Skin microflora

Chiller K, Selkin BA, Murakawa GJ Skin microflora and bacterial infections of the skin. J Investig Dermatol 2001 6 170-174. 

Similarly as in case of stay-on products, there are several questions waiting to be answered about the impact of pH of rinse-off cleansing products on the skin, its pH, and the skin barrier function. One of the issues investigated was the influence on skin microflora, showing that when skin pH increased after repeated use of an alkaline soap, the count of propionibacteria rose significantly 64 Moreover, the irritancy properties of cleansing products have often been associated with their pH, but several studies show that there is no direct correlation between those two features.62,68-70 The reported difference in irritancy potential between cleansers with various pH may depend on the combination of surfactants and their inherent irritating capacity, rather than the pH of the products.61... 

WC Noble, ed. The Skin Microflora and Microbial Skin Disease. Cambridge Cambridge University Press, 1993, 73-101, 135-172. 

Selwyn has examined our view of the skin microflora and how to sample it with some clarity [11,12]. He has asked questions about the flora and how to evaluate it. Selwyn deals with a subject that is clearly critical in infection control... 

Selwyn and Ellis have published an important discussion of where the microflora is located and a comparison of a number of different techniques [11,12]. They used a culture of a full thickness skin biopsy to estimate their 100% count and then compared this with the results from a variety of different sampling techniques. They describe conclusions about the location of and numbers in the skin microflora. Those conclusions were that the total bacterial count per square centimeter ranged from 1,000 to 400,000, and that 20-50% percent are located deep in the crevices of the skin and hair follicles. They also stated that Staphylococcus aureus is never a resident on skin (nares and perineum excluded). Further, skin preparation can be achieved in 30 seconds to 2 minutes, rather than requiring the long exposures that had previously been favored. 

Survival of resident bacteria occurs even when rigorous disinfection of the skin occurs prior to sampling. Also, Sidney Selwyn has described the dilemmas associated with the skin microflora, as well as published an examination of the efficiency of sampling methods. If his data are reexamined, the efficiency of sampling is poor with any method as far as sampling the complete flora of the skin is concerned. 

As the popularity of surgical patient bathing increased, several European and Scandinavian studies were published [20,32,33]. Some of these focused on specific areas of the body and on reduction of numbers of the skin microflora. Effects in orthopedic surgery have been the focus in some of these studies. 

Masako, K., I. Hideyki, O. Shigeyuk, and I. Zenro, 2005a. A novel method to control the balance of skin microflora. 

Part 1. Attack on biofilm of Staphylococcus aureus without antibiotics. J. Dermatol. ScL, 38 197-205. Masako, K., K. Yusuke, I Hideyuki, et al., 2005b. A novel method to control the balance of skin microflora. Part 2. A study to assess the effect of a cream containing farnesol and xylitol on atopic dry skin. J. Dermatol. Set, 38 207-213. 

The chemistry of olfactory cues, probably conveyed in complex secretions and involved in the performance of recognition summarized above, remains unknown. The odors of the human body are composed of at least 350 volatile compounds, the combinations of which indicate individuality, sex, emotional state or health [DOR 13], Environmental factors (related to feeding diet or skin microflora) or shared genetic characteristics may generate shared odor signatures across individuals. Along with these complex chemical signatures, we cannot yet exclude that crucial, universal, compounds shared by different species may also convey critical information. 

When these products appeared at the world market, disputes about ecological properties and the influence of these technologies on the human organism have arisen. There are no accurate data yet how these developments may affect the human organism. However, it should be noted that some specialists do not recommend everyday use of antibacterial socks, because these antibacterial properties affect the natural skin microflora. 

Nordstrom, K. M., Belcher, A. M., Epple, G., et al. (1989). Skin surface microflora of the saddle-back tamarin monkey, Saguinusfuscicollis. Journal of Chemical Ecology 15, 629-639. 

Mycoses are most commonly due to dermatophytes, which affect the skin, hair, and nails following external infection. Candida albicans, a yeast organism normally found on body surfaces, may cause infections of mucous membranes, less frequently of the skin or internal organs when natural defenses are impaired (immunosuppression, or damage of microflora by broad-spectrum antibiotics). 

Wheat is the most common cereal used in poultry feed in Australia, Canada and the UK, conventional broiler diets typically containing more than 600 g/kg wheat. Inclusion of xylanase-based enzymes in these diets is now commonplace, to reduce the effects of soluble carbohydrates in wheat on intestinal viscosity and intestinal function. Responses to enzyme supplementation have been shown to depend on age of the bird. More mature birds, because of the enhanced fermentation capacity of the microflora in their intestines, have a greater capacity to deal with soluble carbohydrates in the diet. Replacing maize with wheat reduces the total xanthophyll content of the feed, thus reducing the pigmentation of the broiler skin and egg yolk. Therefore, supplementary sources of xanthophylls may have to be used in broiler and layer diets when wheat is used to replace maize. 

The gastrointestinal (GI) microflora plays an important role in the health status of people and animals. The GI tract represents a much larger contact area with the environment, compared to the 2 m2 skin surface of our body (van Dijk 1997). The mucosal surface of the small intestine is increased by forming folds, intestinal villi, and the formation of microvilli in the enterocyte resorptive luminal membrane. The resulting surface of GI system is calculated to be 150-200m2, therefore it provides enough space for the interactions related to digestion and for the adhesion to the mucosal wall. 

If they are ingested, dyes and particularly those that have an azo group can be metabolized by the intestinal microflora or by the liver enzymes. So, their effects can occur in organs responsible for metabolism or elimination, like the liver and urinary tract. Skin metabolism may also be responsible for the transformation of dyes, for example, those from colored textiles that can leach from the fabric and migrate to the skin. For example Disperse Orange 3 is degraded to p-phenylenediamine (PPD) and nitro-aniline in the skin (Figure 1). Direct Blue 14 (Cl 23850), after azo reduction, converts to the aromatic amine o-toluidine and other amines when incubated with cultures of Staphylococcus aureus. 

Azo Compounds Azo dyes are widely used in the food, pharmaceutical, cosmetic, textile, and leather industry. They are synthetic compounds characterized by one (monoazo) or several intramolecular N = N bonds. Azo dyes, if they are systemically absorbed, can be metabolized by the way of azoreductases of intestinal microflora by liver cells and skin surface bacteria. This metabolism leads to aromatic amines that can be hazardous. In the 1930s, some azo derivatives like 4-dimethyl aminoazoben-zene (Butter Yellow, Cl Solvent Yellow 2, Cl 11020) and o-aminoazotoluene were experimentally found to be directly carcinogenic to liver and bladder after feeding. Other complex azo dyes like Direct Black 38 or Direct Blue 6 (Figure 28) release the aromatic amine benzidine. Some examples of azo dyes metabolized in benzidine and benzidine-congeners are listed in Table 3. 

In both fresh and salt waters, lindane has demonstrated high stability. It is resistant to photodegradation but will disappear from the water by secondary mechanisms such as adsorption on sediment, biological breakdown by microflora and fauna, and adsorption by fish through gills, skin, and food. 

Paraquat has low but rapid gastrointestinal absorption (5-10%) and low skin absorption. Peak plasma concentrations occur in less than 2 h following ingestion. Generally, paraquat is not metabolized to any large extent. In animal studies, metabolites have been detected in urine, possibly resulting from the action of intestinal microflora. Paraquat is actively... 

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