JA:2021-6. Effectiveness of a Low-cost Intervention: Changes to Cytokines and Microbiome among Bioaerosol Exposed Dairy Workers

Abstract

ABSTRACT Purpose: Livestock workers experience an increased burden of bioaerosol-induced respiratory disease. We have previously demonstrated that dairy operations generate bioaerosols spanning the inhalable size fraction. These aerosols contained complex bacterial communities and inflammagens. Because those particles with an aerodynamic diameter between 10 and 100 μm are known to deposit in the nasopharyngeal region, we believe that exposure health outcomes in the upper respiratory tract are important and need consideration, especially in the context of the nasal microbiome (i.e., collection of bacterial communities suggested to play a key role in health and disease). Methods: We evaluated the effectiveness of a hypertonic saline nasal lavage in reducing inflammatory responses in dairy workers from a high-volume dairy operation. We collected inhalable personal breathing zone (PBZ) samples and pre-/post-shift nasal lavage samples from each participant over five consecutive days. The treatment group (n = 5) received hypertonic saline, while the control group (n = 5) received normotonic saline. PBZ samples were analyzed for particulate concentrations and endotoxin using gravimetric and enzymatic methods, respectively. Pro- and anti-inflammatory cytokines (i.e., IL-8, IL-10, and TNF-α) were measured from nasal lavage samples using a multiplex assay. To measure the air and nasal microbiomes, lavage and dust samples were analyzed using 16S rRNA sequencing. Results/Findings: Inhalable dust concentrations ranged from 0.15 to 1.9 mg/m3. Significant differences in pro-inflammatory cytokines were observed between treatment and control groups for IL-6. Contrary to the hypothesis, IL-6 concentrations were higher in the treatment group than the control group. However, the treatment group had significantly higher IL-10 (anti-inflammatory) concentrations than the control group. Distinct bacterial communities were observed in pre- and post-shift lavage samples, with post-shift communities more closely resembling those found in dust samples. Practical Implications: Based on pilot results, the intervention was successful in upregulating anti-inflammatory cytokines and promoting changes in the nasal microbiome. Therefore, more research is warranted to determine if a hypertonic nasal rinse is an effective intervention that does not cause adverse perturbations to the microbiome.