Microbiological and biochemical origins of human axillary odour

Abstract

The generation of malodour on various sites of the human body is caused by the microbial biotransformation of odourless natural secretions into volatile odorous molecules. On the skin surface, distinctive odours emanate, in particular, from the underarm (axilla), where a large and permanent population of microorganisms thrives on secretions from the eccrine, apocrine and sebaceous glands. Traditional culture-based microbiological studies inform us that this resident microbiota consists mainly of Gram-positive bacteria of the genera Staphylococcus, Micrococcus, Corynebacterium and Propionibacterium. Among the molecular classes that have been implicated in axillary malodour are short- and medium-chain volatile fatty acids, 16-androstene steroids and, most recently, thioalcohols. Most of the available evidence suggests that members of the Corynebacterium genus are the primary causal agents of axillary odour, with the key malodour substrates believed to originate from the apocrine gland. In this article, we examine, in detail, the microbiology and biochemistry of malodour formation on axillary skin, focussing on precursor-product relationships, odour-forming enzymes and metabolic pathways and causal organisms. As well as reviewing the literature, some relevant new data are presented and considered alongside that already available in the public domain to reach an informed view on the current state-of-the-art, as well as future perspectives.

Microbial Odor Profile of Polyester and Cotton Clothes after a Fitness Session

“…These findings are consistent with previous findings, where no growth of corynebacteria on clothing textiles was found (10,34). Corynebacteria are generally known as the most important species causing axillary malodor (36). These bacterial species are thought to be involved in the conversion of sweat compounds into volatile short branched-chain fatty acids, steroid derivatives, and sulfanylalkanols-the three main axillary malodor classes (15).…”

Significant Reduction of Body Odor in Older People with a pH 4.0 Emulsion

“…In vitro and in vivo studies of axillary odor and skin flora of 34 subjects revealed aerobic bacteria within the axillae to be responsible for high malodor intensity [13]. The results of the present study are in line with this finding, as the pH 4.0 emulsion was able to reduce the activity of different bacterial strains putatively involved in malodor [2,14]. Consequently, the reduction in odor-producing bacteria appeared to lead to a concurrent reduction in malodor.…”

“…The quantitative suspension tests EN 1040 and EN 1275 (date of: March 2006) were used to evaluate bactericidal activity and fungicidal activity, respectively, through the dilution-neutralization method. Test strains for the bacteria Staphylococcus (S.) epidermidis, S. aureus, Corynebacterium (C.) minutissimum, Propionibacterium (P.) acnes, and were selected as resident flora of the axilla putatively responsible for body odor [2,14,17]. Test strains for Escherichia (E.) coli, and the yeasts Candida albicans, Malassezia (M.) furfur, and Trichophyton (T.) rubrum were selected according to their incidence on human skin [17].…”

Diversity and evolution of the primate skin microbiome

“…For example, the apocrine glands in the axillary organ in the armpit produce secretions that provide food for the microbes living therein [18 -20]. Microbial constituents of the skin microbe communities play an important role in odour creation due to their production of volatile organic compounds [18,19]. Body odour plays a central role in primate society in the context of mating, child rearing, predatory protection and territorial marking [21,22].…”