Presence of Methicillin Resistant Staphylococcus Aureus among dairy farm workers in Colorado

Abstract

Dairy farmers experience a heavy burden of bioaerosol-related respiratory ailments. Bioaerosols are known to contain inflammagens (specifically endotoxin), and a diverse bacterial community that is associated with upper respiratory inflammation and pulmonary decrement among workers. However, identifying casual agents (beyond endotoxin) is still an area that warrants further research. Industrialization and modernization of the dairy industry have led to dramatic changes to production, work organization and tasks. Consequently, exposure patterns have been altered. It has been demonstrated that the mass of dairy bioaerosols is predominantly present in particle size ranges that span 10-100 μm in aerodynamic diameter; these are known to deposit in the upper respiratory system (i.e., the nasopharyngeal region) (Schaeffer et al., 2017). The nose contains complex bacterial communities, and this microbiome may play a role in the inflammatory response to bioaerosols. Recently, the nasal microbiome in dairy farmers was shown to contain over two times the bacterial diversity and abundance, as compared to non- farmers. It is believed that this diversity is protective against the colonization of methicillin- resistant Staphylococcus aureus (MRSA). In contrast, persistent nasal carriage of MRSA, specifically livestock-associated strain, has been seen in swine production workers. Recent evidence shows an increase in soft tissue infections (SSTI) caused by large animal-derived S. aureus (LA-MRSA) among swine and livestock workers. The objective of this researchwas to characterize the presence and carriage of Staphylococcus spp. with a focus on livestock associated MRSA in the nasal passages of dairy workers.