This high cell count results in decreased milk quality and economic value ( Halasa et al., 2007), which implies that disease control and prevention are essential for dairy farmers' subsistence. This can be problematic for farmers, since subclinical infections, which can go unnoticed without regular cow screenings, are associated with a higher somatic cell count in milk. Even though the inflammatory symptoms are evident in the case of clinical mastitis, prompting producers, or veterinarians to take appropriate action, diagnosis of subclinical mastitis is mainly carried out by milk testing, e.g., using the California Mastitis Test ( Schalm and Noorlander, 1957). Bovine mastitis can be classified as subclinical mastitis (asymptomatic) or clinical mastitis (symptomatic). Mastitis leads to a decline in milk production and quality, which coupled with high treatment costs or early culling of animals, is responsible for significant losses in dairy farms ( Petrovski et al., 2006). uberis in two distinct herds, and gain insights on the impact of herd management practices on pathogen population structure.īovine mastitis is a disease characterized by mammary gland inflammation that affects dairy herds worldwide. This approach allowed to disclose prevalent virulence patterns and clonal lineages of S. Overall, this work showed the utility of dot blot and MLSA to characterize population structure and epidemiological patterns of mastitis-causing S. uberis displaying an environmental or contagious transmission pattern depending on the herd. Seven different clusters were identified, with Barcelos showing a high clonal diversity and Maia a dominant lineage infecting most cows, suggesting distinct epidemiological patterns, with S. In addition, MLSA allowed to disclose the most prevalent S. uberis using taxa-specific markers and to determine the presence of virulence- and antibiotic resistance-related genes. These data allowed to confirm the isolates' identity as S. To overcome operator-dependent analysis of the dot blots and increase the technique's consistency and reliability, the hybridization signals were converted into probability values, with average probabilities higher than 0.5 being considered positive results. uberis isolates were obtained from 24 different cows from the two herds. These herds, located in Portugal (Barcelos and Maia regions), had similar management practices, with the herd from Barcelos being smaller and having a better milking parlor management, since infected cow segregation was immediate. uberis infections were followed in a 6 month period, in order to collect and characterize isolates from cows with persistent infections. uberis, and evaluated its efficiency when compared to multilocus sequence analysis (MLSA) genotyping. In this work, we optimized and validated a dot blot platform, combined with automatic image analysis, to rapidly assess the population structure of infective S. uberis populations are essential to determine the best practices to control this pathogen. Since different control strategies are employed depending on the mode of transmission, in-depth studies of S. uberis has been shown to adopt a contagious epidemiological pattern in several dairy herds. While traditionally acknowledged as an environmental pathogen, S. Streptococcus uberis is considered one of the most important pathogens associated with bovine mastitis. 4Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.3Estudos de Populações, Instituto de Saúde Pública da Universidade do Porto, Porto, Portugal.2Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal.1CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Vairão, Portugal.Pedro Albuquerque 1 *, Niza Ribeiro 2,3, Alexandre Almeida 1,4, Irena Panschin 1,4, Afonso Porfirio 1,2, Marta Vales 1,2, Francisca Diniz 1,4, Helena Madeira 2 and Fernando Tavares 1,4
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