneumoniae ( Spn). The mechanism underlying this phenomenon was suggested to involve, in part, viral compromise of eustachian tube mucosal integrity and function. This study was designed to assess and compare the effect of adenovirus and influenza A virus infection on adherence, the kinetics of colonization, and invasion of the middle ear by Spn in the chinchilla model of OM. Cohorts w ere inoculated intranasally with adenovirus type 1 or influenza A virus, an d then inoculated intranasally 7 days later with Spn 6A. All cohorts were o bserved over a 14-day period after challenge with Spn, and the incidence an d severity of OM were assessed by several methods, including culture of the nasopharynx and middle ear effusions. The data indicated that influenza A virus promotes a significant increase in nasopharyngeal colonization by Spn , an increased incidence and severity of OM, and a sustained presence of Sp n in the effusions. Adenovirus infection, however, did not enhance coloniza tion by Spn or result in an increased incidence or severity of OM.