Our data suggest that health care workers' white coats frequently are contaminated with S aureus
, and that many of those isolates are methicillin-resistant, contradicting the conclusion of a recent review.15
The data are similar to those from previous evaluations of S aureus
but lower than expected for resistant isolates of S aureus
These numbers also mirror the published rates of S aureus
colonization seen in medical and surgical ICU inpatients and non-ICU inpatients at the index hospital.17,18
S aureus, including susceptible and resistant isolates, was found on those working in all positions and in all locations. Characteristics associated with a high likelihood of S aureus colonization included being a resident, having seen an inpatient within the past week, and working in the inpatient or ICU setting. No associations were found among time since laundering, location of laundering, and likelihood of S aureus colonization; however, those with S aureus colonization were more likely to have laundered their white coat in a personal facility. Characteristics associated with increased likelihood of MRSA colonization over MSSA colonization included being an attending and washing the white coat in the hospital laundry. Internal medicine respondents were more likely than surgery respondents to be colonized with MSSA and MRSA.
Previous studies have found variable rates of S aureus
and VRE contamination. In a point-prevalence study, Wong et al9
evaluated white coats of 100 physicians by pressing contact plates onto 3 areas of each coat and found S aureus
contamination in 29 of the coats (none of which was MRSA). They also found that physicians in the surgical specialties were more likely (P
< .05) to be carrying S aureus
than those in medical specialties. Loh et al10
evaluated white coats of 100 medical students at 3 sites with blood agar plates and found bacterial contamination in all coats, but S aureus
in only 5 of these.
In a point prevalence study, Perry et al11
evaluated the uniforms of 57 nurses for bacterial contamination using a Casella slit sampler before and after a usual shift. After the shift, MRSA was detected in 14% of the uniforms; VRE, in 38%. More recently, in 2003, Osawa et al12
evaluated white coats of physicians on wards of a university teaching hospital during 2 MRSA outbreaks. Using stamp medium, they found MRSA contamination in 80% of the white coats overall and even higher rates in those from personnel working in the wards with higher MRSA infection rates.
Our study has several limitations. First, despite the fact that this is the largest study of its kind completed and reported to date, we did not report statistically significant differences between colonized and uncolonized coats, because of the size of the population studied. Second, our sampling technique may have been less effective than that used in previous studies, in which blood agar plates were touched directly to the clothing item. We did not use blood agar, because of concerns that doing so could decrease participation due to concerns over possible staining of the white coat. Third, each participant swabbed his or her own coat, possibly leading to decreased bacterial adherence to the swab due to insufficient swabbing. But because most of the participants were clinicians, we expect that they likely did an adequate job of swabbing. Finally, the study did not include a control group of non-worn white coats, and thus we cannot rule out the possibility that the coats were contaminated in the laundry before clinical activity. However, our aim was to determine the level of contamination of the coats with pathogenic bacteria independent of site of contamination, which would suggest that the coats are potential fomites for transmission of these organisms.
White coats of health care worker may be contaminated with pathogenic and resistant bacteria. Given that in this study, most of the health care workers perceived their white coats as being dirty, and 2/3 of them had not washed their coats in more than a week, efforts could be directed at encouraging workers to launder their coats more frequently. Further studies should be done to evaluate white coats and other health care worker clothing as fomites for the transmission of pathogenic bacteria, and alternatives to white coats, including universal use of protective gowns, should be considered.