Abstract
In this study, we evaluated the antibacterial activity of chlorine dioxide (ClO2) compared with sodium hypochlorite (NaClO) on various multidrug-resistant strains in the presence of bovine serum albumin and sheep erythrocytes to mimic the frequent blood contamination in clinical environment. The 3 most important species causing nosocomial infections, i.e., methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Pseudomonas aeruginosa (MDRP) and multidrug-resistant Acinetobacter baumannii (MDRA) were evaluated, with 3 representative strains from each. At a 10 ppm-concentration, ClO2 drastically reduced the number of all MDRP and MDRA, and 2 out of 3 MRSA strains, but NaClO was unable to cause any remarkable attenuation for any of the 9 strains tested in 60 seconds. Increased concentration of 100 ppm enabled ClO2 to completely kill MRSA strains, whereas NaClO failed to significantly lower the number of 2 MRSA and 1 MDRA strains. A time-course experiment demonstrated that, within 15 seconds, 100 ppm of ClO2 could kill completely all tested strains but NaClO at this concentration failed to do so. Together, these data suggest that ClO2 is more effective than NaClO against MRSA, MDRP and MDRA, and 100 ppm could be a practical concentration of ClO2 against these multidrug-resistant strains, which may cause fatal nosocomial infections.
