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) againstStaphylococcus 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<Sufi soap<Phenol<Sunlite soap<Dettol soap<Lifebuoy red<Lifebuoy white and<Lux soap with MICs values of 256, 1024, 1024, 1024, 2048, 3072, 3072, 3072, and 24576 µg/mL, respectively. E. coli had decreasing sensitivity 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.

Key words: Gram-positive, gram-negative, minimum inhibitory concentration, minimum bactericidal concentration.