Effectiveness of a Low-cost Intervention: Changes to Cytokines and Microbiome Among Bioaerosol Exposed Dairy Workers

1684 

Student Poster 

G Erlandson¹, J Schaeffer²

¹Colorado State University, Fort Collins, CO, ²N/A, Fort Collins, CO

Grant Erlandson  
Colorado State University

Joshua Schaeffer  
N/A

Livestock workers experience an increased burden of bioaerosol-induced respiratory disease. We have previously demonstrated that dairy operations generate bioaerosols that span the inhalable size fraction. These aerosols contain complex bacterial communities and inflammagens. Because particles with an aerodynamic diameter between 10-100 μm are known to deposit in the nasopharyngeal region, we believe that exposure health outcomes in the nose are equally important and need consideration. We conducted a pilot study to evaluate the effectiveness of a hypertonic saline nasal lavage in reducing inflammatory responses in dairy workers. Inhalable dust samples were collected and analyzed for endotoxin; nasal lavage samples were collected from dairy workers and analyzed for pro-inflammatory cytokines. The objective of this study was to determine the effectiveness of the hypertonic saline solution in attenuating the inflammatory response among dairy workers and evaluate its changes to the nasal microbiome.

A disproportionate burden of bioaerosol-induced respiratory disease exists among agricultural workers. Livestock operations generate bioaerosols, which contain complex bacterial communities and associated inflammagens (i.e., endotoxin). Previous research has demonstrated a consistent relationship between endotoxin exposure and pro-inflammatory cytokines and pulmonary function in dairy workers. Controlling biological exposures in the dairy setting is challenging and previous intervention attempts have shown potential but more in-depth systematic evaluations are needed. Further, any intervention to improve respiratory health in dairy workers must be considered in the cultural and economic contexts of the industry. While engineering controls may be the most efficacious in reducing exposures in this setting, such solutions may not be economically feasible or practical. Our study aimed to pilot test a potential intervention using a hypertonic saline nasal lavage and evaluate its efficacy in reducing the inflammatory response in dairy workers exposed to bioaerosols. We hypothesize that the hypertonic saline nasal lavage will reduce the inflammatory response in dairy workers and be an effective intervention.

Exposure assessments and intervention applications were conducted over five consecutive days (8-hour shifts) at a dairy in the high plains and intermountain region. Dairy workers (n=10) were randomly assigned to an experimental group (n=5) that received hypertonic saline while the remaining five workers were administered normotonic saline as part of the control group (normotonic saline). Over a five- day sampling period, all workers received the normotonic saline lavage prior to their shift to acquire a baseline and were fitted with an SKC button sampler to measure inhalable particulate and endotoxin exposure during their shift. Post shift, the control group received a second normotonic saline lavage, whereas the treatment group received a hyptertonic saline lavage. Pre and post-shift nasal lavage samples were then analyzed for pro-inflammatory cytokines using Meso Scale Discovery technology. Dust concentrations were obtained through gravimetric analysis of the dust sampler filter with a microbalance. After gravimetric analysis, bio aerosols were extracted from filters and subjected to a fluorescent assay specific to an endotoxin sensitive protein. Analysis of variance (ANOVA) was implemented to estimate the efficacy of the intervention, incorporating cytokine concentrations, group, day, and time of day. Additional statistical models incorporating dust and endotoxin concentrations are currently being conducted. All analyses were performed using R statistical software (version 3.5.1).

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 the IL-6 pro-inflamatory cytokine. 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.
Given that pro-inflammatory cytokines are a major contributor to poor respiratory conditions in dairy workers, our findings have broad implications for worker health. Even with a very limited sample size the hypertonic saline solution significantly promoted anti-inflammatory cytokines indicating its effectiveness. Equally important, the intervention was handled well by workers with no adverse side effects. Essentially, from a pilot study perspective, the intervention is a cost-effective, simple solution to reducing respiratory inflammation in dairy workers. These findings will and have informed future research on dairy interventions. Another project has already begun to expand upon the pilot findings on a much larger scale. This future research will incorporate the nasal microbiome, lung function, and antibiotic resistance into its model investigating the efficacy of the lavage intervention. Adding these components and a larger sample size will lead to more robust and further reaching results and interpretations about the intervention.

Biosafety

Aerosols

Sampling and Analysis