Quantification Of Bacteria In Isolated Pilosebaceous Follicles In Normal Skin

Abstract

A technique for quantitating bacteria in isolated pilosebaceous follicles is described. This involves microdissection of the follicles from biopsies of skin, using the method of chemical pretreatment of skin to facilitate the separation of the epidermis and epidermal appendages from the dermis. The aerobic cocci and anaerobic diphtheroids in pilosebaceous follicles in 66 biopsies of scalp and 48 biopsies of skin of the upper back were quantitated using this technique. On the back, aerobic staphylococci were very sparse in normal follicles, indicating that their primary habitat on the skin must be on the skin surface rather than within follicles. Of 138 isolated follicles from skin of the upper back, 94 contained no aerobic cocci. Anaerobic organisms were present in high numbers within normal follicles. The geometric mean density of anaerobes in 138 isolated follicles from skin of the upper back was 3.8 X 10(4) diphtheroids per follicle. Eighty-eight follicles contained more than 10(4) anaerobic diphtheroids. Using data from scalp biopsies we found that there was a correlation between the weight of sebaceous glands and the density of anaerobes within the follicles attached to these glands (coefficient of correlation = 0.6).

Acne is Not Associated with Yet-Uncultured Bacteria

“…No other exposed microenvironment of the human body is known to selectively allow colonization by a single bacterial species. It is conceivable that the more heterogeneous microbiota found in previous culture-based studies of healthy follicles (15,23,33) was the result of differences in sampling methods. The cyanoacrylate method employed in the present study has the advantage, in addition to being noninvasive, that the upper part of the stratum corneum is captured in the applied cyanoacrylate, which minimizes the possibility of contamination with skin surface microorganisms when follicles are isolated by dissection.…”

Effect of clindamycin, erythromycin, lincomycin, and tetracycline on growth and extracellular lipase production by propionibacteria in vitro

“…AGENTS CHEMOTHER. pilosebaceous follicles and acne lesions (20), are closely associated with acne vulgaris. Broadspectrum antibiotics used in acne therapy are thought to decrease the numbers of viable P. acnes recovered from lesions and hence reduce the amount of free fatty acids in the sebum (2, 7,8,18).…”

“…It is possible, therefore, that certain antibiotics used in acne therapy may act not only as bactericidal agents but also as inhibitors of enzyme production under non-growth-limiting conditions. Hydrolysis of sebum triglycerides by bacterial lipases, in particular those of propionibacteria (13,20), and the subsequent release of irritating free fatty acids in the pilosebaceous follicles has been proposed as a major factor in the formation of lesions in acne vulgaris (22). Improvement in acne is often achieved by long-term administration of broad-spectrum antibiotics which are thought to decrease the density of propionibacteria (1,12,14) and hence reduce the free fatty acids in the sebum (7, 18).…”

Vernix Caseosa in Neonatal Adaptation

“…An acidic SC is believed to provide an antimicrobial function, with inhibition of growth of pathogenic bacteria. 15,16,32 The acid mantle may facilitate colonization of the skin surface with commensal organisms. 30,33 Additional studies are warranted to assess the impact of vernix retention on the process of skin colonization.…”

“…An acid surface is putatively necessary for the bacterial homeostasis/colonization of the skin. 15,16 Finally, birth marks a time of high oxidative stress. Adult human skin possesses endogenous antioxidant capacity in the form of alpha tocopherol (vitamin E) localized in SC and in sebum.…”