The nasal microbiota of dairy farmers is more complex than oral microbiota, reflects occupational exposure, and provides competition for staphylococci

Abstract

Allergic and autoimmune diseases had been attributed to lack of exposure to biodiversity, an important factor in regulating immune homeostasis in a healthy host. We posit that the microbiome of healthy dairy farmers (DF) will be richer than non-farmers (NF) living in urban settings due to exposure to a greater biodiversity in the dairy environment. However, no studies have investigated the relationships between microbiota of dairy farmers (DF) compared with urban non-farmers (NF). We compared the nasal and oral microbiota of dairy farmers (N_DF, O_DF, respectively) with nasal and oral microbiota of NF in the same geographical area. The N_DF showed high microbial diversity with hundreds of unique genera that reflected environmental/occupational exposures. The nasal and oral microbiomes clustered separately from each other using Principal Coordinate Analysis, and with DF harboring two-fold and 1.5-fold greater exclusive genera in their nose and mouth respectively, than did non-farmers. Additionally, the N_DF group had a lower burden of Staphylococcus spp. suggesting a correlation between higher microbial diversity and competition for colonization by staphylococci. The N_DF samples were negative for the mecA gene, a marker of methicillin-resistance in staphylococci. The lower burden of staphylococci was found to be independent of the abundance of Corynebacterium spp. Exposure to greater biodiversity could enhance microbial competition, thereby reducing colonization with opportunistic pathogens. Future studies will analyze whether exposure to livestock microbiomes offers protection from acute and chronic diseases.

Microbiological Aspects of Acute and Chronic Pediatric Rhinosinusitis

“…In principle, exposure to greater biodiversity could increase competition in the nasal microbiota, and thus reduce colonization by opportunistic pathogens. A recent study by Shukla et al demonstrated that the nasal microbiome among dairy farmers is more complex than their oral microbiota: it protects against infections and competes with Staphylococcus aureus colonization [30]. Another study of adults showed that an abundance of nasal coagulase-negative staphylococci can negatively interfere with and counteract S. aureus colonization [31].…”

Developmental Origins of Health and Disease: Impact of environmental dust exposure in modulating microbiome and its association with non-communicable diseases

“…70 Another study by Shukla et al comparing 21 dairy farm workers and 18 non-farm office workers revealed that a farming environment was associated with higher bacteria species richness in the nasal microbiome as well as elevated levels of Bacteroidetes. 71 Interestingly, exposure to a dairy farm environment comprising of hay, livestock, and compost, as opposed to an urban office environment, was associated with a decreased burden of Staphylococcus in the nasal microbiome, which may confer protection against subsequent pathogenesis of acute and chronic diseases. 71 Direct evidence from an animal study showed that rats exposed to mixture of PM 1 , PM 2.5 , and PM 10 (30 g per exposure) for 4 h, five times weekly, over 4 weeks, had alteration in the composition and diversity of their lung microbiome profiles.…”

“…71 Interestingly, exposure to a dairy farm environment comprising of hay, livestock, and compost, as opposed to an urban office environment, was associated with a decreased burden of Staphylococcus in the nasal microbiome, which may confer protection against subsequent pathogenesis of acute and chronic diseases. 71 Direct evidence from an animal study showed that rats exposed to mixture of PM 1 , PM 2.5 , and PM 10 (30 g per exposure) for 4 h, five times weekly, over 4 weeks, had alteration in the composition and diversity of their lung microbiome profiles. 72 The PM exposure also induced higher number of alveolar macrophages with increased phagocytic capacity, higher levels of IgA, and lower levels of IgG, which may in turn affect the adaptive immune response of the lungs towards infection.…”

Impact of occupational exposure on human microbiota

“…Home studies show that people share microbes with their pets (59,60). In the occupational literature, studies show that the upper respiratory tract of livestock workers are colonized by strainspecific methicillin-resistant Staphylococcus aureus (MRSA) present in their work environment (61,62), Work with animals appears to be associated with increased microbial diversity in the nasal microbiome of adult pig and dairy farmers (63,64); similarly, children living on a farm have higher microbial diversity of their nasal microbiome than their counterparts living in non-farm rural environments (65). However, all of these studies were cross-sectional and so temporality and causation cannot be inferred, and furthermore they did not perform analyses directing tracing the nasal microbiome to the environment as a source.…”