Simulating transmission of ESKAPE pathogens plus C. difficile in relevant clinical scenarios

Abstract

Background: The prevalence of healthcare-acquired infections (HAI) and rising levels of antimicrobial resistance places significant economic and public health burdens on modern healthcare systems. A group of highly drug resistant pathogens known as the ESKAPE pathogens, along with C. difficile, are the leading causes of HAIs. Interactions between patients, healthcare workers, and environmental conditions impact disease transmission. Studying pathogen transfer under varying contact scenarios in a controlled manner is critical for understanding transmission and disinfectant strategies. In lieu of human subject research, this method has the potential to contribute to modeling the routes of pathogen transmission in healthcare settings. Methods: To overcome these challenges, we have developed a method that utilizes a synthetic skin surrogate to model both direct (skin-to-skin) and indirect (skin-to fomite-to skin) pathogen transfer between infected patients and healthy healthcare workers. This surrogate material includes a background microbiome community simulating typical human skin flora to more accurately mimic the effects of natural flora during transmission events. Results: We demonstrate the ability to modulate individual bacterial concentrations within this microbial community to mimic bacterial concentrations previously reported on the hands of human subjects. We also explore the effect of various decontamination approaches on pathogen transfer between human subjects, such as the use of handwashing or surface disinfectants. Using this method, we identify a potential outlier, S. aureus, that may persist and retain viability in specific transfer conditions better than the overall microbial community during decontamination events. Conclusions: Our work describes the development of an in vitro method that uses a synthetic skin surrogate with a defined background microbiota to simulate skin-to-skin and skin-to fomite-to skin contact scenarios. These results illustrate the value of simulating a holistic microbial community for transfer studies by elucidating differences in different pathogen transmission rates and resistance to common decontamination practices. We believe this method will contribute to improvements in pathogen transmission modeling in healthcare settings and increase our ability to assess the risk associated with HAIs, although additional research is required to establish the degree of correlation of pathogen transmission by skin or synthetic alternatives.

A spatiotemporal simulation study on the transmission of harmful microorganisms through connected healthcare workers in a hospital ward setting

“…(ESKAPE) [1]. These harmful microorganisms (HMO) can survive on human skin and hospital surfaces for extended periods and lead to high crosstransmission rates between healthcare workers (HCW) and patients [2][3][4]. The ease of transmission of HMO depends upon the features of the microorganism, patient characteristics and the behaviour of healthcare workers (HCW), whereas the damage caused by the infection that follows ranges from none to potentially fatal [5].…”

Detection of ESKAPE pathogens andClostridioides difficilein Simulated Skin Transmission Events with Metagenomic and Metatranscriptomic Sequencing

“…Our research expands upon previously published data from a study establishing an in vitro method to model ESKAPE+C transmission using a synthetic skin surrogate (Weber et al, 2020). This prior study enabled the investigation of both direct (skin-to-skin) and indirect (skin-to fomite-to skin) pathogen transmission scenarios using VITRO SKIN ® N-19 to mimic human skin, including a simulated commensal skin flora ( Figure 1).…”

“…Microorganisms used for this effort were sourced from American Type Culture Collection (ATCC) or the Centers for Disease Control and Prevention (CDC) Antimicrobial Resistance (AR) Isolate Bank as described previously (Weber et al, 2020). Any isolates that did not have existing published whole genome sequencing reference data were sequenced internally on an Illumina MiSeq ® FGx System.…”

“…Supplementary Tables 1-6 and Supplementary Figures 1-2 describe features of the ESKAPE+C pathogen and background organisms analyzed, as well as their closest matching reference genome in NCBI databases. While culture data was successfully collected from all direct and indirect scenarios previously described (Weber et al, 2020), the indirect wash scenarios were not sequenced in this study because it was anticipated that they would fall well below the sequencing limit of detection ( Figure 1).…”

“…A secondary VITRO-SKIN ® representing a clean health worker hand was then touched to the fomite and harvested as described above. Although our previous study analyzed culture data from the washed indirect transfer events (step 2b), those samples were not sequenced because the amount of available nucleic acid was anticipated to be too low for pathogen detection (Weber et al, 2020).…”