Bacterial transfer to fingertips during sequential surface contacts with and without gloves

Abstract

Bacterial transmission from contaminated surfaces via hand contact plays a critical role in disease spread. However, the fomite‐to‐finger transfer efficiency of microorganisms during multiple sequential surface contacts with and without gloves has not been formerly investigated. We measured the quantity of Escherichia coli on fingertips of participants after 1‐8 sequential contacts with inoculated plastic coupons with and without nitrile gloves. A Bayesian approach was used to develop a mechanistic model of pathogen accretion to examine finger loading as a function of the difference between E coli on surfaces and fingers. We used the model to determine the coefficient of transfer efficiency (λ), and influence of swabbing efficiency and finger area. Results showed that λ for bare skin was higher (49%, 95% CI = 32%‐72%) than for gloved hands (30%, CI = 17%‐49%). Microbial load tended toward a dynamic equilibrium after four and six contacts for gloved hands and bare skin, respectively. Individual differences between volunteers’ hands had a negligible effect compared with use of gloves (P < .01). Gloves reduced loading by 4.7% (CI = −12%‐21%) over bare skin contacts, while 20% of participants accrued more microorganisms on gloved hands. This was due to poor fitting, which created a larger finger surface area than bare hands.

Why is mock care not a good proxy for predicting hand contamination during patient care?

“…Normal (m¼0.60, s¼0.25) [24] Escherichia coli Normal (m¼0.49, s¼0.12) [25] Norovirus Normal (m¼0.05, s¼0.09) [26] Fraction of the hand used for hand-to-surface contact Uniform (0.008, 0.14)…”

Evaluating a transfer gradient assumption in a fomite-mediated microbial transmission model using an experimental and Bayesian approach

“…The Euclidean distance equation was used to measure the distance between the model-estimated and the experimentally measured concentrations on the fingertip and surface after the contact. The sum of the square errors, as is used here (equation (2.6)), has been used in other ABC research [21,28]. Modelestimated concentrations on the fingertip represent the true number of virus particles on the fingertip, while those experimentally measured represent the number of detected virus particles influenced by swabbing efficiency.…”

“…The secondary objective was to use approximate Bayesian computation (ABC) to evaluate distributions for fingertip and surface swabbing efficiencies and transfer efficiency that best explain experimental findings and to demonstrate how these posterior distributions can be applied in QMRAs. This novel method has been applied in a recent transfer efficiency study to relate experimental data to microbial transfer models [21].…”

Integrated environment-occupant-pathogen information modeling to assess and communicate room-level outbreak risks of infectious diseases

“…To assess pathogen transmission to susceptible hosts, the models such as the environmental infection transmission system modeling framework consider the dynamics of contact and pathogen transfer between individuals via their hands and fomites, pathogen persistence in the environment, pathogen shedding, and recovery of infected individuals. Studies [ [13] , [14] , [15] ] also exploited experimentation approaches to measure the transfer of microbiomes between fomites and humans. The measured microbiological and epidemiological data can be used to assess the transmissibility of the pathogens and used in the models for risk assessment.…”