Preliminary Study On The Antimicrobial Activity And Mechanism Of Toad Venom For Staphylococcus

In this work, preliminary studies have been carried out on the mechanism of toad venom against Staphylococcus aureus in aspect of cell growth status, growth curve, cell membrane permeability and RNA transcription level of bacterial GGT femB gene. Study procedure contains 2,3,5-triphenyl tetrazolium chloride(TTC) Staining, bacteria conductivity measurement, RT-PCR experiments, culture microplates, crystal violet staining method for quantifying and observation with laser confocal microscopy imaging system. Results show that the minimum inhibitory concentration(MIC) and the minimum bactericidal concentration(MBC) of toad venom against Staphylococcus aureus are 2mg/mL and 2.5mg/mL, respectively. The membrane permeability significantly increased compared with the control group. RT-PCR experiments showed a decline in mRNA levels of Staphylococcus aureus femB gene with treatment time increasing, while the mRNA levels of femB gene was 0.53 times of the normal bacteria after 9 hours. Besides, along with the suppression on the bacterial growth, an inhibiting effect can be also observed for toad venom on the biofilm formation of Staphylococcus aureus with an effective inhibitory concentration of 1.25mg/mL. Toad venom can suppress growth of Staphylococcus aureus by obstructing cytoderm synthesis and biofilm formatio.