Studies on antagonism between porcine skin bacteria

Strains of Staphylococcus warneri, Staph. epidermidis and Aerococcus viridans isolated from porcine skin were shown to produce substances that inhibited the growth of Staph. hyicus. Studies of interactions between the inhibitor-producing bacteria and Staph. hyicus on cellulose acetate membranes demonstrated a significant reduction (P less than 0.001) of the Staph. hyicus population at various stages of its growth cycle, depending on the inhibitor used. Inhibitor production profiles in batch culture showed a change in production with culture growth. Trypsin and an extracellular substance from Staph. hyicus had similar effects in reducing inhibitor production. Staphylococcus hyicus was shown to produce varying amounts of a proteolytic enzyme during growth in batch culture. Such in vitro models of bacterial interaction enable potential mechanisms of disease control using inhibitor-producing organisms to be investigated and provide a basis for studies in vivo.     

Studies on antagonism between porcine skin bacteria

Strains of Staphylococcus warneri, Staph. epidermidis and Aerococcus viridans isolated from porcine skin were shown to produce substances that inhibited the growth of Staph. hyicus. Studies of interactions between the inhibitor-producing bacteria and Staph. hyicus on cellulose acetate membranes demonstrated a significant reduction ( P < 0.001) of the Staph. hyicus population at various stages of its growth cycle, depending on the inhibitor used. Inhibitor production profiles in batch culture showed a change in production with culture growth. Trypsin and an extracellular substance from Staph. hyicus had similar effects in reducing inhibitor production. Staphylococcus hyicus was shown to produce varying amounts of a proteolytic enzyme during growth in batch culture. Such in vitro models of bacterial interaction enable potential mechanisms of disease control using inhibitor-producing organisms to be investigated and provide a basis for studies in vivo.     

皮肤共生菌在皮肤健康和疾病中的作用研究进展

人体皮肤上有多种微生物定居,这些微生物群落的组成、分布和动态变化对皮肤的健康状况和疾病有着重要的调节作用.然而,人们一直不清楚皮肤微生物群落如何影响人类健康.对皮肤共生菌进行深入研究,不仅有助于发现有益皮肤共生菌菌株,也有助于筛选相应皮肤疾病新的药物靶标.近年来,对皮肤共生菌与宿主之间相互影响和作用机制的研究逐渐深入,...     

Fish skin bacteria: Colonial and cellular hydrophobicity

Dental plaque is a complex community of bacteria coexisting in an environment frequently limited by carbon and energy sources. UnlikeStreptococcus mutans, other oral streptococci such asS. milleri andS. sanguis have an absolute requirement for and actually consume all available arginine when grown glucose limited in a chemically defined medium. The conditions, particularly in terms of arginine concentration, under which the dental plaque bacteriaS. mutans andS. milleri would coexist under glucose-limiting conditions were investigated. The minimum level of arginine supporting optimal growth ofS. milleri was found to be ca. 50M, and above this level these strains outcompetedS. mutans. However, coexistence withS. mutans could be achieved at arginine levels of 14–40M, depending upon theS. milleri andS. mutans strains used. Under such dual limitation,S. milleri was unable to respond to glucose pulses but did respond to pulses of arginine and arginine plus glucose. One of the twoS. milleri strains did not tolerate low pH. In contrast,S. mutans did not tolerate high pH whereasS. milleri was unaffected. This is relevant to dental plaque where arginine catabolism produces a pH rise. Additionally, arginine is an important nutrient since it can be used as an energy source by some oral streptococci.     

Fish skin bacteria: Production of friction-reducing polymers

The supernatant fluids of cultures of four bacterial strains isolated from the skin of barracuda contained extracellular polymer concentrations of 0.2–0.5 mg/ml and reduced factional drag by 2.5–22% in a turbulent flow rheometer. The production and properties of one of the drag-reducing polymers, referred to as PS-6, were studied further. Polymer PS-6 was produced by strain NS-31 in minimal salts medium supplemented with ethanol or glucose. The polymer began to accumulate in the culture medium during exponential phase and continued to be produced during stationary phase. It reduced drag by 55% at a concentration of 0.75 mg/ ml. Acid-base titration of the deproteinized polymer PS-6A gave two inflection points: pK₁=3.26 (2.4 eq/mg) and pK₂=9.66 (0.8 eq/mg).¹³C-NMR spectroscopy of PS-6A resolved 25 peaks, including three methyl groups, three carbonyl groups, and four signals in the anomeric region (99–103 ppm), indicating the presence of four different monosaccharides. Strong acid hydrolysis of PS-6A yielded an amino acid, pyruvate, and four reducing sugars: a hexosamine, a uronic acid, and two hexoses which migrated on TLC similarly to glucose and galactose. The possible role of bacteria in production of drag-reducing mucus is discussed.     

Preliminary studies of the effect of steroid hormones on skin bacteria in vitro

It results from studies on skin hormones that some of steroid hormones reach high concentrations on skin surface mainly during a course of acne vulgaris. Our studies indicate that the activity of hormones on skin bacteria can be multiform. Nineteen hormones of analytical grade of purity were tested. They were derived from different firms of synthesized in the Department of Endocrinology of the Pharmacology Institute of Polish Academy of Sciences in Cracow. Bacterial strains tested in this study were isolated from normal skin flora. The majority of the compounds tested in this study showed different reactivity toward Staphylococcus aureus as well as Staphylococcus epidermidis and anaerobic diphtheroids+ and sometimes aerobic ones.     

Identification of human skin bacteria attractive to the Asian Tiger mosquito

Aedes albopictus is a vector of arboviruses and filarial nematodes. Originating from Asia, this mosquito has rapidly expanded its geographical distribution and colonized areas across both temperate and tropical regions. Due to the increase in insecticide resistance, the use of environmentally friendly vector control methods is encouraged worldwide. Using methods based on semiochemicals in baited traps are promising for management of mosquito populations. Interestingly, human skin microbiota was shown to generate volatile compounds that attract the mosquito species Anopheles gambiae and Aedes aegypti. Here, we investigated the composition of skin bacteria from different volunteers and the attractive potential of individual isolates to nulliparous Ae. albopictus females. We showed that three out of 16 tested isolates were more attractive and two were more repulsive. We identified dodecenol as being preferentially produced by attractive isolates and 2-methyl-1-butanol (and to a lesser extent 3-methyl-1-butanol) as being overproduced by these isolates compared with the other ones. Those bacterial volatile organic compounds represent promising candidates but further studies are needed to evaluate their potential application for baited traps improvement.     

Mast cell tolerance in the skin microenvironment to commensal bacteria is controlled by fibroblasts

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Simple staining of bacteria and fungi in hide, skin and leather

Enhanced detection of bacteria and fungi in raw skin and in skin from the various processing stages in leather production was achieved with a new staining procedure. A combination of cresyl violet and azure A is recommended in conjunction with Young's periodic acid-Schiff's reagent.     

Uneven distribution of aerobic mesophilic bacteria on human skin.

Viable aerobic mesophilic bacteria are not evenly distributed on the skin of the volar forearm. An increase in the size of the area sampled did not result in a proportional increase in the number of the viable aerobic mesophilic bacteria recovered.     

Uneven distribution of aerobic mesophilic bacteria on human skin.

Viable aerobic mesophilic bacteria are not evenly distributed on the skin of the volar forearm. An increase in the size of the area sampled did not result in a proportional increase in the number of the viable aerobic mesophilic bacteria recovered.     

Drag-reducing properties of bacteria from the skin mucus of the cornetfish (Fistularia commersonii)

Scanning electron microscopy and fluorescence microscopy after scanning with DAPI indicated that the skin mucus of the cornetfish contained large numbers of bacteria, 4 × 10⁸ per cm3. However, viable counts yielded only 2 × 104 per cm³. Twelve bacterial strains were isolated directly from the mucus and another ten strains were obtained following enrichment on pasteurized mucus medium. Most of the isolates belonged to the genus Pseudomonas; a smaller number were classified as Micrococcaceae. Cultures of 13 of the isolates were active in reducing friction in a turbulent flow rheometer. The surface active and drag-reducing properties of three strains—JR5, JR8, and GB7—were studied further. The drag-reducing activities, which were extracellular, were concentrated by ultra-filtration. The chemical composition of the concentrated preparations consisted of 14–24% protein and 38–75% polysaccharide. The major components of the polysaccharide fraction were galacturonic acid, galactosamine, and glucosamine, with lesser amounts of glucose and galactose. The most active preparation, from strain JR8, had a specific drag-reducing activity of 77 units per mg. Strain JR5 was the most hydrophobic as measured by the DOS and BATH tests. JR8 gave intermediate values, and GB8 showed low hydrophobicity values in both tests. The hydrocarbon-in-water emulsifying ability of the concentrated polymer fractions from JR8, GB7, and JR5 were high, intermediate, and low, respectively. The emulsifying and drag-reducing activities of the polymer fraction from strain JR8 were separated from each other by extraction with hydrocarbons. The emulsifying activity was due to a carbohydrate-protein complex, whereas the drag-reducing activity was associated with a uronic acid-containing polysaccharide. Offprint requests to: E. Rosenberg.     

Smallpox vaccination induces a substantial increase in commensal skin bacteria that promote pathology and influence the host response

Interactions between pathogens, host microbiota and the immune system influence many physiological and pathological processes. In the 20^th century, widespread dermal vaccination with vaccinia virus (VACV) led to the eradication of smallpox but how VACV interacts with the microbiota and whether this influences the efficacy of vaccination are largely unknown. Here we report that intradermal vaccination with VACV induces a large increase in the number of commensal bacteria in infected tissue, which enhance recruitment of inflammatory cells, promote tissue damage and influence the host response. Treatment of vaccinated specific-pathogen-free (SPF) mice with antibiotic, or infection of genetically-matched germ-free (GF) animals caused smaller lesions without alteration in virus titre. Tissue damage correlated with enhanced neutrophil and T cell infiltration and levels of pro-inflammatory tissue cytokines and chemokines. One month after vaccination, GF and both groups of SPF mice had equal numbers of VACV-specific CD8⁺ T cells and were protected from disease induced by VACV challenge, despite lower levels of VACV-neutralising antibodies observed in GF animals. Thus, skin microbiota may provide an adjuvant-like stimulus during vaccination with VACV and influence the host response to vaccination.     

The use of real-time PCR for quantitative determination of some propionic bacteria inhabiting the human skin

A test system has been developed for determination of propionic bacterial species inhabiting the human skin. This system developed in the real time PCR format is applicable for quantitative determination and also detection of genomes of the following Propionibacterium species: P. acnes, P. granulosum, and P. avidum. This system was used for analysis of wash samples from the skin of 17 pentathlon sportsmen and 16 students. All three species of propionic bacteria were found in all skin wash samples. However, contamination with P. acnes was two times higher in the control group than in the group of pentathlon sportsmen.     

The distribution and ecology of Malassezia furfur and cutaneous bacteria on human skin

The prevalence and abundance of Malassezia furfur on clinically normal skin at 20 sites has been determined. All of the 16 subjects studied (young adults) had high counts on the upper trunk and on at least one site on the head. Counts obtained from the lower trunk and upper thighs of male subjects were considerably higher than those from female volunteers. Organisms isolated, grouped according to their colony morphologies, had distributions consistent with those noted for 'Pityrosporum ovale' and 'P. orbiculare' in previous studies. Mean M. furfur counts were compared with aerobic and anaerobic bacterial counts performed at the same sites. Propionibacteria and M. furfur distributions were similar but not identical. Some factors which might limit the range of M. furfur are discussed.     

Differential attraction of malaria mosquitoes to volatile blends produced by human skin bacteria

The malaria mosquito Anopheles gambiae sensu stricto is mainly guided by human odour components to find its blood host. Skin bacteria play an important role in the production of human body odour and when grown in vitro, skin bacteria produce volatiles that are attractive to A. gambiae. The role of single skin bacterial species in the production of volatiles that mediate the host-seeking behaviour of mosquitoes has remained largely unknown and is the subject of the present study. Headspace samples were taken to identify volatiles that mediate this behaviour. These volatiles could be used as mosquito attractants or repellents. Five commonly occurring species of skin bacteria were tested in an olfactometer for the production of volatiles that attract A. gambiae. Odour blends produced by some bacterial species were more attractive than blends produced by other species. In contrast to odours from the other bacterial species tested, odours produced by Pseudomonas aeruginosa were not attractive to A. gambiae. Headspace analysis of bacterial volatiles in combination with behavioural assays led to the identification of six compounds that elicited a behavioural effect in A. gambiae. Our results provide, to our knowledge, the first evidence for a role of selected bacterial species, common on the human skin, in determining the attractiveness of humans to malaria mosquitoes. This information will be used in the further development of a blend of semiochemicals for the manipulation of mosquito behaviour.