Synergistic antibacterial mechanism of Bi2Te3 nanoparticles combined with the ineffective β-lactam antibiotic cefotaxime against methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) infections have become a serious threat to public health because traditional antibiotics are less efficient. Here, we developed a simple and efficient combination of Bi2Te3 nanoparticles (NPs) with beta-lactam antibiotics cefotaxime (CTX), which presented significant synergistic antibacterial activity against MRSA. The minimal inhibitory concentration of CTX decreased from 256 to 32 mu g/mL in the presence of 8 mu g/mL Bi2Te3 NPs. The results of cell membrane potential and cellular K+ content measurements demonstrated that the destruction of membrane functions is a factor in the synergistic mechanism. Furthermore, the induction of cellular reactive oxygen species generation, inhibition of beta-lactamases induced by CTX and direct damage to the cell structure constituted other factors of the synergistic mechanism. These observations suggest that reviving the efficacy of ineffective fi-lactam antibiotic CTX by Bi2Te3 NPs may be a potentially effective therapeutic strategy to overcome refractory MRSA infections.