Chemical synthesis of silver nanoparticles (Ag-NPs) and evaluation of their antimicrobial potential against some fungal and bacterial causes of diseases in buffaloes were investigated. A total of 75 animal cases of dairy buffaloes were selected from a private farm at Giza governorates in which animals suffered from diarrhea, mastitis and respiratory symptoms. Seventy five samples (25from each of nasal swabs, pharyngeal swabs from dairy buffaloes with respiratory disorders, fecal swabs of diarrheic animals and milk samples of mastitis animals). The main bacterial isolates were Staphylococcus aureus, Sreptococcus spp, Salmonella spp., Escherichia coli, Ps.aeruginosa and Klebsiella spp. The species of Staphylococcus are considered the most predominant isolates from different samples of buffaloes that suffered from respiratory disorders, diarrhea or mastitis at rates of incidence of (32%, 12 % and 36%) respectively. While, S.typhimurium was recovered from diarrheic buffaloes at incidence rate of 8% .On the other hand, the most predominant members of Aspergillus species in samples were A.flavus (60%), A. fumigates (54.6%), A.niger (53.3%), followed by A. ochraceus (41.3%). While, C.albicans was isolated at the rates of (41.33%) and was recovered from 68%, 40% and 16% of samples of buffaloes with mastitis, diarrhea and respiratory disorders respectively. The silver nanoparticles was synthesized by chemical method and the sizes and morphology of Ag-NPs were characterized by visual inspection; in a UV-visible spectrophotometer and scanning by transmission electron microscope (TEM) and scanning electron microscope (SEM) for detection of their particle size and the purity of the prepared powder. The antimicrobial potential of prepared Ag-NPs against C.albicans, A.flavus, S.aureas and Salmonella sp. was concentration dependent, when the concentrations of Ag-NPs increased up to 300 ug/ml, the optical density of treated spore suspension were decreased till reach 100% transmittance and clear medium. The minimum inhibitory concentration (MIC) of Ag-NPs for C.albican, A.flavus, Salmonella sp., S.aureas sp. was (250-, 300,300 and 250ug/ml), respectively. Whereas, the results of combination between AgNPs and traditional antibioticrevealed that the requirement of lower concentrations from both to obtain the antimicrobial effects (200, 150, 200 and 200ug/ml) for C.albican, A.flavus, Salmonella sp., S.aureas sp., respectively. The treated fungal and bacterial cells were subjected to SEM, the damage and rupture of their cell wall was detected or membrane damage and some pits and adhered to respiratory sequence of cytoplasm that had been caused leakage in inter cellular components and finally cell death. Therefore, the synergistic, combination therapy of Ag-NPs with other traditional antibiotics drugs was urgently required to decrease the used concentration of nanoparticles, overcome the microbial resistant to traditional antibiotics and resulted more efficient antimicrobial activity for the treatment of human and animal diseases.
