White Coats as a Vehicle for Bacterial Dissemination

White coats are worn primarily for identification, but there has always been some concern that white coats, like nurses’ uniforms and other hospital garments, may play a part in transmitting pathogenic bacteria in a hospital setting, as white coats are known to be potentially contaminated with pathogenic drug resistant bacteria [1]. Since many medical colleges are closely attached to hospital environments and as there is no changing area in the hospitals, students wear their white coats on the way to their colleges and even in the non-clinical and non-practical classes, library, cafeteria and in the resting areas around their colleges. It is not uncommon to see white coats being left on chairs or being carried around outside the hospital premises [2].

It was the interest of this study to find out the level and the type of microbial contamination which was present on the medical student’s white coats in our college, in order to assess the risk of transmission of the pathogenic organisms by this route in our hospital. The student’s way of handling the coats and cleaning them, as well their perception towards white coat contamination also were investigated.

This cross sectional study was conducted in the Department of Microbiology of a tertiary care hospital which was attached to a medical college. Approval from the institutional ethical committee was duly taken for this study. 100 undergraduate and postgraduate medical students and interns were randomly selected and they were included in this study, of which 65% were males and 35% were females. Of the 100, 83% were undergraduate students, 10% were interns and 7% were postgraduate students. All the students were working in the outpatient and the inpatient wards of our hospital. All the invited students were asked to read the questionnaire and to sign the consent forms.

A brief, self-administered, structured questionnaire was used to collect demographic data and information on the white coat laundering habits of the participants. The demographic variables included gender, place of staying, the subject’s positions (student, intern or post-graduate), their current work locations (paediatrics, medicine, ophthalmology, ENT, skin and STD, microbiology, surgery, public health and obstetrics and gynaecology), the reason for wearing the white coat (to cover clothing, to appear professional, dress code of the hospital, for the usage of pockets or other), length of the usage of the coat (<1 year, 1-2 years, 2-3 years or > 3 years), when the coat was last washed (<3 days, 1 wk, 2-4 weeks or >1 month), the frequency of washing (<3 days, 1 week, 2-4 weeks or > 1 month), type of cleaning (home or laundry), washing agents used (soaps, liquid wash or disinfectants), number of white coats possessed (1, 2, 3 or >3), method of carrying the white coat (cover, bags, hands or shoulder), location of the use of the white coat (hospital only or hospital and college), the wearer’s perception of whether the coat was dirty or clean and whether they believed if their white coats carried microbes and were the possible agents of the transmission of pathogens.

Swabs were taken from four different areas of the white coat (collar, pocket, sides and lapels). The swabs which were used were plain, cotton-tipped and sterilized swabs. Normal saline was used to moisten the swabs before collecting the sample by passing the swabs up and down twice on the desired areas and the swabs were sent immediately to the laboratory. The swabs which were received by the Department of Microbiology were immediately streaked onto blood agar and McConkey’s agar and the plates were incubated overnight at 37°C. The colonies which were obtained were identified by using standard techniques [3]. Antibiotic sensitivity testing was done by using Kirby Bauer’s disc diffusion method as has been described in the CLSI guidelines 2011 [4].

Traditionally, the white coat is thought to bring credibility and dignity to the medical profession [2]. However, white coats have been shown to harbour potential contaminants [1,2,5,6] and so these may have a role in the nosocomial transmission of pathogenic microorganisms. The high rates of the bacterial contamination of white coats may be associated with the following 2 facts: Firstly, patients continuously shed infectious microorganisms in the hospital environment, and the health care providers are in constant contact with these patients. Secondly, it has been demonstrated that microorganisms can survive between 10 and 98 days on fabrics which are used to make white coats, which include cotton, cotton and polyester, or polyester materials [7,8].

Our hospitals were tertiary care hospitals which were attached to a medical college and a research institute, where the incidence of the nosocomial infections was approximately 10%. All the medical students worked in the clinical wards from the 2nd phase and examined patients. These students indiscriminately used the white coats even outside the hospital premises. Since white coats are implicated as major fomites in the transmission of nosocomial infections, we studied 100 medical students who were working in various specialities. Most of them i.e., 83 were undergraduates, 10 were interns and the remaining 7 were postgraduate students. Of the 65 white coats which belonged to the male subjects, 47(74.3%) were contaminated, while of the 35 white coats which belonged to the female subjects, 22(62.8%) were contaminated. This was in contrast to the findings of a study which was conducted by Muhadi et al., [2] who found in their study, that the coats of females tended to be more contaminated.

The medical students who were residing at home tended to have white coats that were more contaminated (72.9%), whereas those who were residing in the hostel had less contaminated coats (63.1%), which was a worrying prospect, as the hospital organisms were likely to spread in the community. Most of the students were of the opinion that white coats were worn to appear professional (67%) and because it was the dress code of the hospital (45%). However, 82 of the subjects used their white coats only in the hospital premises, while the other 18 used it outside the hospital premises too. Although both the clinical and the non-clinical students had a high level of awareness regarding the contamination of the white coats, they still wore it in different areas of the college such as the library, reading rooms, canteen, classes and even outside the hospital premises when it was not necessary. Providing students with changing areas in at the hospital site may reduce their frequency of using the white coats in the college and in the non-clinical areas [2].

Even though the subjects perceived their white coats to be clean, even without stains, 91 were aware that the coats could act as a mode of transmission of the hospital’s pathogenic organisms. The data from the washing practices of the students revealed that most of the students had washed their white coats within the past 1 week (71%). In spite of this, the contamination was high (62%-78%), irrespective of the time gap since the last wash. This was similar to the findings of a study which was done by Wong et al., [1], who found that the microbial counts did not vary with the time in the use of the white coats. A steady state of maximal microbial contamination was attained within the first week of use of the coats and this did not change significantly thereafter. 89 of the white coats were washed at home, whereas 11 were washed in a laundry. The degree of contamination was similar in both the sets.

In the present study, Staphylococcus aureus was the major pathogen which was isolated (64.7%), which is similar to that which was found in the studies of Muhadi et al., [2], Treakle et al., [9] and Wong et al., [1] and different from the findings of a study which was done by Uneke et al., [7], in which diphtheroids were the most common organisms which were isolated. The antimicrobial susceptibility pattern of the gram positive cocci revealed that most of them were resistant to Penicillin (81.6%), Erythromycin (70.6%) and Clindmycin (58.7%). This is consistent with the susceptibility pattern of similar organisms which were isolated from suspected nosocomial infections in our hospital and this indicated a possible link between the contamination of the white coats and the transmission of infections to the susceptible patients. In our study, MRSA was isolated from 4 white coats, which was significantly lower than that which was reported Uneke et al., [7] but similar to the findings of a study which was done by Treakle et al., [9], who reported no MRSA isolation from the white coats.

Coagulase negative Staphylococci were also isolated (10.3%), which are skin commensals and these can be potentially infectious to the patients who are admitted in the hospital. Gram negative bacilli were isolated from the white coats, but these were also significantly lesser in number but were also potentially infectious, as was reported by Zachary, 2001 and Grabsch 2006 [2,5,10,11].

Our study has several limitations. Firstly, the sample size was small and statistically significant differences between the colonized and the uncolonized coats could not be brought out. Secondly, the use of swabs for obtaining the samples may have been less effective than using the sweep plate method, as was done in some previous studies. Also, since the swabbing was done by the participant himself/herself, the sufficiency of the time of contact could not be established. Lastly, our study did not include a control group of non-worn white coats and thus the possibility of the coats being contaminated prior to their use could not be ruled out. However, that would have no bearing on the fact that the coats were contaminated with potentially pathogenic organisms and that they could function as fomites for the transmission of pathogenic organisms [9].

The following suggestions may be made on the basis of the findings of this investigation. Firstly, a yearly purchase of white coats and the possession of 2 or more white coats at any point of time should be made compulsory. The wearers of the white coats should be encouraged to wash their white coats weekly. This study provides microbiological evidence to support the exclusion of white coats from the nonclinical areas of the hospital such as the libraries and the dining rooms. A number of earlier studies had demonstrated that the compliance with the hand-hygiene protocols among all the healthcare workers, including the physicians, was poor [7]. A lack of hand hygiene undoubtedly enhances the contamination of the white coats, since they are often touched by the physicians in the course of their work. As a result, there is a pressing need to promote a scrupulous hand washing among the physicians before and after they attended to patients and also to promote alternatives to the white coats, which includes the universal use of protective gowns.

[1]. Wong D, Nye K, Hollis P, The microbial flora on doctor’s white coats British Medical Journal 1991 303:21-28.  [Google Scholar]

[2]. Muhadi SA, Aznamshah NA, Jahanfar S, A cross sectional study on the microbial contamination of the medical student’s white coats Malayasian Journal of Microbiology 2007 3(1):35-38.  [Google Scholar]

[3]. Mackie Mc Cartney Collee JG, Fraser AG, Marmion BP, Siminons A, Practical Medical Microbiology 1996 14thNew YorkChurchill Livingston  [Google Scholar]

[4]. CLSI Performance standards for Antimicrobial Susceptibility testing; Twenty First Informational Supplement. CLSI document M100-S21 2011 Wayne, PAClinical and Laboratory Standards Institute  [Google Scholar]

[5]. Varghese D, Patel H, Hand washing: stethoscopes and white coats are the is of nosocomial infections British Medical Journal 1999 319:519  [Google Scholar]

[6]. Neely AN, A survey on the survival of gram-negative bacteria on hospital fabrics and plastics Journal of Burn Care and Rehabilitation 2000 21:523-27.  [Google Scholar]

[7]. Uneke CJ, Ijeoma PA, The potential for nosocomial infection transmission of the white coats which were used by physicians in Nigeria: Implications for improved patient-safety initiatives World Health and Population 2010 11(3):44-54.  [Google Scholar]

[8]. Chacko L, Jose S, Issac A, Bhat KG, Survival of nosocomial bacteria on hospital fabrics Indian Journal of Medical Microbiology 2003 21(4):291  [Google Scholar]

[9]. Treakle AM, Thom KA, Furuno JP, Strauss SM, Harris AD, Perencevich EN, Bacterial contamination of the health care workers’ white coats Am J Infect Control 2009 37(2):101-05.  [Google Scholar]

[10]. Zachary KC, Bayne PS, Morrison VJ, Ford DS, Silver LC, Hooper DC, Contamination of gowns, gloves, and stethoscopes with vancomycin resistant enterococci Infection Control and Hospital Epidemiology 2001 22(9):560-64.  [Google Scholar]

[11]. Grabsch EA, Burrell LJ, O’Keeffe JM, Ballard S, Grayson L, Risk of environmental and healthcare worker contamination with vancomycin resistant enterococci during outpatient procedures and haemodialysis Infection Control and Hospital Epidemiology 2006 27:287-93.  [Google Scholar]