Microbiological characterization of stable resuspended dust.

The research involved investigating the microbiological content of dust in a horse stable, with a focus on whether this dust carries potentially harmful bacteria that pose a risk to the health of horses or humans. With the use of a mobile instrument and a technique called next generation sequencing, the researchers identified a variety of microorganisms in the dust, with common soil-dwelling organisms being the most prevalent and pathogens only found in small quantities.

Research Context and Aims

• The study was conducted in response to concerns about air quality in horse stables. Dust and aeroallergens in these environments are known to cause or worsen respiratory issues, such as recurrent airway obstruction, in horses. Moreover, there’s evidence suggesting that such microorganisms may cause inflammation in human airways and go beyond safe levels in stables.
• Past monitoring studies primarily focused on determining the concentration of small, breathable particles and culturable fungi and their toxins. This research, however, sought to explore if these dust particles also carry potentially harmful bacteria.

Methodology

• A mobile instrument was used to sample resuspended dust in a typical 20-horse Hungarian stable. This device consisted of a sampler and a cyclone separator, which collected particulate matter ranging between 1 and 10 micrometers in size.
• Next, culture-independent next generation sequencing (NGS) was used to identify microbial taxa. This method analyzed variable 16S ribosomal ribonucleic acid (rRNA) gene regions, which allows for the identification of various bacteria and archaea.

Results

• The analysis led to the identification of 1491 different taxa. Among these, 384 were identified at the species level, while 961 were identified at the genus level.
• The dust sample was mainly composed of ubiquitous soil and organic material-dwelling species.
• Pathogens were present in the sample but in low abundance. They mostly consisted of facultative human pathogens, with Staphylococcus species being the most common.

Conclusions

• The findings suggested that while the resuspended dust in horse stables carries a variety of microorganisms, pathogens exist in relatively small quantities.
• The most common potential pathogens present were Staphylococcus species, which are primarily opportunistic or ‘facultative’ pathogens that can cause disease in humans, but do not usually do so in healthy individuals.
• The implications of this study could be significant for efforts to improve the air quality in stables and minimize health risks for both horses and humans.