To the Editor—Mobile phones are reservoirs for pathogenic bacteria, and their frequent use by healthcare workers (HCWs) makes them a perfect vehicle for nosocomial transmission.Reference Brady, Verran, Damani and Gibb ^{1 –} Reference Nwankwo, Ekwunife and Mofolorunsho ⁶ Because no study has concentrated on microbial contamination of HCW mobile phones in neonatal units, we investigated this contamination source in this specific environment.

The study was carried out at the neonatal unit of the teaching hospital Umberto I in Rome, Italy. The study participants, healthcare workers and students in this unit, were asked to anonymously answer a 13-item questionnaire including age, sex, job profession, mobile phone type, and cleaning activity, after which culture samples were obtained from their mobile telephones.

Sterile swabs moistened with sterile demineralized water were rotated over the phone’s surface and immediately plated onto blood and MacConkey agars using standard microbiological procedures. Isolates were identified using the bioMerieux API system (bioMerieux, Durham, NC).

Statistical analyses were performed using SPSS software (version 14.0 for Windows, Chicago, IL). When observed frequencies were >5, χ² with Yates correction was used to compare the proportions observed in the 2 groups. When frequencies were ≤5, Fisher’s exact test was used.

A total of 50 mobile phones were sampled from 22 doctors, 19 nurses, and 9 medical students (7 males, 43 females). The average age of the participants was 38.3±12.7 years, (median 37.5 years; range, 20–61 years), and self-reported use in the preceding 24 hours was 14.5±10.9 times (median 10 times; range, 2–40 times). The average duration of mobile phone ownership was 17.6±19.7 months, and 17 HCWs (34%) declared mobile phones “very important for their work.”

Overall, 43 mobile phones (86.0%) demonstrated evidence of some bacterial contamination, and 66 different strains were isolated (1 bacterial species on 26 mobile phones, 2 on 14 mobile phones, and ≥3 on 3 mobile phones). In particular, 10 mobile phones (20.0%) grew bacteria known to cause healthcare infection (Table 1).

TABLE 1 Distribution of Microorganisms Isolated from HCW Mobile Phones

^a Pathogens known to cause healthcare infections.

Only 26 HCWs (52.0%) indicated that they cleaned their mobile phones in the following ways: dump cloth (27.0%), dry cloth (23.1%), spectacles detergent (15.4%), alcohol (11.5%), some disinfectant (7.7%), amukine (7.7%), gel (3.8%), and/or chlorhexidine (3.8%).

Although not statistically significant, microorganism isolation was more frequent when “no cleaning of mobile phone” was reported (95.8% vs 76.9%). Pathogen isolation was associated with a specific mobile phone type, ie, “slide mobiles” (risk ratio [RR], 3.86; 95% confidence interval [CI], 1.44–10.36; P=.048), and this association approached significance when mobile use frequency in the previous 24 hours was considered (20.1±13.3 vs 13.0±9.7; P=.06). In addition, the pathogen isolation rate was higher among students (33.3%) than doctors (22.7%) and nurses (10.5%). Age, sex, and presence of a phone cover were not significantly associated with pathogens (data not shown).

This is the first study to investigate HCWs mobile phone bacterial contamination in a neonatal unit; previously, only parent’s mobile phones had been screened in this specific environment.Reference Beckstrom, Cleman, Classis-Ghavami and Kamitsuka ³ More than 80% of HCW mobile phones showed some bacterial contamination and, most importantly, ~20% carried pathogens that could potentially cause healthcare infections. Gram-positive preponderance, and specifically coagulase-negative staphylococci (CNS), was in agreement with the findings of other researchersReference Brady, Verran, Damani and Gibb ^{1 –} Reference Tekerekoglu, Duman and Serindag ⁷ and in other pediatric wards.Reference Beer, Vandermeer, Brosnikoff, Shokoples, Rennie and Forgie ^{8 ,} Reference Foong, Green and Ogden ⁹

Currently, no study has shown a direct relationship between mobile phone bacterial contamination and healthcare infections. Undoubtedly, however, microorganisms can be transferred from person to person or from inanimate objects to hands. Therefore, fomites such as mobile phones can potentially introduce pathogens to areas such as neonatal units.Reference Goldblatt, Krief and Klonsky ⁴ Despite the possible transmission of pathogens, half of HCWs did not perceive any risk from mobile phone contamination, and the variety of cleansing methods reported by these HCWs reflected the absence of guidelines. It is well known that disinfectant use and cleaning can significantly reduce bacterial contamination,Reference Brady, Verran, Damani and Gibb ^{1 ,} Reference Brady, Wasson, Stirling, McAllister and Damani ^{2 ,} Reference Goldblatt, Krief and Klonsky ^{4 ,} Reference Beer, Vandermeer, Brosnikoff, Shokoples, Rennie and Forgie ^{8 ,} Reference Sumritivanicha, Chintanavilas and Apisarnthanarak ¹⁰ and it was not surprising that “no cleaning of mobile phone” was related to microorganism isolation.

We also considered mobile phones by type and structure (eg, “slide mobiles”) in association with pathogens; these findings were most likely related to difficulties in cleaning and decontamination.

The results of this study reveal considerable mobile phone contamination by bacteria known to cause nosocomial infection. Therefore, the potential of mobile phones to spread microorganisms should be included and seriously considered in any debate regarding contact precautions. Particularly, this issue is of great concern in neonatal areas, where highly susceptible patients, newborns, receive care.