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Wristwatch use and hospital-acquired infection
Journal of Hospital Infection (2010) 74, 16e21
Available online at www.sciencedirect.com
www.elsevierhealth.com/journals/jhin
Wristwatch use and hospital-acquired infection A.R. Jeans a,*,y, J. Moore a,y, C. Nicol b, C. Bates b, R.C. Read a,c a
Department of Infection & Tropical Medicine, Royal Hallamshire Hospital, Sheffield, UK Department of Microbiology, Royal Hallamshire Hospital, Sheffield, UK c Department of Infection and Immunity, Sheffield School of Medicine and Biomedical Science, University of Sheffield, Sheffield, UK b
Received 18 January 2009; accepted 28 June 2009 Available online 13 September 2009
KEYWORDS Hand hygiene; Infection control; Wristwatch
Summary The wrists and hands of hospital-based healthcare workers (HCWs) were sampled for bacterial contamination in two consecutive cross-sectional cohort studies of wristwatch wearers and non-wristwatch wearers. In the first study (N ¼ 100), wrists were sampled by skin swabs and hands by direct plate inoculation. In the second study (N ¼ 155) wrists were sampled after each HCW removed the watch immediately prior to sampling. Staphylococcus aureus was found on the hands of 25% of wristwatch wearers and 22.9% of non-wristwatch wearers in the first study. Watch wearers had higher counts of bacteria on their wrist (P < 0.001) but not on their hands. In the second study, removal of the watch prior to sampling resulted in increased counts of bacteria on both hands as well as on the watch wrist compared with non-watch wearers (P < 0.001). In conclusion, wearing a wristwatch results in an increase in bacterial contamination of the wrist but excess hand contamination does not occur unless the watch is manipulated. ª 2009 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.
Introduction Hospital-acquired infection remains an important problem, causing significant morbidity and
* Corresponding author. Address: Department of Infectious Diseases, North Manchester General Hospital, Delaunays Road, Manchester M8 5RB, UK. Tel.: þ44 161 6240420. y
These authors contributed equally to this work.
economic cost.1 Transmission of pathogens by the contaminated hands of healthcare workers (HCWs) is considered the major route of cross-infection.2 Items such as stethoscopes, tourniquets and white coats can become contaminated with microbes including Staphylococcus aureus and may act as a vector of spread, either directly or via HCWs’ hands.3e5 Wearing rings has been shown to increase the hand carriage of potential pathogens.6 Wristwatches are commonly worn by HCWs in the UK.
0195-6701/$ - see front matter ª 2009 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2009.06.032
Wristwatch use and HAI However, whilst watches have been shown to harbour bacterial pathogens, their effect on carriage of such bacteria on the hands has not been demonstrated.7 Recently, hospitals in the UK have been asked to implement a policy of ‘bare below the elbows’ which includes the banning of wristwatches.8 This has drawn considerable comment, including from those who cite the value of the wristwatch for effective clinical practice.9 This study was undertaken to investigate whether wearing a wristwatch influences the rate of carriage of S. aureus and other bacteria on the hands of HCWs.
Methods Participants HCWs were recruited from the wards of a UK teaching hospital. Only those whose job involved direct patient contact were recruited. For each wristwatch wearer identified, a non-wristwatch wearer was recruited from the same clinical area. The study was approved by the South Sheffield Research Ethics Committee (study number 03/162). Data were collected from two separate study groups: e Samples were collected from 100 HCWs: 52 wristwatch wearers and 48 non-wristwatch wearers. Both hands were sampled by direct imprint of each fingertip on to bacterial culture plates. Watches were then removed and wrists were sampled by swabbing the watch-bearing wrist. In the case of controls (non-wristwatch wearers) the non-dominant arm was swabbed. Demographic and other data were obtained by questionnaire which subjects completed at the time of sample collection. e Samples were collected from 155 HCWs: 85 wristwatch wearers and 70 non-wristwatch wearers. Both hands and wrists were sampled. Subjects removed their watch prior to sampling, allowing assessment of the effect of handling a watch moments before or during patient contact.
17 hand washing or use of alcohol gel. The presence or absence of visible skin disease (e.g. eczema, psoriasis) on the subject’s hands at the time of sampling was also recorded.
Sampling methods Each subject placed their fingertips on to bacterial culture media. Columbia blood agar (Oxoid Ltd, Basingstoke, UK and E&O Laboratories, Bonnybridge, UK) followed by mannitol salt agar (MSA) plates (aztreonam 1% with egg; Mast Diagnostics, Bootle, UK) were used for the first study group, and blood agar alone for the second study group. Subjects’ wrists were sampled after watch removal in a standardised manner by a swab dampened in sterile saline. This was rolled over the area of skin at the point of watch contact, or the equivalent area of the non-dominant arm of non-wristwatch wearers, before being applied on to blood agar and MSA plates and streaked out. Each wrist was sampled on its anterior and posterior aspect by the same swab by making a single pass on each side. For the second study group, MSA and MacConkey agar plates (Oxoid) were used.
Laboratory methods Plates were incubated for 24 h at 37 C; MSA and MacConkey aerobically and blood agar plates in 5% CO2. Semiquantitative bacterial colony counts were then recorded for each blood agar plate by comparison with a visual scale. A recording of ‘0’ indicated no bacterial growth, ‘’ scanty growth, ‘þ’ light growth, ‘þþ’ moderate growth and ‘þþþ’ heavy growth. S. aureus isolates were identified by standard bacterial protocols after 48 h of culture. Colonies with morphology consistent with S. aureus were subcultured on to blood agar and reincubated. Confirmatory identification of S. aureus was made by slide coagulase test (Staphaurex, Prolab) and demonstration of mannitol fermentation and lipase production following subculture on to MSA, and DNase (deoxyribonuclease) production following subculture on DNase agar (Oxoid). Identification of MRSA was made by subculture onto MSA with meticillin 5 mg/mL.
Questionnaire Analysis Subjects completed this anonymously prior to sampling. They were asked to estimate the time period that had elapsed since they last practiced hand decontamination. This was defined as either
c2-Analysis was performed using SPSS v.11. Bonferroni correction was applied to the analyses performed in each study group.
A
30 25 20 15 10 5 0
No watch (N ¼ 48)
11 (21.2) 41 (78.8)
6 (12.5) 42 (87.5)
10 21 11 10
(19.2) (40.4) (21.2) (19.2) 0
6 (12.5) 17 (35.4) 21 (43.8) 4 (8.3) 0
Occupation Nurse Doctor Allied Support
20 (38.5) 20 (38.5) 9 (17.3) 3 (5.8)
34 (70.8) 3 (6.3) 6 (12.5) 5 (10.4)
Handedness Right Left
47 (90.4) 5 (9.6)
44 (91.7) 4 (8.3)
Skin disease on hands
4 (7.7)
3 (6.3)
Last hand decontamination (min) <30 31e120 >120
27 (51.9) 19 (36.5) 6 (11.5)
40 (83.3) 8 (16.7) 0
Male Female Age (years) 16e25 26e35 35e50 51e65 66
B Number of subjects
Watch (N ¼ 52)
Ipsilateral wrist
0
±
+ Colony count
++
+++
0
±
+ Colony count
++
+++
0
±
+ Colony count
++
+++
Subject characteristics of study group 1 No. (%) of subjects
Contralateral hand
Figure 1 Isolation rates of S. aureus after sampling from hands and wrist prior to wristwatch removal (N ¼ 100). No significant difference between watch wearers (grey bars) and non-watch wearers (black bars) by c2-analysis.
C Number of subjects
Table I
30 25 20 15 10 5 0
Any site
Baseline characteristics of the first study group are shown in Table I. All HCWs approached agreed to participate. S. aureus was isolated from the hands of 25% of the wristwatch wearers and from 22.9% of the nonwristwatch wearers in the first study group but was not isolated from the wrists of any of the subjects (Figure 1). Watch wearers had a greater number of bacteria on their wrist as measured by colony count (P < 0.001) but the number of bacteria on their hands was not significantly increased (Figure 2). There were three isolates of MRSA, two from the hands of a non-wristwatch wearer and one from a wristwatch wearer. In the second study group, watches were removed (and therefore handled) by the HCW immediately prior to sampling. Figure 3 shows that the amount of bacteria on both hands as well as the watch wrist was significantly increased in watch wearers compared with non-watch wearers (P < 0.001). The amount of bacteria was not increased on the contralateral, non-watch wrist. The isolation rate of S. aureus (10.6% vs 1.4%) from the hand that removed the watch was increased in
Number of subjects
Results
Ipsilateral hand
A.R. Jeans et al. % S. aureus isolation
18
30 25 20 15 10 5 0
30 25 20 15 10 5 0
Figure 2 Semiquantitative bacterial colony counts following culture of samples taken from the ipsilateral hand (A), contralateral hand (B) and ipsilateral wrist (C) prior to wristwatch removal (N ¼ 100). c2-Analysis shows an increase in the bacterial colony counts from the watch (ipsilateral) wrists of wristwatch wearers (grey bars) compared to the equivalent wrist in nonwatch wearers (black bars) (P < 0.001).
Wristwatch use and HAI
19
B 40
Number of subjects
Number of subjects
A 30 20 10 0
0
±
+ Colony count
++
+++
D 40
Number of subjects
Number of subjects
C 30 20 10 0
0
±
+
++
+++
Colony count
40 30 20 10 0
0
±
0
±
+ Colony count
++
+++
+
++
+++
40 30 20 10 0
Colony count
Figure 3 Semiquantitative bacterial colony counts following culture of samples taken from the ipsilateral hand (A), contralateral hand (B), ipsilateral wrist (C) and contralateral wrist (D) after wristwatch manipulation and removal (N ¼ 155). c 2 -Analysis shows an increase in the bacterial colony counts from the watch (ipsilateral) wrists (P < 0.001), watch hands (P < 0.001) and contralateral hands (P < 0.001) of wristwatch wearers (grey bars) compared to the equivalent areas in non-watch wearers (black bars).
watch wearers, but did not reach statistical significance (Figure 4). Compared with 0% of non-watch wearers, 12.9% of watch wearers had S. aureus isolated from their watch wrist (P < 0.003). No MRSA was isolated from this study group.
Discussion
Contralateral wrist
Ipsilateral wrist
Contralateral hand
14 12 10 8 6 4 2 0
Ipsilateral hand
% S.aureus isolation
This study has shown that wristwatch wearing is associated with increased bacterial colonisation of
Figure 4 Isolation rates of S. aureus after sampling from hands and wrists following watch manipulation and removal (N ¼ 155). c2-Analysis shows an increased rate of S. aureus isolation from the watch (ipsilateral) wrist of wristwatch wearers (grey bars) (P < 0.003) compared with non-watch wearers (black bars).
wrists, but not of the hands, in samples from ward based HCWs. Furthermore, the data also show that removing the watch easily transfers wrist bacteria on to the hands. These data reinforce the notion that wristwatch wearing is a potential infection control hazard. Although our study shows a clear association between wristwatch wearers and bacterial colonisation of the wrists, we attach some reservations to our conclusion. The period of time elapsed from the most recent episode of hand decontamination until sampling was unevenly distributed, with a higher proportion of non-wristwatch wearers having decontaminated their hands within the preceding 30 min. This may represent better adherence to hand hygiene precautions in this group and is a potential confounding factor. It might be envisaged that HCWs who do not wear a wristwatch at work are those who are more likely to comply with other hand hygiene guidance. However, such an association should have produced a greater rate of hand contamination among watch wearers than non-watch wearers within the first study group, and this was not apparent. A subgroup analysis of subjects who had undertaken hand decontamination less than 30 min prior to sampling revealed no deviation from the results of the main analysis (data not shown). It may be that non-wristwatch wearing simply represents greater enforcement of infection control policy in a particular area or group rather than an
20 Table II
A.R. Jeans et al. Rates of Staphylococcus aureus hand carriage
Source
Population
Sampling method
Jeans et al. (2009) (this study) Tammelin et al. (2003)10
100 HCWs
Cespedes et al. (2002)11
193 HCWs
Pittet et al. (1999)12
HCWs, 417 samples following hand cleansing 100 patients with atopic dermatitis 68 HCWs with nasal carriage ICU nurses, 282 samples 20 nurses with hand irritation, samples following hand washing
Williams et al. (1999)13 Reagan et al. (1991)14 Trick et al. (2003)6 Larson et al. (1998)15
133 HCWs
Agar imprints of fingertips, 2 hands Agar imprints of hands, 2 hands Agar imprint of palm and fingertips, 1 hand Agar imprint of fingertips, 1 hand Palm swab, 1 hand Hand rinse 2 hands Hand rinse 1 hand Hand rinse 1 hand
S. aureus rate (%) 24 10.5 10.2 9.4 30 39.7 13 20
HCW, healthcare worker; ICU, intensive care unit.
individual’s commitment to hand hygiene. Other factors, such as visibility of other time-keeping devices within the work area, might also play a role. A further reservation is that, for ease of collection, only the fingertips of each subject were sampled rather than the whole hand. An increase in bacterial contamination of the palms in wristwatch wearers may have been missed by our method, perhaps occurring due to contaminated wash water running down to the palm following hand washing. However, it would be expected that any such palm contamination would quickly spread to the fingertips through the natural closing movements of the hands and this did not occur. Additional factors such as HCW role were not included in the analysis of risk factors for carriage of S. aureus due to the small numbers within each subgroup and due to the fact that the primary endpoint was restricted to the effect of wristwatch wearing on hand contamination. However, doctors were under-represented in the non-wristwatchwearing group, as most doctors within the hospital wore wristwatches. The laboratory methods used varied slightly between the two study groups. This was intended to improve the identification of coliform bacteria in the second study group. However, as comparison was only made between wristwatch wearers and non-wristwatch wearers within each study group e not between the two study groups e this did not affect the conclusions drawn. An absolute rate of S. aureus hand carriage was taken from the first cohort, where watches were not removed prior to sampling; 24% of HCWs were found to have S. aureus on their hands overall in this group. The rate of carriage of S. aureus observed in this study is similar to that reported by other studies. The rate in other published series varies
depending on the sampling technique, the population sampled, the time since hand decontamination and the number of hands sampled from each subject (Table II). It can be seen from our data that sampling more than one site increases the overall estimate of the carriage rate, as many subjects had S. aureus detected on one hand but not the other. In our method, wrists were sampled by swabs. In the first cohort, although bacteria were grown from these samples S. aureus was not isolated. In the second cohort, 12.9% of wristwatch wearers had S. aureus isolated from their watch wrist. This discrepancy probably reflects a higher rate of S. aureus wrist carriage among the second study population. The wrist-sampling process was identical for each cohort, but they were recruited and surveyed six months apart. Demographic data were not recorded for the second study group, although both groups were recruited from the same clinical areas and had a similar composition. Previous work has evaluated ring wearing in the hospital setting, but this is the first study to address directly hand contamination of HCW wristwatch wearers.6 Our results support a policy of ‘bare below the elbows’, but they also suggest that using alternatives to wristwatches such as watch fobs or pocket watches might be an even greater infection control hazard. Such devices require handling to read the time, whereas wristwatches generally do not. Our study clearly demonstrates that the risk of hand contamination stems from manipulating the watch, not simply wearing it. A ban on wristwatches might actually increase the contamination of HCWs’ hands if it led to the greater use of these alternative devices. Further work is therefore needed to examine this
Wristwatch use and HAI question before stronger enforcement of new infection control policy is implemented.
Conflict of interest statement None declared. Funding sources Funded by the Department of Microbiology, Royal Hallamshire Hospital, Sheffield, UK, and sponsored by Sheffield Teaching Hospitals Foundation Trust. The sponsor played no role in the design, execution and reporting of the study.
References 1. Health Protection Agency. Surveillance of healthcare associated infections report: 2008. London: HPA; 2008. 2. Solberg CO. Spread of Staphylococcus aureus in hospitals: causes and prevention. Scand J Infect Dis 2000;32: 587e595. 3. Breathnach AS, Jenkins DR, Pedler SJ. Stethoscopes as possible vectors of infection by staphylococci. Br Med J 1992; 305:1573e1574. 4. Berman DS, Schaefler S, Simberkoff MS, Rahal JJ. Tourniquets and nosocomial methicillin-resistant Staphylococcus aureus infections. New Engl J Med 1986;315:514e515. 5. Loh W, Ng VV, Holton J. Bacterial flora on the white coats of medical students. J Hosp Infect 2000;45:65e68.
21 6. Trick WE, Vernon MO, Hayes RA, et al. Impact of ring wearing on hand contamination and comparison of hand hygiene agents in a hospital. Clin Infect Dis 2003;36:1383e1390. 7. Field EA, McGowan P, Pearce PK, Martin MV. Rings and watches: should they be removed prior to operative dental procedures? J Dent 1996;24:65e69. 8. Department of Health. Uniforms and workwear: an evidence base for developing local policy. London: DoH; 2007. 9. Henderson J, McCracken S. Clinical value of a wristwatch. Br Med J 2008;336:10. 10. Tammelin A, Klo ¨tz F, Hambraeus A, Sta ˚hle E, Ransjo ¨ U. Nasal and hand carriage of Staphylococcus aureus in staff at a department for thoracic and cardiovascular surgery: endogenous or exogenous source? Infect Control Hosp Epidemiol 2003;24:686e689. 11. Cespedes C, Miller M, Quagliarello B, Vavagiakis P, Klein RS, Lowy FD. Differences between Staphylococcus aureus isolates from medical and nonmedical personnel. J Clin Microbiol 2002;40:2594e2597. 12. Pittet D, Dharan S, Touveneau S, Sauvan V, Perneger TV. Bacterial contamination of the hands of hospital staff during routine patient care. Arch Intern Med 1999;159:821e826. 13. Williams JV, Vowels B, Honig P, Leyden JJ. Staphylococcus aureus isolation from the lesions, the hands, and the anterior nares of patients with atopic dermatitis. J Emerg Med 1999;17:207e211. 14. Reagan DR, Doebbeling BN, Pfaller MA, et al. Elimination of coincident Staphylococcus aureus nasal and hand carriage with intranasal application of mupirocin calcium ointment. Ann Intern Med 1991;114:101e206. 15. Larson EL, Hughes CA, Pyrek JD, Sparks SM, Cagatay EU, Bartkus JM. Changes in bacterial flora associated with skin damage on hands of health care personnel. Am J Infect Control 1998;26:513e521.
Available online at www.sciencedirect.com
www.elsevierhealth.com/journals/jhin
Wristwatch use and hospital-acquired infection A.R. Jeans a,*,y, J. Moore a,y, C. Nicol b, C. Bates b, R.C. Read a,c a
Department of Infection & Tropical Medicine, Royal Hallamshire Hospital, Sheffield, UK Department of Microbiology, Royal Hallamshire Hospital, Sheffield, UK c Department of Infection and Immunity, Sheffield School of Medicine and Biomedical Science, University of Sheffield, Sheffield, UK b
Received 18 January 2009; accepted 28 June 2009 Available online 13 September 2009
KEYWORDS Hand hygiene; Infection control; Wristwatch
Summary The wrists and hands of hospital-based healthcare workers (HCWs) were sampled for bacterial contamination in two consecutive cross-sectional cohort studies of wristwatch wearers and non-wristwatch wearers. In the first study (N ¼ 100), wrists were sampled by skin swabs and hands by direct plate inoculation. In the second study (N ¼ 155) wrists were sampled after each HCW removed the watch immediately prior to sampling. Staphylococcus aureus was found on the hands of 25% of wristwatch wearers and 22.9% of non-wristwatch wearers in the first study. Watch wearers had higher counts of bacteria on their wrist (P < 0.001) but not on their hands. In the second study, removal of the watch prior to sampling resulted in increased counts of bacteria on both hands as well as on the watch wrist compared with non-watch wearers (P < 0.001). In conclusion, wearing a wristwatch results in an increase in bacterial contamination of the wrist but excess hand contamination does not occur unless the watch is manipulated. ª 2009 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.
Introduction Hospital-acquired infection remains an important problem, causing significant morbidity and
* Corresponding author. Address: Department of Infectious Diseases, North Manchester General Hospital, Delaunays Road, Manchester M8 5RB, UK. Tel.: þ44 161 6240420. y
These authors contributed equally to this work.
economic cost.1 Transmission of pathogens by the contaminated hands of healthcare workers (HCWs) is considered the major route of cross-infection.2 Items such as stethoscopes, tourniquets and white coats can become contaminated with microbes including Staphylococcus aureus and may act as a vector of spread, either directly or via HCWs’ hands.3e5 Wearing rings has been shown to increase the hand carriage of potential pathogens.6 Wristwatches are commonly worn by HCWs in the UK.
0195-6701/$ - see front matter ª 2009 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2009.06.032
Wristwatch use and HAI However, whilst watches have been shown to harbour bacterial pathogens, their effect on carriage of such bacteria on the hands has not been demonstrated.7 Recently, hospitals in the UK have been asked to implement a policy of ‘bare below the elbows’ which includes the banning of wristwatches.8 This has drawn considerable comment, including from those who cite the value of the wristwatch for effective clinical practice.9 This study was undertaken to investigate whether wearing a wristwatch influences the rate of carriage of S. aureus and other bacteria on the hands of HCWs.
Methods Participants HCWs were recruited from the wards of a UK teaching hospital. Only those whose job involved direct patient contact were recruited. For each wristwatch wearer identified, a non-wristwatch wearer was recruited from the same clinical area. The study was approved by the South Sheffield Research Ethics Committee (study number 03/162). Data were collected from two separate study groups: e Samples were collected from 100 HCWs: 52 wristwatch wearers and 48 non-wristwatch wearers. Both hands were sampled by direct imprint of each fingertip on to bacterial culture plates. Watches were then removed and wrists were sampled by swabbing the watch-bearing wrist. In the case of controls (non-wristwatch wearers) the non-dominant arm was swabbed. Demographic and other data were obtained by questionnaire which subjects completed at the time of sample collection. e Samples were collected from 155 HCWs: 85 wristwatch wearers and 70 non-wristwatch wearers. Both hands and wrists were sampled. Subjects removed their watch prior to sampling, allowing assessment of the effect of handling a watch moments before or during patient contact.
17 hand washing or use of alcohol gel. The presence or absence of visible skin disease (e.g. eczema, psoriasis) on the subject’s hands at the time of sampling was also recorded.
Sampling methods Each subject placed their fingertips on to bacterial culture media. Columbia blood agar (Oxoid Ltd, Basingstoke, UK and E&O Laboratories, Bonnybridge, UK) followed by mannitol salt agar (MSA) plates (aztreonam 1% with egg; Mast Diagnostics, Bootle, UK) were used for the first study group, and blood agar alone for the second study group. Subjects’ wrists were sampled after watch removal in a standardised manner by a swab dampened in sterile saline. This was rolled over the area of skin at the point of watch contact, or the equivalent area of the non-dominant arm of non-wristwatch wearers, before being applied on to blood agar and MSA plates and streaked out. Each wrist was sampled on its anterior and posterior aspect by the same swab by making a single pass on each side. For the second study group, MSA and MacConkey agar plates (Oxoid) were used.
Laboratory methods Plates were incubated for 24 h at 37 C; MSA and MacConkey aerobically and blood agar plates in 5% CO2. Semiquantitative bacterial colony counts were then recorded for each blood agar plate by comparison with a visual scale. A recording of ‘0’ indicated no bacterial growth, ‘’ scanty growth, ‘þ’ light growth, ‘þþ’ moderate growth and ‘þþþ’ heavy growth. S. aureus isolates were identified by standard bacterial protocols after 48 h of culture. Colonies with morphology consistent with S. aureus were subcultured on to blood agar and reincubated. Confirmatory identification of S. aureus was made by slide coagulase test (Staphaurex, Prolab) and demonstration of mannitol fermentation and lipase production following subculture on to MSA, and DNase (deoxyribonuclease) production following subculture on DNase agar (Oxoid). Identification of MRSA was made by subculture onto MSA with meticillin 5 mg/mL.
Questionnaire Analysis Subjects completed this anonymously prior to sampling. They were asked to estimate the time period that had elapsed since they last practiced hand decontamination. This was defined as either
c2-Analysis was performed using SPSS v.11. Bonferroni correction was applied to the analyses performed in each study group.
A
30 25 20 15 10 5 0
No watch (N ¼ 48)
11 (21.2) 41 (78.8)
6 (12.5) 42 (87.5)
10 21 11 10
(19.2) (40.4) (21.2) (19.2) 0
6 (12.5) 17 (35.4) 21 (43.8) 4 (8.3) 0
Occupation Nurse Doctor Allied Support
20 (38.5) 20 (38.5) 9 (17.3) 3 (5.8)
34 (70.8) 3 (6.3) 6 (12.5) 5 (10.4)
Handedness Right Left
47 (90.4) 5 (9.6)
44 (91.7) 4 (8.3)
Skin disease on hands
4 (7.7)
3 (6.3)
Last hand decontamination (min) <30 31e120 >120
27 (51.9) 19 (36.5) 6 (11.5)
40 (83.3) 8 (16.7) 0
Male Female Age (years) 16e25 26e35 35e50 51e65 66
B Number of subjects
Watch (N ¼ 52)
Ipsilateral wrist
0
±
+ Colony count
++
+++
0
±
+ Colony count
++
+++
0
±
+ Colony count
++
+++
Subject characteristics of study group 1 No. (%) of subjects
Contralateral hand
Figure 1 Isolation rates of S. aureus after sampling from hands and wrist prior to wristwatch removal (N ¼ 100). No significant difference between watch wearers (grey bars) and non-watch wearers (black bars) by c2-analysis.
C Number of subjects
Table I
30 25 20 15 10 5 0
Any site
Baseline characteristics of the first study group are shown in Table I. All HCWs approached agreed to participate. S. aureus was isolated from the hands of 25% of the wristwatch wearers and from 22.9% of the nonwristwatch wearers in the first study group but was not isolated from the wrists of any of the subjects (Figure 1). Watch wearers had a greater number of bacteria on their wrist as measured by colony count (P < 0.001) but the number of bacteria on their hands was not significantly increased (Figure 2). There were three isolates of MRSA, two from the hands of a non-wristwatch wearer and one from a wristwatch wearer. In the second study group, watches were removed (and therefore handled) by the HCW immediately prior to sampling. Figure 3 shows that the amount of bacteria on both hands as well as the watch wrist was significantly increased in watch wearers compared with non-watch wearers (P < 0.001). The amount of bacteria was not increased on the contralateral, non-watch wrist. The isolation rate of S. aureus (10.6% vs 1.4%) from the hand that removed the watch was increased in
Number of subjects
Results
Ipsilateral hand
A.R. Jeans et al. % S. aureus isolation
18
30 25 20 15 10 5 0
30 25 20 15 10 5 0
Figure 2 Semiquantitative bacterial colony counts following culture of samples taken from the ipsilateral hand (A), contralateral hand (B) and ipsilateral wrist (C) prior to wristwatch removal (N ¼ 100). c2-Analysis shows an increase in the bacterial colony counts from the watch (ipsilateral) wrists of wristwatch wearers (grey bars) compared to the equivalent wrist in nonwatch wearers (black bars) (P < 0.001).
Wristwatch use and HAI
19
B 40
Number of subjects
Number of subjects
A 30 20 10 0
0
±
+ Colony count
++
+++
D 40
Number of subjects
Number of subjects
C 30 20 10 0
0
±
+
++
+++
Colony count
40 30 20 10 0
0
±
0
±
+ Colony count
++
+++
+
++
+++
40 30 20 10 0
Colony count
Figure 3 Semiquantitative bacterial colony counts following culture of samples taken from the ipsilateral hand (A), contralateral hand (B), ipsilateral wrist (C) and contralateral wrist (D) after wristwatch manipulation and removal (N ¼ 155). c 2 -Analysis shows an increase in the bacterial colony counts from the watch (ipsilateral) wrists (P < 0.001), watch hands (P < 0.001) and contralateral hands (P < 0.001) of wristwatch wearers (grey bars) compared to the equivalent areas in non-watch wearers (black bars).
watch wearers, but did not reach statistical significance (Figure 4). Compared with 0% of non-watch wearers, 12.9% of watch wearers had S. aureus isolated from their watch wrist (P < 0.003). No MRSA was isolated from this study group.
Discussion
Contralateral wrist
Ipsilateral wrist
Contralateral hand
14 12 10 8 6 4 2 0
Ipsilateral hand
% S.aureus isolation
This study has shown that wristwatch wearing is associated with increased bacterial colonisation of
Figure 4 Isolation rates of S. aureus after sampling from hands and wrists following watch manipulation and removal (N ¼ 155). c2-Analysis shows an increased rate of S. aureus isolation from the watch (ipsilateral) wrist of wristwatch wearers (grey bars) (P < 0.003) compared with non-watch wearers (black bars).
wrists, but not of the hands, in samples from ward based HCWs. Furthermore, the data also show that removing the watch easily transfers wrist bacteria on to the hands. These data reinforce the notion that wristwatch wearing is a potential infection control hazard. Although our study shows a clear association between wristwatch wearers and bacterial colonisation of the wrists, we attach some reservations to our conclusion. The period of time elapsed from the most recent episode of hand decontamination until sampling was unevenly distributed, with a higher proportion of non-wristwatch wearers having decontaminated their hands within the preceding 30 min. This may represent better adherence to hand hygiene precautions in this group and is a potential confounding factor. It might be envisaged that HCWs who do not wear a wristwatch at work are those who are more likely to comply with other hand hygiene guidance. However, such an association should have produced a greater rate of hand contamination among watch wearers than non-watch wearers within the first study group, and this was not apparent. A subgroup analysis of subjects who had undertaken hand decontamination less than 30 min prior to sampling revealed no deviation from the results of the main analysis (data not shown). It may be that non-wristwatch wearing simply represents greater enforcement of infection control policy in a particular area or group rather than an
20 Table II
A.R. Jeans et al. Rates of Staphylococcus aureus hand carriage
Source
Population
Sampling method
Jeans et al. (2009) (this study) Tammelin et al. (2003)10
100 HCWs
Cespedes et al. (2002)11
193 HCWs
Pittet et al. (1999)12
HCWs, 417 samples following hand cleansing 100 patients with atopic dermatitis 68 HCWs with nasal carriage ICU nurses, 282 samples 20 nurses with hand irritation, samples following hand washing
Williams et al. (1999)13 Reagan et al. (1991)14 Trick et al. (2003)6 Larson et al. (1998)15
133 HCWs
Agar imprints of fingertips, 2 hands Agar imprints of hands, 2 hands Agar imprint of palm and fingertips, 1 hand Agar imprint of fingertips, 1 hand Palm swab, 1 hand Hand rinse 2 hands Hand rinse 1 hand Hand rinse 1 hand
S. aureus rate (%) 24 10.5 10.2 9.4 30 39.7 13 20
HCW, healthcare worker; ICU, intensive care unit.
individual’s commitment to hand hygiene. Other factors, such as visibility of other time-keeping devices within the work area, might also play a role. A further reservation is that, for ease of collection, only the fingertips of each subject were sampled rather than the whole hand. An increase in bacterial contamination of the palms in wristwatch wearers may have been missed by our method, perhaps occurring due to contaminated wash water running down to the palm following hand washing. However, it would be expected that any such palm contamination would quickly spread to the fingertips through the natural closing movements of the hands and this did not occur. Additional factors such as HCW role were not included in the analysis of risk factors for carriage of S. aureus due to the small numbers within each subgroup and due to the fact that the primary endpoint was restricted to the effect of wristwatch wearing on hand contamination. However, doctors were under-represented in the non-wristwatchwearing group, as most doctors within the hospital wore wristwatches. The laboratory methods used varied slightly between the two study groups. This was intended to improve the identification of coliform bacteria in the second study group. However, as comparison was only made between wristwatch wearers and non-wristwatch wearers within each study group e not between the two study groups e this did not affect the conclusions drawn. An absolute rate of S. aureus hand carriage was taken from the first cohort, where watches were not removed prior to sampling; 24% of HCWs were found to have S. aureus on their hands overall in this group. The rate of carriage of S. aureus observed in this study is similar to that reported by other studies. The rate in other published series varies
depending on the sampling technique, the population sampled, the time since hand decontamination and the number of hands sampled from each subject (Table II). It can be seen from our data that sampling more than one site increases the overall estimate of the carriage rate, as many subjects had S. aureus detected on one hand but not the other. In our method, wrists were sampled by swabs. In the first cohort, although bacteria were grown from these samples S. aureus was not isolated. In the second cohort, 12.9% of wristwatch wearers had S. aureus isolated from their watch wrist. This discrepancy probably reflects a higher rate of S. aureus wrist carriage among the second study population. The wrist-sampling process was identical for each cohort, but they were recruited and surveyed six months apart. Demographic data were not recorded for the second study group, although both groups were recruited from the same clinical areas and had a similar composition. Previous work has evaluated ring wearing in the hospital setting, but this is the first study to address directly hand contamination of HCW wristwatch wearers.6 Our results support a policy of ‘bare below the elbows’, but they also suggest that using alternatives to wristwatches such as watch fobs or pocket watches might be an even greater infection control hazard. Such devices require handling to read the time, whereas wristwatches generally do not. Our study clearly demonstrates that the risk of hand contamination stems from manipulating the watch, not simply wearing it. A ban on wristwatches might actually increase the contamination of HCWs’ hands if it led to the greater use of these alternative devices. Further work is therefore needed to examine this
Wristwatch use and HAI question before stronger enforcement of new infection control policy is implemented.
Conflict of interest statement None declared. Funding sources Funded by the Department of Microbiology, Royal Hallamshire Hospital, Sheffield, UK, and sponsored by Sheffield Teaching Hospitals Foundation Trust. The sponsor played no role in the design, execution and reporting of the study.
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