There are currently several commercial soaps and detergents in the market that claim to be antibacterial, killing almost 99. 9% of germs (Weber et al. , 2003; Messager et al. , 2004). In order to test this claim, the Kirby-Bauer disk diffusion test was performed on four commercial antibacterial products (Shenoy et al. , 2002). The hypothesis of the experiment is that if commercial antibacterial products claim that these kill bacteria, then the application of the Kirby Bauer disk diffusion technique will result in a significant zone of inhibition. Materials and Methods
Two agar plates were inoculated with Salmonella typhimurium were employed in this experiment and two products were introduced to each plate. The products tested were IvoryTM bar soap, PurrelTM hand sanitizer, DawnTM dishwashing soap and CascadeTM dishwasher detergent. The agar plates were incubated for 48 hours at 37oC, after which the plates were noted for zones of inhibition. Control plates were also setup for this experiment. Results No zones of inhibition (0 mm) were observed for the IvoryTM bar soap (0 mm) and DawnTM dishwashing soap (0 mm).
On the other hand, PurrelTM hand sanitizer and CascadeTM dishwasher detergent showed zones of inhibition of 3 and 4 mm, respectively. Conclusion Employment of the Kirby-Bauer disk diffusion test showed that the commercial antibacterial products did not show any antibacterial action. Two of the four commercial products (IvoryTM and DawnTM) did not result in any zone of inhibition and thus did not impart any antibacterial effect on the bacterial plates. PurrelTM and CascadeTM show only a minimal antibacterial action towards the bacterial cultures.
References Messager, S. , Goddard, P. A. , Dettmar, P. W. and Maillard, J. Y. (2004). Comparison of two in vivo and two ex vivo tests to assess the antibacterial activity of several antiseptics. Journal of Hospital Infections, 58, 115-121. Shenoy, S. , Baliga, S. , Saldanha, D. R. and Prashanth, H. V. (2002). Antibiotic sensitivity patterns of Pseudomonas aeruginosa strains isolated from various clinical specimens. Indian Journal of Medical Science, 56, 427-430. Weber, D. J. , Sickbert-Bennett, E. , Gergen, M. F. and Rutala, W. A. (2003).. Efficacy of selected hand hygiene agents used to remove Bacillus atrophaeus (a surrogate of Bacillus anthracis) from contaminated hands. JAMA, 289, 1274-127.