Microbial Exploration in a Dairy Operation; Staphylococcus aureus and other Microbial Communities Through a One Health Lens

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2023-12

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Abstract

The One Health framework explores the interconnectedness of humans, animals, and the environment. In the dairy industry, One Health plays a pivotal role. It aims to preserve animal health and address the potential risks of harmful pathogens in milk affecting human Health. By adopting the One Health approach in dairy production, farms promote food safety and well-being, contributing to global food safety and animal health improvement. In this project, the initial study aimed to investigate Staphylococcus aureus isolates obtained during a significant mastitis outbreak on a dairy farm. The research encompassed the evaluation of responses to various iodine concentrations, susceptibility to antimicrobial agents, and analysis of the strains’ phenotypic. Notably, the results demonstrated the susceptibility of all S. aureus strains to the tested antibiotics. Moreover, the findings revealed the significant impact of iodine concentration on bacterial viability. These results, coupled with the typing analysis, strongly suggested a common source of infection. These findings highlight the significance of factors linked to strain transmission within the farm environment and the subsequent development of persistent infections. The second study involved a comprehensive bio-mapping analysis of a West Texas dairy farm, intending to understand the microbial distribution, their movement within the farm's operations, and potential transmission pathways. The findings from this study unveiled the presence of various pathogens, including Cronobacter spp., Listeria monocytogenes, and E. coli O157:H7, with seasonal variations in different locations across the dairy farm. Moreover, the study underscored the prevalence of both S. aureus and non-aureus staphylococci. Additionally, the microbiome analysis performed in this study identified the dominant microbial communities during seasons and sample types, which showed shifts in the microbial composition. These findings provide a comprehensive understanding of the farm's microbial landscape and offer valuable insights into the environmental cross-contamination risks that may affect the farm's overall biosecurity and management practices. In the third study, the primary objective was to assess the pathogenicity of S. aureus within a One Health framework. To achieve this, a set of forty S. aureus isolates, sourced from environmental samples, underwent a comprehensive array of tests and analyses. These included antimicrobial susceptibility testing, biofilm assessments, microbial typing, and enterotoxin detection. Moreover, a subset of eight isolates also underwent whole-genome sequencing and proteomics analysis. The results demonstrated that the S. aureus isolates showed susceptibility to antibiotics, exhibited biofilm-forming capacity and demonstrated potential for enterotoxin production. Additionally, the investigation highlighted relatedness among the isolates regarding sample type and their persistence across different seasons. The genomic and proteomic characterizations further pinpointed specific virulence factors within the isolates. This study highlights the adaptability and persistence of S. aureus and its significance as a potential threat to the health of animals and humans.

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Keywords

Dairy operations, microbiome, pathogens, Staphylococcus aureus, virulence factors

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