Synergistic antibacterial effect of Bi2S3 nanospheres combined with ineffective antibiotic gentamicin against methicillin-resistant Staphylococcus aureus

In this paper, Bi 2 S 3 nanospheres with size of 212   nm were prepared by a simple hydrothermal process. The selectively enhanced antibacterial effects of Bi 2 S 3 nanospheres with three classes of ineffective antibiotics, β-lactam (cefuroxime, CXM; cefotaxime , CTX and piperacillin , PIP), quinolone (ciprofloxacin, CIP) and aminoglycoside (gentamicin, GEN) against clinical isolated methicillin-resistant Staphylococcus aureus (MRSA) were investigated for the first time. GEN shows significantly synergistic growth inhibition against MRSA when combined with Bi 2 S 3 nanospheres, while CXM, CTX, PIP and CIP do not. Raman spectroscopy and Z potential studies reveal that Bi 2 S 3 could interact with GEN and the combination showed small electronegativity , which probably induced the increase of GEN content in cytoplasm of bacteria. Furthermore, the combination of Bi 2 S 3 nanospheres and GEN can destroy the bacterial membrane function and induce more bactericidal reactive oxygen generation than that of Bi 2 S 3 or GEN alone. The cytotoxicity test indicates that the combination of Bi 2 S 3 and GEN presented low toxicity to human normal hepatocyte L02. This work shows that Bi 2 S 3 nanospheres can be used to enhance the action of ineffective antibiotic GEN against MRSA, thus strengthening the antibiotic capacity for fighting MRSA infections.