Survival of Pathogenic Microorganisms on Human Skin

Raza Aly, Howard I. Maibach, Henry R. Shinefield, Walter G. Strauss
1972 Journal of Investigative Dermatology  
This study was d es igned to establi sh in vivo t he poss ib le presence of antimi crob ia l substa nce(s) in human s kin . If such agents a re present on t he s kin surface, t heir removal might a llow increase d multipli cation of app lied organis ms. One forearm was washed repeated ly for 5 minutes with lipid solvents; t he other served as t he control. T he organis ms app lied (3 x 10 3 -7 x 10" in 0.01 ml Ringe r's solution) on t he forearms were not a llowed to dry and were covered
more » ... tely with plasti c protective cups for 5 hours. The microorga nisms were ha rvested us ing a modified Pach tman-Burtenshaw method . With Staphylococcus aureus a nd Streptococcus py ogenes, acetone washed forearm s ha d 2-to 510-fold more orga nis ms t han t he con t rol arm (P = 0.0008 and 0.08, respective ly). Sim ila r results were noted with ether (average 1:62, P = 0.005). Candida a.lbicans increased 2-to 200-fold (average 1:37, P = 0.002). This effect did not occur with Escherichia co li a nd Pseudomonas aeruginosa (P = 0.8). To determin e t he time required for natura l replenishm en t of t he a ntimicrobi a l substances, bacteria were applied 2, 3, a nd 5 hours after washing wit h acetone . In creased numbers were seen at 2 (P = 0.04) , but not at 5 (P = 0.2) hours. On the con t rary, mi crob ia l fl ora removed by acetone washing were n ot restored durin g the 5 hour period. Regional variation studies showed that the forehead d id not inhibi t S. aureus pers istence (as did the forearm s) (P = 0.003). Forearms treated with acetone and the extracts not re moved did not show increase of S . aureus counts whe n compa red wi t h untreate d a rms (average ratio 1 : 1, P ~ 0.6) . When acetone ext racts of t he s kin surface were removed, eva porated, a nd t hen replaced on the skin, t he increased bacterial coun ts noted a bove were no longer fou nd . Schie ma nn a nd Landau (1) first showed t hat E sch erichia co li d e posited on the s kin were not recovera ble after a short peri od of t ime. Arnold et al. (2) demonstrated t hat S. aureus, Pseudomonas aeruginosa and E. coli rapidl y disappea r from
doi:10.1111/1523-1747.ep12539912 pmid:4623202 fatcat:ayxrhm4erbcxndg4mhkf2c3fk4