Analysis of bacterial contamination and the effectiveness of UV light-based reprocessing of everyday medical devices.

BACKGROUND: The reprocessing of daily used medical devices is often inadequate, making them a potential source of infection. In addition, there are usually no consistent and technically standardized procedures available for this purpose. Hence, the aim of this study is to analyze the bacterial contamination and the effectiveness of Ultraviolet light-based (UV light-based) reprocessing of daily used medical devices. MATERIAL AND METHODS: Six different everyday medical devices (20 each; stethoscopes, tourniquets, bandage scissors, reflex hammers, tuning forks, and nystagmus glasses) were tested for bacterial contamination. All medical devices were then exposed to UV-C light for 25 seconds. Medical devices with a smooth surface were pre-cleaned with a water-based wipe. Contact samples were taken before and after reprocessing. RESULTS: Immediately after clinical use, 104 of 120 contact samples showed an average bacterial contamination of 44.8±64.3 colony forming units (CFU) (0-300 CFU), also including potentially pathogenic bacteria. Two further culture media were completely overgrown with potentially pathogenic bacteria. The stethoscopes were found to have the highest average contamination of 90±91.6 CFU. After reprocessing, 118 of 120 samples were sterile, resulting in an average residual contamination of 0.02±0.1 CFU in two samples, whereby only bacteria of the ordinary skin flora were found. CONCLUSION: The present study shows the potentially clinically relevant bacterial contamination of everyday used medical devices. The reprocessing method tested here using UV light appears to be a suitable method for disinfection, especially for objects that up to now have been difficult to disinfect or cannot be disinfected in a standardized manner.

Influence of public health and infection control interventions during the severe acute respiratory syndrome coronavirus 2 pandemic on the in-hospital epidemiology of pathogens: in hospital versus community circulating pathogens.

BACKGROUND: The first detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Germany was reported in early February 2020. In addition, extensive control measures on the coronavirus disease 2019 (COVID-19) pandemic have been placed in Germany since March 2020. These include contact and travel restrictions, distance rules, mandatory wearing of face masks and respirators, cancellation of mass events, closures of day-care centers, schools, restaurants and shops, isolation measures, and intensified infection control measures in medical and long-term care facilities. Changes in demand or access to health care services and intensified control measures can lead to changes in transmission dynamics and imply effects on the overall occurrence of infectious diseases in hospitals. METHODS: To analyze the impact of infection control measures implemented in public on infectious diseases in hospitals, surveillance data from Marburg University Hospital were analyzed retrospectively. The analysis was conducted from January 2019 to June 2021, referred to hospital occupancy and mobility data in the county of Marburg-Biedenkopf, and correlated to control measures in hospitals and the general population. RESULTS: The COVID-19 pandemic and associated measures immediately impacted the occurrence of infectious diseases at the Marburg University Hospital. Significant changes were detected for virus-associated respiratory and gastrointestinal diseases. The massive drop in norovirus infections was significantly affected by the onset of the pandemic (P = 0.028). Similar effects were observed for rotavirus (up to - 89%), respiratory syncytial virus (up to - 98%), and adenovirus infections (up to - 90%). The decrease in gastrointestinal and respiratory virus detection rates was significantly affected by the decline in mobility (P < 0.05). Of note, since April 2020, there have been no detected influenza cases. Furthermore, Clostridioides difficile-related infections declined after late 2020 (- 44%). In contrast, no significant changes were detected in the prevalence of susceptible and drug-resistant bacterial pathogens. In particular, the detection rates of methicillin-resistant Staphylococcus aureus isolates or multidrug resistant (MDR) and extended drug resistant (XDR) bacteria remained constant, although the consumption of hand disinfectants and protective equipment increased. CONCLUSIONS: The COVID-19 pandemic and associated public health measures had a significant impact on infectious diseases and the detection of pathogens at the Marburg University Hospital. Significant changes were observed for community transmissible infections, while no such effects on pathogens primarily associated with nosocomial transmission could be detected.

UV-C Light-Based Surface Disinfection: Analysis of Its Virucidal Efficacy Using a Bacteriophage Model.

Background: The reprocessing of medical devices has become more complex due to increasing hygiene requirements. Previous studies showed satisfactory bactericidal disinfection effects of UV-C light in rigid and flexible endoscopes. Especially in the context of the current COVID-19 pandemic, virucidal properties are of high importance. In the present study, the virucidal efficacy of UV-C light surface disinfection was analyzed. Methods: MS-2 bacteriophages were applied to the test samples and irradiated by UV-C light using the UV Smart D25 device; unirradiated test samples were used as controls. A dilution series of the samples was mixed with 1 × 108 Escherichia coli and assayed. Results: 8.6 × 1012 pfu could be harvested from the unprocessed test samples. In the control group without UV-C exposure, a remaining contamination of 1.2 × 1012 pfu was detected, resulting in a procedural baseline reduction rate with a LOG10 reduction factor of 0.72. The LOG10 reduction factor was found to be 3.0 after 25 s of UV-C light exposure. After 50 and 75 s of UV-C radiation LOG10 reduction factors 4.2 and 5.9, respectively, were found, with all reductions being statistically significantly different to baseline. Conclusions: The tested UV system seems to provide a significant virucidal effect after a relatively short irradiation time.

Development of a web-based contact tracing and point-of-care-testing workflow for SARS-CoV-2 at a German University Hospital.

INTRODUCTION: In late 2019, a novel coronavirus was detected in China. Supported by its respiratory transmissibility, even by people infected without symptomatic disease, this coronavirus soon began to rapidly spread worldwide. BACKGROUND: Many countries have implemented different infection control and containment strategies due to ongoing community transmission. In this context, contact tracing as well as adequate testing and consequent quarantining of high-risk contacts play leading roles in containing the virus by interrupting infection chains. This approach is especially important in the hospital setting where contacts often cannot be avoided and physical distance is usually not possible. Furthermore, health care workers (HCWs) usually have contact with a variety of vulnerable people, making it essential to identify infections among hospital employees as soon as possible to interrupt the rapid spread of SARS-CoV-2 in the facility. Several electronic tools for contact tracing, such as specific software or mobile phone apps, are available for the public health sector. In contrast, contact tracing in hospitals often has to be carried out without helpful electronic tools, and an enormous amount of human resources is typically required. AIM: For rapid contact tracing and effective infection control and management measures for HCWs in hospitals, adapted technical solutions are needed. METHODS: In this study, we report the development of our containment strategy to a web-based contact tracing and rapid point-of-care-testing workflow. RESULTS/CONCLUSION: Our workflow yielded efficient control of the rapidly evolving situation during the SARS-CoV-2 pandemic from May 2020 until January 2021 at a German University Hospital.

UV light-based reprocessing of flexible endoscopes without working channel in Oto-Rhino-Laryngology: an effective method?

BACKGROUND: Reprocessing of flexible endoscopes (FEs) is often expensive, time consuming, and becomes increasingly complex, due to rising demands of hygiene. After beneficial results in reprocessing of rigid endoscopes using Impelux™ UV-C light technology, we tested the same method for reprocessing of FEs without working channel. MATERIALS AND METHODS: Testing was performed on FEs without working channel after routine clinical use (transnasal flexible endoscopy). Disinfection consisted of mechanical precleaning and 60 s exposure to Impelux™ UV-C light technology. Bacterial contamination was tested on 50 FEs before and after disinfection. Further 50 FEs regarding protein residuals. The absolute effectiveness of the D60 was tested on 50 test bodies (RAMS) with a standardized contamination of 107 colony-forming units (CFU) of Enterococcus faecium. RESULTS: The FEs were contaminated with a high average value of 916.7 CFU (± 1057 CFU) after clinical usage. After reprocessing, an average contamination of 2.8 CFU (± 1.6) on 14% (n = 7) of the FEs was detected consisting of non-pathogenic species, the remaining FE were sterile. After reprocessing, all FEs were protein-free (< 1 µg). The artificially contaminated test bodies showed no remaining bacterial contamination after disinfection, resulting in an average absolute germ reduction of about 107 CFU. CONCLUSION: Impelux™ UV-C light technology efficiently reduces bacterial contamination of FEs and might be useful in daily practice.

UV light-based decontamination: an effective and fast way for disinfection of endoscopes in otorhinolaryngology?

BACKGROUND: Reprocessing of endoscopes becomes increasingly complex, due to rising demands of hygiene. Established methods are often expensive/time-consuming. Recent studies suggest beneficial aspects of disinfection by UV light. In this study we analyzed the efficiency of UV light disinfection of rigid otorhinolaryngological endoscopes. MATERIALS AND METHODS: After mechanical pre-cleaning, the endoscopes were decontaminated for 25 s in the D25 using Impelux™ UV C light technology (UV Smart B.V., Delft, The Netherlands). First, the surface contact samples were taken from 50 used endoscopes to evaluate the bacterial load. Additionally, surface contact samples were taken from further 50 used endoscopes after reprocessing with the D25. Another 50 endoscopes were tested on protein residuals. Furthermore, the absolute effectiveness of the D25 was tested on 50 test bodies (RAMS) with a standardized contamination of 107 colony-forming units (CFU) of Enterococcus faecium. RESULTS: The used endoscopes showed a high bacterial contamination with an average value of 66.908 (± 239.215) CFU. After reprocessing, only a minimal contamination on 10% (n = 5) of the endoscopes with a mean value of 0.12 CFU (± 0.39) was found, resulting in a log-5 reduction in a clinical environment. The documented bacteria were components of the normal skin flora. All tested endoscopes were practically protein-free (< 1 µg). Furthermore, the average absolute germ reduction of the D25 was about 106 CFU on the tested RAMS. CONCLUSION: The D25 UV light system seems to be an effective device for the reprocessing of rigid ORL endoscopes, and therefore, might be suitable for the usage in clinical practice on site.