There are seven main sources of contamination of clean operative wounds, namely, instruments, drapes, hands of operating personnel, droplet infection from nose and throat, suture material, air-borne bacteria and organisms in the skin. Hart,1 Meleney,2 Weaver,3 Dandy4 and many others have carried out investigations to prove the existence of these sources of contamination and have devised methods of combating all of them with the exception of bacteria of the skin. In a previous publication,5 it has been shown that most of the transient organisms of the skin are superficial and can be removed by mechanical and chemical cleansing. The resident bacteria are situated so deep in the hair follicles and sebaceous glands that they cannot be removed by mechanical means without injury to the skin. The antiseptics generally used do not penetrate sufficiently to reach the organisms located in the deeper parts of these structures.
LOVELL DL. SKIN BACTERIATHEIR ROLE IN CONTAMINATION AND INFECTION OF WOUNDS. Arch Surg. 1945;51(2):78-80. doi:10.1001/archsurg.1945.01230040083002