contamination of computer keyboards in clinical areas: potential reservoir for nosocomial spread of...

4
http://bji.sagepub.com/ British Journal of Infection Control http://bji.sagepub.com/content/6/3/22 The online version of this article can be found at: DOI: 10.1177/14690446050060030601 2005 6: 22 British Journal of Infection Control DJ Waghorn, WY Wan, C. Greaves, N. Whittome, HC Bosley and S. Cantrill organisms Contamination of computer keyboards in clinical areas: potential reservoir for nosocomial spread of Published by: http://www.sagepublications.com On behalf of: Infection Prevention Society can be found at: British Journal of Infection Control Additional services and information for http://bji.sagepub.com/cgi/alerts Email Alerts: http://bji.sagepub.com/subscriptions Subscriptions: http://www.sagepub.com/journalsReprints.nav Reprints: http://www.sagepub.com/journalsPermissions.nav Permissions: http://bji.sagepub.com/content/6/3/22.refs.html Citations: What is This? - May 1, 2005 Version of Record >> at Universiti Teknologi MARA (UiTM) on July 18, 2014 bji.sagepub.com Downloaded from at Universiti Teknologi MARA (UiTM) on July 18, 2014 bji.sagepub.com Downloaded from

Upload: s

Post on 31-Jan-2017

217 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: Contamination of computer keyboards in clinical areas: potential reservoir for nosocomial spread of organisms

http://bji.sagepub.com/British Journal of Infection Control

http://bji.sagepub.com/content/6/3/22The online version of this article can be found at:

 DOI: 10.1177/14690446050060030601

2005 6: 22British Journal of Infection ControlDJ Waghorn, WY Wan, C. Greaves, N. Whittome, HC Bosley and S. Cantrill

organismsContamination of computer keyboards in clinical areas: potential reservoir for nosocomial spread of

  

Published by:

http://www.sagepublications.com

On behalf of: 

  Infection Prevention Society

can be found at:British Journal of Infection ControlAdditional services and information for    

  http://bji.sagepub.com/cgi/alertsEmail Alerts:

 

http://bji.sagepub.com/subscriptionsSubscriptions:  

http://www.sagepub.com/journalsReprints.navReprints:  

http://www.sagepub.com/journalsPermissions.navPermissions:  

http://bji.sagepub.com/content/6/3/22.refs.htmlCitations:  

What is This? 

- May 1, 2005Version of Record >>

at Universiti Teknologi MARA (UiTM) on July 18, 2014bji.sagepub.comDownloaded from at Universiti Teknologi MARA (UiTM) on July 18, 2014bji.sagepub.comDownloaded from

Page 2: Contamination of computer keyboards in clinical areas: potential reservoir for nosocomial spread of organisms

Contamination of computer keyboards in clinical areas: potential reservoir for nosocomial spread of organismsWaghorn DJ1, Wan WY2, Greaves C3, Whittome N4, Bosley HC5, Cantrill S6

1. Consultant Microbiologist2. Senior House Officer, Department of Microbiology

3. Senior Nurse Infection Control

4. Infection Control Surveillance Nurse

5. Infection Control Nurse

6. Infection Control Nurse

1,2,3,4,5,6 Departments of Microbiology and Infection Control, Wycombe Hospital, Queen Alexandra Road, High Wycombe, Buckinghamshire HP11 2TT

here has been a dramatic increase in the use ofcomputers in healthcare settings in recent years.Staff move from computer to patient and back as

part of their daily routine. To ascertain whether comput-er keyboards may harbour organisms and act aspotential reservoirs for nosocomial spread, swabs weretaken from the keyboards and mice of 48 computers sit-uated in a variety of clinical areas. All 48 keyboards werecontaminated; 4% were colonised with recognised bac-terial pathogens and 96% harboured organisms that incertain clinical circumstances could cause nosocomialinfections. Computer keyboards and mice should becleaned regularly and the use of plastic covers may facil-itate this. Cleaning requirements should take a higherpriority when both purchasing and designing new health-care equipment. However, all such improvements remainsecondary to the need for strict hand hygiene practice inclinical areas.

IntroductionHospital-acquired or nosocomial infections are an increasinglyimportant cause of morbidity and mortality in modern medicine.The upsurge of multiresistant bacteria has only served to worsen theproblem as treatment of infections caused by these organisms,which are often acquired within hospital, is both complex and cost-ly. To prevent cross-infection it is necessary to determine the manysources that facilitate transmission of pathogens to patients. Thereis no doubt that organism carriage and transfer on the hands of alltypes of healthcare workers is a major factor (Pittet, 2001; Teare etal, 2001).

The role of the hospital environment as a reservoir of potentialpathogens has also received increasing attention. There have beenseveral reports demonstrating contamination of a wide variety ofenvironmental sites including bed rails, doors, furniture surfaces,blood pressure cuffs, thermometers, stethoscopes and other medicalequipment with the potential to lead to nosocomial spread (Laytonet al, 1993; Noskin et al, 1995; Bonten et al, 1996; Smith et al, 1996;Boyce et al, 1997; Weber et al, 1997; van den Berg et al, 2000;Rampling et al, 2001).

Computers have become more prevalent in the hospital settingincluding acute clinical areas. They are being used to enter andretrieve data by all types of clinical staff, who then have directpatient contact. As a consequence, the potential exists for hospital

computer equipment to act as a reservoir in organism transmission. One recent study suggested that ward-based computers pose a

low risk for cross-infection problems (Devine et al, 2001). However,two other investigations, describing the presence of Acinetobacterbaumannii and methicillin-resistant Staphylococcus aureus (MRSA)on computer keyboards within a burns unit and an intensive careunit respectively (Neely et al, 1999; Bures et al, 2000), suggestedthat nosocomial infections may occur as a direct result of such envi-ronmental contamination.

Very few studies have evaluated the extent of contamination ofcomputer keyboards across a variety of clinical areas within onemedical establishment.

We undertook a point prevalence study to assess the degree ofcontamination of computer keyboards being used in many directclinical care areas of a busy district general hospital. Prior to thestudy, there was no designated cleaning regime for computer equip-ment. If cleaning was undertaken by users, it occurred in an ad hocmanner and did not follow any formal policy.

MethodA total of 48 computer keyboards were sampled. The computerswere in use by a wide variety of clinical staff including doctors,nurses, physiotherapists and operative theatre assistants, all ofwhom had direct patient contact.

The computers were situated in the following clinical areas: gen-eral medical, general surgical, orthopaedic, care of the elderly,dermatology and paediatric wards, intensive care unit, accident andemergency department, out-patient department and theatre suite.

Individual sterile swabs, moistened with the Amies transportmedium used for subsequent transportation, were rubbed over eachkeyboard surface including any ‘mouse’ attachment. Swabs wereimmediately taken to the microbiology laboratory, where they wereinoculated onto blood, MacConkey and Clostridium difficile selec-tive agar plates. The blood and MacConkey plates were thenincubated aerobically and the C. difficile selective plate was incu-bated anaerobically for 48 hours, all at 37oC.

Accurate quantitative bacterial sampling of the keyboards was notappropriate. However, to allow comparison between different com-puters, a semi-quantitative assessment was carried out, based onthe number of colonies appearing on the agar plates.

Scanty’ growth was represented by the appearance of bacterialcolonies confined to the initial swab inoculation area; ‘moderate’reflected more profuse growth within the inoculation area together

22 British Journal of Infection Control JUNE 2005 VOL. 6 NO. 3

Key words: Computer keyboards, contamination, nosocomial spread, cleaningAccepted for publication: 1 March 2005

Abstract

Dou

ble-

blin

d pe

er re

view

ed p

aper

T

22-24 computers-Waghorn.qxd 23/5/05 4:47 pm Page 1

at Universiti Teknologi MARA (UiTM) on July 18, 2014bji.sagepub.comDownloaded from

Page 3: Contamination of computer keyboards in clinical areas: potential reservoir for nosocomial spread of organisms

VOL. 6 NO. 3 JUNE 2005 British Journal of Infection Control 23

with colonies on the first agar streaking; ‘heavy’ growth saw thepresence of bacteria on all dilutional streaks across the plates.Organisms were subsequently identified using the standard labora-tory methods.

The following bacterial species were specifically looked for: S.aureus, haemolytic streptococci, Pseudomonas aeruginosa and C.difficile. Other organisms were grouped together within the follow-ing categories: normal skin flora, coliforms or miscellaneous (toinclude organisms such as Bacillus spp. and fungi). Susceptibilitytesting was performed on any S. aureus or streptococcal isolates byroutine laboratory disc diffusion methods.

ResultsAll 48 computer keyboards grew organisms of some kind. Overall,79% of sampled computers grew either moderate or heavy num-bers of organisms (see Table 1).

In particular, five of six computers examined from the theatresuite grew heavy numbers of organisms. Nearly all swabs (46 outof 48) grew various combinations of skin type bacteria, with 25%also revealing mixed coliforms.

Over half of the keyboards grew environmental flora with Bacillusspp. being a predominant type. One computer was found to be pos-itive for C. difficile and another for MRSA (see Table 2). Overall 4%of keyboards were colonised by recognised bacterial pathogens,while 96% harboured organisms which, in certain clinical circum-stances, may have the potential to cause nosocomial infections.

DiscussionIn this study, all computer keyboards grew organisms of some kindwith skin flora being the predominant growth. Although only 4%revealed recognised pathogens, the overall level of bacterial conta-mination supports the concern that computers and theirattachments used in the clinical environment may have the capac-ity to act as reservoirs of cross-infection. The two computers foundto be contaminated with C. difficile and MRSA were both situatedon general medical wards containing acutely ill patients. Even thepotential transmission of skin or environmental type flora may besignificant, if this occurs in a setting where immunocompromisedor severely debilitated individuals are being treated.

Two previous reports have shown similar findings to this investi-gation. In one study, 95% of computer keyboards were colonisedby skin flora and 5% showed likely pathogens such as S. aureus(Schultz et al, 2003), while in another study a contamination rateof 5.9% was found on keyboards and their ‘mouse’ attachments,which was significantly higher than the bacterial contaminationfound on other pieces of clinical equipment within a surgical inten-sive care unit (Hartmann et al, 2004).

Whenever detected in the hospital environment, the presence ofS. aureus signifies a human source. MRSA strains pose further prob-lems, but their prevalence on computer equipment has reportedlyvaried from 1% in a specialised tertiary referral centre (Man et al,2002) to 24% in another district general hospital setting (Devine etal, 2001). In one study, evidence suggested that contaminatedcomputer keyboards and tap handles acted as reservoirs for thenosocomial spread of an MRSA strain on an intensive care unit,which subsequently caused clinical infection in two patients (Bureset al, 2000).

Regular procedures should be instigated for the maintenance andcleaning of all equipment used in clinical areas, including comput-ers. However, there had been no routine cleaning policy forcomputers in this hospital and it is questionable whether such apolicy exists in the majority of hospitals.

We could find no evidence of a specific cleaning regime for com-puters or their attachments in the medical literature. Manufacturer’srecommendations seem confined to cleaning the keyboards with a‘damp cloth’. The use of plastic covers may help in preventingorganisms such as spore-bearing C. difficile from contaminatingcomputer keyboards, but this is not the full solution.

Dou

ble-

blin

d pe

er re

view

ed p

aper

Growth of organisms Number (%)

Heavy 20 (42)

Moderate 18 (37)

Scanty 10 (21)

No growth 0 (0)

Total 48 (100)

Table 1. Degree of organism growth from computer keyboards and mouse

Organism Number

(Maximum = 48)

Skin flora (includes coagulase negative staphylococci Corynebacterium spp.) 46

Miscellaneous (includes Bacillus spp., fungal moulds) 25

Coliforms 12

Staphylococcus aureus (MRSA isolate) 1

Clostridium difficile 1

Pseudomonas aeruginosa 0

Streptococcus spp. 0

Table 2. Types of organisms isolated from computer keyboards and mouse

22-24 computers-Waghorn.qxd 23/5/05 4:47 pm Page 2

at Universiti Teknologi MARA (UiTM) on July 18, 2014bji.sagepub.comDownloaded from

Page 4: Contamination of computer keyboards in clinical areas: potential reservoir for nosocomial spread of organisms

An outbreak of A. baumannii colonisation and infection on aburns unit was associated with contamination of computer key-boards which were already protected by plastic covers (Boyce et al,1997). Observation revealed that gloved clinical care staff movedback and forth between the patient and keyboard, while unglovedsupport staff, who had no direct patient contact, then touched thecomputer keyboards to enter and retrieve data before moving toanother patient area.

Following the study, the possibility of moving to rubber washablekeyboards was explored, as they were considered the easiest to

clean, but this option was discounted as they are not designed forlarge volume typing/data input. Therefore in this hospital the use ofkeyboard covers is being pursued with a view to their applicationon both new and existing equipment.

It is planned to instigate a daily cleaning regime using alcoholwipes and performed by a ward housekeeper or other relevant staffmember. Advice from the hospital’s computer centre has revealedthe importance of ensuring that at the time of cleaning, computersmust be ‘logged out’, in order to prevent any accidental corruptionof data. However, it is not considered necessary to disconnecteither the computer or its attachments from the power supply.

ConclusionThere is good evidence that environmental surfaces may serve aspotential reservoirs for the nosocomial transmission of a wide vari-ety of organisms. This study and others support therecommendation that frequent cleaning of clinical areas, includingequipment such as computer keyboards, should become routinepractice. However, emphasis must continue to be placed on com-pliance with proper hand hygiene by all staff before and afterpatient contact. These are the most important ways to try andreduce the overall risks of nosocomial infections.

More consideration should also be given regarding the ease andmethod of cleaning before all clinically based equipment is pur-chased. The manufacturers themselves have a role to play in thedevelopment of products that allow easier decontamination.

Dou

ble-

blin

d pe

er re

view

ed p

aper

ReferencesBonten MJ, Hayden MK, Nathan C, van-Voorhis J, Matushek M,

Slaughter S, Rice T, Weinstein RA. (1996) Epidemiology of coloni-sation of patients and environment with vancomycin-resistantenterococci. Lancet 348: 1615-9.

Boyce JM, Potter-Bynoe G, Chenevert C, King T. (1997)Environmental contamination due to methicillin-resistantStaphylococcus aureus: possible infection control implications.Infect Control Hosp Epidemiol 18: 622-7.

Bures S, Fishbain JT, Uyehara CF, Parker JM, Berg BW. (2000)Computer keyboards and faucet handles as reservoirs of nosocomialpathogens in the intensive care unit. Am J Infect Control 28: 465-70.

Devine J, Cooke RP, Wright EP. (2001) Is methicillin-resistantStaphylococcus aureus (MRSA) contamination of ward-based com-puter terminals a surrogate marker for nosocomial MRSAtransmission and handwashing compliance? J Hosp Infect 48: 72-5.

Hartmann B, Benson M, Junger A, Quinzio L, Rohrig R, Fengler B,Farber UW, Wille B, Hempelmann G. (2004) Computer keyboardand mouse as a reservoir of pathogens in an intensive care unit. JClin Monit Compt 18: 7-12.

Layton MC, Perez M, Heald P, Paterson JE. (1993) An outbreak ofmupirocin-resistant Staphylococcus aureus on a dermatology wardassociated with an environmental reservoir. Infect Control HospEpidemiol 14: 369-75.

Man GS, Olapoju M, Chadwick MV, Vuddamalay P, Hall AV, EdwardsA, Kerr JR. (2002) Bacterial contamination of ward-based computer

terminals. J Hosp Infect 52: 314-5.Neely AN, Maley MP, Warden GD. (1999) Computer keyboards as

reservoirs for Acinetobacter baumannii in a burn hospital. Clin InfectDis 29: 1358-60.

Noskin GA, Stosor V, Cooper I, Peterson LR. (1995) Recovery of van-comycin-resistant enterococci on fingertips and environmentalsurfaces. Infect Control Hosp Epidemiol 16: 577-81.

Pittet D. (2001) Compliance with hand disinfection and its impact onhospital-acquired infections. J Hosp Infect 48(Suppl. A): S40-S46.

Rampling A, Wiseman S, Davis L, Hyett AP, Walbridge AN, PayneGC, Cornaby AJ. (2001) Evidence that hospital hygiene is importantin the control of methicillin-resistant Staphylococcus aureus. J HospInfect 49: 109-16.

Schultz M, Gill J, Zubairi S, Huber R, Gordin F. (2003) Bacterial cont-amination of computer keyboards in a teaching hospital. InfectControl Hosp Epidemiol 24: 302-3.

Smith MA, Mathewson JJ, Ulert IA, Scerpella EG, Ericsson CD. (1996)Contaminated stethoscopes revisited. Arch Intern Med 156: 82-4.

Teare L, Cookson B, Stone S. (2001) Hand hygiene. BMJ 323: 411-2.van den Berg RW, Claahsen HL, Niessen M, Muytjens HL, Liem K,

Voss A. (2000) Enterobacter cloacae outbreak in the NICU relatedto disinfected thermometers. J Hosp Infect 45: 29-34.

Weber DJ, Rutala WA. (1997) Role of environmental contaminationin the transmission of vancomycin-resistant enterococci. InfectControl Hosp Epidemiol 18: 306-9.

24 British Journal of Infection Control JUNE 2005 VOL. 6 NO. 3

The editors are always seeking papers suitable for publication in the British Journal of Infection Control.

If you have recently undertaken any research orstudies on aspects of care related to infection controlthen we would be pleased to consider it forpublication.

Manuscripts of up to 4000 words, short papers up

to 1000 words or communication/letters up to 500words in length should be forwarded to: Editor,British Journal of Infection Control, McMillan-Scottplc, 9 Savoy Street, London WC2E 7HR, or via emailto: [email protected]

Please note that all papers are subject to a double-blind peer review process.

British Journal of Infection Control – Call for papers

� Frequent cleaning of clinical areas must include items suchas computer keyboards. This must become routine practice

� The need to perform proper hand hygiene before and afterevery patient contact must be emphasised, in order toreduce environmental contamination of equipment

� Greater consideration must be given to methods of cleaning and decontamination before equipment such ascomputers are purchased and introduced into the clinicalarea

� Manufacturers must take greater responsibility for designing equipment that facilitates easy cleaning anddecontamination.

Recommendations

22-24 computers-Waghorn.qxd 23/5/05 4:50 pm Page 3

at Universiti Teknologi MARA (UiTM) on July 18, 2014bji.sagepub.comDownloaded from