Bacterial colonization of rings and cell phones carried by health-care providers: are these mobile bacterial zoos in the hospital?

Abstract

Our objective was to assess the presence of pathogenic organisms on the rings (worn on fingers) and cell phones carried by health-care workers (HCWs) and the public. Forty-two percent of mobile phones carried by HCWs and 18% carried by the general public were found to carry one or more organisms; 82% of the rings worn by HCWs and 36% of those worn by the general public were found to be positive for the presence of at least one type of microbe.

Introduction

There has been an increase in hospital-acquired infection by antimicrobial-resistant organisms which has resulted in substantial morbidity and higher health-care costs.¹ Despite the emphasis on hand washing, most health-care workers (HCWs) wash their hands less than half as often as they should.²

Several studies have demonstrated that the skin underneath rings is more heavily colonized than comparable areas of skin on fingers without rings. Long fingernails, rings and all sorts of nail treatments are known to harbour bacteria.² Handling of cell phones and the heat they generate make them a breeding ground for microbes. The role of cell phones and rings in spreading infections in hospitals has long been suspected.³

In view of the above, a study was conducted on the colonization of the objects commonly worn or carried by health-care providers. Our objective was to examine rings (worn on fingers) and cell phones carried by HCWs and the general public for the presence of pathogenic organisms.

Methods

The subjects were divided into two groups: group A consisted of HCWs including doctors and nurses handling the patients; group B included the general public who had not been exposed to any health-care setup in the two weeks before taking the sample and whose socio-economic status and other variables were similar to those of group A. Only those wearing rings or carrying cell phones were included in the study.

A sterile swab moistened with sterile saline was rotated over the surfaces of both sides of the mobile phones in order to collect samples. A similar swab was rotated on all surfaces of the rings. These swabs were immediately inoculated onto two plates of 5% sheep blood agar and MacConkey agar. The plates were incubated overnight at 37°C in anaerobic conditions. Isolated organisms were identified using colony morphology, Gram staining, motility and other biochemical reactions using standard techniques. A slide coagulase test was used to differentiate between Staphylococcus aureus and coagulase negative staphylococcus.⁴ Cefoxitin 30 µg disc sensitivity was used in order to identify methicillin-resistant S. aureus (MRSA) as per the Clinical and Laboratory Standards Institute guidelines.⁵ The chi-squared test was applied in order to determine the significance in the difference between the two groups.

Results

A total of 200 samples were taken from each group. In all, 42% of the mobile phones in group A and 18% in group B were found to be carrying one or more organisms (P = 0.001), while 82% of rings worn by the HCWs and 36% of rings worn by the general public were found to be positive for the presence of at least one type of microbe. This difference was significant (P = 0.001). Within group A, 56% of the samples taken from doctors and 68% taken from nurses were found to be positive for one or more bacteria. Thus, the group A members showed a higher degree of greater contamination than controls and rings were more contaminated than cell phones (Tables 1 and 2).

Table 1

Bacterial colonization of rings and cell phones

Sample no.	Group	Object worn/carried	No. of samples	Doctors (50)	Nurses (50)	Positive*
1	A	Rings	100	38	44	82
2	A	Cell phones	100	18	24	42
Total			200	56	68	124
3	B	Rings	100	–	–	36
4	B	Cell phones	100	–	–	18
Total			200	–	–	54

*Number of samples positive for the presence of any bacteria

Table 2

Organisms isolated from group A and group B

	Group A				Group B		Total	%
Organism	Doctors' cell phones	Doctors' rings	Nurses' cell phones	Nurses' rings	Cell phones	Rings	Total	%
Staphylococcus aureus [MRSA]	10 [8]	22 [16]	16 [9]	28 [12]	2 [0]	4 [0]	82 [45]	36.6 [55]
Coagulase negative staphylococcus	6	12	8	12	12	22	72	32.1
Klebsiella	0	4	2	8	2	6	22	9.8
Acinetobacter	0	8	0	6	2	4	20	9
Escherichia coli	0	2	0	4	0	4	10	4.5
Micrococcus	2	0	0	2	0	4	8	3.6
Diphtheroids	0	0	2	2	0	2	6	2.6
Viridans streptococci	0	2	0	0	0	0	2	0.9
Candida	0	0	0	2	0	0	2	0.9
Total	18	50	28	64	18	46	224	100

MRSA, methicillin-resistant Staphylococcus aureus; Figs in brackets give numbers of MRSA out of S. aureus isolates

A total of 128 organisms were isolated in a single isolate (84 in group A and 44 in group B). More than one bacterial species was isolated in 46 cases (36 in group A and 10 in group B).

S. aureus was the most frequent organism isolated (48% in group A and 9% in group B) followed by coagulase negative staphylococcus (23% in group A and 53% in group B). Other organisms included the Klebsiella species (9% in group A and 12% in group B); Escherichia coli (4% in group A and 6% in group B); Acinetobacter (3% in group A and 9% in group B); Micrococcus (3% in group A and 6% in group B); diphtheroids (3% in both groups) and Candida albicans.

A total of 45 (55%) isolates of MRSA were isolated. The majority of these were obtained from rings worn by members of group A (Table 2).

Discussion

In this study, the mobile phones used by HCWs demonstrated a high bacteria contamination rate, especially with nosocomial pathogens. The difference of colonization with various bacteria in the two groups, both on rings and cell phones, was significant (P = 0.001). This was similar to the findings of Brady et al., who reported a high rate of mobile phone contamination by pathogens known to cause nosocomial infections.³ A similar study in Israel found that 12% of mobile phones belonging to HCWs carried drug-resistant bacteria.⁶

The potential for mobile phones belonging to HCWs to serve as a reservoir of bacteria known to cause nosocomial infection was also reported by Khivsara et al. ⁷ They reported high levels (40%) of contamination in these phones by S. aureus including MRSA. Singh et al. reported that over 47% of immobile phones were contaminated with pathogenic microbes.⁸ Most studies, including ours, have found coagulase negative staphylococcus and S. aureus to be the prevalent bacterial agents.^3,9 The isolation of drug-resistant and established nosocomial pathogens, such as MRSA, clearly suggest that close contact objects, such as rings and mobile phones, could serve as reservoirs of bacteria. This may facilitate the intra- and inter-ward (and perhaps inter-hospital) transmission of these bacteria.

Rings and jewellery are thought to harbour food debris, microbial contaminants, food allergens and caustic sanitizers or disinfectants.¹⁰ Rings, especially those parts that are in contact with skin, also act as moisture traps, providing another haven for microscopic life. Additionally, the sharp edges of jewellery or ragged fingernails have the potential to tear examination gloves, thus breaking their protective barrier. It makes sense for nurses to trim their fingernails to the tips of the fingers (i.e. no longer than about 3 mm) and file them, and to relegate all but the simplest adornments to the jewellery box before reporting for duty.³ Rings and artificial nails result in higher levels of persistent hand colonization with pathogenic bacteria after hand disinfection compared with unadorned hands.¹⁰

Developing preventive strategies, such as adherence to frequent hand washing, the removal of jewellery at work and the routine disinfection of mobile phones, may help to reduce the bio-burden. Changing the behaviour of HCWs is challenging but all these observations make it obvious that HCWs must be given training in strict infection control, hand hygiene and environment disinfection procedures. The potential benefit of using the mobile phones versus the contamination risk in intensive care units and operating rooms must be carefully weighed. However, the development of effective preventive strategies, such as the regular decontamination of mobile phones and rings with alcohol disinfectant wipes to reduce the bio-burden combined with an emphasis on hand hygiene, are necessary in order to prevent cross infection in the health-care system.

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