The activity of silver nanoparticles (axonnite) on clinical and environmental strains of Enterococcus spp.

Aims: The spread of bacterial antibiotic resistance among clinical strains is a growing problem nowadays. Resistance in Enterococcus spp. strains has merited special concern of late, as they have become significant nosocomial pathogens. Hence, the use of compounds such as silver nanoparticles (AgNPs), displaying various mechanisms of action, is a growing new approach against virulent, drug-resistant infections. Therefore, the activity of AgNPs obtained by a physical method (microexplosion method) was tested against 30 clinical and environmental Enterococcus spp. strains presenting diverse virulence and resistance patterns.

Results: The minimal inhibitory concentration for all the species ranged from 0.39 to 3.125 μg/ml. No statistical differences (p=0.26) were found between resistance to AgNPs and resistance to antibiotics, suggesting high activity of AgNPs even against multidrug-resistant strains.

Conclusions: AgNPs obtained by this method seem to be a promising alternative to chemotherapeutics in the treatment or prevention of enterococcal infections.