Abstract
In this study, the microbial contamination of smartphones from Italian University students was analyzed. A total of 100 smartphones classified as low, medium, and high emission were examined. Bacteria were isolated on elective and selective media and identified by biochemical tests. The mean values of cfu/cm2 were 0.79 ± 0.01; in particular, a mean of 1.21 ± 0.12, 0.77 ± 0.1 and 0.40 ± 0.10 cfu/cm2 was present on smartphones at low, medium, and high emission, respectively. The vast majority of identified microorganisms came from human skin, mainly Staphylococci, together with Gram-negative and positive bacilli and yeasts. Moreover, the main isolated species and their mixture were exposed for 3 h to turned on and off smartphones to evaluate the effect of the electromagnetic wave emission on the bacterial cultivability, viability, morphology, and genotypic profile in respect to the unexposed broth cultures. A reduction rate of bacterial growth of 79 and 46% was observed in Staphylococcus aureus and Staphylococcus epidermidis broth cultures, respectively, in the presence of turned on smartphone. No differences in viability were observed in all detected conditions. Small colony variants and some differences in DNA fingerprinting were detected on bacteria when the smartphones were turned on in respect to the other conditions. The colonization of smartphones was limited to human skin microorganisms that can acquire phenotype and genotypic modifications when exposed to microwave emissions.
Similar content being viewed by others
References
Akinyemi KO, Atapu AD, Adetona OO, Coker AO (2009) The potential role of mobile phones in the spread of bacterial infections. J Infect Dev Ctries 3:628–632
Al-Abdalall AHA (2010) Isolation and identification of microbes associated with mobile phones in Dammam in eastern Saudi Arabia. J Family Community Med 17:11–14
Bhoonderowa A, Gookool S, Biranjia-Hurdoyal SD (2014) The importance of mobile phones in the possible transmission of bacterial infections in the community. J Community Health 39:965–967. https://doi.org/10.1007/s10900-014-9838-6
Cellini L, Grande R, Di Campli E, Di Bartolomeo S, Di Giulio M, Robuffo I, Trubiani O et al (2008) Bacterial response to the exposure of 50 Hz electromagnetic fields. Bioelectromagnetics 29:302–311
Cellini L, Grande R, Di Campli E, Di Bartolomeo S, Capodicasa S, Marzio L (2006) Analysis of genetic variability, antimicrobial susceptibility and virulence markers in Helicobacter pylori identified in Central Italy. Scand J Gastroenterol 41:280–287
Di Giulio M, D’Ercole S, Zara S, Cataldi A, Cellini L (2012) Streptococcus mitis/human gingival fibroblasts co-culture: the best natural association in answer to the 2-hydroxyethyl methacrylate release. APMIS 120:139–146. https://doi.org/10.1111/j.1600-0463.2011.02828
Egert M, Späth K, Weik K, Kunzelmann H, Horn C, Kohl M, Blessing F (2015) Bacteria on smartphone touchscreens in a German university setting and evaluation of two popular cleaning methods using commercially available cleaning products. Folia Microbiol 60:159–164. https://doi.org/10.1007/s12223-014-0350-2
Gerner-Smidt P, Graves LM, Hunter S, Swaminathan B (1998) Computerized analysis of restriction fragment length polymorphism patterns: comparative evaluation of two commercial software packages. J Clin Microbiol 36:1318–1323
Hammon M, Kunz B, Dinzl V, Kammerer FJ, Schwab SA, Bogdan C, Uder M et al (2014) Practicability of hygienic wrapping of touchscreen operated mobile devices in a clinical setting. PLoS ONE 9:e106445. https://doi.org/10.1371/journal.pone.0106445
Jayalakshmi J, Appalaraju B, Usha S (2008) Cellphones as reservoirs of nosocomial pathogens. J Assoc Physicians India 56:388–389
Loyola S, Gutierrez LR, Horna G, Petersen K, Agapito J, Osada J, Rios P et al (2016) Extended-spectrum β-lactamase—producing Enterobacteriaceae in cell phones of health care workers from Peruvian pediatric and neonatal intensive care units. Am J Infect Control 44:910–916. https://doi.org/10.1016/j.ajic.2016.02.020
Masika MM, Omondi GB, Natembeya DS, Mugane EM, Bosire KO, Kibwage IO (2015) Use of mobile learning technology among final year medical students in Kenya. Pan Afr Med J 21:127. https://doi.org/10.11604/pamj.2015.21.127.6185
McIntosh RL, Iskra S, McKenzie RJ, Chambers J, Metzenthen B, Anderson V (2008) Assessment of SAR and thermal changes near a cochlear implant system for mobile phone type exposures. Bioelectromagnetics 29(1):71–80
Meadow JF, Altrichter AE, Green JL (2014) Mobile phones carry the personal microbiome of their owners. PeerJ 2:447. https://doi.org/10.7717/peerj.447
Melendez JH, Santaus TM, Brinsley G, Kiang D, Mali B, Hardick J, Gaydos CA, Geddes CD (2016) Microwaves-accelerated method for ultra-rapid extraction of Neisseria gonorrhoeae DNA for downstream detection. Anal Biochem 510:33–40. https://doi.org/10.1016/j.ab.2016.06.017
Pal S, Juyal D, Adekhandi S, Sharma M, Prakash R, Sharma N, Rana A, Parihar A (2015) Mobile phones: reservoirs for the transmission of nosocomial pathogens. Adv Biomed Res 4:144. https://doi.org/10.4103/2277-9175.161553
Ruediger HW (2009) Genotoxic effects of radiofrequency electromagnetic filds. Pathophysiology 16:89–102
Shahin-Jafari A, Bayat M, Shahhosseiny MH, Tajik P, Roudbar-Mohammadi S (2016) Effect of long-term exposure to mobile phone radiation on alpha-Int1 gene sequence of Candida albicans. Saudi J Biol Sci 23:426–433. https://doi.org/10.1016/j.sjbs.2015.05.001
Soghomonyan D, Trchounian K, Trchounian A (2016) Millimeter waves or extremely high frequency electromagnetic fields in the environment: what are their effects on bacteria? Appl Microbiol Biotechnol 100:4761–4771. https://doi.org/10.1007/s00253-016-7538-0
Taheri M, Darabyan M, Izadbakhsh E, Nouri F, Haghani M, Mortazavi SAR, Mortazavi G, Mortazavi SMJ, Moradi M (2017) Exposure to visible light emitted from smartphones and tablets increases the proliferation of Staphylococcus aureus: can this be linked to acne? J Biomed Phys Eng 7:163–168
Torgomyan H, Trchounian A (2013) Bactericidal effects of low-intensity extremely high frequency electromagnetic field: an overview with phenomenon, mechanisms, targets and consequences. Crit Rev Microbiol 39:102–111
Tubby S, Wilson M, Wright JA, Zhang P, Nair SP (2013) Staphylococcus aureus small colony variants are susceptible to light activated antimicrobial agents. BMC Microbiol 13:201. https://doi.org/10.1186/1471-2180-13-201
Ulger F, Esen S, Dilek A, Yanik K, Gunaydin M, Leblebicioglu H (2009) Are we aware how contaminated our mobile phones with nosocomial pathogens? Ann Clin Microbiol Antimicrob 8:7. https://doi.org/10.1186/1476-0711-8-7
Walia SS, Manchanda A, Narang RS, N A, Singh B, Kahlon SS (2014) Cellular telephone as reservoir of bacterial contamination: myth or fact. J Clin Diagn Res 8:50–53. https://doi.org/10.7860/JCDR/2014/6398.3948
Acknowledgements
We thank Prof. Rossella Grande for her contribution in the collection of the data from the Microbiology Teaching Laboratory and all students of the Microbiology Teaching Laboratory of the Department of Pharmacy of University “G. d’Annunzio” Chieti-Pescara A.A. 2015/2016 who participated in this study.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Ethical Approval
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Informed Consent
Informed consent was obtained from all individual participants included in the study.
Rights and permissions
About this article
Cite this article
Di Lodovico, S., Del Vecchio, A., Cataldi, V. et al. Microbial Contamination of Smartphone Touchscreens of Italian University Students. Curr Microbiol 75, 336–342 (2018). https://doi.org/10.1007/s00284-017-1385-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00284-017-1385-9