The axillary microflora of 229 subjects was characterized quantitatively and the results correlated with whether the odor was pungent body odor or instead a faint "acid odor". The axillary flora was found to be a stable mixture of Micrococcaceae, aerobic diphtheroids and Propionibacteria. Significantly higher numbers of bacteria were recovered from the axilla of those with pungent axillary odor than in those with acid odor. Aerobic diphtheroids in high numbers were recovered in all subjects having typical body odor. These included lipophilic as well as large-colony diphtheroids. When droplets of apocrine sweat placed on the forearm were inoculated with various bacteria which reside in the axilla, only diphtheroids generated typical body odor. Cocci produced a sweaty odor attributable to isovaleric acid.

No abstract

Propionibacterium species were quantified on the foreheads and cheeks of persons with and without acne in three age groups: 11 to 15, 16 to 20, and 21 to 25. Propionibacteria were virtually absent in the pubertal non-acne group compared to a geometric mean density of 114,800 per sq cm in the acne group. A similar sharp difference existed between the acne subjects and normals in the age range of 16 to 20 years: 85,800 organisms per sq cm compared to 588 per sq cm. Patients with acne and normal subjects over age 21 showed no difference in Propionibacterium levels. In acne patients, while there was a trend for lower levels, no significant difference was seen as the severity of inflammation increased.

Gas chromatographic-mass spectrometric analysis of headspace volatiles was performed on cultures of 11 strains of Pseudomonas aeruginosa and 1 strain each of Pseudomonas cepacia, Pseudomonas putida, Pseudomonas putrefaciens, Pseudomonas fluorescens, and Pseudomonas maltophilia. Ail strains of Pseudomonas aeruginosa produced a distinctive series of odd-carbon methyl ketones, particularly 2-nonanone and 2-undecanone, and 2-aminoacetophenone. The other strains failed to produce 2-aminoacetophenone. Two sulfur compounds, dimethyldisulfide and dimethyltrisulfide, were present in all strains of P. aeruginosa and in variable amounts in other species. Butanol, 2-butanone, 1-undecene, and isopentanol were also detected in P. aeruginosa cultures.

Propionibacterium acnes is a member of the resident bacterial flora and resides in sebaceous follicles. Age-related and body-dependent quantitative differences exist, indicating the role of sebum as an important ecological factor for P. acnes. Acne patients demonstrate marked increases in this organism which generates inflammation through a variety of mechanisms.