The Bacterial Flora of the Antecubital Fossa: The Efficacy of Alcohol Disinfection of this Site, the Palm and the Forehead

The surface flora of the antecubital fossa (ACF) of 25 subjects comprised the same kinds of bacteria as are commonly found on the hands, arms, back and forehead. The population density was bimodal. Fifteen subjects had a sparse flora. After alcohol disinfection there were no surviving bacteria on these subjects. The other 10 subjects had a more abundant flora (310 to 10,000 per cm2) and after alcohol treatment there remained on 9 of these subjects a surviving population showing no quantitative correlation with the surface flora.On the palm (hypothenar eminence) of 5 subjects all bacteria were eliminated by alcohol disinfection despite initial surface populations equal to those of the 5 ACF subjects with the greatest alcohol resistant flora. On the forehead, bacterial population densities were much greater than on the palm or ACF. Alcohol disinfection reduced the surface population on the average, more than the subsurface populations, but did not eliminate either propionibacteria or gram positive cocci.Five ACF subjects with the highest alcohol resistant populations in the initial survey were retested several times over 7 mo (1 subject) or 2½ yr (4 subjects). On each person, the surviving bacteria in the initial test were of one particular species, Propionibacterium acnes, Peptococcus saccharolyticus, Staphylococcus epidermidis or an aerobic diphtheroid. In subsequent tests, S. epidermidis disappeared but the other 4 organisms continued to be present as alcohol resistant populations on both arms of their respective subjects throughout the study (22 of 25 tests positive).We suggest that the terms sheltered and exposed flora would be more accurate than transient and resident in discussing skin disinfection