The non-protein fraction of embryonic stem cell secretome exerts antibacterial effects against antibiotic-resistant bacterial strains

Abstract

In recent years, it has been extremely evident to seek out for new antibacterial agents, because the burgeoning problem of antibiotic resistance and the toxicity of many antimicrobial compounds has forced scientists to turn attention to alternative approaches. Investigating stem cell secretomes, including the non-protein portion, to find new antimicrobials is a promising area in the field. We examined an effect of the non-protein portion within the embryonic stem cell secretome on various bacterial strains, including antibiotic-resistant members. The non-protein fraction of the stem cell secretome was obtained by preparative high-performance liquid chromatography. Bactericidal activity was tested against eight museum bacterial strains and 206 clinical strains by comparing the secretome-related effects on growth of bacterial cultures. The museum strains showed some dose-dependent effects at concentrations of 25100 g/ml. Some bactericidal activity was shown at a concentration of 100 g/ml against the clinical strains of Gram-negative microorganisms of different species, but bacterial sensitivity to the secretome fraction varied, with growth stimulation being detected in some strains. Applying non-protein fraction of the stem cell secretome at higher concentrations of 1001000 g/ml showed no dose-dependent effect. The clinical strains of E. coli and P. aeruginosa were shown to have reduced bactericidal activity after 24-hour incubation. Thus, this study has shown that the non-protein fraction of the embryonic stem cell secretome exerts bactericidal effects against some bacterial strains. However, more detailed studies are needed to identify a mechanism of action and to determine the most effective dose as well as frequency of administration.