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 DOI: 10.1177/1757177410364866

2010 11: 87Journal of Infection PreventionSangappan Mariappan and Kalyani Jagannathan

Padma Srikanth, Ezhilarasan Rajaram, Suchithra Sudharsanam, Anandhi Lakshmanan, Umamageswari SivamuruganMobile phones: emerging threat for infection control

  

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VOL. 11 NO. 3 MAY 2010 Journal of Infection Prevention 87

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his study was conducted to determine whether mobile phones of healthcare workers (HCWs) and corporate users harbour micro-organisms. Swabs

collected from mobile phones were inoculated in solid and liquid media, and incubated aerobically. Growth was identifi ed as per standard microbiological proce-dures. Antibiotic susceptibility was determined for Staphylococcus aureus . A questionnaire was used for data collection on awareness of mobile phone use. Of 51 HCWs and 36 corporate mobile phones sampled, only 5 (6 % ) showed no growth. Pathogens isolated from HCW samples included S. aureus [meticillin-sensitive S. aureus (4), meticillin-resistant S. aureus (2)], Escherichia coli (1), Klebsiella pneumoniae (1) and Pseudomonas aeruginosa (1). Coagulase-negative Staphylococci (43) were also isolated. Among corporate isolates, 29 % were patho-genic. Polymicrobial growth was detected in 71 % of HCW and 78 % of corporate mobile phones. Only 12 % of HCWs used disinfectants to wipe their mobile phones. Mobile phones serve as a ready surface for colonisation of noso-comial agents indicating the importance of hand hygiene to prevent cross-transmission.

Introduction The global burden of healthcare-associated infections (HAIs) is on the rise, and contributes signifi cantly to the morbidity and mortality of patients ( WHO, 2006 ). The increase in HAIs is concomitantly associ-ated with an increase in expenditure for healthcare facilities ( WHO, 2006 ). The majority of HAIs are inadvertently transmitted through the hands of healthcare workers (HCWs), with the environment only being the source of nosocomial agents occasionally.

Inanimate objects in the hospital environment are known to be con-taminated with micro-organisms ( Sehulster and Chinn, 2002 ). Mobile phones have become an extension of the offi ce practice for physi-cians, and may serve as the perfect substrate for micro-organisms, especially in high-temperature and humid conditions. Extensive use of mobile phones by HCWs acts as a vehicle for the transmission of nosocomial agents.

There are few reports on the role of mobile phones in the spread of nosocomial infections ( Borer et al, 2005 ; Brady et al, 2006 ; Goldblattet al, 2007 ; Karabay et al, 2007 ; Sepehri et al, 2009 ), and even fewer in a tropical setting ( Jayalakshmi et al, 2008 ). This study was under-taken to determine whether the mobile phones of HCWs are con-taminated, since they are used in an environment that harboursnosocomial agents. The mobile phones of corporate offi ce workerswere also sampled since their work environment was considered to befree from contamination.

Materials and methodsSurface samples were taken from mobile phones of HCWs and non-hospital (corporate) personnel in June–July 2007 after obtaining con-sent. Each mobile phone was sampled only once during the studyperiod. The corporate offi ce is located in the centre of Chennai city, ina very urban, completely air-conditioned, well-maintained, dust-freeenvironment, where the nature of work is mainly administrative. Ster-ile swabs moistened with sterile demineralised water were rotated over both the surfaces of the mobile phone or the casing surface for casedmobile phones and collected. Sampled swabs were streaked over blood agar and MacConkey agar plates, and inoculated in thioglyco-late medium (Hi-Media Company Limited, India) for characterisationof aerobic bacteria; no anaerobic/fungal cultures were taken. Plateswere incubated aerobically at 37° C for 24–48 h. Gram-positive andGram-negative bacteria were identifi ed as per standard microbiologicalprocedures ( Collee et al, 1999 ).

Gram-positive cocci were identifi ed by Gram staining, colony mor-phology and haemolysis. Staphylococci were further identifi ed basedon catalase, slide and tube coagulase, and utilisation of oxidation/fermentation (OF)-glucose and mannitol. Gram-negative bacilli wereidentifi ed by Gram staining, colony morphology, lactose fermentationand motility, and further biochemical tests such as indole production,sugar fermentation and H 2 S production, urease production, citrate uti-lisation and methyl red Voges–Proskauer (MR-VP) test for the natureof fermentation. Non-fermenters were further identifi ed using catalaseand oxidase tests, ability to grow on MacConkey agar and growth at42°C, and biochemical tests such as OF-dextrose utilisation, nitratereduction and gelatin hydrolysis. Antibiotic susceptibility test was

© The Author(s) 2010 Reprints and permissions:http://www.sagepub.co.uk/journalsPermissions.nav10.1177/1757177410364866

Mobile phones: emerging threat for infection control Padma Srikanth 1 * , Ezhilarasan Rajaram 2 , Suchithra Sudharsanam1 , Anandhi Lakshmanan1 ,Umamageswari Sivamurugan Sangappan Mariappan 1 , Kalyani Jagannathan1

1. Sri Ramachandra Medical College and Research Institute, Sri Ramachandra University, Porur, Chennai, Tamil Nadu, 600116, India. Email: srikanth_padma@rediffmail.com2. Prince George’s Park, National University of Singapore, Singapore*Corresponding author

Accepted for publication: 10 January 2010Key words: Bacterial contamination , hand hygiene , infection control , mobile phones , nosocomial infections

Abstract

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performed for Staphylococcus aureus isolates using the Kirby–Bauer disc diffusion method.

ResultsIn all, 51 mobile phones of HCWs and 36 of corporate offi ce workers were sampled. Among the mobile phones sampled, 94% were con-taminated and only 6 % were free of aerobic bacterial growth. Themajority (74 % ) of the mobile phones had polymicrobial growth, 48%had two species and 26% had three or more species (Figure 1 ). Poly-microbial growth was documented in a larger number (71 %) of mobile phones belonging to HCWs. A total of 89 bacterial isolates were iso-lated from mobile phones of HCWs, of which 15 (17 % ) were patho-genic. Majority of isolates were Coagulase-negative Staphylococci (CNS) (43), followed by S. aureus (6) [meticillin-sensitive S. aureus(MSSA), 4; meticillin-resistant S. aureus (MRSA), 2], Acinetobacter spp. (6), Escherichia coli (1), Pseudomonas aeruginosa (1) and Kleb-siella pneumoniae (1). Table 1 shows the frequency of distribution of pathogens on mobile phones. A higher percentage (42 %) of mobile phones of doctors were contaminated (Figure 2 ).

Among 79 bacterial isolates in 36 samples from corporate personnel, 23 (29%) were pathogens ( Table 1 ). Polymicrobial growth was

detected in 28 (78 % ) of the mobile phones of offi ce users. MSSA (1),E. coli (2), P. aeruginosa (3), Acinetobacter spp. (16) and K. pneumo-niae (1) and CNS (20) were also isolated.

Analysis of the questionnaire showed that 38 (75% ) HCWs and 11(37 % ) corporate workers were aware that mobile phones harbour

Table 1 . Microbiological profi le of pathogenic isolates from mobile phones

Organisms isolated Healthcare personnel (n = 51) Corporate personnel (n = 36)

Gram-positive bacteria

meticillin resistant Staphylococcus aureus 2 (3.9%) 0 meticillin sensitive Staphylococcus aureus 4 (7.8%) 1 (2.8 %)

Gram-negative bacteria

Escherichia coli 1 (1.96% ) 2 (5.6 %) Klebsiella spp. 1 (1.96% ) 1 (2.8 %) Pseudomonas spp. 1 (1.96% ) 3 (8.3 %) Acinetobacter spp. 6 (11.8% ) 16 (44.4%)

Note. Mobile phones of both hospital and non-hospital settings also yielded coagulase-negative Staphylococci, micrococci and aerobicspore bearers as incidental isolates, some of which probably represent normal skin fl ora.

100%

1

4

11

Number of bacterial species

No growth Growth of1

organism

Growth of2

organisms

Growth of3

organisms

Growth of4

organisms

Growth of5

organisms

30

5

0

12

4

0

1

Corporate office

Hospital

712

Num

ber

of m

obile

pho

nes

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%

Figure 1 . Extent of mobile phone contamination in hospital and non-hospital settings

6(13%)

5(11%)

16(34%)20(42%)

Doctor

Nurse

Paramedical

Internee

Figure 2 . Percentage of bacterial contamination of mobile phones among healthcareworkers

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micro-organisms and transmit infectious agents. Only 12 % of HCWs used disinfectants to wipe their mobile phones. The majority (73 %; n = 37) of the HCWs felt the need for restricted use of mobile phones during working hours, especially in critical areas, while 18 % (9) felt it unnecessary and impractical. Only 29 % of the HCWs followed restricteduse of mobile phones (less than three times) and 57 % handled mobile phones more than three times to a maximum of 20 time during working hours; 14% used their phones more frequently (greater than 20 times).

DiscussionSeveral reports have documented the contamination of mobile phones among HCWs ( Borer et al, 2005 ; Brady et al, 2006 ; Goldblatt et al, 2007 ; Jayalakshmi et al, 2008 ; Karabay et al, 2007 ; Sepehri et al, 2009 ); However, so far no study has determined the contamination of mobile phones in a non-hospital environment versus the hospital environment. The corporate offi ce was chosen as a representative clean, dust-free environment in a tropical country. Our study docu-ments the presence of a high level of contamination on mobile phones of offi ce workers and HCWs, thus indicating that contamination occurs irrespective of the environment. Hands may contaminate mobile phones at the time of use especially when it is hot and humid and hands are sweaty.

Previously, S. aureus , P. aeruginosa, Acinetobacter sp., K. pneumo-niae and E. coli have been reported to colonise mobile phones ( Borer et al, 2005 ; Brady et al, 2006 ; Goldblatt et al, 2007 ; Karabay et al, 2007 ; Jayalakshmi et al, 2008 ; Sepehri et al, 2009 ). In our study also, S. aureus (including MRSA), P. aeruginosa , Acinetobacter sp., K.pneumoniae and E. coli were isolated. Surprisingly, the same pattern of micro-organisms was found on mobile phones of corporate offi ce workers; however, no MRSA was isolated. Since the profi le of organ-isms was similar, this suggests that hands may temporarily colonise and contaminate mobile phones.

Micrococci and CNS were the predominant isolates among Gram-positive cocci; the isolation of MRSA in a small percentage (4 %) from mobile phones of HCWs is a cause for concern. This represents an additional route for cross-transmission of MRSA. The percentage of isolation of Gram-negative bacilli may show some geographic dispar-ity. Acinetobacter was the commonest isolate among Gram-negative bacilli. This fi nding corroborates with the fi ndings from a study from Israel, where Acinetobacter was the predominant isolate recovered from cell phones ( Borer et al, 2005 ). Most organisms die within hours due to dehydration but bacteria such as S. aureus and Acinetobacter are resistant to drying and survive for weeks and multiply rapidly in a warm environment ( Kramer et al, 2006 ; Smith et al, 1996 ). The source of Gram-negative bacilli is not clear since surface sampling of the envi-ronment was not undertaken in this study.

While the range of pathogenic organisms isolated from mobile phones is small, all are nosocomial and may represent transient or resident fl ora from the hands of HCWs or surfaces frequently touched by HCWs. Since the sampling was undertaken only once, it is not possible to con-clude from the study whether the organisms are transient or resident. Simultaneous cultures from the hands of HCWs or environmental sur-faces were not carried out: this is a limitation of the study. Also the purpose of the study was to determine the presence of aerobic bacteria, so cultivation of anaerobic bacteria and fungi was not done.

This study has demonstrated that although a majority of the HCWs are aware of the likelihood of mobile phone contamination, only a

small minority (12% ) practice the use of disinfectants to wipe mobilephones. There is an urgent need to disseminate knowledge amongHCWs regarding the possible contamination of mobile phones and theimportance of periodic cleaning of the phones, as well as the impor-tance of hand hygiene. One study reported the use of 70 % isopropylalcohol as an effective disinfectant ( Jayalakshmi et al, 2008 ). Another study reported that restricted use of mobile phones during workinghours along with proper hand hygiene practices enabled mobile phonesto remain free of contamination ( Goldblatt et al, 2007 ).

Previous reports ( Borer et al, 2005 ; Brady et al, 2006 ; Goldblattet al, 2007 ; Karabay et al, 2007 ; Sepehri et al, 2009 ) and fi ndingsfrom our study do suggest that mobile phones pose a risk, althoughsmall, for transmission of nosocomial pathogens. Should the use of mobile phones be restricted in healthcare facilities due to this risk of transmission of nosocomial agents? The benefi ts of mobile phoneuse far outweigh the risks. Mobile phones allow for easy accessibil-ity of the clinician so can help in providing timely patient care. Themobile phone technology not only allows for rapid communication,but also enables storage of formulary data, clinical and diagnosticprotocols that can be made available to a busy clinician at his fi nger-tips. The lack of awareness regarding the possibility of mobile phonecontamination occurring in the grooves and keys (although thephone appears to be clean and shiny) suggest the need for an aware-ness campaign to ensure hygienic practices in their handling.

Given the benefi ts of mobile phone use in healthcare facilitiesamong HCWs, we advocate that infection control guidelines includerecommendations for periodic disinfection with appropriate disinfect-ants to avoid mobile phone contamination. We also advocate hand-washing prior to and after usage to prevent cross-transmission of nosocomial pathogens

To best of the authors’ knowledge, this is the fi rst report that hasstudied the potential for mobile phones to harbour micro-organisms inboth hospital and non-hospital settings. The high level of contamina-tion (92–97 % ) of mobile phones irrespective of the environment sug-gests that the hands might be the source of contamination. Thecolonisation of nosocomially signifi cant pathogens such as MRSA,P. aeruginosa , Acinetobacter spp. on HCWs’ mobile phones demon-rstrates a hitherto unsuspected and inadvertent source of transmission of nosocomial agents to vulnerable patients. The presence of pathogenicorganisms on the mobile phones of corporate users is surprising, raisingthe concern for the spread of infectious agents to family, especially chil-dren. The benefi ts of a mobile phone to the HCW far outweigh the riskof cross-transmission of nosocomial pathogens; hand-hygiene proto-cols must include directions for handwashing before and after mobilephone usage. Further studies may be undertaken to target simultaneoussampling of mobile phones, environmental surfaces and hands of theHCWs to identify possible sources of contamination. Periodical sam-pling of the mobile phones may be undertaken to determine whether the organisms are transient or resident.

AcknowledgementsThe authors thank all of the participants for their kind cooperation andthe authorities of the corporate offi ce for permission to carry out thisstudy.

Confl ict of interest statement None declared.

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