BACKGROUND: In recent decades, the increase in antibiotic-resistant bacteria has become one of themost significant problems in public health. Titanium dioxide (TiO2) has the potential to inactivate antibiotic-resistant bacteria. RESULTS: In this study, TiO2 that had been activated by ultraviolet A (UV-A) irradiation was used to inactivate the following three antibiotic-resistant bacteria in suspension: methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Acinetobacter baumannii (MDRAB) and vancomycin-resistant Enterococcus faecalis (VRE). For comparison, the following antibiotic-sensitive strainswere used as controls: S. aureus (MSSA), A. baumannii (MDSAB), E. faecalis (VSE), Escherichia coli and the bacteriophage MS2. Results demonstrated that MSSA and MRSA were equally susceptible to TiO2 photocatalysis, and the susceptibility of MDRAB was double that of MDSAB (P < 0.05). The susceptibility of VSE was 2.4 times that of VRE (P < 0.05). The results obtained from multiple regression analysis indicated that TiO2 reaction time had the greatest influence onmicrobial survival following TiO2 exposure in the presence of UV-A. CONCLUSION: The development of antibiotic resistance does not appear to be correlated to increased resistance to TiO2 photocatalysis, but TiO2 in the presence of UV-A still effectively reduces the number of antibiotic-resistant microbes in suspension by 1-3 logs. (C) 2010 Society of Chemical Industry