K J McGinley’s research while affiliated with University of Pennsylvania and other places

A cross-sectional quantitative study of cutaneous bacterial and yeast flora at seven body sites in 99 human immunodeficiency virus-seropositive and 50 seronegative military personnel was performed. Statistically significant differences in carriage rates were only observed for Staphylococcus aureus on the foreheads of seropositive individuals. Seronegative individuals demonstrated staphylococcal carriage rates 1.3 to 2 times as great as those of historical controls (defined as healthy individuals not receiving any medications) at five of six body sites. We conclude that seropositive military personnel do not exhibit statistically significant elevations in densities and carriage rates of the microorganisms examined (except Staphylococcus aureus), relative to seronegative individuals. Seropositive individuals may be predisposed to staphylococcal carriage. The elevated staphylococcal carriage rates of military personnel undergoing basic training warrants a formal evaluation of the impact of training exercises on cutaneous flora. The information gained may serve to limit the spread of infection during training exercises and battlefield conditions.

Propionibacterium acnes is a number of the resident bacterial flora and resides in sebaceous follicles. Age-related and body-dependent quantitative differences exist, indicating the role of sebum as an important ecological factor for P. acnes. Acne patients demonstrate marked increases in this organism which generates inflammation through a variety of mechanisms.

Previously, we described methods for measuring in vivo antimicrobial activity in which the resident bacterial flora of the forearm is expanded by occlusion with an impermeable plastic film, test agents are applied and quantitative cultures are obtained at varying time points. This methodology allows for an in vivo quantitative assessment of antimicrobial effects directed against a dense flora comprised primarily of staphylococci. This method may not be applicable to situations in which there is a high density of multiple species of bacteria. We describe herein new methods which permit in vivo determination of antimicrobial activity against a dense, mixed flora. Swabs moistened with a dilute nonionic detergent are used to remove bacteria from the subject's axilla or groin which are then translocated to the subject's forearm. Occlusion of the forearm with a large, sterile plastic chamber provides the necessary humid environment to yield a dense flora (10(5)-10(6) CFU) consisting of gram-positive cocci, gram-positive coryneforms and gram-negative rods. In this manner, multiple test sites are created on each forearm allowing for the simultaneous evaluation of multiple antimicrobial agents in a single subject. This method allows for the evaluation of the immediate, as well as sustained, in vivo bactericidal effect of an antimicrobial agent against a dense mixed flora with quantitative cultures obtained at varying time points after application of the test agent. Furthermore, ecological pressures which select for resistant organisms or allow for an overgrowth of nonsensitive bacteria can be evaluated by determining the composition of the flora after single or repeated applications of a test agent. The testing methodologies described herein can provide relevant information regarding the antimicrobial effectiveness of an agent in a variety of situations such as use against the axillary flora (including its utility as a deodorant), use as a perineal cleanser for critically ill, hospitalized patients and use in situations where a dense mixed flora exists, e.g. stasis ulcers and infected intertriginous dermatoses.

Previous studies have indicated that cutaneous bacteria, particularly coagulase-negative staphylococci, play a role in the pathogenesis of miliaria. An accumulation of periodic acid-Schiff (PAS)-positive material has been described as blocking the sweat duct in miliaria. Furthermore, a PAS-positive extracellular polysaccharide substance (EPS) has been identified as a product of some strains of Staphylococcus epidermidis. We evaluated the relative ability of various species of coagulase-negative staphylococci to induce miliaria with particular reference to the potential role of EPS. We inoculated various strains of coagulase-negative staphylococci on the volar forearms of subjects under an occlusive dressing coupled with thermal stimulation. Ability to induce miliaria as well as microbiologic, histologic, and immunostaining features were evaluated. Miliaria was induced only with strains of S. epidermidis; other species including S. haemolyticus, S. hominis, S. cohnii, S. saprophyticus, and S. simulans were not capable of inducing miliaria. Moreover, only S. epidermidis strains capable of producing EPS were capable of inducing miliaria. Our data indicate that EPS is the PAS-positive material that obstructs the delivery of sweat to the skin surface in miliaria and therefore demonstrate that the EPS produced by S. epidermidis plays a central role in the pathogenesis of miliaria. Furthermore, in a survey of staphylococcal flora isolated from 68 subjects, EPS-producing strains were found to be common.

To quantify and characterize the asymptomatic carrier state of tinea capitis in school children from the inner city. All students attending a parochial school (kindergarten through seventh grade) in the city of Philadelphia were cultured for tinea capitis periodically over 16 months (1404 hemi-scalp cultures from 224 children). Our initial prevalence study of this all-black population (ages 5 to 13 years) found a 3% rate of index cases (symptomatic) and a 14% rate of asymptomatic carriers (without black-dot lesions, obvious hair loss, scaling, crusts, pustules, or erythema). Trichophyton tonsurans was the predominant dermatophyte (96% of 125 positive cultures; Microsporum canis was the only other isolate). Fifty percent of all positive cultures came from children in kindergarten and first grade; first grade had the highest rate of index cases. The overall prevalence of asymptomatic carriers was not higher in the classes containing index cases. Fifty-nine percent of asymptomatic carriers had a 1+ spore load (1 to 10 colonies isolated per scalp), while 74% of index cases had a 4+ spore load (> 150 total colonies). Forty-five untreated asymptomatic carriers were followed for 2 to 5 months: 19 (42%) became culture-negative; of these, 17 (90%) had a 1+ spore load. We found that inner-city black school children who are asymptomatic carriers of T tonsurans had lower spore loads than index cases. Index cases did not appear to be the primary mode of transmission within a classroom. More than half of untreated asymptomatic carriers remained culture-positive after 2 months and probably play a role in the transmission of tinea capitis within this population.

Therapy for kerions was evaluated by randomly assigning 30 patients to one of four treatment groups: group A griseofulvin, group B griseofulvin plus erythromycin, group C griseofulvin plus prednisone, and group D griseofulvin, erythromycin, and prednisone. Data indicate that antibiotic and steroid therapy, in addition to griseofulvin, may reduce scaling and pruritus, but does not reduce the time it takes for kerions to flatten.

Qualitative and semiquantitative bacterial culture specimens were obtained from 44 patients with kerions. Staphylococcus aureus was isolated from the scalp surface overlying the kerion in 29% of patients and from the pus within the kerion in 48% of patients. Gram-negative bacteria were found in the same locations in 11.3% and 18% of patients, respectively. The data indicate that bacteria are frequently cultured from kerions.

We studied the effects of four kinds of antimicrobial detergents, 4% chlorhexidine gluconate (CHG), chlorbenzarconium (CBC), 10% povidone‐iodine (PVI), 0.3% triclosan (TRI), and one non‐medicated detergent (NMD) using the full‐hand touch plates method. Before and after 3 minutes of hand scrubbing with a brush, bacterial colonies on the hand surface and subungual bacteria were counted. CHG, CBC, and PVI were excellent antimicrobial detergents against hand surface bacteria, but most of the subungual bacteria remained. The subungual space was the most difficult region from which to eradicate bacteria. TRI was much less effective than hand soap against hand surface bacteria.

A book which surveys the world of the skin and its microflora, in health and disease, and in animals as well as man. The approach is essentially an ecological one, moving from the physical and chemical properties of the skin as a microbial habitat, through a consideration of the various major groups of microorganisms associated with it, to an account of the complex associations between these microorganisms. The skin flora in health is introduced as a prelude to the understanding of microbial skin disease, and the mechanisms of pathogenicity are explained as the major groups of infective skin conditions are reviewed. The principles of treatment, disinfection and prevention receive proper attention, as does the important topic of hospital-acquired infection, where the skin is so often implicated. The text is accompanied by numerous tables containing a wealth of practical and experimental detail, and is extensively referenced. This is a book which will be essential to dermatologists, medical microbiologists, veterinarians and research workers in these fields.

A book which surveys the world of the skin and its microflora, in health and disease, and in animals as well as man. The approach is essentially an ecological one, moving from the physical and chemical properties of the skin as a microbial habitat, through a consideration of the various major groups of microorganisms associated with it, to an account of the complex associations between these microorganisms. The skin flora in health is introduced as a prelude to the understanding of microbial skin disease, and the mechanisms of pathogenicity are explained as the major groups of infective skin conditions are reviewed. The principles of treatment, disinfection and prevention receive proper attention, as does the important topic of hospital-acquired infection, where the skin is so often implicated. The text is accompanied by numerous tables containing a wealth of practical and experimental detail, and is extensively referenced. This is a book which will be essential to dermatologists, medical microbiologists, veterinarians and research workers in these fields.