Brief Report

Are You "Coated" with Bacteria?

By Carol A. Kemper, MD, FACP, Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases. Dr. Kemper does research for Abbott Laboratories and Merck.This article originally appeared in the July issue of Infectious Disease Alert. At that time it was peer reviewed by Timothy Jenkins, MD, Assistant Professor of Medicine, University of Colorado, Denver Health Medical Center. Dr. Jenkins reports no financial relationship to this field of study.

Source: Burden M, et al. Newly cleaned physician uniforms and infrequently washed white coats have similar rates of bacterial contamination after an 8-hour workday. J Hosp Med 2011;6:177-182.

The National Health Service in Britain in 2007 elected to ban traditional white coats and other long-sleeved garments for physicians in the workplace (including long-sleeved blouses and shirts). Subsequently, Scotland adopted similar policies. This decision was based on limited data suggesting that the cuffs and lower pockets of long-sleeved garments are more heavily colonized with bacteria than shorter garments.

These authors have succeeded in debunking this notion. One hundred residents and hospitalists working on the internal medicine service in hospital (in Colorado) were randomly assigned either to start the day fresh with a newly laundered standard short-sleeved uniform or to wear their own (presumably not recently laundered) white coats. The latter group was not informed of their randomization assignment till the day they showed up for work, giving them no chance to switch to an unused coat. Cultures were obtained throughout the workday, beginning before the coat was put on to 2.5, 5, and 8 hours later. Cultures were obtained from the breast pocket, sleeve cuff (of either the short uniform sleeve or the long sleeve), and the skin of the volar surface of the wrist area. Cultures were incubated for 18-22 hours, and colony counts (up to 200) were determined. In addition, colonies of Staphylococcus were tested for coagulase production and methicillin resistance.

At the end of the day, no differences were found between the colony counts cultured from the clean uniforms and that of the white coats (respectively, mean colony counts, 142 [range 83-213] vs 104 [range 80-127]; P = 0.61). No significant differences were found between the colony counts cultured from the sleeve cuffs of the short-sleeved uniforms vs. the longer sleeve cuffs of the white coats (mean colony counts, 37 vs 58), or between the pockets of either garment (mean colony counts, 75 vs 46). Colony counts were generally greater for the sleeve cuffs compared with the breast pocket of the long-sleeved coat (although the difference was small), whereas no difference in colony counts was observed between the short sleeve cuffs and breast pockets of the uniforms. No differences were found between the degree of bacterial colonization of the wrists for either those wearing a white coat or a short-sleeved uniform.

In addition, colonization with methicillin-resistant Staphylococcus aureus was similar for those wearing their own long white coats compared with the group assigned to wear clean uniforms (16% vs 20%).

Serial cultures obtained throughout the workday demonstrated that a freshly laundered uniform starts out nearly sterile. But within 2.5-3 hours, the uniform is colonized with 50% of the bacterial colonies found at 8 hours of wear.


These data demonstrate that, when worn by a resident or hospitalist on the hospital wards, bacterial colonization of a freshly laundered garment is remarkably fast, and within 1 workday is similar to that of an unwashed days-old long-sleeved white coat. There is no evidence that long sleeves vs. short sleeves is less likely to result in bacterial colonization of either the garment or the wearer's wrists.