In vitro antimicrobial activity of a novel compound, Mul-1867, against clinically important bacteria

The antimicrobial activity of Mul-1867, a novel synthetic compound, was tested against 18 bacterial strains, including clinical isolates and reference strains from culture collections.

The minimal inhibitory concentration (MICs) and minimal bactericidal concentration (MBCs) were determined by using the broth macrodilution method. The kinetics of the inhibitory effects of Mul-1867 against biofilm-growing microorganisms was assessed at time-kill test in vitro against 48-h-old biofilms of Staphylococcus aureus and Escherichia coli. Transmission electron microscopy analyses was conducted to examine cell disruption.

A comparative assessment of the antimicrobial activities of Mul-1867 and chlorhexidine digluconate (CHG), used as a control antimicrobial, indicated that Mul-1867 was significantly more effective as a disinfectant than CHG. Mul-1867 showed potent antimicrobial activities against all the tested bacteria (MIC: 0.03-0.5 μg/mL). Furthermore, MBC/MIC ratio of Mul-1867 for all tested strains was less than or equal to 4. Time-kill studies showed that treatment with Mul-1867 (0.05-2 %) reduced bacterial numbers by 2.8-4.8 log10 colony forming units (CFU)/mL within 15-60 s. Bactericidal activity of Mul-1867 was confirmed by morphological changes revealed by TEM suggested that the killing of bacteria was the result of membrane disruption.

Overall, these data indicated that Mul-1867 may be a promising antimicrobial for the treatment and prevention of human infections.