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Biomedical subjects

J R LeBrun

Publications and source records attributed to J R LeBrun.

3 recordsLinked to original sources

Effect of experimental dermatophyte infection on cutaneous flora.

The cutaneous aerobic bacterial flora was monitored during the course of experimental dermatiphyte (ringworm) infections on the forearms of 9 volunteers. Micrococcaceae were identified by the new Baird-Parker classification with the aid of a replica-plating technique. There were significant differences in total populations but not in kinds of flora compared with control (opposite) forearms. The proportion of penicillin-resistant microorganisms, however increased the infection, to a degree which varied as to individual. All coccal groups were affected; resistant flora diminished when the fungus was no longer DETECTED. Staphylococci were more frequently isolated than micrococci on the infected areas, but Staphylococcus aureus was not found. Trends toward hierarchies in persistance and quantities IV were observed among the flora, with Staphylococcus subgroups II and dominating the infected sites. On both areas almost all diphtheroids were nonfluorescent, lipophilic, and lipolytic. One subject consistently carried Bacillus firmus; another's normal microbiota contained Alcaligenes faecalis.

Aerobiosis↗

Changes in cutaneous flora after wet occlusion.

Aerobic flora from wet-occluded forearms of six volunteers was sampled the day before treatment, on the 3rd day when dressings were removed, and daily, when possible, for 8 days thereafter. Erythema was not present. All bacterial colonies appearing on appropriate dilution plates were identified with the aid of a replica-plating technique. Flora of each individual increased to over 10-4 colony-forming units/cm2 as a result of wet-occlusion, but counts rapidly fell by about 10-2 units once dressings were removed. Although similar types of bacteria were found on all subjects, the composition of each individual's flora during the recovery response appeared to be unique. Enterobacteriaceae were found on half the subjects with Enterobacter aerogenes being the most successful colonizer. Besides the expected presence of Baird-Parker Staphylococcus subgroup II, high numbers of subgroup IV and some colonies of subgroup III were also observed. Almost all cutaneous diphtheroids were lipophilic and lipolytic.

Adult↗

A replica-plating method for the identification of Micrococcaceae.

A procedure of replica plating is described whereby all isolated colonies of Micrococcaceae can be identified with relative ease and rapidity. The method is as accurate as the recommended procedure, but permits a more complete and economical analysis of cutaneous flora in large-scale surveys. In this system, Baird-Parker carbohydrate medium was found somewhat superior to standard medium as was incubation at 35 degrees C instead of the customary 30 degrees C. Baird-Parker's broth medium for acetoin production yielded more positive results than did commercial medium, although the reactions were less distinct. However, an agar acetoin test medium was found as good or perhaps even better than Baird-Parker's medium. The classification schemes of Baird-Parker and Bergey's Manual were contrasted in the analysis of data.

Bacteriological Techniques↗