Antibacterial activity of ZnO quantum dots and its protective effects of chicks infected with Salmonella pullorum

Abstract

In light of emerging antibiotic resistance, synthesis of active, environmental friendly antimicrobial alternatives becomes increasingly necessary. In this study, ZnO quantum dots (ZnO QDs) were developed by the sol-gel method and characterized. The antibacterial activities of ZnO QDs against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Salmonella Pullorum (S. Pullorum) were systematically investigated. Moreover, the protective effects of ZnO QDs on Salmonella-caused pullorosis in chicks were also explored. The results indicated that the size range of ZnO QDs was 3-6 nm. Antibacterial results showed that ZnO QDs treatment inhibited the growth of E. coli, S. aureus, and S. Pullorum in the rate of 87.06 +/- 0.98%, 94.75 +/- 2.28%, and 85.55 +/- 1.15%, respectively. Its excellent antibacterial property was manifested with the minimum inhibitory concentration of 0.7812, 0.0976, and 0.1953 mg ml(-1), which may be attributed to the production of reactive oxygen species, the dissolution of Zn2+ ions, and the loss of cell integrity. Furthermore, in the in vivo test, the ZnO QDs effectively reduced the mortality of chicks infected with S. Pullorum via regulating the balance of the intestinal flora, protecting liver and intestine, and modulating the balance of antioxidation systems. This study reveals that ZnO QDs exerts remarkably antibacterial activity in vitro and anti-pullorosis effect in chicks.