H.I. Maibach

Microbial adherence to vulvar epithelial cells.

Under uniform experimental conditions, different degrees of selective attachment of Staphylococcus aureus and Candida albicans to epithelial cells of the labium majus, the labium minus, and the vagina were compared and contrasted with those found in studies with cells of the buccal and nasal mucosa and forearm skin by a novel analysis of adherence density. For both micro-organisms, the larger, rougher cells of the labium majus gave the highest adherence scores matched only by the interaction of S. aureus with fully keratinised nasal epithelial cells. Increasing acidity to pH 3.5 enhanced microbial adherence to vaginal cells. Menstruation also influenced attachment; highest densities were reached between the third and fourth weeks of the cycle. Autogenous ribitol teichoic acid was found to block the attachment of S. aureus to labium majus and labium minus cells by 76% and 81% respectively, and to vaginal cells by 66%. Adherence is considered to be an important attribute of vulvar ecology and may be a determinant of infectious disease.

Factors Controlling Skin Bacterial Flora

Several factors contorl skin colonization of bacteria, including pathogens, on human skin. When artificially applied on human skin, many pathogenic microorganisms (such as s-hemolytic streptococci and Staphylococcus aureus) do not survive for more than a few hours.Yet, on some, these organisms survive, multiply, and produce disease. Cutaneous bacterial flora do not numerically reflect the types of organisms in ambient air, suggesting that skin controls the survival of bacteria contracting it. In our view, the skin environment is unfriendly to most microbial species but sufficient nutrients are available to allow a certain number of bacteria to survive and multiply.

Staphylococcus Aureus Adherence to Nasal Epithelial Cells: Studies of Some Parameters

In many infectious processes, the initial event is the binding of organisms to host epithelial cells. The capacity to colonize the mucosa is proportional to the ability of bacteria to adhere.7,12 In the past, the emphasis has been on understanding the factors involved in the pathogenesis of a disease, i.e., after the organism has invaded the host and clinical symptoms have become apparent. While the pathogenic aspects are eminently worthy of scientific inquiry, the mechanisms involved in the initial binding of bacteria to the epithelia were not seriously invetigated. The lack of knowledge in this field has been partly due to the lack of suitable models for studying the natural ecology of several pathogenic bacteria. Some experimental animals are susceptible to infection by human pathogens and, as a result, most of the studies in this field have relied upon systematic infections caused by intravenous or interperitoneal inoculation of the pathogens in question. Such studies have not taken into consideration the natural routes by which pathogenic organisms usually initiate an infectious cycle. Consequently, this aspect of biology has not been well-studied. The current in vitro model utilizing isolated epithelial cells and bacteria represents procedures that most closely resemble the human system, thus enbling us to study the bacterial and host factors independently.

Dermatitic Skin: Microbiology and Treatment

The microbial flora of dermatitic skin varies from the resident flora of normal skin.2,3 The normal skin flora consists mainly of coagulase-negative staphylococci are more common in moist areas (axilla, groin and toe webs), than on dry skin. A small number of gram-negative rods are found in the humid skin regions. The nose and the perineum are the common resident carriage sites of S. aureus. The general skin surface yields S. aureus in about 5%–10% of the normal population.