Otitis media is an extremely common pediatric ailment caused by opportunists that reside within the nasopharynx. Inflammation within the upper airway can promote ascension of these opportunists into the middle ear chamber. Otitis media can be chronic/recurrent in nature, and a wealth of data indicates that in these cases the bacteria persist within biofilms. Epidemiological data demonstrates most cases of otitis media are polymicrobial, which may have significant impact on antibiotic resistance. In this study, we used in vitro biofilm assays and rodent infection models to examine the impact of polymicrobial infection with Moraxella catarrhalis and Streptococcus pneumoniae (pneumococcus) on biofilm resistance to antibiotic treatment and persistence in vivo. Consistent with prior work, M. catarrhalis conferred beta-lactamase dependent passive protection from beta-lactam killing to pneumococci within polymicrobial biofilms. Moreover, pneumococci increased resistance of M. catarrhalis to macrolide killing in polymicrobial biofilms. However, pneumococci increased colonization in vivo by M. catarrhalis in a quorum signal-dependent manner. We also found that co-infection with M. catarrhalis affects middle ear ascension of pneumococci in both mice and chinchillas. Therefore, we conclude that residence of M. catarrhalis and pneumococci within the same biofilm community significantly impacts resistance to antibiotic treatment and bacterial persistence in vivo.

Even in the vaccine era, Streptococcus pneumoniae (the pneumococcus) remains a leading cause of otitis media, a significant public health burden, in large part because of the high prevalence of nasal colonization with the pneumococcus in children. The primary pneumococcal neuraminidase, NanA, which is a sialidase that catalyzes the cleavage of terminal sialic acids from host glycoconjugates, is involved in both of these processes. Coinfection with influenza A virus, which also expresses a neuraminidase, exacerbates nasal colonization and disease by S. pneumoniae, in part via the synergistic contributions of the viral neuraminidase. The specific role of its pneumococcal counterpart, NanA, in this interaction, however, is less well understood. We demonstrate in a mouse model that NanA-deficient pneumococci are impaired in their ability to cause both nasal colonization and middle ear infection. Coinfection with neuraminidase-expressing influenza virus and S. pneumoniae potentiates both colonization and infection but not to wild-type levels, suggesting an intrinsic role of NanA. Using in vitro models, we show that while NanA contributes to both epithelial adherence and biofilm viability, its effect on the latter is actually independent of its sialidase activity. These data indicate that NanA contributes both enzymatically and nonenzymatically to pneumococcal pathogenesis and, as such, suggest that it is not a redundant bystander during coinfection with influenza A virus. Rather, its expression is required for the full synergism between these two pathogens.

Streptococcus pneumoniae (pneumococcus) is both a widespread nasal colonizer and a leading cause of otitis media, one of the most common diseases of childhood. Pneumococcal phase variation influences both colonization and disease and thus has been linked to the bacteria's transition from colonizer to otopathogen. Further contributing to this transition, coinfection with influenza A virus has been strongly associated epidemiologically with the dissemination of pneumococci from the nasopharynx to the middle ear. Using a mouse infection model, we demonstrated that coinfection with influenza virus and pneumococci enhanced both colonization and inflammatory responses within the nasopharynx and middle ear chamber. Coinfection studies were also performed using pneumococcal populations enriched for opaque or transparent phase variants. As shown previously, opaque variants were less able to colonize the nasopharynx. In vitro, this phase also demonstrated diminished biofilm viability and epithelial adherence. However, coinfection with influenza virus ameliorated this colonization defect in vivo. Further, viral coinfection ultimately induced a similar magnitude of middle ear infection by both phase variants. These data indicate that despite inherent differences in colonization, the influenza A virus exacerbation of experimental middle ear infection is independent of the pneumococcal phase. These findings provide new insights into the synergistic link between pneumococcus and influenza virus in the context of otitis media.

Two research questions are explored in this paper: what are the specific leader activities that contribute most to successful change in the Royal Air Force? And, what are the specific dimensions of leadership that contribute to successful change in the Royal Air Force? The results of a study into the part that leadership plays in successful change in the Royal Air Force (RAF) are presented. The Leadership Dimensions questionnaire was used to measure the dimensions of leadership and change contexts, and a 3608 feedback questionnaire gathered data on leader activities and the success of change programmes. The sample population was senior management in the RAF with 3608 feedback from colleagues. Hierarchies of the leader activities and dimensions of leadership are presented to identify the components that exert the strongest influence on the success of leading change in the RAF. Managing resources, engaging communication and empowering were identified as the three dimensions that contribute most towards successful change; and 'creating a clear vision', 'adjusting the work culture to meet the long term needs of the change' and 'generating early successes' were the three leader activities that exhibited the strongest influence on success. Recommendations are presented for future research in this area and for the RAF, based on these findings.

Infection with influenza A virus (IAV) can lead to increased susceptibility to subsequent bacterial infection, often with Streptococcus pneumoniae. Given the substantial modification of the lung environment that occurs following pathogen infection, there is significant potential for modulation of immune responses. Here we show that coinfection of mice with influenza virus followed by the non-invasive EF3030 strain of Streptococcus pneumoniae leads to a significant decrease in the virus specific CD8+ T cell response in the lung. Adoptive transfer studies suggest this reduction contributes to disease in coinfected animals. The reduced number of lung effector cells in coinfected animals was associated with increased death as well as a reduction in cytokine production in surviving cells. Further, cells that retained the ability to produce interferon γ exhibited a decreased potential for co-production of tumor necrosis factor α. Reduced cytokine production was directly correlated with a decrease in the level of mRNA. Negative regulation of cells in the mediastinal lymph node (MLN) was minimal compared to that present in the lung, supporting a model of negative regulation in the tissue harboring high pathogen burden. These results elucidate a new aspect of immune regulation as a result of entry of a coinfecting pathogen, modulation of ongoing adaptive immune responses in the lung. These findings reveal a novel dynamic interplay between concurrently infecting pathogens and the adaptive immune system.