الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Staphylococcus species are one of the most common pathogens isolated in mastitis cases, and are categorized into coagulase-positive staphylococci (CPS), which include S. aureus, and coagulase-negative staphylococci (CNS). Staphylococci are the most typical bacteria found in cattle with mastitis, either S.aureus or coagulase-negative staphylococci (CNS). The antibiotic sensitivity testing of isolates established high resistance to β-lactam, cephalosporines and macrolides. Concerning the prudent use of antibiotics, Staphylococcal mastitis should not be treated with antibiotics unless there is a clinical need for it, and more research is being conducted to investigate methods for controlling staphylococcal mastitis. Microbiological analysis of 400 samples of milk obtained from symptomatic and asymptomatic mastitis cows revealed that 73% of the isolates were Staphylococcus species :( 64%) came from cows with clinical mastitis and (36%) from subclinical mastitis cases. Based on the coagulase test, Coagulase-positive staphylococci (CPS) (54%) and coagulase-negative staphylococci (CNS) (19%) were identified in staphylococcal isolates. S. aureus was completely identified in all CPS isolates (54%) using a nuc gene PCR assay. The S. aureus isolates revealed higher resistance to ampicillin (100%), followed by amoxicillin-clavulanic acid (98.1%), cefotaxime (88.9%), erythromycin (79.6%), cefuroxime (63%), and tetracycline (61.1%). Furthermore, the CNS isolates showed high resistance against amoxicillin-clavulanic acid (100%), followed by ampicillin (94.7%), cefotaxime (89.5%), cefuroxime (89.5%).The CPS isolates showed high susceptibility to imipenem (94.4%) and ciprofloxacin (72.2%) and the susceptibility of CNS was observed to be highest for imipenem (94.7 %) and ciprofloxacin (63.1).Cows with clinical mastitis reported high levels of IL-6 in both their serum and their milk. While they have much lower levels of IL-4 and IL-10 than normal ones (P < 0.001).