Gerardo U Lopez

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Scholarly Contributions

Journals/Publications

• Betancourt, W. Q., Lopez, G. U., Gerba, C. P., Pepper, I. L., Quintanar, D. R., & Morrison, C. (2020). Potential indicators of virus transport and removal during soil aquifer treatment of treated wastewater effluent. Water Research. doi:10.1016/j.watres.2020.115812
• Morrison, C. M., Betancourt, W. Q., Quintanar, D. R., Lopez, G. U., Pepper, I. L., & Gerba, C. P. (2020). Potential Indicators of Virus Transport and Removal during Soil Aquifer Treatment of Treated Wastewater Effluent. International Water Association.
• Lamori, J. G., Xue, J., Taruna, A., Lopez, G. U., Kitajima, M., Gerba, C. P., Pepper, I. L., & Sherchan, S. (2019). Removal of fecal indicator bacteria and antibiotic resistant genes in constructed wetlands. Environmental Science and Pollution Research.
• Lopez, G. U., Gerba, C. P., Abd-Elmaksoud, S., Wissler, A., Sifuentes, L. Y., & Mitchell, J. (2019). Modelling of ultraviolet light inactivation kinetics of methicillin-resistantStaphylococcus aureus, vancomycin-resistantEnterococcus,Clostridium difficilespores and murine norovirus on fomite surfaces. Journal of Applied Microbiology, 126(1), 58-67. doi:10.1111/jam.14103
• Mitchell, J., Sifuentes, L., Wissler, A., Abd-Elmaksoud, S., Lopez, G. U., & Gerba, C. P. (2018). Modeling of ultraviolet light inactivation kinetics of methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, Clostridium difficile spores and murine norovirus on fomite surfaces. Journal of Applied Microbiology. doi:10.1111/jam.14103
• Wagoner, R., Lopez, G. U., Diaz, D., Cabrera, D., & Benally, K. (2018). A Pilot Project Assessing Exposure of Livestock Workers in the Southwest U.S. to E.Coli O157:H7 and Salmonella. ISEE Conference Abstracts, 2018(1). doi:10.1289/isesisee.2018.p01.3060
• Gerba, C. P., Lopez, G. U., Raisanen, P., & Wuollet, A. L. (2016). Bacterial contamination of computer touch screens. American Journal of Infection Control. doi:10.1016/j.ajic.2015.10.013
• Gerba, C. P., Sifuentes, L. Y., Lopez, G. U., Abd-Elmaksoud, S., Calabrese, J., & Tanner, B. (2016). Wide-spectrum activity of a silver-impregnated fabric. American journal of infection control, 44(6), 689-90. doi:http://dx.doi.org/10.1016/j.ajic.2015.11.033.
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  Fabrics, such as clothing, drapes, pillowcases, and bedsheets are potential sources of pathogenic bacteria and viruses. We found fabrics (ie, professional clothing, pillowcases, and lab coats) treated with a silver-impregnated material to be effective in significantly reducing a wide spectrum of ordinary and drug-resistant microorganisms, including Salmonella, methicillin-resistant Staphylococcus aureus, Propionibacterium acnes, Trichphyton mentagrophytes, and norovirus. Fabrics impregnated with antimicrobial agents help provide an additional barrier to the transport or reservoir of pathogens in health care environments.
• Lopez, G. U., Gerba, C. P., & Ikner, L. A. (2016). Distribution of Bacteria in Dental Offices and the Impact of Hydrogen Peroxide Disinfecting Wipes. The Journal of Dental Hygiene, 90(6), 354-361.
• Sassi, H. P., Sassi, H. P., Pivo, T., Lopez, G. U., Gerba, C. P., & Cabrera, D. (2016). Movement of Pathogens From Public Restroom to Clinical Areas in a Hospital. American Journal of Infection Control, 44(6), S44. doi:10.1016/j.ajic.2016.04.199
• Gerba, C. P., Wuollet, A. L., Raisanen, P. K., & Lopez, G. U. (2015). Bacterial Contamination of Computer Touch Screens. American Journal of Infection Control, 44(3), 358-360. doi:10.1016/j.ajic.2015.10.013
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  The goal of this study was to determine the occurrence of opportunistic bacterial pathogens on the surfaces of computer touch screens used in hospitals and grocery stores. Opportunistic pathogenic bacteriawere isolated on touch screens in hospitals; Clostridium difficile and vancomycin-resistant Enterococcus and in grocery stores; methicillin-resistant Staphylococcus aureus. Enteric bacteria were more common on grocery store touch screens than on hospital computer touch screens.
• Lopez, G. U., Gerba, C. P., Reynolds, K. A., Sifuentes, L. Y., Sexton, J. D., Sherchan, S., & Kitajima, M. (2015). Impact of disinfectant wipes on the risk of Campylobacter jejuni infection during raw chicken preparation in domestic kitchens. Journal of Applied Microbiology, 119(1), 245-252. doi:10.1111/jam.12834
• Lopez, G. U., Kitajima, M., Sherchan, S. P., Sexton, J. D., Sifuentes, L. Y., Gerba, C. P., & Reynolds, K. A. (2015). Impact of disinfectant wipes on the risk of Campylobacter jejuni infection during raw chicken preparation in domestic kitchens. Journal of applied microbiology, 119(1), 245-52. doi:10.1111/jam.12834
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  In the present study, we conducted a quantitative microbial risk assessment forecasting the exposure to Campylobacter jejuni contaminated surfaces during preparation of chicken fillets and how using a disinfectant-wipe intervention to clean a contaminated work area decreases the risk of infection following the preparation of raw chicken fillet in a domestic kitchen.
• Lopez, G. U., Kitajima, M., Havas, A., Gerba, C. P., & Reynolds, K. A. (2014). Evaluation of a Disinfectant Wipe Intervention on Fomite-to-Finger Microbial Transfer. Applied and Environmental Microbiology, 80(10), 3113-3118.
• Lopez, G. U., Gerba, C. P., Tamimi, A. H., Kitajima, M., Maxwell, S. L., & Rose, J. B. (2013). Transfer Efficiency of Bacteria and Viruses from Porous and Nonporous Fomites to Fingers under Different Relative Humidity Conditions. Applied and Environmental Microbiology, 79(18), 5728-5734.
• Lopez, G. U., Rose, J. B., Maxwell, S. L., Kitajima, M., Tamimi, A. H., & Gerba, C. P. (2013). Transfer Efficiency of Bacteria and Viruses from Porous and Nonporous Fomites to Fingers under Different Relative Humidity Conditions. Applied and Environmental Microbiology, 79(18), 5728-5734. doi:10.1128/aem.01030-13
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  ABSTRACT Fomites can serve as routes of transmission for both enteric and respiratory pathogens. The present study examined the effect of low and high relative humidity on fomite-to-finger transfer efficiency of five model organisms from several common inanimate surfaces (fomites). Nine fomites representing porous and nonporous surfaces of different compositions were studied. Escherichia coli , Staphylococcus aureus , Bacillus thuringiensis , MS2 coliphage, and poliovirus 1 were placed on fomites in 10-μl drops and allowed to dry for 30 min under low (15% to 32%) or high (40% to 65%) relative humidity. Fomite-to-finger transfers were performed using 1.0 kg/cm 2 of pressure for 10 s. Transfer efficiencies were greater under high relative humidity for both porous and nonporous surfaces. Most organisms on average had greater transfer efficiencies under high relative humidity than under low relative humidity. Nonporous surfaces had a greater transfer efficiency (up to 57%) than porous surfaces (

Presentations

• Lopez, G. U. (2021, Spring). How Do You Decide On An Area of Speciality For Graduate School?. 2021 Wester Alliance to Expand Student Opportunities, Arizona State University. Virtual, Online: Arizona State University.
• Lopez, G. U. (2021, Summer). Cyclospora: Potential Reservoirs and Occurrence in Irrigation Waters. 2021 CPS Research Symposium. Virtual, Online: Center for Produce Safety.
• Lopez, G. U. (2019, Fall). Cyclospora cayetanensis. Oregon Food Safety Workshop. Clackamas, OR: BiosafeSystems.
• Lopez, G. U. (2019, Fall). Water- & Food-borne Parasites Crypto, Giardia & Cyclsopora. Yuma Food Safety Council Monthly Meeting. Yuma, AZ: Yuma Food Safety Council.
• Lopez, G. U. (2019, Spring). Cyclospora Outbreaks and Importance of Working with Stakeholders. UA Food Safety Consortium Seminar Series. UA ACBS Tucson, Arizona.
• Lopez, G. U. (2019, Summer). Cyclospora Prevalence in Irrigation Water in Fresh Produce Growing Regions. 2019 CPS Research Symposium. Austin, TX: Center For Produce Safety.
• Lopez, G. U. (2019, Summer). Cyclospora: Potential Reservoirs and Occurrence in Irrigation Waters. 2019 CPS Research Symposium. Austin, TX: Center for Produce Safety.
• Lopez, G. U. (2018, June). Cyclospora: Potential Reservoirs and Occurrence in Irrigation Waters. 2018 CPS Research Symposium. Charlotte North Carolina: Center for Produce Safety.
• Lopez, G. U. (2018, Summer). Transmissin De Cyclospora En Ambientes Agrícolas. Expo Simposium Baja Food Safety. Ensenada, Baja California, MX.
• Hauser, M. W., Christman, K. A., Gouker, S., Lopez, G. U., Moore, J. D., Horn, K., & Yarnes, A. (2017, February). 21st Century Community Learning Centers - Northern Arizona. 21st CCLC Site Coordinators Workshop. Flagstaff, AZ: Arizona Department of Education.
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  Presentation by 4-H Agents and staff from Northern Arizona counties to 21st Century Learning Centers to provide resources and programming to possible sites.
• Lopez, G. U. (2017, June). Cyclospora: Potential Reservoirs and Occurrence in Irrigation Waters. 2017 CPS Research Symposium. Denver Colorado: Center for Produce Safety.
• Lopez, G. U. (2016, February). Collaborating with County 4-H STEM programs in Arizona. Annual Cooperative Extension 4-H and Family and Consumer Science In-service. Maricopa County Extension Office 4341 E. Broadway Rd. Phoenix AZ 85040: Cooperative Extension.
• Lopez, G. U. (2016, November). 4-H STEM Discovery Camp. Arizona Health Sciences Center’s Working Group of student affairs and services staffers representing the four colleges at Medicine, Pharmacy, Nursing and Public Health.. The University of Arizona, College of Pharmacy Drachman Hall A326: College of Pharmacy.

Poster Presentations

• Lopez, G. U., Lonchar, T., Johnson, K. R., Ruiz, N. E., DeVeau, S. N., Sekaquaptewa, S. K., Kaye, Y., Parra, A. P., Lester, D. F., Morris, N. A., Elliott-Engel, J., & Geel, E. (2020, September). 4-H STEM YOUniversity: Robotics 101 Virtual Camp Fall 2020. 4-H STEM YOUniversity Program. Tucson, AZ.
• Lopez, G. U., Lonchar, T., Yee, K., Hanson, H., Rivas, E. L., Ruiz, N. E., DeVeau, S. N., Vasovski, S., Johnson, K. R., Sekaquaptewa, S. K., Kaye, Y., Josytewa, S., Arias, J. M., Muwanas-Arias, N., Kinlicheenie, K. L., Contreras, S., Munoz, E., Smith, D., Parra, A. P., , Lester, D. F., et al. (2020, August). 4-H STEM YOUniversity: Robotics CoderZ Virtual Camp Fall 2020. Annual University of Arizona Cooperative Extension Conference. Tucson, AZ.
• Rodriguez, A., Lopez, G. U., DeVeau, S. N., Vasovski, S., Johnson, K. R., Ruiz, N. E., Parra, A. P., Lester, D. F., Morris, N. A., & Elliott-Engel, J. (2020, August). 4-H STEM YOUniversity: AR Floating Farm Virtual Camp Fall 2020. Annual University of Arizona Cooperative Extension Conference. Tucson, AZ.
• Lopez, G. U., Christman, K. A., Cooper, M. A., Carstens, R., Thoutt, E., Gonzalez, M., Vasovski, S., Cabrera, D. D., Lonchar, T., Geel, E., Torres, M. A., Lopez, J., Perez, S., & Villa Barbosa, G. (2019, Summer). The University of Arizona Cooperative Extension 4-H Program Collaborating Statewide in Preparing the Next Generation of STEM Innovators. Arizona Cooperative Extension Conference "Pillar of the Community". Tucson, AZ: UA Cooperative Extension.
• Morris, N. A., Elliott-Engel, J., Lopez, G. U., Moore, J. D., Christman, K. A., Avery, D., & Walsh, M. E. (2019, August). Arizona 4-H Summit: Campus, Career, and Community Engagement. Annual Conference. Tucson, AZ: Arizona Cooperative Extension.
• Morris, N. A., Elliott-Engel, J., Lopez, G. U., Moore, J. D., Christman, K. A., Avery, D., & Walsh, M. E. (2019, August). Arizona 4-H Summit: Campus, career, and community engagement. Annual University of Arizona Cooperative Extension Conference. Tucson, AZ.
• Morris, N. A., Morris, N. A., Elliott-Engel, J., Elliott-Engel, J., Lopez, G. U., Lopez, G. U., Moore, J. D., Moore, J. D., Christman, K. A., Christman, K. A., Avery, D., Avery, D., Walsh, M. E., & Walsh, M. E. (2019, August). Arizona 4-H Summit: Campus, Career, and Community Engagement [EC1]. Annual University of Arizona Cooperative Extension Conference. Tucson, AZ.
• Walsh, M. E., Morris, N. A., Avery, D., Elliott-Engel, J., Christman, K. A., Lopez, G. U., Moore, J. D., Moore, J. D., Lopez, G. U., Christman, K. A., Avery, D., Elliott-Engel, J., Morris, N. A., & Walsh, M. E. (2019, August). Arizona 4-H Summit: Campus, Career, and Community Engagement. Annual University of Arizona Cooperative Extension Conference. Tucson, AZ.

Other Teaching Materials

• Ortega, Y., DaSilva, A., Durigan, M., Murphy, H., Qvarnstrom, Y., Arrowood, M. J., Kahler, A., Mandrell, R., Brennan, J., Gurrisi, J., Osterholm, M., Cabrera, D., Torres, M., & Lopez, G. U. (2019. Cyclospora cayetanensis Fact Sheet. Blue Ribbon Panel.