Sweating the small stuff: Glycoproteins in human sweat and their unexplored potential for microbial adhesion.

There is increasing evidence that secretory fluids such as tears, saliva and milk play an important role in protecting the human body from infection via a washing mechanism involving glycan-mediated adhesion of potential pathogens to secretory glycoproteins. Interaction of sweat with bacteria is well established as the cause of sweat-associated malodor. However, the role of sweat glycoproteins in microbial attachment has received little, if any, research interest in the past. In this review, we demonstrate how recent published studies involving high-throughput proteomic analysis have inadvertently, and fortuitously, exposed an abundance of glycoproteins in sweat, many of which have also been identified in other secretory fluids. We bring together research demonstrating microbial adhesion to these secretory glycoproteins in tears, saliva and milk and suggest a similar role of the sweat glycoproteins in mediating microbial attachment to sweat and/or skin. The contribution of glycan-mediated microbial adhesion to sweat glycoproteins, and the associated impact on sweat derived malodor and pathogenic skin infections are unchartered new research areas that we are beginning to explore.

Refining the continuum of CFTR-associated disorders in the era of newborn screening.

Clinical heterogeneity in cystic fibrosis (CF) often causes diagnostic uncertainty in infants without symptoms and in older patients with milder phenotypes. We performed a cross-sectional evaluation of a comprehensive set of clinical and laboratory descriptors in a physician-defined cohort (N = 376; Children's Hospital of Wisconsin and the American Family Children's Hospital CF centers in Milwaukee and Madison, WI, USA) to determine the robustness of categorizing CF (N = 300), cystic fibrosis transmembrane conductance regulator (CFTR)-related disorder (N = 19), and CFTR-related (CRMS) metabolic syndrome (N = 57) according to current consensus guidelines. Outcome measures included patient demographics, clinical measures, sweat chloride levels, CFTR genotype, age at diagnosis, airway microbiology, pancreatic function, infection, and nutritional status. The CF cohort had a significantly higher median sweat chloride level (105 mmol/l) than CFTR-related disorder patients (43 mmol/l) and CFTR-related metabolic syndrome patients (35 mmol/l; p ≤ 0.001). Patient groups significantly differed in pancreatic sufficiency, immunoreactive trypsinogen levels, sweat chloride values, genotype, and positive Pseudomonas aeruginosa cultures (p ≤ 0.001). An automated classification algorithm using recursive partitioning demonstrated concordance between physician diagnoses and consensus guidelines. Our analysis suggests that integrating clinical information with sweat chloride levels, CFTR genotype, and pancreatic sufficiency provides a context for continued longitudinal monitoring of patients for personalized and effective treatment.

Molecular basis of human body odour formation: insights deduced from corynebacterial genome sequences.

During the past few decades, there has been an increased interest in the essential role of commensal skin bacteria in human body odour formation. It is now generally accepted that skin bacteria cause body odour by biotransformation of sweat components secreted in the human axillae. Especially, aerobic corynebacteria have been shown to contribute strongly to axillary malodour, whereas other human skin residents seem to have little influence. Analysis of odoriferous sweat components has shown that the major odour-causing substances in human sweat include steroid derivatives, short volatile branched-chain fatty acids and sulphanylalkanols. In this mini-review, we describe the molecular basis of the four most extensively studied routes of human body odour formation, while focusing on the underlying enzymatic processes. Considering the previously reported role of ß-oxidation in odour formation, we analysed the genetic repertoire of eight Corynebacterium species concerning fatty acid metabolism. We particularly focused on the metabolic abilities of the lipophilic axillary isolate Corynebacterium jeikeium K411.

Material-dependent growth of human skin bacteria on textiles investigated using challenge tests and DNA genotyping.

AIMS: To investigate the influence of different fibre materials on the colonization of textiles by skin bacteria present in human sweat. METHODS AND RESULTS: The total bacterial content of axillary sweat samples was determined using DNA quantification, and the diversity of bacteria present was investigated. Fabrics made of different fibres were then challenged with these sweat samples; the bacterial DNA was quantified, and the bacterial taxa present were determined. We found differences in the overall colonization, with polyester and polyamide showing the highest bacterial mass. Also, significant differences in the various taxa of bacteria present on the different materials were found. In general, synthetic materials showed a selective growth of bacterial taxa underrepresented in sweat. In contrast, a cellulose-based material showed only very few taxa, identically with those predominant in sweat. CONCLUSIONS: Our investigations demonstrated that besides the bacterial content of sweat itself, the type of material has a strong impact on the bacterial colonization of textiles. SIGNIFICANCE AND IMPACT OF THE STUDY: Odour generation is one of several effects resulting from an interaction of skin bacteria with textiles, and it is a common experience that there are differences in odour generation by different materials. Our investigations suggest that a selective growth of potentially odour-producing bacteria may account for this.

Candida auris Forms High-Burden Biofilms in Skin Niche Conditions and on Porcine Skin.

Emerging pathogen Candida auris causes nosocomial outbreaks of life-threatening invasive candidiasis. It is unclear how this species colonizes skin and spreads in health care facilities. Here, we analyzed C. auris growth in synthetic sweat medium designed to mimic axillary skin conditions. We show that C. auris demonstrates a high capacity for biofilm formation in this milieu, well beyond that observed for the most commonly isolated Candida sp., Candida albicans The C. auris biofilms persist in environmental conditions expected in the hospital setting. To model C. auris skin colonization, we designed an ex vivo porcine skin model. We show that C. auris proliferates on porcine skin in multilayer biofilms. This capacity to thrive in skin niche conditions helps explain the propensity of C. auris to colonize skin, persist on medical devices, and rapidly spread in hospitals. These studies provide clinically relevant tools to further characterize this important growth modality.IMPORTANCE The emerging fungal pathogen Candida auris causes invasive infections and is spreading in hospitals worldwide. Why this species exhibits the capacity to transfer efficiently among patients is unknown. Our findings reveal that C. auris forms high-burden biofilms in conditions mimicking sweat on the skin surface. These adherent biofilm communities persist in environmental conditions expected in the hospital setting. Using a pig skin model, we show that C. auris also forms high-burden biofilm structures on the skin surface. Identification of this mode of growth sheds light on how this recently described pathogen persists in hospital settings and spreads among patients.

Changes in Airway Microbiome and Inflammation with Ivacaftor Treatment in Patients with Cystic Fibrosis and the G551D Mutation.

Rationale: Modulation of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein improves clinical outcomes in patients with CF and specific CFTR genetic mutations. It remains unclear how improving CFTR function modifies existing airway infection and inflammation.Objectives: To compare sputum microbiome and markers of inflammation before and after 6 months of ivacaftor treatment.Methods: The study included 31 people with CF, ages 10 years and older, with at least one G551D CFTR allele and an forced expiratory volume in 1 second (FEV1) of 40% predicted or greater who were enrolled in the GOAL (G551D Observational) study. Sputum samples were collected either by induction (n = 14) or by spontaneous expectoration (n = 17) before and 6 months after initiation of ivacaftor. Changes in bacterial community indices by sequencing of 16S rRNA amplicons, total and specific bacterial load, and a panel of proteases, antiproteases, and inflammatory cytokines were determined.Results: The cohort that spontaneously expectorated sputum had a lower FEV1, a higher proportion with Pseudomonas aeruginosa infection, and higher concentrations of sputum inflammatory markers compared with the cohort that provided sputum by induction. Although the overall cohort experienced significant improvements in FEV1 and reductions in sweat chloride, no significant changes in bacterial diversity, specific bacterial pathogens, or markers of inflammation were observed in these subjects. Neither total bacterial load nor presence of Pseudomonas changed significantly between paired samples with ivacaftor treatment. Younger patients experienced more shifts in their microbial communities than older patients.Conclusions: In this multicenter cohort, 6 months of ivacaftor treatment were not associated with significant changes in airway microbial communities or measures of inflammation. These data suggest that concomitant antimicrobial and antiinflammatory treatments will still be needed to manage airway disease in patients with CF treated with highly effective CFTR modulator therapy, especially in older patients with more advanced disease.

Gender-specific differences between the concentrations of nonvolatile (R)/(S)-3-methyl-3-sulfanylhexan-1-Ol and (R)/(S)-3-hydroxy-3-methyl-hexanoic acid odor precursors in axillary secretions.

The volatile fatty acid, (R)/(S)-3-hydroxy-3-methylhexanoic acid ((R)/(S)-HMHA), and the human specific volatile thiol, (R)/(S)-3-methyl-3-sulfanylhexan-1-ol ((R)/(S)-MSH), were recently identified as major components of human sweat malodor. Their 2 corresponding precursors were subsequently isolated from sterile and odorless axillary secretions. The purpose of this work was to analyze these 2 odor precursors in 49 male and female volunteers over a period of 3 years to elucidate to which extent they are implicated in the gender-specific character of body odor. Surprisingly, the ratio between the acid precursor 1, a glutamine conjugate, and the "sulfur" precursor 2, a cysteinylglycine-S-conjugate, was 3 times higher in men than in women with no correlation with either the sweat volume or the protein concentration. Indeed, women have the potential to liberate significantly more (R)/(S)-MSH, which has a tropical fruit- and onion-like odor than (R)/(S)-HMHA (possibly transformed into (E)/(Z)-3-methyl-2-hexenoic acid) that has a cheesy, rancid odor. Parallel to this work, sensory analysis on sweat incubated with isolated skin bacteria (Staphylococcus epidermidis Ax3, Corynebacterium jeikeium American Type Culture Collection 43217, or Staphylococcus haemolyticus Ax4) confirmed that intrinsic composition of sweat is important for the development of body odors and may be modulated by gender differences in bacterial compositions. Sweat samples having the highest sulfur intensity were also found to be the most intense and the most unpleasant.

Differential involvement of glycans in the binding of Staphylococcus epidermidis and Corynebacterium spp. to human sweat.

Sweat is a secretory fluid that can be a source of unpleasant body odour due to interaction of resident bacteria with sweat components. Identification of glycoproteins in sweat suggests that protein-conjugated glycans may act as binding epitopes for bacteria, as found in other secretory fluids such as human milk, tears and saliva which help to protect epithelial surfaces from infection. We conducted proteomic and glycomic analysis of sweat to reveal an abundance of glycoproteins, predominantly carrying bi-antennary sialylated N-glycans with or without fucose. A fluorescent plate assay was used to determine whether glycans on sweat proteins provide binding epitopes for odour-producing skin commensals Staphylococcus epidermidis and Corynebacterium. Sialic acid and fucose were found to be important binding epitopes for S. epidermidis 3-22-BD-6, a strain recently isolated from human sweat, whereas fucose (but not sialic acid) contributed to the binding of Type strain S. epidermidis ATCC 12228. In contrast, our results indicate that sweat N-glycans do not provide binding epitopes for Corynebacterium. Synthetic sugar mimics of Lewis blood group antigens were investigated as potential inhibitors of the binding of S. epidermidis 3-22-BD-6 to sweat. Pre-incubation of the bacterium with LeB, LeX, LeY and sLeX (pentaose) resulted in a significant reduction in sweat protein adhesion indicating that terminal fucose is a key binding epitope, particularly when linked to a Type 2 chain (Galß1-4GlcNAc) configuration (LeY). Our results form an impetus for future studies seeking to elucidate the role of glycans in sweat associated malodour, with possible implications for cosmetic and medical fields.

Understanding the microbial basis of body odor in pre-pubescent children and teenagers.

BACKGROUND: Even though human sweat is odorless, bacterial growth and decomposition of specific odor precursors in it is believed to give rise to body odor in humans. While mechanisms of odor generation have been widely studied in adults, little is known for teenagers and pre-pubescent children who have distinct sweat composition from immature apocrine and sebaceous glands, but are arguably more susceptible to the social and psychological impact of malodor. RESULTS: We integrated information from whole microbiome analysis of multiple skin sites (underarm, neck, and head) and multiple time points (1 h and 8 h after bath), analyzing 180 samples in total to perform the largest metagenome-wide association study to date on malodor. Significant positive correlations were observed between odor intensity and the relative abundance of Staphylococcus hominis, Staphylococcus epidermidis, and Cutibacterium avidum, as well as negative correlation with Acinetobacter schindleri and Cutibacterium species. Metabolic pathway analysis highlighted the association of isovaleric and acetic acid production (sour odor) from enriched S. epidermidis (teen underarm) and S. hominis (child neck) enzymes and sulfur production from Staphylococcus species (teen underarm) with odor intensity, in good agreement with observed odor characteristics in pre-pubescent children and teenagers. Experiments with cultures on human and artificial sweat confirmed the ability of S. hominis and S. epidermidis to independently produce malodor with distinct odor characteristics. CONCLUSIONS: These results showcase the power of skin metagenomics to study host-microbial co-metabolic interactions, identifying distinct pathways for odor generation from sweat in pre-pubescent children and teenagers and highlighting key enzymatic targets for intervention.

Structural basis of malodour precursor transport in the human axilla.

Mammals produce volatile odours that convey different types of societal information. In Homo sapiens, this is now recognised as body odour, a key chemical component of which is the sulphurous thioalcohol, 3-methyl-3-sulfanylhexan-1-ol (3M3SH). Volatile 3M3SH is produced in the underarm as a result of specific microbial activity, which act on the odourless dipeptide-containing malodour precursor molecule, S-Cys-Gly-3M3SH, secreted in the axilla (underarm) during colonisation. The mechanism by which these bacteria recognise S-Cys-Gly-3M3SH and produce body odour is still poorly understood. Here we report the structural and biochemical basis of bacterial transport of S-Cys-Gly-3M3SH by Staphylococcus hominis, which is converted to the sulphurous thioalcohol component 3M3SH in the bacterial cytoplasm, before being released into the environment. Knowledge of the molecular basis of precursor transport, essential for body odour formation, provides a novel opportunity to design specific inhibitors of malodour production in humans.

Comparison of two alcohol-based surgical scrub solutions with an iodine-based scrub brush for presurgical antiseptic effectiveness in a community hospital.

The antiseptic effectiveness and acceptability of a commercial alcohol-based waterless (ABWL) and an alcohol-based water-aided (ABWA) scrub solution were compared with a brush-based iodine solution (BBIS) under conditions encountered in community hospital operating rooms. This randomized partially blinded study was based on guidelines from the American Society for Testing and Methods. The three scrub solutions were compared for antimicrobial efficacy, using criteria within the Food and Drug Administration's Tentative Final Monograph for Healthcare Antiseptic Products (FDA-TFM), and for participants' acceptance of the products. Volunteer surgical staff that worked daily in the same operating room for the entire duration of the study were enrolled. In total, 1126 surgical scrub procedures were performed over the duration of the study. Only the ABWL met all of the FDA-TFM criteria. The BBIS performed better than both of the alcohol-based solutions at the end of Day 1 (P=0.03), but the ABWL was more efficacious than the ABWA and the BBIS at the end of Days 2 and 5 (P=0.02 and 0.01, respectively). When colony-count reductions were compared over the entire duration of the study, there was no significant difference between the three solutions (P=0.2). The participants found the ABWL easiest to use (P<0.001), with the fewest adverse effects on skin (P=0.007), and it was their preferred product (P<0.001). Although both of the commercially available alcohol-based solutions may be considered as acceptable alternatives to the BBIS for presurgical antisepsis, the ABWL was found to have significantly higher user acceptability.

Symptom screening rules to identify active pulmonary tuberculosis: Findings from the Zambian South African Tuberculosis and HIV/AIDS Reduction (ZAMSTAR) trial prevalence surveys.

BACKGROUND: High tuberculosis (TB) burden countries should consider systematic screening among adults in the general population. We identified symptom screening rules to be used in addition to cough ≥2 weeks, in a context where X-ray screening is not feasible, aiming to increase the sensitivity of screening while achieving a specificity of ≥85%. METHODS: We used 2010 Zambia South Africa Tuberculosis and HIV/AIDS Reduction (ZAMSTAR) survey data: a South African (SA) training dataset, a SA testing dataset for internal validation and a Zambian dataset for external validation. Regression analyses investigated relationships between symptoms or combinations of symptoms and active disease. Sensitivity and specificity were calculated for candidate rules. RESULTS: Among all participants, the sensitivity of using only cough ≥2 weeks as a screening rule was less than 25% in both SA and Zambia. The addition of any three of six TB symptoms (cough <2 weeks, night sweats, weight loss, fever, chest pain, shortness of breath), or 2 or more of cough <2 weeks, night sweats, and weight loss, increased the sensitivity to ~38%, while reducing specificity from ~95% to ~85% in SA and ~97% to ~92% in Zambia. Among HIV-negative adults, findings were similar in SA, whereas in Zambia the increase in sensitivity was relatively small (15% to 22%). CONCLUSION: High TB burden countries should investigate cost-effective strategies for systematic screening: one such strategy could be to use our rule in addition to cough ≥2 weeks.

Comparison of bacterial counts in glove juice of surgeons wearing smooth band rings versus those without rings.

BACKGROUND: Removal of rings is recommended before surgeons aseptically prepare for surgical procedures. OBJECTIVES: This study was undertaken to determine whether there is a difference between bacterial counts under surgical gloves of ring wearers compared with nonring wearers after proper aseptic hand preparation and 3 hours of wear. METHODS: Twenty volunteer veterinary medical students were divided into 2 groups: One group wore a smooth ring band (without projections or mounted stones) on their ring finger, and the other group did not wear a ring. A modified glove juice method was used to obtain bacterial counts (colony-forming units/mL) inside surgically gloved hands prior to a proper aseptic hand preparation and 3 hours after hand preparation and wear. Each of the pre- and postsurgical glove juice samples were inoculated onto Letheen agar plates, which were incubated aerobically under atmospheric conditions for 48 hours at 35 degrees C. Gloves were tested for perforations using a water pressure test. RESULTS: No differences, or significant change, in bacterial counts were found before or after surgery between all ring hands and nonring hands or between ring and nonring hands for ringed participants. No differences in bacterial counts were found within perforated versus nonperforated gloves. CONCLUSION: There is no compelling evidence to suggest that surgeons wearing rings possess higher bacterial counts under their gloves during surgery.

Source, impact and removal of malodour from soiled clothing.

Static headspace--multi-capillary column--gas chromatography--ion mobility spectrometry (SHS-MCC-GC-IMS) has been applied to the analysis of malodour compounds from soiled clothing (socks and T-shirts), pre- and post washing, at low temperature (20°C). Six volatile compounds (VCs) (i.e. butyric acid, dimethyl disulfide, dimethyl trisulfide, 2-heptanone, 2-nonanone and 2-octanone) were identified. After sensory evaluation of soiled garments they were subjected to laundering with non-perfumed washing powder. The efficiency of the laundering process was evaluated by determining the reduction of each detected volatile compound (VC) post-wash (damp) for socks and T-shirts; VC concentration reductions of between 16 and 100% were noted, irrespective of sample type. Additionally the T-shirt study considered the change in VC concentration post-wash (dry) i.e. after the drying process at ambient temperature. Overall VC concentration reductions of between 25 and 98% were noted for T-shirt samples pre-wash to post-wash (dry). Finally, a potential biochemical metabolic pathway for the formation of malodour compounds associated with bacteria in axillary sweat is proposed.

Identification of the precursor of (S)-3-methyl-3-sulfanylhexan-1-ol, the sulfury malodour of human axilla sweat.

A careful study of human axillary microflora led us to the identification of a new strain of Staphylococcus haemolyticus. The role in axillary malodour formation of this microorganism was compared to those of Corynebacterium xerosis and Staphylococcus epidermidis, upon incubation on sterile human eccrine and apocrine axilla sweat. St. haemolyticus was responsible for the strongest sulfury malodour and the generation of the volatile sulfur compound (VSC) (S)-3-methyl-3-sulfanylhexan-1-ol (3). In this study, we investigated the nonvolatile precursors of VSCs. Human axillary sweat was collected, fractionated and analysed by HPLC/APCI-MS (High-Pressure Liquid Chromatography coupled to Atmospheric Pressure Chemical Ionisation Mass Spectrometry). The precursor of 3 was identified as [1-(2-hydroxyethyl)-1-methylbutyl]-L-cysteinylglycine (Cys-Gly-(S)-conjugate; 12). Because Cys-Gly-(S)-conjugates are key intermediates in the glutathione biodetoxification pathway, other derivatives of 12, specifically glutathione-(S)-conjugate 11 and Cys-(S)-conjugate 13, were prepared. Compounds 11 and 13 were not detected by HPLC/MS of sterile sweat. Synthetic homologues 11, 12, and 13 were incubated with C. xerosis, St. heamolyticus, and St. epidermidis. We observed efficient conversion of precursors 12 and 13 to form VSCs when incubated with St. haemolyticus, with a clear preference for 12. C. xerosis and St. epidermidis were less efficient in cleaving Cys-Gly-(S)-conjugate 12 to form the corresponding thiol 3. Incubation of glutathione-(S)-conjugate 11 never led to the formation of 3 under the experimental conditions employed.

Comparison of 16-androstene steroid concentrations in sterile apocrine sweat and axillary secretions: interconversions of 16-androstenes by the axillary microflora--a mechanism for axillary odour production in man?

The concentrations of five 16-androstene steroids were determined, by a GC-MS method, in freshly-produced apocrine sweat (adrenaline-induced), in 8 men and 2 women. The ranges of concentrations (nmol/microliter) in apocrine sweat were: 5 alpha-androst-16-en-3-one (5 alpha-A), 0.1-2.0 and 4,16-androstadien-3-one (androstadienone), 0-1.9, 5,16-Androstadien-3 beta-ol (androstadienol) was also found in 5 of the subjects (range 0.05-1.05). 5 alpha-Androst-16-en-3 alpha- or 3 beta-ols [3 alpha (beta)-androstenols] were only found in small amounts (< 0.1 nmol/microliters) in a few subjects. In the second study, prior to apocrine sweat collection (adrenaline injection), the axillary skin of 6 of the male subjects was washed with diethyl ether on an adjacent site of the axillary vault. The concentrations of 16-androstenes were compared in the ethereal extracts and apocrine sweat. The former contained detectable levels (pmol/cm2) of androstadienone (17.9 +/- 2.4), 3 alpha-androstenol (6.9 +/- 3.7), 3 beta-androstenol (1.8 +/- 1.0) and androstadienol (1.9 +/- 0.5) (means +/- SEM) in all 6 subjects. All but 1 subject also had 5 alpha-androstenone, the mean value for the others being 2.5 +/- 0.6. The axillary skin levels of 3 alpha- and 3 beta-androstenols, androstadienol and, in 3 subjects, androstadienone exceeded those in the apocrine sweat obtained from the same subjects, whereas levels of 5 alpha-androstenone in the skin extracts were all lower than in apocrine sweat samples, when related to the corresponding areas of skin sampled. The metabolism of 16-androstenes was studied in vitro in the presence of two aerobic coryneform bacteria, previously shown to metabolize testosterone as well as being capable of producing odour from extracts of axillary sweat in an odour-generation test. Although both coryneforms caused complex metabolic reactions and were capable of oxidation or reduction at C-3 and C-4, the overall direction favoured reduction. For example, large quantities of the more odorous 5 alpha-androstenone and 3 alpha-androstenol were formed from androstadienol and androstadienone. In contrast, strains of corynebacteria, unable to produce odour and incapable of metabolizing testosterone, were also unable to metabolize 16-androstenes.(ABSTRACT TRUNCATED AT 400 WORDS)

Identification of new odoriferous compounds in human axillary sweat.

3-Hydroxy-3-methylhexanoic acid (1) and the 3-sulfanylalkan-1-ols 2-5 were identified to contribute to the odor of human axillary sweat. Quantitative analyses of axillary sweat extracts from 50 healthy men showed an unambiguous correlation between the detected levels of 1 and the intensity of the axillary odor. Chiral-GC analyses revealed 1 to be a 72:28 mixture of the (S)/(R)-isomers. Optically pure (S)-1 (>97% ee) emanated a strong spicy note, which recalled typical axillary odors. 3-Methyl-3-sulfanylhexan-1-ol (2), the enantiomeric ratio of which equaled that of 1, was present in greater quantity than any of the other 3-sulfanylalkanols. Optically pure (S)-2 (>97% ee) had a strong meaty, fruity note, also reminiscent of axillary odor. The compounds identified, in particular (S)-1 and (S)-2, contribute significantly to the olfactory impression of human axillary odor.

3-Methyl-3-sulfanylhexan-1-ol as a major descriptor for the human axilla-sweat odour profile.

This study sets out to redress the lack of knowledge in the area of volatile sulfur compounds (VSCs) in axillary sweat malodour. Sterile odourless underarm sweat (500 ml) was collected from 30 male volunteers after excessive sweating. Five strains of bacteria, Corynebacterium tuberculostearicum, Corynebacterium minutissimum, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Bacillus licheniformis, were isolated and characterised for their ability to generate an authentic axillary odour from the sweat material collected. As expected, all of the five bacterial strains produced strong sweat odours. Surprisingly, after extensive olfactive evaluation, the strain of Staphylococcus haemolyticus produced the most sulfury sweat character. This strain was then chosen as the change agent for the 500 ml of odourless underarm sweat collected. After bacterial incubation, the 500-ml sample was further processed for GC-olfactometry (GC-O), GC/MS analysis. GC-O of an extract free of organic acids provided three zones of interest. The first was chicken-sulfury, the second zone was onion-like, and the third zone was sweat, clary sage-like. From the third zone, a new impact molecule, (R)- or (S)-3-methyl-3-sulfanylhexan-1-ol, was isolated and identified by GC/MS, MD-GC, and GC AED (atomic emission detector). (S)-3-methyl-3-sulfanylhexan-1-ol was sniff-evaluated upon elution from a chiral GC column and was described as sweat and onion-like; its opposite enantiomer, (R)-3-methyl-3-sulfanylhexan-1-ol, was described as fruity and grapefruit-like. The (S)-form was found to be the major enantiomer (75%).