Superiority of manual disinfection using pre-soaked wipes over automatic UV-C radiation without prior cleaning.

BACKGROUND: The efficacy of ultraviolet C (UV-C) radiation against a broad spectrum of micro-organisms has been demonstrated in several studies, but differences in the specific doses and the extent of microbial reduction were found. Furthermore, the conditions of laboratory tests differ greatly from reality, such that efficacy achieved in tests may not necessarily be assumed in reality. Consequently, it is important to investigate the effectiveness of UV-C in representative field trials. The aim was therefore to develop and establish a field test to evaluate automatic UV-C in comparison to manual disinfection. METHODS: Before and after disinfection, samples were repeatedly collected from naturally highly contaminated surfaces using the swab technique to obtain representative data sets for disinfected and non-disinfected surfaces. Subsequently, the log reduction values (LRV) and the disinfection success were evaluated for UV-C radiation and full compliant manual disinfection using alcohol-based wipes. RESULTS: Surfaces that are naturally contaminated with bacteria on a regular and nearly uniform basis have been identified as particularly suitable for field testing. Mean contamination was reduced from 23.3 to 1.98 cfu/cm2 (LRV 0.9) and 29.7 to 0.26 cfu/cm2 (LRV 1.2) for UV-C and manual disinfection, respectively. UV-C disinfection achieved 75.5% successful disinfected surfaces, whereas manual disinfection showed 98.1%. CONCLUSIONS: Full compliant manual disinfection showed slightly higher LRVs and disinfection success than automatic UV-C disinfection. Successful, operator-independent UV-C disinfection still has the potential to improve disinfection performance in addition to manual disinfection.

Tolerance of clinical vancomycin-resistant Enterococcus faecium isolates against UV-C light from a mobile source.

BACKGROUND: Admission to a room previously occupied by patients carrying environmentally robust pathogens implies an increased risk of acquiring those pathogens. Therefore, 'No-touch' automated room disinfection systems, including devices based on UV-C irradiation, are discussed to improve terminal cleaning. It is still unclear if clinical isolates of relevant pathogens behave differently under UV-C irradiation compared to laboratory strains used in the approval process of disinfection procedures. In this study we analysed the susceptibility of well characterized clonally divergent vancomycin-resistant enterococci (VRE) strains, including a linezolid-resistant isolate, against UV-C radiation. METHODS: Susceptibility against UV-C of ten clonally divergent clinical isolates of VRE was determined in comparison to the commonly used test organism Enterococcus hirae ATCC 10541. Ceramic tiles contaminated with 105 to 106 colony forming units/25 cm² of the different enterococci were positioned at a distance of 1.0 and 1.5 m and irradiated for 20 s, resulting in a UV-C dose of 50 and 22 mJ/cm², respectively. Reduction factors were calculated after quantitative culture of the bacteria recovered from treated and untreated surfaces. RESULTS: Susceptibility to UV-C varied considerably among the strains studied, with the mean value of the most robust strain being up to a power of ten lower compared to the most sensitive strain at both UV-C doses. The two most tolerant strains belonged to MLST sequence types ST80 and ST1283. The susceptibility of the laboratory strain E. hirae ATCC 10541 ranged between the most sensitive and most tolerant isolates for both irradiation doses. However, for UV-C dose of 22 mJ/cm², the reduction of the most tolerant isolate of ST1283 was statistically significantly lower compared to E. hirae ATCC 10541. The most susceptible strains belonged to the MLST sequence types ST117 and ST203. CONCLUSIONS: These results indicate that UV-C doses reported in the literature are sufficient for the reduction of commonly used reference strains of enterococci but could be insufficient for the reduction of tolerant patient VRE-isolates in a hospital setting. Therefore, for future studies, the most tolerant clinical isolates should be used to validate automated UV-C devices or longer exposure times should be expected to ensure efficacy in the real world.

Overview of tight fit and infection prevention benefits of respirators (filtering face pieces).

Regulations for measures to protect against SARS-CoV-2 transmission vary widely around the world, with very strict regulations in Germany where respirators (filtering face piece FFP2 or comparable) are often mandatory. The efficiency of respirators, however, depends essentially on the tight facial fit avoiding the bypass of contaminated air via gaps between mask and wearer's face. The facial fit can be verified in a fit test. The aim of this review was to describe the quantitative fit test results depending on the respirator designs. A literature search revealed 29 suitable studies. Of all respirators with circumferential head straps, three-panel folded dome-shaped respirators showed the best fit (80.8% of 4625 fit tests passed), followed by rigid-dome-shaped respirators (72.4% of 8234 fit tests passed), duckbill-shaped respirators (31.6% of 2120 fit tests passed), and coffee-filter-shaped respirators (30.9% of 3392 fit tests passed). Respirators with ear loops showed very poor tight fit (3.6% of 222 fit tests passed). In four randomized control trials, single-use respirators were not shown to be superior to surgical masks for the prevention of laboratory-confirmed viral respiratory infections, even when adjusted with a fit test. Therefore, we consider the mandatory use of respirators to be disproportionate and not supported by evidence. Further evidence should be generated, in which scenarios respirators might provide an effective benefit as part of occupational health and safety. For situations with confirmed benefits, only high-quality disposable respirators with head straps or respiratory protective equipment of higher protective levels should be used.

Interlaboratory reproducibility of a touch-transfer assay for the assessment of antimicrobial surfaces.

BACKGROUND: Various assay methods have been developed to study antimicrobial activity based on contamination of surfaces with different amounts of liquid bacterial suspensions. Since surfaces with frequent hand contact are typically touched in a dry state in clinical settings, these tests may be inappropriate at assessing effectiveness to reduce pathogen transmission. AIM: To investigate a surface previously confirmed to display antimicrobial activity even after drying of small volumes of bacterial suspension (Egger antimicrobial surfaces: EAS) under conditions modelling dry contamination using a touch-transfer method. METHODS: EAS, an antimicrobial copper alloy, as well as a negative control were examined to assess interlaboratory test reproducibility. FINDINGS: Significantly fewer bacteria on EAS after touch transfer and some differences in the touch transmission were detected between the two laboratories. However, an identical assessment of effectiveness for EAS came from both laboratories. Interestingly, despite previously detected antimicrobial efficacy of EAS and the antimicrobial copper alloy after liquid contamination, insufficient activity was observed under dry conditions during a contact time of 4 h by both laboratories. Experiments under standardized air humidity in one laboratory revealed at least for copper a strong influence of humidity on antimicrobial activity. These data indicate that procedures involving contamination of surfaces with organisms suspended in liquids are not directly comparable to dry contamination. CONCLUSION: Since, in the real world of a hospital, organisms are typically transferred between dry surfaces, further standardization of the touch-transfer method is worthwhile for a better understanding of the efficacy of such surfaces.

Characterizing materials for superconducting radiofrequency applications-A comprehensive overview of the quadrupole resonator design and measurement capabilities.

Test cavities to characterize superconductor samples are of great interest for the development of materials suitable for superconducting radio frequency (SRF) accelerator systems. They can be used to investigate fundamental SRF loss mechanisms and to study the material limitations for accelerator applications. Worldwide, this research is based on only few systems that differ in operating frequency, sample size and shape, and the accessible parameter space of frequency, temperature, and RF field strength. For useful performance predictions in future accelerators, it is important that the operating parameter range is close to that employed in accelerating systems. Since 2014, the Helmholtz-Zentrum Berlin has operated such a system built around a redesigned Quadrupole Resonator (QPR). It is based on a system originally developed at CERN. Important new design modifications were developed, along with new measurement techniques and insight into their limitations. In the meantime, an increasing number of laboratories are adopting the QPR for their measurement campaigns. This paper provides a comprehensive overview of the state-of-the-art, the wide spectrum of measurement capabilities, and a detailed analysis of measurement uncertainties, as well as the limitations one should be aware of to maximize the effectiveness of the system. In the process, we provide examples of measurements performed with Nb3Sn and bulk niobium.

An automated room disinfection system using ozone is highly active against surrogates for SARS-CoV-2.

BACKGROUND: The presence of coronaviruses on surfaces in the patient environment is a potential source of indirect transmission. Manual cleaning and disinfection measures do not always achieve sufficient removal of surface contamination. This increases the importance of automated solutions in the context of final disinfection of rooms in the hospital setting. Ozone is a highly effective disinfectant which, combined with high humidity, is an effective agent against respiratory viruses. Current devices allow continuous nebulization for high room humidity as well as ozone production without any consumables. AIM: In the following study, the effectiveness of a fully automatic room decontamination system based on ozone was tested against bacteriophage Φ6 (phi 6) and bovine coronavirus L9, as surrogate viruses for the pandemic coronavirus SARS-CoV-2. METHODS: For this purpose, various surfaces (ceramic tile, stainless steel surface and furniture board) were soiled with the surrogate viruses and placed at two different levels in a gas-tight test room. After using the automatic decontamination device according to the manufacturer's instructions, the surrogate viruses were recovered from the surfaces and examined by quantitative cultures. Then, reduction factors were calculated. FINDINGS: The ozone-based room decontamination device achieved virucidal efficacy (reduction factor >4 log10) against both surrogate organisms regardless of the different surfaces and positions confirming a high activity under the used conditions. CONCLUSION: Ozone is highly active against SARS-CoV-2 surrogate organisms. Further investigations are necessary for a safe application and efficacy in practice as well as integration into routine processes.

Practical recommendations for routine cleaning and disinfection procedures in healthcare institutions: a narrative review.

Healthcare-associated infections (HAIs) are the most common adverse outcomes due to delivery of medical care. HAIs increase morbidity and mortality, prolong hospital stay, and are associated with additional healthcare costs. Contaminated surfaces, particularly those that are touched frequently, act as reservoirs for pathogens and contribute towards pathogen transmission. Therefore, healthcare hygiene requires a comprehensive approach whereby different strategies may be implemented together, next to targeted, risk-based approaches, in order to reduce the risk of HAIs for patients. This approach includes hand hygiene in conjunction with environmental cleaning and disinfection of surfaces and clinical equipment. This review focuses on routine environmental cleaning and disinfection including areas with a moderate risk of contamination, such as general wards. As scientific evidence has not yet resulted in universally accepted guidelines nor led to universally accepted practical recommendations pertaining to surface cleaning and disinfection, this review provides expert guidance for healthcare workers in their daily practice. It also covers outbreak situations and suggests practical guidance for clinically relevant pathogens. Key elements of environmental cleaning and disinfection, including a fundamental clinical risk assessment, choice of appropriate disinfectants and cleaning equipment, definitions for standardized cleaning processes and the relevance of structured training, are reviewed in detail with a focus on practical topics and implementation.

Nanoscale transient gratings excited and probed by extreme ultraviolet femtosecond pulses.

Advances in developing ultrafast coherent sources operating at extreme ultraviolet (EUV) and x-ray wavelengths allow the extension of nonlinear optical techniques to shorter wavelengths. Here, we describe EUV transient grating spectroscopy, in which two crossed femtosecond EUV pulses produce spatially periodic nanoscale excitations in the sample and their dynamics is probed via diffraction of a third time-delayed EUV pulse. The use of radiation with wavelengths down to 13.3 nm allowed us to produce transient gratings with periods as short as 28 nm and observe thermal and coherent phonon dynamics in crystalline silicon and amorphous silicon nitride. This approach allows measurements of thermal transport on the ~10-nm scale, where the two samples show different heat transport regimes, and can be applied to study other phenomena showing nontrivial behaviors at the nanoscale, such as structural relaxations in complex liquids and ultrafast magnetic dynamics.

Combined culture and metagenomic analyses reveal significant shifts in the composition of the cutaneous microbiome in psoriasis.

BACKGROUND: The treatment of psoriasis has been revolutionized by the development of biologic therapies. However, the pathogenesis of psoriasis, in particular the role of the cutaneous microbiome, remains incompletely understood. Moreover, skin microbiome studies have relied heavily on 16S rRNA sequencing data in the absence of bacterial culture. OBJECTIVES: To characterize and compare the cutaneous microbiome in 20 healthy controls and 23 patients with psoriasis using metagenomic analyses and to determine changes in the microbiome during treatment. METHODS: Swabs from lesional and nonlesional skin from patients with psoriasis, and from controls matched for site and skin microenvironment, were analysed using both 16S rRNA sequencing and traditional culture combined with mass spectrometry (MALDI-TOF) in a prospective study. RESULTS: Psoriasis was associated with an increased abundance of Firmicutes and a corresponding reduction in Actinobacteria, most marked in lesional skin, and at least partially reversed during systemic treatment. Shifts in bacterial community composition in lesional sites were reflected in similar changes in culturable bacteria, although changes in the microbiota over repeated swabbing were detectable only with sequencing. The composition of the microbial communities varied by skin site and microenvironment. Prevotella and Staphylococcus were significantly associated with lesional skin, and Anaerococcus and Propionibacterium with nonlesional skin. There were no significant differences in the amount of bacteria cultured from the skin of healthy controls and patients with psoriasis. CONCLUSIONS: Shifts in the cutaneous microbiome in psoriasis, particularly during treatment, may shed new light on the pathogenesis of the disease and may be clinically exploited to predict treatment response. What's already known about this topic? Alterations in the composition of the cutaneous microbiome have been described in psoriasis, although methodological differences in study design prevent direct comparison of results. To date, most cutaneous microbiome studies have focused on 16S rRNA sequencing data, including both living and dead bacteria. What does this study add? This prospective observational study confirms that changes in the composition of the cutaneous microbiome, detected by 16S rRNA sequencing, are consistent with those identified by bacterial culture and mass spectrometry. The changes in the microbiome during antipsoriasis therapy should be further investigated to determine whether these represent potential novel biomarkers of treatment response. What is the translational message? Characterization of cutaneous microbiota may ultimately move into the clinic to help facilitate treatment selection, not only by optimizing currently available treatments, but also by identifying new therapeutic targets.

Magnetometric mapping of superconducting RF cavities.

A scalable mapping system for superconducting RF (SRF) cavities is presented. Currently, it combines local temperature measurement with 3D magnetic field mapping along the outer surface of the resonator. This allows for the observation of dynamic effects that have an impact on the superconducting properties of a cavity, such as the normal to superconducting phase transition or a quench. The system was developed for a single cell 1.3 GHz TESLA-type cavity, but can be easily adopted to arbitrary other cavity types. A data acquisition rate of 500 Hz for all channels simultaneously (i.e., 2 ms acquisition time for a complete map) and a magnetic field resolution of currently up to 14 mA/m/µ0 = 17 nT have been implemented. While temperature mapping is a well known technique in SRF research, the integration of magnetic field mapping opens the possibility of detailed studies of trapped magnetic flux and its impact on the surface resistance. It is shown that magnetic field sensors based on the anisotropic magnetoresistance effect can be used in the cryogenic environment with improved sensitivity compared to room temperature. Furthermore, examples of first successful combined temperature and magnetic-field maps are presented.

The role of the microbiome in psoriasis: moving from disease description to treatment selection?

BACKGROUND: With several million microbes per square centimetre of skin, the task of mapping the physiological cutaneous microbiome is enormous. Indeed, the reliance on bacterial culture to identify cutaneous bacterial communities has led to a systematic underappreciation of cutaneous microbial diversity, potentially limiting our understanding of common inflammatory skin diseases, including psoriasis. However, based heavily on developments in molecular biology and bioinformatics, including next-generation sequencing, the last decade has witnessed a marked increase in our understanding of the extent and composition of the cutaneous microbiome. It is already clear that skin-specific (skin site and skin microenvironment), individual-specific (hygiene, sex, age and hormonal status), disease-specific (atopic eczema, acne) and genetic factors can all influence the cutaneous microbiome, albeit to varying and, as yet, ill-defined extents. OBJECTIVES: To investigate the role of the microbiome in psoriasis and to outline how microbiome studies can be harnessed to provide new insights into disease pathogenesis and treatment selection. METHODS: This review briefly describes the process of 16S ribosomal RNA sequencing and then charts our current understanding of the cutaneous microbiome in health and the alterations (dysbiosis) associated with chronic inflammatory diseases, with particular reference to psoriasis. RESULTS: The possibility and clinical relevance of intraindividual cross-talk between the various microbiomes is discussed and potential mechanisms underpinning the interactions between resident skin flora and the immune system are highlighted. CONCLUSIONS: Ultimately, in the age of personalized medicine, the integration of cutaneous microbiome signatures and comprehensive disease and drug response endotypes will herald a novel approach in the clinical management of chronic multisystem inflammatory diseases.

The Molecular Mechanisms of Thalidomide Teratogenicity and Implications for Modern Medicine.

Thalidomide is a teratogen that affects many organs but primarily induces limb truncations like phocomelia. Rodents are thalidomide resistant. In the 1950s, this has led to misinterpretations of animal tests and to the fatal assumption that the drug was safe for pregnant women to use against morning sickness. The result was one of the biggest scandals in medical history: 10.000 and more infants with birth defects in Europe. Nonetheless, thalidomide still has its place in modern medicine as it has strong therapeutic potential: it has been approved by the FDA for multiple myeloma and erythema nodosum leprosum, and its anti-inflammatory, immunomodulatory and antiangiogenic activities are considered in many other refractory diseases. The aim is to develop derivatives that are not teratogenic but maintain the therapeutic potential. This requires detailed knowledge about the underlying molecular mechanisms. Much progress has been made in deciphering the teratogenic mechanisms in the last decade. Here, we summarize these mechanisms, explain thalidomide resistance of rodents, and discuss possible mechanisms that could explain why the drug primarily targets the developing limb in the embryo. We also summarize the most important therapeutic mechanisms. Finally, we discuss which therapeutic and teratogenic mechanisms do and do not overlap, and if there is a chance for the development of non-teratogenic thalidomide derivatives with therapeutic potential.

In vitro susceptibility to 19 agents other than ß-lactams among third-generation cephalosporin-resistant Enterobacteriaceae recovered on hospital admission.

Objectives: As part of the multicentre Antibiotic Therapy Optimisation Study, MIC values of 19 non-ß-lactam agents were determined for third-generation cephalosporin-resistant Escherichia coli , Klebsiella species and Enterobacter species (3GCREB) isolates collected in German hospitals. Methods: A total of 328 E. coli , 35 Klebsiella spp. (1 Klebsiella oxytoca and 34 Klebsiella pneumoniae ) and 16 Enterobacter spp. (1 Enterobacter aerogenes and 15 Enterobacter cloacae ) isolates were submitted to broth microdilution antimicrobial susceptibility testing with the MICRONAUT system. MICs of fluoroquinolones (levofloxacin and moxifloxacin), aminoglycosides (gentamicin, tobramycin, amikacin, streptomycin, neomycin and paromomycin), tetracyclines (tetracycline, minocycline and tigecycline), macrolides (erythromycin, clarithromycin and azithromycin) and miscellaneous agents [trimethoprim/sulfamethoxazole, chloramphenicol, nitrofurantoin, colistin and fosfomycin intravenous (iv)] were determined and reviewed against 2016 EUCAST breakpoints. Results: The MIC of levofloxacin was >2 mg/L for 128 of 328 E. coli and 8 of 35 Klebsiella spp., but only 1 of 16 Enterobacter spp. Rates of resistance to trimethoprim/sulfamethoxazole were high (>70%), except for Enterobacter spp. Rates of resistance to colistin and fosfomycin iv were still low. About 20% of the tested isolates were resistant to chloramphenicol. Only 1 (of 328) E. coli isolate had an MIC of amikacin >16 mg/L and only 33 of 328 E. coli and 1 of 35 Klebsiella spp. had an MIC of tobramycin >4 mg/L, whereas average gentamicin MICs were in general more elevated. A tigecycline MIC >2 mg/L was only found for 1 of 16 Enterobacter spp., but in none of the E. coli or Klebsiella spp. isolates. Conclusions: Our study gives insight into previously unreported non-ß-lactam MIC distributions of 3GCREB isolates.

Colonization with third-generation cephalosporin-resistant Enterobacteriaceae on hospital admission: prevalence and risk factors.

OBJECTIVES: The objectives of this study were to prospectively assess the rectal carriage rate of third-generation cephalosporin-resistant Enterobacteriaceae (3GCREB) in non-ICU patients on hospital admission and to investigate resistance mechanisms and risk factors for carriage. METHODS: Adult patients were screened for 3GCREB carriage at six German tertiary care hospitals in 2014 using rectal swabs or stool samples. 3GCREB isolates were characterized by phenotypic and molecular methods. Each patient answered a questionnaire about potential risk factors for colonization with MDR organisms (MDROs). Univariable and multivariable risk factor analyses were performed to identify factors associated with 3GCREB carriage. RESULTS: Of 4376 patients, 416 (9.5%) were 3GCREB carriers. Escherichia coli was the predominant species (79.1%). ESBLs of the CTX-M-1 group (67.3%) and the CTX-M-9 group (16.8%) were the most frequent ß-lactamases. Five patients (0.11%) were colonized with carbapenemase-producing Enterobacteriaceae. The following risk factors were significantly associated with 3GCREB colonization in the multivariable analysis (P < 0.05): centre; previous MDRO colonization (OR = 2.12); antibiotic use within the previous 6 months (OR = 2.09); travel outside Europe (OR = 2.24); stay in a long-term care facility (OR = 1.33); and treatment of gastroesophageal reflux disease (GERD) (OR = 1.22). CONCLUSIONS: To our knowledge, this is the largest admission prevalence study of 3GCREB in Europe. The observed prevalence of 9.5% 3GCREB carriage was higher than previously reported and differed significantly among centres. In addition to previously identified risk factors, the treatment of GERD proved to be an independent risk factor for 3GCREB colonization.

Dark current measurements on a superconducting cavity using a cryogenic current comparator.

This paper presents nondestructive dark current measurements of tera electron volt energy superconducting linear accelerator cavities. The measurements were carried out in an extremely noisy accelerator environment using a low temperature dc superconducting quantum interference device based cryogenic current comparator. The overall current sensitivity under these rough conditions was measured to be 0.2 nA/Hz(1/2), which enables the detection of dark currents of 5 nA.

Adapting TESLA technology for future cw light sources using HoBiCaT.

The HoBiCaT facility has been set up and operated at the Helmholtz-Zentrum-Berlin and BESSY since 2005. Its purpose is testing superconducting cavities in cw mode of operation and it was successfully demonstrated that TESLA pulsed technology can be used for cw mode of operation with only minor changes. Issues that were addressed comprise of elevated dynamic thermal losses in the cavity walls, necessary modifications in the cryogenics and the cavity processing, the optimum choice of operational parameters such as cavity temperature or bandwidth, the characterization of higher order modes in the cavity, and the usability of existing tuners and couplers for cw.

[Diagnosis of infections in pneumology]. / Infektionsdiagnostik in der Pneumologie.

Lower respiratory tract infections rank among the leading causes of morbidity and mortality worldwide. In clinical practice, especially in the care of severely ill patients, discrimination between tracheobronchial colonisation with potentially pathogenic microorganisms and infection is a common diagnostic challenge. While prompt antibiotic treatment is needed in critically ill patients with pneumonia, an inadequate use of antibiotics is the major cause for the emergence of drug-resistant microorganisms. The first part of this review provided a detailed overview of the currently available methods for the diagnosis of pulmonary infectious diseases. In the present second part of the manuscript, we focus upon methods and criteria for the differentiation between lower respiratory tract bacterial colonisation and lower respiratory tract infections, highlighting important pathogens.

[Diagnosis of infections in pneumology]. / Infektionsdiagnostik in der Pneumologie.

Lower respiratory tract infections play an important role in the ambulatory and hospital health-care sectors. State-of-the-art diagnoses of lower respiratory tract infections and methods to differentiate bacterial lower respiratory tract infections from colonisation have been described in the first two parts of this review series. The present article summarises current diagnostic methods and treatment indications for viral and fungal respiratory infections. These recommendations may guide clinicians in their decision to prescribe or withhold antibiotic therapies in daily clinical practice.

Abiotrophia defectiva endophthalmitis with retinal involvement and infiltrative keratitis: case report and review of the literature.

We report the exceptional case of a severe intraocular Abiotrophia defectiva infection which developed after cataract surgery. Retinal involvement as a complication of A. defectiva endophthalmitis or the combination of acute-onset endophthalmitis with infiltrative keratitis caused by this pathogen has not been described. Moreover, our report represents the first documented ocular A. defectiva infection in Germany. A. defectiva was identified using biotyping and 16S ribosomal RNA gene sequence analysis. Despite vigorous antimicrobial therapy and repeated ocular surgery, visual outcome was poor.