Skip to main content

Assessing the Likelihood of Hand-to-Hand Cross-Transmission of Bacteria: An Experimental Study

  • Fernando Bellissimo-Rodrigues (a1) (a2), Daniela Pires (a1) (a3), Hervé Soule (a1), Angèle Gayet-Ageron (a1) and Didier Pittet (a1)...

Although the hands of healthcare workers (HCWs) are implicated in most episodes of healthcare-associated infections, the correlation between hand contamination and the likelihood of cross-transmission remains unknown.


We conducted a laboratory-based study involving pairs of HCWs. The hands of a HCW (transmitter) were contaminated with Escherichia coli ATCC 10536 before holding hands with another HCW (host) for 1 minute. Meanwhile, the unheld hand of the transmitter was sampled. Afterward, the host’s held hand was also sampled. Each experiment consisted of 4 trials with increasing concentrations of E. coli (103–106 colony-forming units [cfu]/mL). The primary outcome was the likelihood of transmission of at least 1 cfu from transmitter to host. We used a mixed logistic regression model with a random effect on the subject to assess the association between transmission and bacterial count on the transmitter’s hands.


In total, 6 HCWs performed 30 experiments and 120 trials. The bacterial counts recovered from host hands were directly associated with the bacterial counts on transmitter hands (P<.001). The probability of cross-transmission was 8.22 higher (95% confidence interval [CI], 0.98–68.8) when transmitter hand bacterial count was >1 and ≤3 log10 cfu compared to ≤1 log10. When transmitter contamination was <1 log10 cfu, no cross-transmission was detected.


There is a direct relationship between the bacterial burden on HCWs hands and the likelihood of cross-transmission. Under the described conditions, at least 1 log10 cfu must be present on HCW hands to be potentially transmitted. Further studies are needed at the low contamination range.

Infect Control Hosp Epidemiol 2017;38:553–558

Corresponding author
Address correspondence to Professor Didier Pittet, MD, MS, Infection Control Programme and WHO Collaborating Centre on Patient Safety, University of Geneva Hospitals and Faculty of Medicine, 4 Rue Gabrielle-Perret-Gentil, 1211, Geneva, Switzerland (
Hide All

Authors of equal contribution.

PREVIOUS PRESENTATION: These data were presented in part (no. 2016-A-2528) at the American Society of Microbiology (ASM) Microbe 2016 Congress in Boston, Massachusetts, on the June 18, 2016.

Hide All
1. GBD 2013 Mortality and Causes of Death Collaborators. Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet 2015;385:117171.
2. Willmott, M, Nicholson, A, Busse, H, MacArthur, GJ, Brookes, S, Campbell, R. Effectiveness of hand hygiene interventions in reducing illness absence among children in educational settings: a systematic review and meta-analysis. Arch Dis Child 2016;101:4250.
3. Liu, L, Johnson, HL, Cousens, S, et al; Child Health Epidemiology Reference Group of WHO and UNICEF. Global, regional, and national causes of child mortality: an updated systematic analysis for 2010 with time trends since 2000. Lancet 2012;379:21512161.
4. Pittet, D, Hugonnet, S, Harbarth, S, et al. Effectiveness of a hospital-wide programme to improve compliance with hand hygiene. Infection Control Programme. Lancet 2000;356:13071312.
5. Boyce, JM, Pittet, D, Healthcare Infection Control Practices Advisory Committee, HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force. Guideline for hand hygiene in health-care settings. Recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force. Society for Healthcare Epidemiology of America/Association for Professionals in the Infection Control/Infectious Diseases Society of America. MMWR Recomm Rep 2002;51:145.
6. WHO guidelines on hand hygiene in health care: first global patient safety challenge Clean Care is Safer Care. World Health Organization website. Published 2009. Accessed July 20, 2016.
7. A Guide to the implementation of the WHO multimodal hand hygiene improvement strategy. Geneva, Switzerland: World Health Organization, Patient Safety, 2009.
8. Allegranzi, B, Gayet-Ageron, A, Damani, N, et al. Global implementation of WHO’s multimodal strategy for improvement of hand hygiene: a quasi-experimental study. Lancet Infect Dis 2013;13:843851.
9. Luangasanatip, N, Hongsuwan, M, Limmathurotsakul, D, et al. Comparative efficacy of interventions to promote hand hygiene in hospital: systematic review and network meta-analysis. BMJ 2015;351:h3728.
10. WHO model list of essential medicines, 18th list, 2013. World Health Organization website. Published 2013. Accessed March 5, 2015.
11. Willmott, M, Nicholson, A, Busse, H, MacArthur, GJ, Brookes, S, Campbell, R. Effectiveness of hand hygiene interventions in reducing illness absence among children in educational settings: a systematic review and meta-analysis. Arch Dis Child 2016;101:4250.
12. Bifulco, M, Capunzo, M, Marasco, M, Pisanti, S. The basis of the modern medical hygiene in the medieval Medical School of Salerno. J. Maternal Fetal Neonatal Med 2015;28:16911693.
13. Stewardson, A, Pittet, D. Ignác Semmelweis-celebrating a flawed pioneer of patient safety. Lancet 2011;378:2223.
14. Pittet, D, Allegranzi, B, Sax, H, et al. WHO Global Patient Safety Challenge, World Alliance for Patient Safety. Evidence-based model for hand transmission during patient care and the role of improved practices. Lancet Infect Dis 2006;6:641652.
15. Sax, H, Allegranzi, B, Uçkay, I, Larson, E, Boyce, J, Pittet, D. ‘My five moments for hand hygiene’: a user-centred design approach to understand, train, monitor and report hand hygiene. J Hosp Infect 2007;67:921.
16. Loftus, RW, Koff, MD, Burchman, CC, et al. Transmission of pathogenic bacterial organisms in the anesthesia work area. Anesthesiology 2008;109:399407.
17. Jabbar, U, Leischner, J, Kasper, D, et al. Effectiveness of alcohol-based hand rubs for removal of Clostridium difficile spores from hands. Infect Control Hosp Epidemiol 2010;31:565570.
18. Waters, V, Larson, E, Wu, F, et al. Molecular epidemiology of gram-negative bacilli from infected neonates and health care workers’ hands in neonatal intensive care units. Clin Infect Dis 2004;38:16821687.
19. Del Campo, R, Sánchez-Díaz, AM, Zamora, J, et al. Individual variability in finger-to-finger transmission efficiency of Enterococcus faecium clones. Microbiologyopen 2014;3:128132.
20. Lingaas, E, Fagernes, M. Development of a method to measure bacterial transfer from hands. J Hosp Infect 2009;72:4349.
21. Duckro, AN, Blom, DW, Lyle, EA, Weinstein, RA, Hayden, MK. Transfer of vancomycin-resistant enterococci via health care worker hands. Arch Intern Med 2005;165:302307.
22. Ehrenkranz, NJ, Alfonso, BC. Failure of bland soap handwash to prevent hand transfer of patient bacteria to urethral catheters. Infect Control Hosp Epidemiol 1991;12:654662.
23. Morgan, DJ, Liang, SY, Smith, CL, et al. Frequent multidrug-resistant Acinetobacter baumannii contamination of gloves, gowns, and hands of healthcare workers. Infect Control Hosp Epidemiol 2010;31:716721.
24. Rotter, M, Sattar, S, Dharan, S, Allegranzi, B, Mathai, E, Pittet, D. Methods to evaluate the microbicidal activities of hand-rub and hand-wash agents. J Hosp Infect 2009;73:191199.
25. European Committee for Standardization. European Norm 1500: Chemical Disinfectants and Antiseptics. Hygienic Handrub. Test method and requirements (phase 2/step 2). Version 2013. University of Iowa Computational Epidemiology Research website. Published 2013. Accessed January 5, 2017.
26. American Society for Testing and Materials (ASTM). Designation: E2755–10. Standard test method for determining the bacteria-eliminating effectiveness of hand sanitizer formulations using hands of adults. West Conshohocken, PA: ASTM International.
27. Real, LA, Biek, R. Infectious disease modeling and the dynamics of transmission. Curr Top Microbiol Immunol 2007;315:3349.
28. Chowell, G, Nishiura, H, Viboud, C. Modeling rapidly disseminating infectious disease during mass gatherings. BMC Med 2012;10:159.
29. Hsu, Y-W, Yu, C-Y. Hand surface area estimation formula using 3D anthropometry. J Occup Environ Hyg 2010;7:633639.
30. Bellissimo-Rodrigues, F, Soule, H, Gayet-Ageron, A, Martin, Y, Pittet, D. Should alcohol-based handrub use be customized to healthcare workers’ hand size? Infect Control Hosp Epidemiol 2016;37:219221.
31. Brankston, G, Gitterman, L, Hirji, Z, Lemieux, C, Gardam, M. Transmission of influenza A in human beings. Lancet Infect Dis 2007;7:257265.
32. Bridges, CB, Kuehnert, MJ, Hall, CB. Transmission of influenza: implications for control in health care settings. Clin Infect Dis 2003;37:10941101.
33. Siegel, JD, Rhinehart, E, Jackson, M, Chiarello, L, and the Healthcare Infection Control Practices Advisory Committee. Guideline for isolation precautions: preventing transmission of infectious agents in healthcare settings. Centers for Disease Control and Prevention website. Published 2007. Accessed January 5, 2017.
34. Pandemic Influenza Risk Management WHO Interim Guidance. World Health Organization website. Published 2013. Accessed August 10, 2016.
35. Dharan, S, Hugonnet, S, Sax, H, Pittet, D. Comparation of waterless hand antisepsis agents at short application times: raising the flag of concern. Infect Control Hosp Epidemiol 2003;24:160164.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Infection Control & Hospital Epidemiology
  • ISSN: 0899-823X
  • EISSN: 1559-6834
  • URL: /core/journals/infection-control-and-hospital-epidemiology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Altmetric attention score

Full text views

Total number of HTML views: 14
Total number of PDF views: 194 *
Loading metrics...

Abstract views

Total abstract views: 1595 *
Loading metrics...

* Views captured on Cambridge Core between 22nd February 2017 - 23rd March 2018. This data will be updated every 24 hours.