A simulation model of microbe overlapping for the correct estimation of UV-C device log-reduction

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
G Cevenini ◽  
D Amodeo ◽  
N Nante ◽  
S Messina ◽  
G Messina
Keyword(s):  
Stainless Steel ◽  
Distribution Model ◽  
Log10 Reduction ◽  
Candida Auris ◽  
Surface Distribution ◽  
Healthcare Facilities ◽  
Log Reduction ◽  
Inactivation Rate Constant ◽  
Average Size ◽  
Uv C

Abstract Background Candida auris is an emerging pathogen responsible for several outbreaks within healthcare facilities. It can be found on hospital surfaces and patient care devices. UV- C sanitisation may constitute an effective adjunct to routine room cleaning to prevent the spreading of this yeast. Previous findings with this technology suggest to investigate different sources of variability in the study of the biocidal effect of UV devices on C. auris. In this study we develop a computer simulation of surface distribution of microorganisms on a stainless steel carrier, to optimize UV-device experiments. Methods Based on the literature about C. auris studies and its estimated average size (about 5 μm diameter), several Matlab simulations have been performed to include as many microorganisms as possible to be ideally placed on a 20 cm2 stainless steel support, avoiding cell overlapping. This was done in order to maximize the effectiveness of UV exposure. Results Two initial simulations were performed to evaluate a random arrangement of a very large number of microorganisms (8x107 CFU) on the steel support, widely overlapped. In this case, due to the poor UV-C penetrability, we would not exceed two log10 reduction. By randomly distributing 1x106 CFU, the probability of overlapping was about 1.3%, but even a partial overlap limits the log10 reduction. By randomly distributing 1x105 CFU, the overlaps were at least 10 times less likely. Conclusions The simulation results allowed us to evaluate the most appropriate microorganism distribution model able to optimize the biocidal effects of UV-C devices. The overlapping of microorganisms reduces UV-C penetrability. Our simulated study is consistent with literature results where we observed a lower log-reduction by increasing the concentration of microorganisms and therefore the probability of overlapping. The resulting model would simulate any log-reduction scenario, at any distance and any concentration, with and without overlapping. Key messages The complete or partial microorganism overlapping plays a relevant role in the outcome of UV-C biocidal experiments. To identify the exponential CFU reduction curve and estimate accurately the inactivation rate constant, simulated experiments should be performed to assess the real effectiveness of UV devices.

scholarly journals 1146. Effectiveness of Ultraviolet Irradiation on Candida auris: A Laboratory Study

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S345-S345
Author(s):  
Gennifer Garmon ◽  
Dhammika Navarathna ◽  
John Coppin ◽  
Marjory Williams ◽  
Chetan Jinadatha
Keyword(s):  
Stainless Steel ◽  
Prolonged Exposure ◽  
Uv Light ◽  
Multidrug Resistant ◽  
Published Data ◽  
Log10 Reduction ◽  
Healthcare Associated Infection ◽  
Candida Auris ◽  
Light Emitting Devices ◽  
Log Reduction

Abstract Background Candida auris is a multidrug-resistant yeast which persists on healthcare surfaces for prolonged periods of time and is an emerging pathogen in hospitals. It has been linked to healthcare-associated infection (HAI) through surface transmission. Mobile ultraviolet (UV) light emitting devices from mercury sources have been shown to be effective in reducing C. auris bioburden but require prolonged exposure. In this study, we demonstrate the efficacy of an UV emitting device used in our hospital for terminal disinfection on C. auris. Methods Two C. auris strains (AR-381-CAU-01 and CAU-02) isolates obtained from Centers for Disease Prevention and Control (CDC) were used along with a Candida albicans (C. albicans) strain. An organism load of 10 μL containing 106 colony forming unit (CFU) was spread on a 20-mm diameter stainless steel coupon and exposed to the UV source from a pulsed xenon device at 5 feet distance and 4 feet height for 5, 10, and 30 minutes. Killing efficacy in terms of log reduction was calculated in comparison to untreated control coupons. Results Mean CFU log10 reduction for C. albicans, CAU-01, and CAU-02 was 0.547, 1.051, and 0.952 at 5 minutes; 1.412, 1.975, and 1.879 at 10 minutes; and 2.639, 3.971, and 4.145 at 30 minutes, respectively. Figure 1 describes the mean log10 reduction as well as the minimum and maximum log reduction by isolates. Conclusion Our study demonstrates the UV from a pulsed xenon device is effective in reducing the C. auris on stainless steel coupons. Similar to previously published data on reduction of C. auris by other UV sources, extended exposure is required to achieve a higher log reduction of C. auris. We did not have any C. auris clinical infections to assess efficacy of UV on HAI reduction. Disclosures C. Jinadatha, Xenex Healthcare Service: Grant Investigator, Research grant.

scholarly journals Inactivation of Candida auris and Candida albicans by Ultraviolet-C

2020 ◽  
Vol 41 (S1) ◽  
pp. s292-s292
Author(s):  
William Rutala ◽  
Hajime Kanamori ◽  
Maria Gergen ◽  
Emily Sickbert-Bennett ◽  
David Jay Weber
Keyword(s):  
Infection Prevention ◽  
Antifungal Drugs ◽  
Candida Auris ◽  
Healthcare Facilities ◽  
Environmental Surfaces ◽  
Route Of Transmission ◽  
Indirect Exposure ◽  
Ultraviolet C ◽  
Severe Infections ◽  
Uv C

Background:Candida auris is an emerging fungal pathogen that is often resistant to major classes of antifungal drugs. It is considered a serious global health threat because it has caused severe infections with frequent mortality in over a dozen countries. C. auris can survive on healthcare environmental surfaces for at least 7 days, and it causes outbreaks in healthcare facilities. C. auris has an environmental route of transmission. Thus, infection prevention strategies, such as surface disinfection and room decontamination technologies (eg, ultraviolet [UV-C] light), will be essential to controlling transmission. Unfortunately, data are limited regarding the activity of UV-C to inactivate this pathogen. In this study, a UV-C device was evaluated for its antimicrobial activity against C. auris and C. albicans. Methods: We tested the antifungal activity of a single UV-C device using the vegetative bacteria cycle, which delivers a reflected dose of 12,000 µW/cm2. This testing was performed using Formica sheets (7.6 × 7.6 cm; 3 × 3 inches). The carriers were inoculated with C. auris or C. albicans and placed horizontal on the surface or vertical (ie, perpendicular) to the vertical UV-C lamp and at a distance from 1. 2 m (~4 ft) to 2.4 m (~8 ft). Results: Direct UV-C, with or without FCS (log10 reduction 4.57 and 4.45, respectively), exhibited a higher log10 reduction than indirect UV-C for C. auris (log10 reduction 2.41 and 1.96, respectively), which was statistically significant (Fig. 1 and Table 1). For C. albicans, although direct UV-C had a higher log10 reduction (log10 reduction with and without FCS, 5.26 and 5.07, respectively) compared to indirect exposure (log10 reduction with and without FCS, 3.96 and 3.56, respectively), this difference was not statistically significant. The vertical UV had statistically higher log10 reductions than horizontal UV against C. auris and C. albicans with FCS and without FCS. For example, for C. auris with FCS the log10 reduction for vertical surfaces was 4.92 (95% CI 3.79, 6.04) and for horizontal surfaces the log10 reduction was 2.87 (95% CI, 2.36–3.38). Conclusions:C. auris can be inactivated on environmental surfaces by UV-C as long as factors that affect inactivation are optimized (eg, exposure time). These data and other published UV-C data should be used in developing cycle parameters that prevent contaminated surfaces from being a source of acquisition by staff or patients of this globally emerging pathogen.Funding: NoneDisclosures: None

scholarly journals 1215. Ultraviolet-C (UV-C) Monitoring Made Ridiculously Simple: UV-C Dose Indicators for Convenient Measurement of UV-C Dosing

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S437-S437
Author(s):  
Jennifer Cadnum ◽  
Annette Jencson ◽  
Sarah Redmond ◽  
Thriveen Sankar Chittoor Mana ◽  
Curtis Donskey
Keyword(s):  
Methicillin Resistant Staphylococcus Aureus ◽  
Fetal Calf Serum ◽  
Color Change ◽  
Calf Serum ◽  
Organic Load ◽  
Healthcare Facilities ◽  
Log Reduction ◽  
Ultraviolet C ◽  
Effective Doses ◽  
Uv C

Abstract Background Ultraviolet-C (UV-C) light is increasingly used as an adjunct to standard cleaning in healthcare facilities. However, most facilities do not have a means to measure UV-C to determine whether effective doses are being delivered. We tested the efficacy of 2 easy-to-use colorimetric indicators for monitoring UV-C dosing in comparison to log reductions in pathogens. Methods In a laboratory setting, we exposed methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile spores on steel disk carriers with or without an organic load (5% fetal calf serum) to UV-C for varying times resulting in fluence exposures ranging from 10,000 to 100,000 µJ/cm2. The UV-C indicators were placed adjacent to the carriers. Log reductions were calculated in comparison to untreated controls and the change in color of the indicators was correlated with dose and log reductions. Results The UV-C doses required to achieve a 3-log reduction in MRSA and C. difficile were 10,000 and 46,000 µJ/cm2, respectively. For both indicators, there was a visible color change from baseline at 10,000 µJ/cm2 and a definite final color change by 46,000 µJ/cm2 (Figure 1). Organic load had only a modest impact on UV-C efficacy. The indicators required only a few seconds to place and were easy to read (Figure 2). Conclusion UV-C doses of 10,000 and 46,000 µJ/cm2 were required to achieve 3 log reductions of MRSA and C. difficile spores, respectively. The colorimetric indicators provide an easy means to monitor UV-C dosing. Disclosures All authors: No reported disclosures.

Relative Resistance of the Emerging Fungal Pathogen Candida auris and Other Candida Species to Killing by Ultraviolet Light

2017 ◽  
Vol 39 (1) ◽  
pp. 94-96 ◽  
Author(s):  
Jennifer L. Cadnum ◽  
Aaron A. Shaikh ◽  
Christina T. Piedrahita ◽  
Annette L. Jencson ◽  
Emily L. Larkin ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Candida Species ◽  
Fungal Pathogen ◽  
Laboratory Testing ◽  
Multidrug Resistant ◽  
Relative Resistance ◽  
Candida Auris ◽  
Healthcare Facilities ◽  
Ultraviolet C ◽  
Uv C

Mobile ultraviolet-C (UV-C) light room decontamination devices are frequently used as an adjunct to standard cleaning in healthcare facilities, but their efficacy in killing Candida species is not clear. In laboratory testing, the emerging multidrug-resistant Candida auris and 2 other Candida species were significantly less susceptible to killing by UV-C than methicillin-resistant Staphylococcus aureus.Infect Control Hosp Epidemiol 2018;39:94–96

scholarly journals Tuning a UV-C device to challenge new threats in the sanitization setting of healthcare facilities

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
D Amodeo ◽  
L Pallecchi ◽  
C Nagaia ◽  
G Spataro ◽  
R Cardaci ◽  
...  
Keyword(s):  
Light Exposure ◽  
Multidrug Resistant ◽  
Candida Auris ◽  
Healthcare Facilities ◽  
Hospital Environments ◽  
Cross Transmission ◽  
Different Strains ◽  
Healthcare Associated ◽  
Uv Technology ◽  
Uv C

Abstract Background Environmental hospital hygiene plays a role in healthcare-associated infections emergency caused by resistant multi-drug organisms. The implementation of new and effective disinfection procedures is now more than ever important to prevent the cross-transmission of pathogens in the hospital facilities. In combination with common chemicals biocides, UV technology is a realistic option for environmental disinfection. In this study, we evaluate a UV device for its effectiveness on an emerging pathogen. Methods A laboratory cross section experiment was performed between August and October 2019. Two different strains of Candida auris (CBS 10913 and CBS 12372) were tested on 20 cm2 stainless steel carriers inoculated with 10 µl of bacterial culture at a concentration of 1x105 CFU/mL. The inoculum was spread until dry in aseptic condition. Carriers were placed parallel to the UV device, having 4 UV-C lamps that emit 325 W, at a fixed distance of 2.44 m. Biocidal tests were carried out in triple at three different light exposure times (5, 10 and 20 minutes). After treatment, laboratories procedures were used to detach and transfer the remaining microorganisms from the carriers to plates and compared them to controls after incubation at 37 °C for 48 h. Results A significant inactivation of C. auris already occurred at 5 minutes, reaching 3-4 log10 reduction at 20 minutes of UV-C exposure. No substantial differences were identified by analyzing the results between the two strains. Conclusions The chosen distance of 2.44 m from the target allows to ideally sanitize an entire hospital room. However, to avoid the limit of shaded areas due to the presence of non-movable objects, a couple of positions are recommended, so that shorter distances can reduce the exposure time or increase the average irradiance level of exposed surfaces. Key messages In sanitation of hospital environments, the use of viable alternatives as UV-C can contribute to the reduction of infections caused by multidrug-resistant microorganisms. Accurate testing of different space-time irradiation configurations allows to achieve important results related to the biocidal effects of UV devices.

Identification by Electron Microdiffraction of Intermetallic Phases in a Duplex Stainless Steel

1990 ◽  
Vol 48 (2) ◽  
pp. 494-495
Author(s):  
A. Redjaïmia ◽  
J.P. Morniroli ◽  
G. Metauer ◽  
M. Gantois
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Convergent Beam Electron Diffraction ◽  
Intermetallic Phases ◽  
Small Particles ◽  
Parallel Beam ◽  
Diffraction Patterns ◽  
Average Size ◽  
Convergent Beam ◽  
Electron Microdiffraction

2D and especially 3D symmetry information required to determine the crystal structure of four intermetallic phases present as small particles (average size in the range 100-500nm) in a Fe.22Cr.5Ni.3Mo.0.03C duplex stainless steel is not present in most Convergent Beam Electron Diffraction (CBED) patterns. Nevertheless it is possible to deduce many crystal features and to identify unambiguously these four phases by means of microdiffraction patterns obtained with a nearly parallel beam focused on a very small area (50-100nm).From examinations of the whole pattern reduced (RS) and full (FS) symmetries the 7 crystal systems and the 11 Laue classes are distinguished without ambiguity (1). By considering the shifts and the periodicity differences between the ZOLZ and FOLZ reflection nets on specific Zone Axis Patterns (ZAP) which depend on the crystal system, the centering type of the cell and the glide planes are simultaneously identified (2). This identification is easily done by comparisons with the corresponding simulated diffraction patterns.

scholarly journals Preparedness and response to an emerging health threat—Lessons learned from Candida auris outbreaks in the United States

2021 ◽  
pp. 1-6
Author(s):  
Diane Meyer ◽  
Elena K. Martin ◽  
Syra Madad ◽  
Priya Dhagat ◽  
Jennifer B. Nuzzo
Keyword(s):  
United States ◽  
New York ◽  
Qualitative Interviews ◽  
The United States ◽  
Lessons Learned ◽  
Infection Prevention And Control ◽  
Healthcare Organizations ◽  
Candida Auris ◽  
Term Care ◽  
Healthcare Facilities

Abstract Objective: Candida auris infections continue to occur across the United States and abroad, and healthcare facilities that care for vulnerable populations must improve their readiness to respond to this emerging organism. We aimed to identify and better understand challenges faced and lessons learned by those healthcare facilities who have experienced C. auris cases and outbreaks to better prepare those who have yet to experience or respond to this pathogen. Design: Semi-structured qualitative interviews. Setting: Health departments, long-term care facilities, acute-care hospitals, and healthcare organizations in New York, Illinois, and California. Participants: Infectious disease physicians and nurses, clinical and environmental services, hospital leadership, hospital epidemiology, infection preventionists, emergency management, and laboratory scientists who had experiences either preparing for or responding to C. auris cases or outbreaks. Methods: In total, 25 interviews were conducted with 84 participants. Interviews were coded using NVivo qualitative coding software by 2 separate researchers. Emergent themes were then iteratively discussed among the research team. Results: Key themes included surveillance and laboratory capacity, inter- and intrafacility communication, infection prevention and control, environmental cleaning and disinfection, clinical management of cases, and media concerns and stigma. Conclusions: Many of the operational challenges noted in this research are not unique to C. auris, and the ways in which we address future outbreaks should be informed by previous experiences and lessons learned, including the recent outbreaks of C. auris in the United States.

scholarly journals Public Health Oversight of Interfacility Transfers During a Candida auris Outbreak—Orange County, California, 2019

2020 ◽  
Vol 41 (S1) ◽  
pp. s76-s77
Author(s):  
Kathleen O'Donnell ◽  
Ellora Karmarkar ◽  
Brendan R Jackson ◽  
Erin Epson ◽  
Matthew Zahn
Keyword(s):  
Public Health ◽  
Acute Care ◽  
Orange County ◽  
Acute Care Hospitals ◽  
Nursing Facilities ◽  
Candida Auris ◽  
Retrospective Case ◽  
California Department ◽  
Healthcare Facilities ◽  
Contact Precautions

Background: In February 2019, the Orange County Health Care Agency (OCHCA) identified an outbreak of Candida auris, an emerging fungus that spreads rapidly in healthcare facilities. Patients in long-term acute-care hospitals (LTACHs) and skilled nursing facilities that provide ventilator care (vSNFs) are at highest risk for C. auris colonization. With assistance from the California Department of Public Health and the Centers for Disease Control and Prevention, OCHCA instituted enhanced surveillance, communication, and screening processes for patients colonized with or exposed to C. auris. Method: OCHCA implemented enhanced surveillance by conducting point-prevalence surveys (PPSs) at all 3 LTACHs and all 14 vSNFs in the county. Colonized patients were identified through axilla/groin skin swabbing with C. auris detected by PCR and/or culture. In facilities where >1 C. auris colonized patient was found, PPSs were repeated every 2 weeks to identify ongoing transmission. Retrospective case finding was instituted at 2 LTACHs with a high burden of colonized patients; OCHCA contacted patients discharged after January 1, 2019, and offered C. auris screening. OCHCA tracked the admission or discharge of all colonized patients, and facilities with ongoing transmission were required to report transfers of any patient, regardless of colonization status. OCHCA tracked all patients discharged from facilities with ongoing transmission to ensure that accepting facilities conducted admission surveillance testing of exposed patients and implemented appropriate environmental and contact precautions. Result: From February–October 2019, 192 colonized patients were identified. All 3 LTACHs and 6 of 14 VSNFs had at least 1 C. auris–colonized patient identified on initial PPS, and 2 facilities had ongoing transmission identified on serial PPS. OCHCA followed 96 colonized patients transferred a total of 230 times (an average of 2.4 transfers per patient) (Fig. 1) and 677 exposed patients discharged from facilities with ongoing transmission (Fig. 2). Admission screening of 252 exposed patients on transfer identified 13 (5.2%) C. auris–colonized patients. As of November 1, 2019, these 13 patients were admitted 21 times to a total of 6 acute-care hospitals, 2 LTACHs, and 3 vSNFs. Transferring facilities did not consistently communicate the colonized patient’s status and the requirements for isolation and testing of exposed patients. Conclusion: OCHCA oversight of interfacility transfer, though labor-intensive, improved identification of patients colonized with C. auris and implementation of appropriate environmental and contact precautions, reducing the risk of transmission in receiving healthcare facilities.Funding: NoneDisclosures: None

scholarly journals 1579. Multidrug-Resistant Candida auris Isolates From New York Hospitals and Healthcare Facilities Are Susceptible to Antifungal Combinations

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S576-S577
Author(s):  
Brittany O’Brien ◽  
Sudha Chaturvedi ◽  
Vishnu Chaturvedi
Keyword(s):  
New York ◽  
Diagnostic System ◽  
Multidrug Resistant ◽  
Drug Combinations ◽  
Antifungal Drugs ◽  
Drug Resistant ◽  
Candida Auris ◽  
Current Case ◽  
Healthcare Facilities ◽  
Broth Microdilution Method

Abstract Background Candida auris outbreak continues unabated in New York with the current case counts exceeding 300 patients. We used a modification of standard CLSI broth microdilution method (BMD) if two-drug combinations are efficacious against C. auris isolates with high-resistance to fluconazole (FZ, MIC50 >256 mg/L), and variable resistance to other broad-spectrum antifungal drugs. Methods BMD plates were custom-designed and quality controlled by TREK Diagnostic System. The combination tests of 15 drug-resistant C. auris involved microtiter wells with the initial 144 two-drug combinations and their two-fold dilutions (1/2–1/32) to get 864 two-drug combinations finally. We utilized MIC100 endpoints for the drug combination readings as reported earlier for the intra- and inter-laboratory agreements obtained against Candida species and Aspergillus fumigatus (Antimicrob Agents Chemother. 2015. 59:1759–1766). We also tested minimum fungicidal concentrations (MFC). Results We tested all possible 864 two-drug antifungal combinations for nine antifungal drugs in use to yield 12,960 MIC100 readings, and MFC readings for 15 C. auris isolates. Flucytosine (FLC) at 2.0 mg/L potentiated most successful combinations with other drugs. Micafungin (MFG), Anidulafungin (AFG), Caspofungin (CAS) at individual concentrations of 0.25 mg/L combined well with FLC (2.0 mg/L) to yield MIC100 for 14, 13, and 12 of 15 C. auris isolates tested, respectively. MFG/FLC combination was also fungicidal for 4 of 15 isolates. AMB / FLC (0.25/1.0 mg/L) yielded MIC100 for 13 isolates and MFC for three test isolates. Posaconazole (POS), and Isavuconazole (ISA) and Voriconazole (VRC) also combined well with FLC (0.25/2.0 mg/L) to yield MIC100 for 12, 13, and 13 isolates, respectively. POS/FLC combination was fungicidal for three isolates. Conclusion We identified seven two drug-combinations of antifungals efficacious against drug-resistant C. auris strains. The modified BMD combination susceptibility testing could be used by the clinical laboratories to assist providers with the selection of optimal treatment for C. auris candidemia. Disclosures All authors: No reported disclosures.

Tools for detecting a “superbug”: updates on Candida auris testing

2022 ◽  
Author(s):  
Shawn R. Lockhart ◽  
Meghan M. Lyman ◽  
D. Joseph Sexton
Keyword(s):  
Dna Sequencing ◽  
Clinical Microbiology ◽  
Yeast Species ◽  
Antifungal Resistance ◽  
Candida Auris ◽  
Healthcare Facilities ◽  
Maldi Tof ◽  
Rapid Transmission ◽  
Skin Colonization

Candida auris is an emerging yeast species that has the unique characteristics of patient skin colonization and rapid transmission within healthcare facilities and the ability to rapidly develop antifungal resistance. When C. auris first started appearing in clinical microbiology laboratories, it could only be identified using DNA sequencing. In the decade since its first identification outside of Japan there have been many improvements in the detection of C. auris . These include the expansion of MALDI-TOF databases to include C. auris , the development of both laboratory-developed tests and commercially available kits for its detection, and special CHROMagar for identification from laboratory specimens. Here we discuss the current tools and resources that are available for C. auris identification and detection.

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