Comparative bactericidal activity of various soaps against gram-positive and gram-negative bacteria

Abstract

The aim of this study was to check bactericidal activity of eight market soaps from different manufacturers against gram-positive and gram-negative bacteria. Minimum inhibitory concentration disinfectants were determined by broth dilution method. Minimum bactericidal concentration (MBC) of soaps was determined by agar method. Phenol was used as control to compare its activity with soaps. In the list of soaps, along with the standard (Phenol), safeguard was found with highest efficacy in terms of its minimum inhibitory concentration (MIC 256 μg/mL) against Staphylococcus aureus and Escherichia coli, whereas Johnson and Johnson baby soap (MIC1024 μg/mL) had highest activity against Salmonella typhi. S. typhi had decreasing sensitivity against various soaps in order as: Johnson and Johnson>Dettol>Safeguard>Phenol>Lifebuoy Red>Lux>Lifebuoy white>Sunlite with MICs values of 1024, 2048, 3072, 6144, 6144, 8192, 12288, 12288 and 16384 μg/mL, respectively. S. aureus had increasing resistance against various soaps as: Safeguard Johnson and Johnson>Lifebuoy red>Lux>Sufi>Sunlite>Lifebuoy white>Phenol>Dettol soap (MICs 256, 256, 2048, 2048, 3072, 4096, 6144, 8192 and 9216 μg/mL, respectively). The MBC values were found to be two to three times greater than its MIC values. The results confirm that medicinal soaps have a greater effect on inhibition and removal of bacterial population than plain soaps. © 2011 Academic Journals.