Background: S. aureus is one of the main pathogens involved in ruminant mastitis worldwide. The severity of staphylococcal infection is highly variable, ranging from subclinical to gangrenous mastitis. This work represents an in-depth characterization of S. aureus mastitis isolates to identify bacterial factors involved in severity of mastitis infection.
Methodology/principal Findings: We employed genomic, transcriptomic and proteomic approaches to comprehensively compare two clonally related S. aureus strains that reproducibly induce severe (strain O11) and milder (strain O46) mastitis in ewes. Variation in the content of mobile genetic elements, iron acquisition and metabolism, transcriptional regulation and exoprotein production was observed. In particular, O11 produced relatively high levels of exoproteins, including toxins and proteases known to be important in virulence. A characteristic we observed in other S. aureus strains isolated from clinical mastitis cases.
Conclusions/significance: Our data are consistent with a dose-dependant role of some staphylococcal factors in the hypervirulence of strains isolated from severe mastitis. Mobile genetic elements, transcriptional regulators, exoproteins and iron acquisition pathways constitute good targets for further research to define the underlying mechanisms of mastitis severity.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0027354 | PLOS |
Vet Res Commun
December 2024
Institute of Biochemistry and Biotechnology, University of Veterinary and Animal Sciences, Lahore, 54000, Pakistan.
Camel mastitis especially caused by Staphylococcus aureus (S. aureus), is a major risk to animal health and milk production. The current investigation evaluated the antibiotic susceptibility and virulence factors of S.
View Article and Find Full Text PDFJ Agric Food Chem
December 2024
Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Yuanmingyuan West Road, Beijing 100193, China.
In clinical mastitis of dairy cows, the abnormal accumulation of apoptotic cells (ACs) and subsequent secondary necrosis and inflammation pose significant concerns, with macrophage-mediated efferocytosis, crucial for ACs clearance, remaining unexplored in this context. In nonruminants, MER proto-oncogene tyrosine kinase (MERTK) receptors are essential for efferocytosis and A Disintegrin and Metalloproteinase 17 (ADAM17) is thought to play a role in regulating MERTK integrity. This study aimed to delineate the in situ role of efferocytosis in clinical mastitis, with a particular focus on the interaction between MERTK and ADAM17 in bovine macrophages.
View Article and Find Full Text PDFBMC Res Notes
December 2024
Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Box 63, Buea, Cameroon.
Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a zoonotic pathogen that poses a serious threat to veterinary and public health worldwide. We investigated mastitis milk samples for contamination with MRSA and also characterized the MRSA isolates by investigating antimicrobial resistance and virulence factors.
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Vet Sci
December 2024
Faculty of Veterinary Science, University of Thessaly, 43100 Karditsa, Greece.
This study aimed to investigate the incidence of subclinical mastitis (SCM), the implicated pathogens, and their impact on milk quality in dairy sheep in Greece. Furthermore, we preliminarily evaluated infrared thermography and the application of AI tools for the early, non-invasive diagnosis of relevant cases. In total, 660 milk samples and over 2000 infrared thermography images were obtained from 330 phenotypically healthy ewes.
View Article and Find Full Text PDFVet Sci
December 2024
Department of Veterinary and Animal Sciences, Section for Production, Nutrition and Health, University of Copenhagen, DK-1870 Frederiksberg C, Denmark.
Udder health consulting is an essential aspect of mastitis control and is based on herd-specific intervention often provided by the herd veterinarian, focusing on managing the bulk tank somatic cell count. Effective communication and alignment of expectations between dairy farmers and herd veterinarians are more critical than ever due to the substantial increase in herd sizes, which amplifies both potential gains and losses. To facilitate future cooperation between dairy farmers and herd veterinarians, it is important to understand the current level of agreement in communication, and therefore, we conducted a study to describe the agreement in the perception of their communication during udder health consulting.
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