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Wallner M, Pfuderer L, Bašková L, Dollischel K, Grass RN, Kücher A, Lüscher AM, Kern JM. Outbreak simulation on the neonatal ward using silica nanoparticles with encapsulated DNA - unmasking of key spread areas. J Hosp Infect 2024:S0195-6701(24)00296-2. [PMID: 39278266 DOI: 10.1016/j.jhin.2024.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Revised: 08/19/2024] [Accepted: 09/01/2024] [Indexed: 09/18/2024]
Abstract
PURPOSE Nosocomial infections pose a serious threat. In neonatal intensive care units (NICUs) in particular, there are repeated outbreaks caused by microorganisms without the sources or dynamics being conclusively determined. This study aims to use amorphous silica nanoparticles with encapsulated DNA (SPED) to simulate outbreak events and to visualize dissemination patterns in a NICU to gain a better understanding of these dynamics. METHODS Three types of SPED were strategically placed on the ward to mimic three different dissemination dynamics among real-life conditions and employee activities. SPED DNA, resistant to disinfectants, was sampled at 22 predefined points across the ward for four days and qPCR analysis was conducted. RESULTS Starting from staff areas, a rapid ward-wide SPED dissemination including numerous patient rooms was demonstrated. In contrast, a primary deployment in a patient room only led to the spread in the staff area, with no distribution in the patient area. CONCLUSION This study pioneers SPED utilization in simulating outbreak dynamics. By unmasking staff areas as potential key trigger spots for ward-wide dissemination the revealed patterns could contribute to a more comprehensive view of outbreak events leading to rethinking of hygiene measures and training to reduce the rate of nosocomial infections in hospitals.
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Affiliation(s)
- Markus Wallner
- Institute of Clinical Microbiology and Hygiene, University Hospital Salzburg, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Lara Pfuderer
- Functional Materials Laboratory, Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Lenka Bašková
- Institute of Clinical Microbiology and Hygiene, University Hospital Salzburg, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Kerstin Dollischel
- Institute of Clinical Microbiology and Hygiene, University Hospital Salzburg, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Robert N Grass
- Functional Materials Laboratory, Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Andreas Kücher
- Institute of Clinical Microbiology and Hygiene, University Hospital Salzburg, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Anne Michelle Lüscher
- Functional Materials Laboratory, Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Jan Marco Kern
- Institute of Clinical Microbiology and Hygiene, University Hospital Salzburg, Paracelsus Medical University Salzburg, Salzburg, Austria.
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Green LJ, Bhatia ND, Toledano O, Erlich M, Spizuoco A, Goodyear BC, York JP, Jakus J. Silica-based microencapsulation used in topical dermatologic applications. Arch Dermatol Res 2023; 315:2787-2793. [PMID: 37792034 PMCID: PMC10616207 DOI: 10.1007/s00403-023-02725-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 07/31/2023] [Accepted: 09/06/2023] [Indexed: 10/05/2023]
Abstract
Microencapsulation has received extensive attention because of its various applications. Since its inception in the 1940s, this technology has been used across several areas, including the chemical, food, and pharmaceutical industries. Over-the-counter skin products often contain ingredients that readily and unevenly degrade upon contact with the skin. Enclosing these substances within a silica shell can enhance their stability and better regulate their delivery onto and into the skin. Silica microencapsulation uses silica as the matrix material into which ingredients can be embedded to form microcapsules. The FDA recognizes amorphous silica as a safe inorganic excipient and recently approved two new topical therapies for the treatment of rosacea and acne. The first approved formulation uses a novel silica-based controlled vehicle delivery technology to improve the stability of two active ingredients that are normally not able to be used in the same formulation due to potential instability and drug degradation. The formulation contains 3.0% benzoyl peroxide (BPO) and 0.1% tretinoin topical cream to treat acne vulgaris in adults and pediatric patients. The second formulation contains silica microencapsulated 5.0% BPO topical cream to treat inflammatory rosacea lesions in adults. Both formulations use the same amorphous silica sol-gel microencapsulation technology to improve formulation stability and skin compatibility parameters.
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Affiliation(s)
- Lawrence J Green
- George Washington University School of Medicine, Washington, DC, USA.
| | | | | | | | | | | | | | - Jeannette Jakus
- SUNY Downstate Health Sciences University, Brooklyn, NY, USA
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Burke KB, Berryhill BA, Garcia R, Goldberg DA, Manuel JA, Gannon PR, Levin BR, Kraft CS, Mumma JM. A methodology for using Lambda phages as a proxy for pathogen transmission in hospitals. J Hosp Infect 2023; 133:81-88. [PMID: 36682626 PMCID: PMC10795484 DOI: 10.1016/j.jhin.2023.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 01/21/2023]
Abstract
BACKGROUND One major concern in hospitalized patients is acquiring infections from pathogens borne on surfaces, patients, and healthcare workers (HCWs). Fundamental to controlling healthcare-associated infections is identifying the sources of pathogens, monitoring the processes responsible for their transmission, and evaluating the efficacy of the procedures employed for restricting their transmission. AIM To present a method using the bacteriophage Lambda (λ) to achieve these ends. METHODS Defined densities of multiple genetically marked λ phages were inoculated at known hotspots for contamination on high-fidelity mannequins. HCWs then entered a pre-sanitized simulated hospital room and performed a series of patient care tasks on the mannequins. Sampling occurred on the scrubs and hands of the HCWs, as well as previously defined high-touch surfaces in hospital rooms. Following sampling, the rooms were decontaminated using procedures demonstrated to be effective. Following the conclusion of the simulation, the samples were tested for the presence, identity, and densities of these λ phages. FINDINGS The data generated enabled the determination of the sources and magnitude of contamination caused by the breakdown of established infection prevention practices by HCWs. This technique enabled the standardized tracking of multiple contaminants during a single episode of patient care. Unlike other biological surrogates, λ phages are susceptible to common hospital disinfectants, and allow for a more accurate evaluation of pathogen transmission. CONCLUSION Whereas our application of these methods focused on healthcare-associated infections and the role of HCW behaviours in their spread, these methods could be employed for identifying the sources and sites of microbial contamination in other settings.
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Affiliation(s)
- K B Burke
- Department of Biology, Emory University, Atlanta, GA, USA; Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - B A Berryhill
- Department of Biology, Emory University, Atlanta, GA, USA; Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, USA
| | - R Garcia
- Department of Biology, Emory University, Atlanta, GA, USA
| | - D A Goldberg
- Department of Biology, Emory University, Atlanta, GA, USA
| | - J A Manuel
- Department of Biology, Emory University, Atlanta, GA, USA
| | - P R Gannon
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - B R Levin
- Department of Biology, Emory University, Atlanta, GA, USA
| | - C S Kraft
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA; Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - J M Mumma
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA.
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Ullrich C, Luescher AM, Koch J, Grass RN, Sax H. Silica nanoparticles with encapsulated DNA (SPED) to trace the spread of pathogens in healthcare. Antimicrob Resist Infect Control 2022; 11:4. [PMID: 35012659 PMCID: PMC8743744 DOI: 10.1186/s13756-021-01041-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 12/06/2021] [Indexed: 01/05/2023] Open
Abstract
Background To establish effective infection control protocols, understanding pathogen transmission pathways is essential. Non-infectious surrogate tracers may safely explore these pathways and challenge pre-existing assumptions. We used silica nanoparticles with encapsulated DNA (SPED) for the first time in a real-life hospital setting to investigate potential transmission routes of vancomycin-resistant enterococci in the context of a prolonged outbreak. Methods The two study experiments took place in the 900-bed University Hospital Zurich, Switzerland. A three-run ‘Patient experiment’ investigated pathogen transmission via toilet seats in a two-patient room with shared bathroom. First, various predetermined body and fomite sites in a two-bed patient room were probed at baseline. Then, after the first patient was contaminated with SPED at the subgluteal region, both patients sequentially performed a toilet routine. All sites were consequently swabbed again for SPED contamination. Eight hours later, further spread was tested at predefined sites in the patient room and throughout the ward. A two-run ‘Mobile device experiment’ explored the potential transmission by mobile phones and stethoscopes in a quasi-realistic setting. All SPED contamination statuses and levels were determined by real-time qPCR. Results Over all three runs, the ‘Patient experiment’ yielded SPED in 59 of 73 (80.8%) predefined body and environmental sites. Specifically, positivity rates were 100% on subgluteal skin, toilet seats, tap handles, and entertainment devices, the initially contaminated patients’ hands; 83.3% on patient phones and bed controls; 80% on intravenous pumps; 75% on toilet flush plates and door handles, and 0% on the initially not contaminated patients’ hands. SPED spread as far as doctor’s keyboards (66.6%), staff mobile phones (33.3%) and nurses’ keyboards (33.3%) after eight hours. The ‘Mobile device experiment’ resulted in 16 of 22 (72.7%) positive follow-up samples, and transmission to the second patient occurred in one of the two runs. Conclusions For the first time SPED were used to investigate potential transmission pathways in a real hospital setting. The results suggest that, in the absence of targeted cleaning, toilet seats and mobile devices may result in widespread transmission of pathogens departing from one contaminated patient skin region.
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Kianfar B, Tian J, Rozemeijer J, van der Zaan B, Bogaard TA, Foppen JW. Transport characteristics of DNA-tagged silica colloids as a colloidal tracer in saturated sand columns; role of solution chemistry, flow velocity, and sand grain size. JOURNAL OF CONTAMINANT HYDROLOGY 2022; 246:103954. [PMID: 35114497 DOI: 10.1016/j.jconhyd.2022.103954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 12/23/2021] [Accepted: 01/01/2022] [Indexed: 06/14/2023]
Abstract
In recent years, DNA-tagged silica colloids have been used as an environmental tracer. A major advantage of this technique is that the DNA-coding provides an unlimited number of unique tracers without a background concentration. However, little is known about the effects of physio-chemical subsurface properties on the transport behavior of DNA-tagged silica tracers. We are the first to explore the deposition kinetics of this new DNA-tagged silica tracer for different pore water chemistries, flow rates, and sand grain size distributions in a series of saturated sand column experiments in order to predict environmental conditions for which the DNA-tagged silica tracer can best be employed. Our results indicated that the transport of DNA-tagged silica tracer can be well described by first order kinetic attachment and detachment. Because of massive re-entrainment under transient chemistry conditions, we inferred that attachment was primarily in the secondary energy minimum. Based on calculated sticking efficiencies of the DNA-tagged silica tracer to the sand grains, we concluded that a large fraction of the DNA-tagged silica tracer colliding with the sand grain surface did also stick to that surface, when the ionic strength of the system was higher. The experimental results revealed the sensitivity of DNA-tagged silica tracer to both physical and chemical factors. This reduces its applicability as a conservative hydrological tracer for studying subsurface flow paths. Based on our experiments, the DNA-tagged silica tracer is best applicable for studying flow routes and travel times in coarse grained aquifers, with a relatively high flow rate. DNA-tagged silica tracers may also be applied for simulating the transport of engineered or biological colloidal pollution, such as microplastics and pathogens.
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Affiliation(s)
- Bahareh Kianfar
- Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, the Netherlands.
| | - Jingya Tian
- Department of Water Resources and Ecosystems, IHE-Delft Institute for Water Education, Delft, the Netherlands
| | | | | | - Thom A Bogaard
- Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, the Netherlands
| | - Jan Willem Foppen
- Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, the Netherlands; Department of Water Resources and Ecosystems, IHE-Delft Institute for Water Education, Delft, the Netherlands.
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Luescher AM, Koch J, Stark WJ, Grass RN. Silica-encapsulated DNA tracers for measuring aerosol distribution dynamics in real-world settings. INDOOR AIR 2022; 32:e12945. [PMID: 34676590 PMCID: PMC9298268 DOI: 10.1111/ina.12945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 09/25/2021] [Accepted: 10/08/2021] [Indexed: 06/13/2023]
Abstract
Aerosolized particles play a significant role in human health and environmental risk management. The global importance of aerosol-related hazards, such as the circulation of pathogens and high levels of air pollutants, have led to a surging demand for suitable surrogate tracers to investigate the complex dynamics of airborne particles in real-world scenarios. In this study, we propose a novel approach using silica particles with encapsulated DNA (SPED) as a tracing agent for measuring aerosol distribution indoors. In a series of experiments with a portable setup, SPED were successfully aerosolized, recaptured, and quantified using quantitative polymerase chain reaction (qPCR). Position dependency and ventilation effects within a confined space could be shown in a quantitative fashion achieving detection limits below 0.1 ng particles per m3 of sampled air. In conclusion, SPED show promise for a flexible, cost-effective, and low-impact characterization of aerosol dynamics in a wide range of settings.
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Affiliation(s)
- Anne M. Luescher
- Institute for Chemical and BioengineeringETH ZurichZurichSwitzerland
| | - Julian Koch
- Institute for Chemical and BioengineeringETH ZurichZurichSwitzerland
| | - Wendelin J. Stark
- Institute for Chemical and BioengineeringETH ZurichZurichSwitzerland
| | - Robert N. Grass
- Institute for Chemical and BioengineeringETH ZurichZurichSwitzerland
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Abstract
Hand hygiene by health care personnel is an important measure for preventing health care-associated infections, but adherence rates and technique remain suboptimal. Alcohol-based hand rubs are the preferred method of hand hygiene in most clinical scenarios, are more effective and better tolerated than handwashing, and their use has facilitated improved adherence rates. Obtaining accurate estimates of hand hygiene adherence rates using direct observations of personnel is challenging. Combining automated hand hygiene monitoring systems with direct observations is a promising strategy, and is likely to yield the best estimates of adherence. Greater attention to hand hygiene technique is needed.
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Affiliation(s)
- John M Boyce
- J.M. Boyce Consulting, LLC, 62 Sonoma Lane, Middletown, CT 06457, USA.
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