The human nasal and oropharyngeal microbiomes and Staphylococcus aureus colonization

Abstract

Staphylococcus aureus has been extensively studied, yet it remains unclear why certain individuals continually carry the bacteria while others do not. Livestock workers are known to be at an increased risk of S. aureus colonization, but have not been as studied as other high risk groups, including hospitalized patients, have been. Culture based studies have shown other bacteria may decrease the likelihood of S. aureus colonization. Here, we utilize 16s rRNA sequencing to better characterize the ecologic relationships between S. aureus and the other microbes in the nares and oropharynx in a population of livestock workers.A cross-sectional, epidemiological study was conducted enrolling 59 participants (26 of which had livestock contact) in Iowa. Participants were enrolled in one of four ways: from an existing prospective cohort study (n=38), from the Iowa Department of Natural Resources Animal Feeding Operations database (n=17), through Iowa county fairs (n=3), and through snowball sampling (n=1). We collected two sets of swabs from the nares and oropharynx of each participant. The first set of swabs was used to assess the microbiome via 16s rRNA sequencing and the second was used to culture S. aureus.We observed livestock workers to have greater diversity in their microbiomes compared to those with no livestock contact. In the nares, there were 26 operational taxonomic units found to be different between livestock workers and non-livestock workers with the greatest difference seen with Streptococcus and Proteobacteria. In the oropharynx, livestock workers with swine exposure were more likely to carry several pathogenic organisms. We also observed colonized livestock workers to be more likely to