226 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS oo

PSEUDOMONAS ON SKIN 227 swabbed, as were the finger web (between the first and second digits) and toe web (between the first and second toes). The samples obtained were serially diluted in 0.037 M PBS and pH 7.9, containing 0.05% Triton X-100, and cultured on Pseudomonas isolation agar (Difco). Plates were incubated at 37 ø C for 48 hours, and the colony-forming units were counted. P. aeruginosa was identified by appropriate biochemical methods (3). RESULTS AND DISCUSSION Four of the 166 individuals (2.5%) initially screened (subjects//5, 9, 10, and 11) carried P. aeruginosa (Table II, trial 1). One of the four subjects (//11) was negative for P. aeruginosa on three subsequent rescreenings (Table II, trials 2, 3, and 4). Subject//9 was positive for toe web carriage on initial screening, but became positive for the axilla (1 of 3 times) upon screening. P. aeruginosa had not disappeared from the toe site of this individual when the axilla was positive for this organism. When the remaining 162 subjects were resampled, seven additional P. aeruginosa carriers were detected. Of the combined total of 11 individuals who carried P. aeruginosa on the skin, seven (63%) were positive just once in the four times sampled. Of the remaining four individuals, three carried the organism twice and one carried it three times in four samplings. Those subjects from whom P. aeruginosa had disappeared repeatedly did not, however, carry the organism in the same site at each sampling. No subjects consistently carried P. aeruginosa. In no instance was P. aeruginosa recovered from the skin of nurses working either in the burn unit or in pediatrics. The ratio of P. aeruginosa skin carriage in nurses from females to males (7 females, 4 males, 64%, 36%) was approximately the same as the female to male ratio in the test population (65% females, 35% males). The mean age of individuals who harbored P. aeruginosa on their skin was 45 years (range: 26-70 years). Table II Carriage of Pseudomonas Aeruginosa at Various Skin Sites in 166 Subjects Over a 6-month Period Trial Subject a 1 2 3 4 1 -- -- toe b (40) -- 2 -- groin (350) -- -- 3 -- axilla (20) -- toe, groin (300) 4 -- axilla (10) -- -- 5 groin • (+) toe (300) toe (50) -- 6 -- -- -- axilla (200) 7 -- -- axilla (300) -- 8 -- -- -- toe (102) 9 toe (40) -- axilla (300) -- 10 groin (102) -- axilla, groin, -- (107, 800) toe (102) 11 groin, toe (+) -- -- -- aOnly subjects with P. aeruginosa at any given site are shown here. bcounts/site Ccounts not determined