Abstract
BackgroundCystic fibrosis is a debilitating, autosomal recessive disease which results in chronic upper and lower airway infection and inflammation. In this study, four adult patients presenting with cystic fibrosis and chronic rhinosinusitis were recruited. Culture and molecular techniques were employed to evaluate changes in microbial profiles, host gene expression and antimicrobial resistance (AMR) in the upper respiratory tract over time.MethodsSwab samples from the sinonasal cavity were collected at the time of surgery and at follow-up clinics at regular time intervals for up to 18 months. Nucleic acids were extracted, and DNA amplicon sequencing was applied to describe bacterial and fungal composition. In parallel, RNA was used to evaluate the expression of 17 AMR genes and two inflammatory markers (interleukins 6 and 8) using custom qPCR array cards. Molecular results were compared with routine sinus and sputum culture reports within each patient.ResultsBacterial amplicon sequencing and swab culture reports from the sinonasal cavity were mostly congruent and relatively stable for each patient across time. The predominant species detected in patients P02 and P04 were Pseudomonas aeruginosa, Staphylococcus aureus in patient P03, and a mixture of Enterobacter and S. aureus in patient P01. Fungal profiles were variable and less subject specific than bacterial communities. Increased expressions of interleukins 6 and 8 were observed in all patients throughout the sampling period compared with other measured genes. The most prevalent AMR gene detected was ampC. However, the prevalence of AMR gene expression was low in all patient samples across varying time-points.ConclusionsWe observed a surprising degree of stability of sinonasal microbial composition, and inflammatory and AMR gene expression across all patients post sinus surgery.
Highlights
Cystic fibrosis is a debilitating, autosomal recessive disease which results in chronic upper and lower airway infection and inflammation
We describe the stability of the sinonasal microbiota in four adult Cystic fibrosis (CF)-chronic rhinosinusitis (CRS) patients up to 18 months post sinus surgery
Respiratory samples were collected from four patients presenting with CF and CRS at baseline functional endoscopic sinus surgery (FESS) surgery
Summary
Cystic fibrosis is a debilitating, autosomal recessive disease which results in chronic upper and lower airway infection and inflammation. The upper and lower airways of adult CF patients are typically dominated by potentially pathogenic bacteria such as Staphylococcus aureus, Pseudomonas aeruginosa, Haemophilus spp., Streptococcus spp., Achromobacter spp., Burkholderia spp., and Enterobacter spp. Similar bacteria can be detected in the lungs of healthy adults, bacterial diversity is significantly increased, meaning more bacterial species are detected, and the dominance of a single species is not observed [13]. When comparing adult CF patients experiencing pulmonary acute exacerbations to those that are clinically stable, the bacterial load of the dominant bacterial pathogen increases [14]. In addition to an increased colonisation of pathogens, the airways of CF patients have significantly increased expression of inflammatory markers and extensive airway remodelling compared to healthy controls [15, 16]
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