226 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS for the double-blind study on the basis of high axillary odor. The subjects were divided into two subgroups with equivalent odor distribution, and the selected spray applied to the selected axilla, following a standard soap wash, once daily for three days. Odor assessments were carried out independently by four judges, 12 h and 24 h after treat- ment, using a 10-point scoring system (0 = no objectionable odor, 5 = moderate malodor, 10 = strong disagreeable odor). RESULTS AND DISCUSSION Previous studies have demonstrated that the unwashed axilla maintains a fairly constant microbial population over three days, varying from 4.9 x 104 tO 5.9 X 105 bacteria/ cm 2 skin. When the axillae are washed with soap, the microbial count is initially reduced, but the intermediate counts each day show a build-up, with the axillary popu- lation increasing up to the unwashed level by the end of the day (4). The same tendency is evident following three days' application of an ethanol-based aerosol spray, although the initial reduction in microbial count is much greater, presumably due to the intrinsic antibacterial action of the alcohol itself. With 0.2% triclosan included, though, micro- bial counts are maintained at a reduced level even 9 h after product application (Table I). In olfactory studies, both sprays with and without triclosan gave odor score reduc- tions, but spray A containing 0.15% triclosan was clearly superior, in particular when malodor was assessed 12 h after application (Table II). In the study of six months' duration and prior to use of the test aerosol sprays, the total aerobic bacteria count was found to be on average 5.2 x 105/cm 2 skin. Of the sixteen test subjects, 50% normally carried Gram-negative bacteria in the axillae (5.2 x 10 •- 1.0 X 103/cm 2 skin), in particular Proteus mirabilis, Enterobacter cloacae, and Kleb- sMla spp. None of the Gram-negative bacteria isolated throughout the study were oxi- dase-positive, and no bacteria were recovered on Pseudosel agar. Carriage of Pseudomonas spp. in the axillae is therefore not indicated. From 430 primary isolates characterized during the course of the study, 88% could be identified further into three predominent genera, Staphylococcus, Micrococcus, and Coryne- bacterium spp. The majority of Micrococcus spp. and Corynebacterium spp. isolated were lipophilic, with optimal growth on nutrient media supplemented with Tween 80. During six months' application of deodorant spray with 0.15% triclosan (average usage 580 ml/subject) or antiperspirant deodorant spray with 0.25% triclosan (average usage Table II Olfactory Evaluation of Deodorant Sprays: Axillae Malodor Levels 12 h and 24 h Following Application Application Time number Spray A Spray B % Diff. Sig. level 12 h 24 h 1 3.34 3.67 9.1 + 9.4 0.056 2 2.72 3.46 21.4 -+ 9.6 0.001 3 2.72 3.23 15.7 ñ 10.3 0.001 1 3.47 3.60 3.7 + 8.3 0.338 2 3.31 3.66 9.6 ñ 7.6 0.021 3 3.20 3.59 10.9 -+ 8.9 0.028

EFFICACY OF TRICLOSAN 227 Table III Effect of Six Months' Deodorant Usage on Axillae Bacteria Recoveries Application period Mean bacteria recoveries/cm 2 skin 0.15% triclosan deodorant spray 0.25 % triclosan antiperspirant/ deodorant spray Day 5 (pre-) Day 1 Day 2 Day 5 Day 15 Day 29 Day 85 Day 180 4.1 x 105 6.76 x 102 1.31 x 10 3 3.32 x 102 1.44 x 103 9.54 x 102 1.32 x 103 1.24 x 103 6.3 x 105 4.75 x 102 3.43 x 102 2.93 x 102 3.01 x 102 2.94 x 102 4.29 x 102 4.81 x 102 X 1.04 x 103 3.74 Day 4 (post-) 3.7 X 105 4.6 Day 7 (post-) 6.4 X 105 8.9 X 10 2 x 10 5 x 10 5 deodorant spray plus 0.15% triclosan subject:A/6 Total bacteria Corynebocterium spp. ½Drom--negatives period day 7(powt--) Figure 1. Effect of six months' usage of a triclosan-containing deodorant spray on axillary microflora composition.