A Link Between Components of the Nasal Microbiome and an Individual’s Susceptibility to Influenza.

Abstract

According to CDC influenza estimates, the flu infects ~40 million people and causes 24,000 to 60,000 deaths in the United States annually. Vaccination can be highly effective but is often a neglected tool for preventing infection. In this project, three methods were developed to compare an individual’s reported self-history of influenza infection to the types and amounts of nasal bacteria collected by nasal swab to assess if certain bacteria may correlate with less history of influenza infection. These three methods quantified species from four genera of bacteria - Staphylococcus, Micrococcus, Streptococcus and Haemophilus - and compared the amounts of each type of bacteria with participant survey answers regarding their history of influenza infection. In Method 1, a disk diffusion test with bacitracin distinguished isolates of Staphylococcus from Micrococcus. Higher ratios of Staphylococcus to Micrococcus were found in individuals less susceptible to influenza (p = 0.003). In Method 2, S. pyogenes and S. pneumoniae were distinguished based on their hemolytic patterns. A higher proportion S. pneumoniae significantly correlated with more history of influenza (p = 0.002). In Method 3, total numbers of Staphylococcus spp. and H. influenzae were compared. More frequent H. influenzae significantly correlated with higher influenza frequency (p = 0.006). While all three methods indicate correlations between specific nasal bacteria and influenza susceptibility, Method 2 was the simplest and least expensive to perform. Commercialization of one or more of these methods could result in a simple and inexpensive test to identify at-risk individuals for influenza.