Staphylococcus aureus Nasal Colonization and Asthma in Adults: Systematic Review and Meta-Analysis

Background: Staphylococcus aureus (SA) is a frequent colonizer in humans, and it is known to be associated with chronic allergic diseases including asthma. Recent individual studies suggested that nasal SA colonization may be positively associated with asthma. Objective: To examine relationships between nasal SA colonization and asthma prevalence and activity in adults. Methods: Electronic databases were searched for studies published until June 2018. Studies that reported nasal SA colonization prevalence and asthma outcome (prevalence and disease activity) in general adult populations or patients with chronic rhinosinusitis (CRS) were included. Random effects meta-analyses were performed to calculate pooled odds ratio (OR) of the relationships. Subgroup analysis was conducted for the presence of nasal polyps within CRS populations. Results: A total of 21 cross-sectional studies were identified, and the data from 16 studies using culture methods for SA detection were meta-analyzed (5 general population-based studies and 11 studies of patients with CRS). In studies of general populations, nasal SA colonization had significant relationships with asthma prevalence (OR 1.19; 95% confidence interval [CI] 1.06-1.34; I² = 1%). In studies of patients with CRS, positive associations were also found but had a considerable heterogeneity (OR 1.87; 95% CI 1.18-2.97; I² = 72%). However, the results were comparable between CRS with and without nasal polyps. Conclusions: This study demonstrated modest but significant relationships between nasal SA colonization and asthma, supporting potential roles of SA in adult patients with asthma. Further longitudinal cohort and intervention studies are warranted to identify host determinants and to clarify causality of the relationships.