Bacterial pathogens in the nasopharynx, nasal cavity, and osteomeatal complex during wellness and viral infection.

BACKGROUND: Viral sinusitis can precede acute bacterial sinusitis, but the influence of viral infection on bacterial colonization is unclear. The objective of this study was to evaluate the presence of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis in the osteomeatal complex (OMC), nasal cavity, and nasopharynx in adults during wellness and viral upper respiratory illness (URI). METHODS: Subjects were recruited for the study during wellness and at the time of acute viral rhinosinusitis. Swab cultures were obtained from the OMC, nasal cavity, and the nasopharynx. Swab eluates were inoculated on selective agars to detect S. pneumoniae, H. influenzae, and M. catarrhalis. RESULTS: The study included 237 subjects, 100 adults with URI and 137 well adults. Positive culture results were found for any site in 70% (n = 70) of ill subjects and 64% (n = 88) of well subjects (p = 0.393). Of the 91 OMC cultures, positive cultures were over five times more likely to be found in ill subjects than in well subjects (31% versus 8%; p = 0.010). The nasal cavity cultures were positively statistically significant more often in ill subjects versus well subjects (39% versus 25%; p = 0.022). The overall nasopharyngeal cultures did not show a statistically significant difference (65% versus 60%; odds ratio, 1.2; p = 0.461). S. pneumoniae was positively cultured in at least one site in 15% of ill subjects and 31% of well subjects (p = 0.006). H. influenzae was positively cultured in at least one site in 45% of ill subjects and 31% of well subjects (p = 0.027). M. catarrhalis was positively cultured in at least one site in 42% of ill subjects and 27% of well subjects (p = 0.018). CONCLUSION: This study defines the carriage rates of the three most common bacterial pathogens for acute sinusitis in the nasopharynx, nasal cavity, and OMC during illness and in the healthy state.

Dynamics of Moraxella bovis infection and humoral immune response to bovine herpes virus type 1 during a natural outbreak of infectious bovine keratoconjunctivitis in beef calves.

Infectious bovine keratoconjunctivitis (IBK) is an acute disease caused by Moraxella bovis (Mb). Several factors may predispose animals to an IBK outbreak; one commonly observed is infection with bovine herpes virus type 1 (BHV-1). The aim of this study was to investigate the dynamics of BHV-1 virus infection and its relation with clinical cases of IBK in weaned calves from a beef herd with a high prevalence of lesions caused by Mb. Sampling was carried out in six stages and included conjunctival swabs for isolating Mb as well as blood samples for identifying antibodies specific for BHV-1. A score for IBK lesions after observing each eye was determined. The findings of this study showed a high prevalence of BHV-1 virus infection (100% of animals were infected at the end of the trial); 67% of animals were culture-positive for Mb, but low rates of clinical IBK (19% of calves affected) were detected at the end of the trial. These results suggest that infection with BHV-1 did not predispose these animals to IBK, and that Mb infection produced clinical and subclinical disease in the absence of BHV-1 co-infection.