Project description:Infection caused by bacteria from environmental reservoirs such as E. coli and S. uberis have not decreased in prevalence. Lack of success in controlling bovine mastitis due to S. uberis is associated with the route of infection which is not well understood and there is inadequate information on pathogenesis of S. uberis. Therefore, this study was to investigate the virulence factors of S. uberis using comparative genome analyses using isolates from cows with clinical mastitis and isolates from cows with a low cell count in their milk using a Subtracted Diversity Array (SDA). This study also reports the construction and validation of a microarray capable of fingerprinting the virulent and non-virulent isolates using the SDA technique.
Project description:Escherichia coli and Staphylococcus aureus are two common pathogenic microorganisms that cause mastitis in dairy cows. They can cause clinical mastitis and subclinical mastitis. In recent studies, lncRNAs have been found to play an important role in the immune responses triggered by microbial inducers. However, the actions of lncRNAs in bovine mastitis remain unclear. The purpose of this study was to explore the lncRNA profile on mastitis.
Project description:Group C Streptococcus dysgalactiae subsp. dysgalactiae (GCS) field strains causative of bovine mastitis and group C or group G Streptococcus dysgalactiae subsp. equisimilis (GCS/GGS) isolates from human infections were tested for the presence of virulence genes employing a microarray containing 220 virulence genes of S. pyogenes (GAS).
Project description:Bovine mastitis causes changes in the serum exosomal miRNAs expression. Serum samples from healthy dairy cows (n = 7) were compared to those of cows with subclinical (n = 7 ) using small RAN sequencing. Three hundred fifty-five miRNAs (341 known and 14 novel ones) were identified. There were 42 miRNAs up-regulated in serum-derived EVs from cows with subclinical mastitis, including bta-miR-1246, bta-miR-2431-3p, bta-miR-126-3p, bta-miR-29a, etc. The MAPK signaling pathway was the most affected pathway by clinical mastitis. Thus, miRNA alterations in mastitis serum-derived EVs support the potential regulator role of specific miRNAs as exosomal cargo in clinical mastitis physiology.
Project description:Early detection of bovine subclinical mastitis may improve treatment strategies and reduce the use of antibiotics. Herein, individual milk samples from Holstein cows affected by subclinical mastitis induced by S. agalactiae and Prototheca spp. were analyzed by untargeted and targeted mass spectrometry approaches to assess changes in their peptidome profiles and identify new potential biomarkers of the pathological condition. Results showed a higher amount of peptides in milk positive at the bacteriological examination when compared with the negative control. However, the different pathogens seemed not to trigger specific effects on milk peptidome. The peptides that best distinguish positive from negative samples are mainly derived from the most abundant milk proteins, especially from β- and αs1-casein, but also include the antimicrobial peptide casecidin 17. These results provide new insights into the physiopathology of mastitis. Upon further validation, the panel of potential discriminant peptides could help to the development of new diagnostic and therapeutic tools.
Project description:In a subclinical infection such as bovine streptococcal mastitis, early recognition is a great challenge, and miRNAs profiling could potentially assist in the diagnosis and contribute to the understanding of pathogenicity and defense mechanisms. We have examined the miRNA repertoire during the early phase response of bovine macrophages to in vitro infection with live Streptococcus agalactiae. Next generation sequencing of 20 small RNA libraries from blood monocyte-derived macrophages exposed to two sequence types of S. agalactiae (ST103 and ST12) for 6 hours in vitro was performed. Analyzes of over 356 million of high quality sequence reads, revealed that 17 and 44 miRNAs were differentially expressed (P < 0.05) between the control unchallenged macrophages and the macrophages infected with ST103 and ST12, respectively. We also identified the expression of 31 potentially novel bovine miRNAs.
Project description:The Gram-positive bacterium S. aureus is one of the most common causes of contagious bovine mastitis. A predominant S. aureus clone persists within its host over a long period. In the present study, we compared the surface proteome of two isolates, collected from a naturally infected dairy cow with chronic, subclinical mastitis: an initial isolate (IN) and a host-adapted strain (HA). The isolates were grown under iron- and oxygen-limiting conditions in RPMI 1640 medium. Bacterial cells were isolated at the early stationary phase and used for preparation of surface-associated proteins by applying a surface-shaving and a surface-biotinylation approach. Proteins were identified by gelfree (surface-shaving approach) and GeLC-MS/MS (biotinylation approach) analyses.