In the recent years, emergence of infectious diseases caused by drug resistant pathogens had been increased; therefore there is an urgent need to search for new alternative and effective antimicrobial agents to overcome the drug resistance. In the present investigation, the study group consisted of 90 sheep and 90 goats with clinical evidences of mastitis in 17(18.89%) goats and 5 sheep (5.56%) that manifested   swollen udder with or without systemic signs of illness related to mastitis. Standard bacteriology was performed on pretreatment milk samples from the 17 goats and 5 mastitic ewes as well as 60 soil samples and 60 pail water samples. The bacteria isolated were identified as Staphylococcus aureus 12 (70.6%) from goats and 5 (100%) from sheep. In addition, S. aureus could also be identified in 41 (68.3%) soil samples and 42 (70%) water samples. The current study aimed to explore the bactericidal effect of silver nanoparticles (AgNPs) on methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) strains isolated from mastitic milk and their surrounding environment (water and soil) in Aswan, Egypt. AgNPs solution was synthesized by typical one-step synthesis protocol using soluble starch and was characterized using transmission electron microscopy and atomic absorption spectrophotometer. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs were examined to evaluate the bactericidal efficiency. In the present study, no significant discrepancy was observed between the influence of AgNPs on MRSA and MSSA (P> 0.05). It can be concluded that Ag-NPs have strong bactericidal effect against both MRSA and MSSA strains.