Anti-quorum sensing effect of streptococcus agalatiaceae by Zinc Oxide, Copper Oxide, and Titanium Oxide nanoparticles

Abstract Quroum sensing system found in many species of bacteria, including Streptococcus agalactiae that use to regulate many virulence and pathogenicity characteristics. So, this study achieved to detect the inhibitory effect of (CuO, ZnO, TiO2) nanoparticles on quorum sensing of Streptococcus agalactiae. The bacterial isolates of Streptococcus agalactiae were obtained from vaginal and rectal swabs from pregnant women who visited maternity and children hospital in Al-Diwaniyah city from 7/2018 to 4/2019. Three metal oxides nanoparticles (CuO, ZnO, TiO) were used which was examined using a scanning electron microscope and then three different concentrations were prepared (100,250,500) μg\ml to study its effectiveness against quorum sensing. The nanoparticles showed their effectiveness in inhibiting the quorum sensing of Streptococcus agalactiae through the formation of a clear inhibition zone around the wells. Copper oxide nanoparticles showed high efficiency in inhibition of the quorum sensing with a diameter of (35) mm. Also, zinc oxide nanoparticles showed efficacy against the quorum sensing with diameter (27) mm, while the less inhibition effect appeared with the use of titanium oxide, where the diameter of inhibition was (20) mm. The results of the study showed the efficiency of nano-oxides (TiO2, ZnO, CuO) in inhibiting the quroum sensing of S.agalactiae bacteria, and copper oxide was the most efficient among them. So, there is need to further studies to detect the effect of nanoparticles on quorum sensing and virulence factors of other bacteria.