Brief Report How well does transfer of bacterial pathogens by culture swabs correlate with transfer by hands? Anubhav Kanwar MBBS a , Thriveen S.C. Mana MS a , Jennifer L. Cadnum BS b , Heba Alhmidi MD b , Sreelatha Koganti MD b , Curtis J. Donskey MD a,c, * a Division of Infectious Diseases, Department of Medicine, University Hospitals Case Medical Center, Cleveland, OH b Research Service, Louis Stokes Veterans Affairs Medical Center, Cleveland, OH c Geriatric Research, Education, and Clinical Center, Louis Stokes Veterans Affairs Medical Center, Cleveland, OH Key Words: Clostridium difficile Methicillin-resistant Staphylococcus aureus Carbapenem-resistant Enterobacteriaciae Environment Recovery In laboratory testing and in isolation rooms, pickup and transfer of health care-associated pathogens by premoistened rayon swabs correlated well with pickup and transfer by bare hands or moistened gloves. These results suggest that swab cultures provide a useful surrogate indicator of the risk for pathogen pickup and transfer by hands. Published by Elsevier Inc. on behalf of Association for Professionals in Infection Control and Epidemiology, Inc. Studies involving culturing of the environment have contributed to an increased appreciation of the role of contaminated surfaces in trans- mission of health care-associated pathogens. 1-3 In a majority of these studies, swabs have been used to sample environment surfaces, often with direct plating onto selective agar. 1,4,5 Although swabs may be less sensitive for detection of low levels of pathogens on surfaces than methods involving use of sponges or replicate organism detection and counting (RODAC) contact plates, 4-7 they have important advantages, including ease of use, low cost, and lack of a requirement for special- ized equipment such as stomachers and centrifuges. Moreover, it is plausible that swab cultures may mimic the pickup and transfer of pathogens by hands better than methods that are intended to opti- mize the sensitivity of recovery and sample large surface areas. Here, we examined the correlation between pickup and transfer of patho- gens from surfaces by swabs and by hands, the most important source of transmission in health care settings. METHODS The study protocol was approved by the Cleveland VA Medical Center’s Institutional Review Board. Because it was not deemed feasible to conduct studies on bare hand transfer of pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), we con- ducted initial experiments to determine whether moist gloves could serve as a surrogate for bare hands in the pickup and transfer of a microorganism. Spores of nontoxigenic Clostridium difficile (Amer- ican Type Culture Collection strain 43602) in concentrations ranging from 10 1 -10 4 CFU in 10 μL sterile water were spread on 1 cm 2 areas of benchtop surfaces and allowed to air dry. Finger pads of bare hands or of vinyl gloves moistened with sterile water were imprinted onto the inoculated surfaces and then onto prereduced cycloserine- cefoxitin-brucella agar containing 0.1% taurocholic acid and lysozyme 5 mg/L. 8 The plates were incubated in a Whitley MG1000 anaero- bic workstation (Microbiology International, Frederick, MD) for 48 hours and colony forming units were counted. In the laboratory, we compared pickup and transfer of bacterial pathogens from benchtop surfaces to culture plates by rayon swabs (BBL CultureSwabs; Becton, Dickinson, and Company, Franklin Lakes, NJ) premoistened with phosphate-buffered saline (PBS) versus bare hands (for nontoxigenic C difficile spores) or vinyl gloves premoistened with PBS for other organisms. RODAC contact plates were also used to provide comparison with a method involving pickup of organ- isms directly onto culture media without the requirement for a transfer step. Test pathogens included nontoxigenic C difficile spores of American Type Culture Collection strain 43602, MRSA (a clinical isolate of pulsed-field gel electrophoresis type USA300), and carbapenem-resistant Escherichia coli (New Delhi metallo-β- lactamase-1–producing strain). The organisms were applied to benchtop surfaces as previously described in concentrations ranging from 10 1 -10 4 CFU and sampled with hands or gloves, premoistened swabs, or RODAC plates. The RODAC plates were imprinted onto the surfaces and then placed in an incubator. The RODAC plates for C * Address correspondence to Curtis J. Donskey, MD, Geriatric Research, Education, and Clinical Center, Louis Stokes Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH 44106. E-mail address: curtisd123@yahoo.com (C.J. Donskey). Supported by a Merit Review grant from the Department of Veterans Affairs to CJD. Conflicts of interest: CJD serves on an advisory board for 3M and has received research funding from GOJO, EcoLab, Clorox, and Altapure. ARTICLE IN PRESS 0196-6553/Published by Elsevier Inc. on behalf of Association for Professionals in Infection Control and Epidemiology, Inc. http://dx.doi.org/10.1016/j.ajic.2017.03.001 American Journal of Infection Control ■■ (2017) ■■-■■ Contents lists available at ScienceDirect American Journal of Infection Control journal homepage: www.ajicjournal.org American Journal of Infection Control