Coinfection with influenza B virus does not affect association of Neisseria meningitidis with human nasopharyngeal mucosa in organ culture

There is an epidemiological association between influenza virus infection a nd meningococcal disease, Proposed mechanisms are the destruction of the no rmal epithelial barrier function of the upper respiratory tract by influenz a virus or the expression of human or viral surface-exposed proteins that e nhance bacterial adherence and/or invasion, To test these hypotheses, human nasopharyngeal mucosa specimens from a total of 19 individual donors were successfully infected with influenza B virus and then inoculated with serog roup B Neisseria meningitidis. Subsequent bacterial association with the ep ithelial surface was measured in three separate series of experiments by us ing transmission electron microscopy (n = 6), scanning electron microscopy (n = 6), and counting of viable bacteria within homogenates of explants (n = 7). Penetration of the mucosa was estimated by measuring the count of via ble bacteria recovered from explants after exposure to sodium taurocholate, Bacterial association with the surface of explants was time dependent over 24 h of superinfection. Influenza virus did not positively or negatively i nfluence bacterial attachment to or penetration of explant mucosa compared to those of uninfected controls, even when the period of preincubation with virus was extended to 7 days. When proteins were purified from mucosal epi thelium and immobilized on nitrocellulose membranes, N. meningitidis attach ed predominantly to bands corresponding to proteins of 210 and 130 kDa, In the presence of influenza virus infection, these proteins were gradually lo st over the course of 72 h. In conclusion, influenza B virus did not increa se association of serogroup B N. meningitidis with human nasopharyngeal muc osa.