Aim:To characterize Staphylococcus aureus from clinical and subclinical mastitis and identify virulence factors.Materials and Methods:Two hundred and two milk samples were collected, 143 from mastitic cattle and buffaloes 94 and 49, respectively, and 59 from apparently healthy cattle and buffaloes 35 and 24, respectively.Results:California mastitis test was applied and positive prevalence were 91.48% and 75.51% for cattle and buffalo with clinical mastitis and 37.14% and 45.83% for cattle and buffalo with subclinical mastitis. S. aureus was isolated from clinically mastitic cattle and buffaloes were 39.29% and 50%, respectively. While, from subclinical mastitic cattle and buffaloes were 80% and 72.73%, respectively. Hemolytic activity was assessed for S. aureus isolated from clinically and subclinical mastitic cases with prevalences of 100% and 56.25%, respectively. Thermo nuclease production from clinically and subclinical mastitic cases was 25% and 56.25%, respectively. Simplex polymerase chain reaction (PCR) conducted on S. aureus using 16S rRNA, clumping factor A, Panton valentine leukocidin, coagulase (Coa), alpha-hemolysin and beta-hemolysin those proved existence in 100%, 46.9%, 65.6%, 100%, 34.4%, and 43.75% of the isolates, respectively. While, multiplex PCR is utilized for detection of enterotoxins and proved that 12.5% was positive for enterotoxine Type D.Conclusions:It is concluded that simplex and multiplex PCR assays can be used as rapid and sensitive diagnostic tools to detect the presence of S. aureus and characterize its virulence factors that help in detection of severity of infection, distribution and stating preventive and control strategies.

Bovine mastitis constitutes an economic and serious problem in dairy industry worldwide. This study aimed to determine the phenotypic and molecular characterization of methicillin-resistant Staphylococcus aureus isolated from bovine mastitis in Menoufiya governorate, Egypt. A total of 530 mastitic samples (280 clinical and 250 subclinical) were collected and subjected to bacteriological examination. The result revealed that prevalence rate of clinical and subclinical mastitis was 52.83% and 47.16%, while S. aureus prevalence rate was 28.57% and 24.4% in clinical and subclinical mastitis respectively. Out of 157 staphylococci isolates on MSA medium, 141(89.9%) were identified as S. aureus isolates through biochemical activities and confirmed by amplifying of nuc gene at 279 bp. All S. aureus isolates confirmed by nuc gene (141 isolates) were tested for antibiogram profile against some β-lactams antibiotics (oxacillin, penicillin and amoxicillin/clavulanic acid) that recorded high resistance against these antibiotics. Out of 141 isolates, 128 (90.78%) were confirmed as MRSA strains based on phenotypic resistance to oxacillin and confirmed by molecular detection of the mecA gene at 310 bp. In conclusion, these results showed the significance of continuous surveillance of antibiogram pattern of S. aureus isolates of mastitis origin to design effective control measures for S. aureus mastitis.

Xenotransplantation, in its broadest sense, is the transplantation, implantation, or infusion of cells, tissues, or organs from one species to another. While there is a high demand for human tissues, cells, and organs for use in clinical transplantation, they are often in short supply. Recent scientific and biotechnological advancements, coupled with the scarcity of human allografts, have led to renewed interest in developing exploratory treatment strategies that use xenotransplantation products in human recipients. However, despite its potential benefits, the use of xenotransplantation is still limited due to various considerations, as discussed in this review of the past, present, and future directions of xenotransplantation. One of the key ethical concerns surrounding xenotransplantation is the potential impact on the animals from which the cells, tissues, or organs are obtained. As with genetic modification to fix genetic defects or prevent disease, the ideal outcome for these animals is that they will be better off as a result of the change. However, unless there are major changes in the way science is taught to incorporate ethics into recognized scientific theory and practice, these concerns will not be adequately addressed

S. aureus is one of the most important causes of nosocomial infections, main contagious pathogens that can play a vital and important role in bovine mastitis in veterinary medicine causing high worldwide economic losses, where the primary reservoir harboring the pathogens is cow, and recently recorded as zoonotic microbe which able to transmitted from human to animal and vice versa, identification of staphylococcus species mainly S. aureus become more quickly and accurate with molecular technique as phenotypic technique due to multidrug resistance developed some mutation and production of biofilm which interference phenotypic identification, as nuc gene, and coa gene become the golden standard technique for identification S. aureus and the study concerned the differentiation between phenotypic and genotypic characterization of isolates collected from milk samples of bovine mastitis, as directed 157 phenotypic staphylococcus isolates on MSA media to biochemical phenotypic tests as 81/157 (51.6%) isolates of them were phenotypic S. aureus, and by molecular technique, 16S universal primer detected 141/157 (89.8%) were confirmed staphylococcus about 130/141(92.2%) were CoPS by coa gene detection, and 111/141 (78.7%) were typical S. aureus detected by nuc gene, as most of them produced biofilm that detected by ica gene in 81/141(57.4%) was the main cause of interrupting the phenotypic characterization by biochemical tests.