Infection Control & Hospital Epidemiology (2019), 40, 214–216 doi:10.1017/ice.2018.320


Concise Communication


Sharing is not always a good thing: Use of a DNA marker to investigate the potential for ward-to-ward dissemination of healthcare-associated pathogens


Heba Alhmidi MD1, Jennifer L. Cadnum BS1, Annette L. Jencson BS, CIC1, Ali Abdulfatah Gweder MD2 and


Curtis J. Donskey MD3,4 1Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, 2Department of Medicine, Zawia University Hospital, Zawia, Libya, 3Geriatric Research, Education and Clinical Center, Cleveland VA Medical Center, Cleveland, Ohio and 4Case Western Reserve University School of Medicine,


Cleveland, Ohio Abstract


A DNA marker inoculated onto portable equipment on a medical ward was disseminated to other wards when equipment was shared and to a physician work room and the hospital cafeteria by personnel. These results demonstrate the plausibility of pathogen transmission in healthcare facilities in the absence of shared ward exposure.


(Received 30 August 2018; accepted 13 November 2018; electronically published 7 December 2018)


Understanding routes of pathogen transmission in healthcare settings is essential for development of effective control measures. In recent years, molecular typing techniques, such as whole-genome sequencing, have provided highly discriminatory methods to deter- mine the relatedness of pathogens recovered from patients and the environment. To identify potential routes of transmission, these methods are typically used in conjunction with tracking of patient movement.1,2 One striking observation from many studies using discriminatory typing methods is that genetically related organisms are often detected in patients with no shared exposure on the same ward.1–4 For example, Kong et al1 reported that 23% of incident hospital-associated Clostridium difficile infection (CDI) cases shared genetically related strains with prior hospitalized CDI cases or asymptomatic carriers who were never on the same ward. Such lin- kages have either not been considered plausible transmission events or have been classified as potential non-ward transmissions.1–4 Benign surrogate markers, such as nonpathogenic viruses and viral


DNA, provide powerful tools to investigate pathogen transmission.5–7 On individual wards, surrogate markers inoculated onto surfaces were disseminated to environmental sites and patients.6,7 Because personnel and equipment often move between wards, we hypothesized that ward-to-ward dissemination of pathogens might be common in the absence of shared ward exposure. Here, we used a DNA surrogate marker that is not affected by alcohol hand sanitizer in conjunction with observations of personnel to investigate the potential for dis- semination from contaminated equipment on one hospital ward to other sites in the hospital.


Author for correspondence: Curtis J. Donskey MD, Geriatric Research, Education,


and Clinical Center, Cleveland Veterans Affairs Medical Center, 10701 East Boulevard, Cleveland, Ohio 44106. E-mail: Curtis.Donskey@va.gov


Cite this article: Alhmidi H, et al. (2019). Sharing is not always a good thing: Use of a


DNA marker to investigate the potential for ward-to-ward dissemination of healthcare- associated pathogens. Infection Control & Hospital Epidemiology 2019, 40, 214–216. doi: 10.1017/ice.2018.320


© 2018 by The Society for Healthcare Epidemiology of America. All rights reserved.


Methods Setting


The Cleveland Veterans Affairs Medical Center is a 215-bed acute-care hospital with 6 medical-surgical wards and 2 intensive care units. Portable equipment includes devices that are typically dedicated to a ward (eg, bladder scanners) and devices that are routinely shared (eg, wheelchairs). Nursing staff are primarily based on a single ward, whereas physicians care for patients on multiple wards. The study protocol was approved by the facility’s institutional review board.


Characteristics of the viral DNA surrogate marker


The surrogate marker for pathogen transmission was a 222-base pair DNA marker from the cauliflower mosaic virus.5,7 In simulations of patient care, 1 µg DNA surrogate marker was transferred from a contaminated mannequin to environmental surfaces in a manner similar to bacteriophage MS2 and nontoxigenic C. difficile spores, both with a relatively large inoculum size of 105 plaque-forming or colony-forming units, respectively.5 The DNA marker remained detectable for weeks on surfaces by polymerase chain reaction (PCR) and was inactivated by bleach. The DNA marker was not inactivated by quaternary ammonium disinfectants or alcohol but was reduced to undetectable levels through mechanical removal by hand washing and by wiping of surfaces with antimicrobial or nonantimicrobial wipes.5


Dissemination of the DNA surrogate marker


We inoculated 1 µg of DNA marker in 30 µL water onto high- touch areas of 6 portable devices on a medical ward, including 3 bladder scanners, an electrocardiogram machine, a portable vital signs device, and a cardiac monitor. Hospital personnel and


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