Abstract
Background:
Cattle mastitis is a widespread and affluent illness that threatens the dairy industry. Numerous common infectious diseases, mostly zoonotic, impact Egypt’s dairy cow production. According to their remarkable affordability, high safety, and biocompatibility, and their exceptional effectiveness against microbes, zinc oxide nanoparticles (ZnO-NPs) have shown great promise in biomedicine, particularly in the areas of antibacterial and anticancer treatment, and so have become the most broadly used nanoparticles of metal oxides in various biological treatments throughout the last 20 years.

Aim:
The present study emphasized the potential for dispersed, non-agglomerated ZnO-NPs produced by sonochemical irradiation with starch serving as a capping agent to be considered more economical and effective germicidal agents in the eradication of bacteria of bovine mastitis such as: Staphylococcus epidermidis (S. epidermidis), Pseudomonas aeruginosa (P. aeruginosa), Salmonella enterica serovar Typhimurium (S. Typhimurium), and Enterococcus faecium (E. faecium).

Methods:
To improve their antibacterial effectiveness against specific zoonotic pathogens that can cause bovine mastitis, three suspensions of ZnO-NPs were created: auto-combustion reaction-synthesized ZnO-NPs, auto-combustion reaction-prepared uncapped ZnO-NPs, and sonochemically prepared starch-capped ZnO-NPs. The three suspensions were exposed to the zoonotic pathogens S. epidermidis, P. aeruginosa, S. Typhimurium, and E. faecium at concentrations ranging from 1 to 50 mg/ml.

Results:
The prepared three nano-ZnO suspensions showed minimum bactericidal concentration (MBC) total suppression of S. epidermidis at doses of 1–10 mg/ml of nano-ZnO and minimum inhibitory concentration (MIC) against S. epidermidis at concentrations <1 to 5 mg/ml. According to the suspension (No. 1), MBC was detected at a concentration of 30 mg/ml and the MIC was 20 mg/ml for P. aeruginosa. Concerning S. Typhimurium, the MIC was found at a concentration of 5 mg/ml, while MBC was measured at 10 mg/ml. Lastly, at a concentration of 30 mg/ml, the nano-ZnO suspension (No. 1) demonstrated MBC activity against E. faecium, with MIC activity at a concentration of 2 mg/ml.

Conclusion:
This point will be useful for future research on ZnO-NPs because it focuses on their biological and antibacterial applications.

Key words: Zoonoses, Bovine mastitis, Zinc oxide nanoparticles, Egypt, Antibiotic residues