Strong and Nonspecific Synergistic Antibacterial Efficiency of Antibiotics Combined with Silver Nanoparticles at Very Low Concentrations Showing No Cytotoxic Effect
This clinical study, published in December 2015 in the journal Molecules, demonstrates that silver nanoparticles “are suitable candidates for use in combinations with traditional antibiotics in order to improve their antibacterial action.” In other words, when the researchers used antibiotic drugs in combination with silver nanoparticles, they found improved action against the pathogens.
The researchers studied the synergistic effects of combinations of silver nanoparticles with a variety of antibiotic drugs against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The tested antibiotics included Ampicillin, Ampicillion/Sulbactam, Piperacillin, Piperacillin/tazobactam, Penicillin, Oxacillion, Cefazolin, Cefuroxime, Cefepime, Cefoperazone, Ceftazidime, Meropenem, Teicoplanin, Vancomycin, Aztreonam, Gentamicin, Tetracycline, Amikacin, Chloramphenicol, Erythromycin, Clindamycin, Oxolinic acid, Ofloxacin, Ciprofloxacin, Co-trimoxazole, and Colistin. The researchers found that “strong synergistic effects were shown for all tested antibiotics combined with silver nanoparticles at very low concentrations of both antibiotics and silver nanoparticles.” In other words, combining the silver particles with antibiotic drugs allowed the researchers to use very low concentrations of both — levels well below what the individual antibiotic drugs would normally have to be used at — and still achieve improved effectiveness against the pathogens. According to the researchers, “…a very low amount of silver is needed for effective antibacterial action of the antibiotics, which represents an important finding for potential medical applications due to the negligible cytotoxic effect of AgNPs towards human cells at these concentration levels.” The study authors concluded, “The antibacterial activity of the tested antibiotics increased markedly when combined with AgNPs…the synergistic effect of antibiotics combined with AgNPs was proved at very low concentrations showing no cytotoxic effect on mammalian cells.”