Synergistic antibacterial activity of new isomeric carborane derivatives through combination with nanoscaled titania.

As a novel strategy to combat the nosocomial infection caused by multidrug-resistant (MDR) bacteria like Acinetobacter baumannii, the antibacterial effect of a pair of geometrical isomers ferrocene-carborane derivatives (designated as FcSB1 and FcSB2) combining with nanoscaled titania (nano TiO2) against five MDR A. baumannii strains were explored in this contribution. The drug interaction assay and time-kill studies demonstrate the considerable enhancement effect of the TiO2 nanoparticles on the antibacterial activity of FcSB1/or FcSB2 against clinically MDR-resistant A. baumannii. Meanwhile, the relevant antibacterial efficiency assessed by a nonparametric approach (fractional inhibitory concentration [FIC] index model) illustrates that the FIC index values ranged from 0.375 to 0.106 for the combination of FcSB1 and nano TiO2, and 0.250 to 0.083 for that of FcSB2 with nano TiO2, indicating the synergistic antibacterial activity of FcSB1/or FcSB2 with nano TiO2 on target bacteria. This might shed light on the promising bio-application of these new carborane derivatives in combination with nano TiO2 to combat the nosocomial infection caused by multidrug-resistant (MDR) bacteria including A. baumannii.