Selenium nanoparticles and evaluation of their antimicrobial activity on bacterial isolates obtained from clinical specimens

Our main objective was to determine the antimicrobial effects of selenium nanoparticles (SeNPs). For the testing of their influence we exploited isolates obtained from swabs from patients (n = 25) with hard-to-heal skin infections. Using mass spectrometry we identified 49 various bacterial strains. Antimicrobial properties of SeNPs were tested using measurement of inhibition zones; determination of growth curves and measurement of possible toxicity by inhibition of nucleic acid replication. Clinical isolates were exposed to the constant concentration of SeNPs (100 μg/mL). In almost all of bacterial strains we observed inhibition zones higher than 5 mm, which are the legislatively given as the lowest value for confirmation of effectivity of tested antimicrobial agents. The most sensitive strains were further exposed to the concentration range of selenium nanoparticles (0; 1; 2; 4; 8; 16; 32 and 48 μg/mL). Growth curves exhibited inhibition effects caused even by the lowest applied concentration (1 μg/mL) in all of tested bacterial isolates. In Escherichia fergusonii, Pseudomonas aeruginosa and Streptococcus agalactiae, application of 64 μg/mL of SeNPs resulted in total growth inhibition. We confirmed the antimicrobial effects of SeNPs, which may be used in the future for the elimination of hard-to-heal bacterial infections.