Evaluation of the effect of nanocopper oxide and nanochitosan on highly antibiotic resistant Staphylococcus aureus isolated from normal and mastitic bovine milk

T he objective of study was to determine the rate of isolation of Staph- ylococcus aureus (S. aureus) in normal and mastitic bovine milk and their relationship with the milk composition also microbial, and chemical parameters changes in milk of normal apparently healthy bovine.Moreover, we study the effects of copper oxide Nano particles (Cuo-Nps) and chitosan Nano particles (Ch-Nps) on isolated antibiotic-resistant strains of S. aureus.One hundred milk samples (50 samples from apparently healthy lactating cows and buffaloes 25 for each) and (50 samples of mastitic milk 25 cows' milk and 25 buffaloes' milk from the neighboring animals in the same farms) were randomly collected from 10 privet farms (5 cows farm and 5 buffalo's farms) in Kafrelsheikh Governorate, Egypt.Ten of 50 raw milk samples were positive for S.aureus (six raw cow , s milk and 4 raw buffalo , s milk samples) whereas 26 of 50 mastitic milk samples were positive for S.aureus (fifteen mastitic cow , s milk samples and 11 mastitic buffalo , s milk samples).Our results revealed that direct relationship between isolation of S. aureus from normal milk samples and TBC, SCC, minerals (ash)g%, SNF g% and Total solid g% (significant increase) and inverse relationship with PH, Fat %, Lactose % and Water % (significant decrease), and no significant change with other parameters.Susceptibility test of isolated S. aureus to antibiotics show that highly susceptible to Amoxicillin+Clavulonic acid (77.77%) but high resistant to Oxytetracycline (94.44%).PCR analysis of S. aureus for general gene (23S rRNA) was 100%, while