Luisa A Ikner

Interests

Research

Pathogen Reduction using Advanced Water Treatment Technologies, Direct Potable Reuse, Microbial Disinfection, Soil Health, Real-Time Microbial Sensors, Method Development for Pathogen Detection in Water

Teaching

Laboratory skills development for undergraduates with emphasis on basic and applied microbiological techniques; transmission of pathogens in the environment

Courses

Scholarly Contributions

Chapters

• Ikner, L. A., & Gerba, C. P. (2021). Antiviral Coatings as Continuously Active Disinfectants. In Disinfection of Viruses.

Journals/Publications

• Gerba, C. P., Ikner, L. A., Leija, B., Gundy, P., & Rutala, W. (2023). Transfer efficiency of an enveloped virus, human coronavirus 229E, from various hard surface fomites to finger pads of the hands. Infection Control & Hospital Epidemiology.
• Yasui, M., Ikner, L., Yonetani, T., Liu, M., & Katayama, H. (2023).

  Effects of surface hydrophobicity on the removal of F-specific RNA phages from reclaimed water by coagulation and ceramic membrane microfiltration

  . Water Science & Technology, 87(9), 2304-2314. doi:10.2166/wst.2023.133
• Gerba, C. P., Ikner, L., Bright, K., Ma, B., Ley, C., Seyedi, S., Sobsey, M. D., Piper, P., & Linden, K. G. (2022). UV Inactivation of Common Pathogens and Surrogates Under 222 nm Irradiation from KrCl* Excimer Lamps. Photochemistry and Photobiology. doi:10.1111/php.13724
• Ikner, L. A., Gerba, C. P., Castro, T. L., Umsza-Guez, M. A., Galvéz-Ruíz, J. C., & Silva-Beltrán, N. P. (2022). In vitro antiviral effect of Mexican and Brazilian propolis and phenolic compounds against human coronavirus 229E. International Journal of Environmental Health Research, 1-13. doi:10.1080/09603123.2022.2110576
• Ikner, L. A., Pepper, I. L., Stark, E. R., & Foster, A. R. (2022). Bench scale investigation of the effects of a magnetic water treatment device in pool systems on chlorine demand. Journal of Water Process Engineering.
• Ikner, L. A., Achilli, A., Hickenbottom, K., Hardikar, M., Felix, V., Presson, L., & Rabe, A. (2021). Membrane distillation provides a dual barrier for coronavirus and bacteriophage removal. Environmental Science & Technology Letters.
• Ikner, L. A., Gerba, C. P., Leija, B., Gundy, P., & Rutala, W. (2021). Transfer efficiency of an enveloped virus, human coronavirus 229E, from various hard surface fomites to finger pads of the hands. Infection Control & Hospital Epidemiology.
• Ikner, L. A., Gerba, C. P., Rutala, W., Donskey, C., & Weber, D. (2021). Continuously active disinfectant inactivates SARS-CoV-2 and human coronavirus 229E two days after the disinfectant was applied and following wear exposures. Infection Control & Hospital Epidemiology.
• Ikner, L. A., Gerba, C. P., Torrey, J., & Gundy, P. (2021). Efficacy of an antimicrobial surface coating against human coronavirus 229E and SARS-CoV-2. American Journal of Infection Control.
• Pearce-Walker, J., Troup, D., Ives, R., Ikner, L. A., Rose, J., Kennedy, M., & Verhougstraete, M. (2019). UVGI system impact on airborne indicators of common veterinary pathogens.. American Journal of Veterinarian Research.
  More info

  Pearce-Walker, J. D.J. Troup, R. Ives, L.A. Ikner, J.B. Rose, M.A. Kennedy, M.P. Verhougstraete (Accepted). UVGI system impact on airborne indicators of common veterinary pathogens. American Journal of Veterinarian Research.
• Verhougstraete, M. P., Troup, D. J., Rose, J. B., Pearce-walker, J. I., Kennedy, M. A., Ives, R., & Ikner, L. A. (2020). Investigation of the effects of an ultraviolet germicidal irradiation system on concentrations of aerosolized surrogates for common veterinary pathogens.. American journal of veterinary research, 81(6), 506-513. doi:10.2460/ajvr.81.6.506
  More info

  To determine whether exposure to UV germicidal irradiation (UVGI) reduces concentrations of viable aerosolized microorganisms (attenuated strains of common veterinary pathogens) in a simulated heating, ventilation, and air conditioning (HVAC) system..42 air samples seeded with bacteriophage MS2 or attenuated strains of Bordetella bronchiseptica, feline calicivirus, feline herpesvirus-1, canine parvovirus, or canine distemper virus (6/microorganism) or with no microorganisms added (6)..A simulated HVAC unit was built that included a nebulizer to aerosolize microorganisms suspended in phosphate-buffered water, a fan to produce airflow, 2 UVGI bulb systems, and an impinger for air sampling. Ten-minute trials (3 with UVGI, 3 without UVGI, and 1 negative control) were conducted for each microorganism. Impingers collected microorganisms into phosphate-buffered water for subsequent quantification with culture-based assays. Results for samples yielding no target microorganisms were recorded as the assay's lower limit of detection. Statistical analysis was not performed..The UVGI treatment resulted in subjectively lower concentrations of viable MS2, B bronchiseptica, and canine distemper virus (arithmetic mean ± SD log10 microorganism reduction, 2.57 ± 0.47, ≥ 3.45 ± 0.24, and ≥ 1.50 ± 0.25, respectively) collected from air. Feline herpesvirus-1 was detected in only 1 sample without and no samples with UVGI treatment. Feline calicivirus and canine parvovirus were not detectable in any collected samples..Results for some surrogates of veterinary pathogens suggested a potential benefit to supplementing manual disinfection practices with UVGI-based air cleaning systems in animal care environments. Further research is needed to investigate the utility of UVGI in operating HVAC systems.
• Adhikari, U., Chabrelie, A., Wang, M., Wang, Q., Young, K., Haas, C. N., Mitchell, J., Weir, M. H., Rose, J. B., Mckenzie, E. R., Ikner, L. A., & Boehnke, K. F. (2019). A Case Study Evaluating the Risk of Infection from Middle Eastern Respiratory Syndrome Coronavirus (MERS-CoV) in a Hospital Setting Through Bioaerosols.. Risk analysis : an official publication of the Society for Risk Analysis, 39(12), 2608-2624. doi:10.1111/risa.13389
  More info

  Middle Eastern respiratory syndrome, an emerging viral infection with a global case fatality rate of 35.5%, caused major outbreaks first in 2012 and 2015, though new cases are continuously reported around the world. Transmission is believed to mainly occur in healthcare settings through aerosolized particles. This study uses Quantitative Microbial Risk Assessment to develop a generalizable model that can assist with interpreting reported outbreak data or predict risk of infection with or without the recommended strategies. The exposure scenario includes a single index patient emitting virus-containing aerosols into the air by coughing, leading to short- and long-range airborne exposures for other patients in the same room, nurses, healthcare workers, and family visitors. Aerosol transport modeling was coupled with Monte Carlo simulation to evaluate the risk of MERS illness for the exposed population. Results from a typical scenario show the daily mean risk of infection to be the highest for the nurses and healthcare workers (8.49 × 10-4 and 7.91 × 10-4 , respectively), and the lowest for family visitors and patients staying in the same room (3.12 × 10-4 and 1.29 × 10-4 , respectively). Sensitivity analysis indicates that more than 90% of the uncertainty in the risk characterization is due to the viral concentration in saliva. Assessment of risk interventions showed that respiratory masks were found to have a greater effect in reducing the risks for all the groups evaluated (>90% risk reduction), while increasing the air exchange was effective for the other patients in the same room only (up to 58% risk reduction).
• Ikner, L. A., Pepper, I. L., Gerba, C. P., Abd-Elmaksoud, S., & Sassi, H. P. (2018). Comparative survival of viruses during thermophilic and mesophilic anaerobic digestion.. Science of The Total Environment.
• Bright, K. R., Ikner, L. A., & Soto-Beltran, M. (2013). Effectiveness of poliovirus concentration and recovery from treated wastewater by two electropositive filter methods. FOOD AND ENVIRONMENTAL VIROLOGY, 5(2), 91-6. doi:https://doi.org/10.1007/s12560-013-9104-6
  More info

  Enteric viruses are often present in low numbers in various water matrices. Virus sampling therefore involves multiple concentration steps to condense large samples down to small volumes for detection by cell culture or molecular assays. The NanoCeram® Virus Sampler has been demonstrated to be effective for the recovery of viruses from tap water, surface waters, and seawater. The goal of this study was to evaluate a new method using NanoCeram® filters for the recovery of poliovirus 1 (PV-1) from treated wastewater. Activated sludge effluent samples were spiked with PV-1 and concentrated in side-by-side tests by two methods: (1) NanoCeram® filtration, elution with sodium polyphosphate buffer, secondary concentration via centrifugal ultrafiltration; and (2) 1MDS filtration, elution with beef extract, secondary concentration via organic flocculation. The virus retention and elution efficiencies did not differ significantly between the two methods. In contrast, the secondary concentrate volume was smaller for the NanoCeram® method (8.4 vs. 30 mL) and the secondary concentration efficiencies were different between the two methods with 98 % for centrifugal ultrafiltration (NanoCeram® and 45 % for organic flocculation (1MDS). The overall method efficiencies were significantly different (P ≤ 0.05) with the NanoCeram® method yielding a 57 % and the 1MDS a 23 % virus recovery. In addition, there appeared to be less interference with viral detection via polymerase chain reaction with the NanoCeram® concentrates. This NanoCeram® method therefore is able to efficiently recover PV-1 from large volumes of wastewater and may serve as an inexpensive alternative to the standard 1MDS filter method for such applications.
• Bright, K. R., Gerba, C. P., & Ikner, L. A. (2012). Concentration and recovery of viruses from water: a comprehensive review. FOOD AND ENVIRONMENTAL VIROLOGY, 4(2), 41-67. doi:https://doi.org/10.1007/s12560-012-9080-2
  More info

  Enteric viruses are a cause of waterborne disease worldwide, and low numbers in drinking water can present a significant risk of infection. Because the numbers are often quite low, large volumes (100-1,000 L) of water are usually processed. The VIRADEL method using microporous filters is most commonly used today for this purpose. Negatively charged filters require the addition of multivalent salts and acidification of the water sample to effect virus adsorption, which can make large-volume sampling difficult. Positively charged filters require no preconditioning of samples, and are able to concentrate viruses from water over a greater pH range than electronegative filters. The most widely used electropositive filter is the Virosorb 1MDS; however, the Environmental Protection Agency has added the positively charged NanoCeram filters to their proposed Method 1615. Ultrafilters concentrate viruses based on size exclusion rather than electrokinetics, but are impractical for field sampling or processing of turbid water. Elution (recovery) of viruses from filters following concentration is performed with organic (e.g., beef extract) or inorganic solutions (e.g., sodium polyphosphates). Eluates are then reconcentrated to decrease the sample volume to enhance detection methods (e.g., cell culture infectivity assays and molecular detection techniques). While the majority of available filters have demonstrated high virus retention efficiencies, the methods to elute and reconcentrate viruses have met with varying degrees of success due to the biological variability of viruses present in water.
• Bright, K. R., Soto-Beltran, M., & Ikner, L. A. (2011). New method using a positively charged microporous filter and ultrafiltration for concentration of viruses from tap water. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 77(10), 3500-6. doi:https://doi.org/10.1128/AEM.02705-10
  More info

  The methods used to concentrate enteric viruses from water have remained largely unchanged for nearly 30 years, with the most common technique being the use of 1MDS Virozorb filters followed by organic flocculation for secondary concentration. Recently, a few studies have investigated alternatives; however, many of these methods are impractical for use in the field or share some of the limitations of this traditional method. In the present study, the NanoCeram virus sampler, an electropositive pleated microporous filter composed of microglass filaments coated with nanoalumina fibers, was evaluated. Test viruses were first concentrated by passage of 20 liters of seeded water through the filter (average filter retention efficiency was ≥ 99.8%), and then the viruses were recovered using various salt-based or proteinaceous eluting solutions. A 1.0% sodium polyphosphate solution with 0.05 M glycine was determined to be the most effective. The recovered viruses were then further concentrated using Centricon Plus-70 centrifugal ultrafilters to a final volume of 3.3 (±0.3 [standard deviation]) ml; this volume compares quite favorably to that of previously described methods, such as organic flocculation (~15 to 40 ml). The overall virus recovery efficiencies were 66% for poliovirus 1, 83% for echovirus 1, 77% for coxsackievirus B5, 14% for adenovirus 2, and 56% for MS2 coliphage. In addition, this method appears to be compatible with both cell culture and PCR assays. This new approach for the recovery of viruses from water is therefore a viable alternative to currently used methods when small volumes of final concentrate are an advantage.