Abstract

In recent years, significant research efforts have focused on developing antibacterial agents derived from natural products, especially those formulated at the nanoscale. This work study antibacterial effect of Curcumin Nano-emulsion (Cur-NE) against Staphylococcus aureus (S.aureus) isolated from clinical bovine mastitis, both in vitro and in vivo assessment studies were used. Firstly, S.aureus was isolated with a total rate of 28% using antimicrobial susceptibility test showed multidrug resistance against oxacillin, amoxicillin/clavulanic acid and tetracycline. Minimal inhibitory and bactericidal concentrations were 150 μg/ml and 300 μg/ml respectively. Using of 150 μg/ml of Cur-NE in combination with different antimicrobials by applying the agar well diffusion technique enhance the inhibition activity of gentamicin and norfloxacin However, it slightly suppressed the activity of amoxicillin/clavulanic acid, Oxacillin and tetracycline, by using Transmission electron microscope (TEM) Cur-NE lead to destruction of cell wall and leakage of cellular contents of bacterial cell. Then, a total of 25 lactating rabbits were grouped to 5 groups (5 each), G1: negative-control, G2: infected-control, G3: gentamicin treated group, G4: Cur-NE treated group and G5: gentamicin + Cur-NE treated group after the end of treatment, re isolation of S.aureus ,gene expression of TNF-α and IL-6 in infected tissue and histopathological examination were investigated. Our result revealed that Cur-NE has a potent antibacterial effect on S.aureus and can significantly decrease the expression of TNF-α and IL-6 genes with a greater noticeable effect for its combination with gentamicin. Histopathological findings revealed that S.aureus induced severe, toxin-mediated mastitis, while treatment with gentamicin and Cur-NE especially in combination significantly improved outcomes. Cur-NE showed enhanced antibacterial and anti-inflammatory effects, highlighting its potential as an effective adjunct therapy

Key words: Curcumin Nano-emulsion, S.aureus, Mastitis, TEM, TNF-αand IL-6