Katharina Hönes

Technische Hochschule Ulm · Biotechnology

Nicht nur ultraviolette Strahlung wirkt antimikrobiell. Auch sichtbares violettes und blaues Licht kann Bakterien, Pilze und Viren reduzieren und aufgrund ihres Blauanteils gilt das auch für das Licht weißer LEDs. Diese Wirkung weißen LED-Lichts, die eher schwach ist, kann durch Kombination mit violettem Licht verstärkt werden, aber erfordert auch...

The spread of infections, as in the coronavirus pandemic, leads to the desire to perform disinfection measures even in the presence of humans. UVC radiation is known for its strong antimicrobial effect, but it is also harmful to humans. Visible light, on the other hand, does not affect humans and laboratory experiments have already demonstrated tha...

Bacteria belonging to the group of ESKAPE pathogens are responsible for the majority of nosocomial infections. Due to the increase of antibiotic resistance, alternative treatment strategies are of high clinical relevance. In this context visible light as disinfection technique represents an interesting option as microbial pathogens can be inactivat...

Objective Ultraviolet radiation is known for its antimicrobial properties but unfortunately, it could also harm humans. Currently, disinfection techniques against SARS-CoV-2 are being sought that can be applied on air and surfaces and which do not pose a relevant thread to humans. In this study, the bacteriophage phi6, which like SARS-CoV-2 is an e...

Artificial respiration is saving lives especially in the COVID-19 pandemic, but it also carries the risk to cause ventilator-associated pneumonia (VAP). VAP is one of the most common and severe nosocomial infections, often leading to death and adding a major economic burden to the healthcare system. To prevent a proliferation of microbial pathogens...

Beatmungsassoziierte Lungenentzündungen gehören zu den häufigsten Krankenhausinfektionen und verursachen nicht nur hohe Kosten für das Gesundheitssystem, sondern enden auch oft tödlich für den betroffenen Patienten. Mit neuen Endotrachealtuben, die von blauen oder violette LEDs beleuchtet werden, soll die Zahl dieser Fälle reduziert werden.

The antimicrobial impact of visible violet and blue light has been known for more than a century but hardly been applied for purposeful pathogen reduction or prevention. The disinfecting properties of wide-spread warm-white and cool-white light emitting diodes (LEDs) are investigated by irradiation of staphylococci with different LEDs and varying...

Interest in visible light irradiation as a microbial inactivation method has widely increased due to multiple possible applications. Resistance development is considered unlikely, because of the multi-target mechanism, based on the induction of reactive oxygen species by wavelength specific photosensitizers. However, the affected targets are still...

The globally observed rise in bacterial resistance against antibiotics has increased the need for alternatives to antibiotic treatments. The most prominent and important pathogen bacteria are the ESKAPE pathogens, which include among others Staphylococcus aureus, Klebsiella pneumoniae and Acinetobacter baumannii. These species cause ventilator-asso...

Due to the globally observed increase in antibiotic resistance of bacterial pathogens and the simultaneous decline in new antibiotic developments, the need for alternative inactivation approaches is growing. This is especially true for the treatment of infections with the problematic ESKAPE pathogens, which include Enterococcus faecium, Staphylococ...

To stop the coronavirus spread, new inactivation approaches are being sought that can also be applied in the presence of humans or even on humans. Here, we investigate the effect of visible violet light with a wavelength of 405 nm on the coronavirus surrogate phi6 in two aqueous solutions that are free of photosensitizers. A dose of 1300 J c/m2 of...

Microorganisms can be photoinactivated with 405 and 450 nm irradiation, due to endogenous photosensitizers, which absorb light of these wavelengths and generate reactive oxygen species that destroy the cells from within. The photosensitizers assumed to be responsible are porphyrins in the spectral region around 405 nm and flavins at about 450 nm. T...

Multiple use contact lenses have to be disinfected overnight to reduce the risk of infections. However, several studies demonstrated that not only microorganisms are affected by the disinfectants, but also ocular epithelial cells, which come into contact via residuals at reinsertion of the lens. Visible light has been demonstrated to achieve an ina...

Background: Ventilator-associated pneumonia (VAP) is one of the most common nosocomial infections in intensive care units, which not only leads to prolonged hospital stays and higher treatment costs but is also associated with high mortality. Objective: An approach to equip endotracheal tubes (ETT) with blue LEDs for photoinactivation of bacterial...

Coronavirus inactivation data belonging to "Selection of parameters for thermal coronavirus inactivation – a data-based recommendation"

Background: Healthcare workers and large parts of the population are currently using personal protective equipment, such as face masks, to avoid infections with the novel coronavirus SARS-CoV-2. This equipment must be sterilized as gently as possible before reuse. One possibility is thermal inactivation, but professional autoclaves with their high...

Background: To slow the increasing global spread of the SARS-CoV-2 virus, appropriate disinfection techniques are required. Ultraviolet radiation (UV) has a well-known antiviral effect, but measurements on the radiation dose necessary to inactivate SARS-CoV-2 have not been published so far. Methods: Coronavirus inactivation experiments with ultrav...

This study presents a device for efficient, low-cost and eye-friendly overnight disinfection of contact lenses by visible violet light as an alternative to disinfection with biocide-containing solutions. Bacterial solutions with one Pseudomonas and one Staphylococcus strain each were irradiated for up to 8 h in commercial transparent contact lens c...

Despite the high number of legionella infections, there are currently no convincing preventive measures. Photoinactivation with visible light is a promising new approach and the photoinactivation sensitivity properties of planktonic Legionella rubrilucens to 450, 470, and 620 nm irradiation were thus investigated and compared to existing 405 nm ina...

Inactivation properties of visible light are of increasing interest due to multiple possible fields of application concerning antibacterial treatment. For violet wavelengths, the generation of reactive oxygen species by porphyrins is accepted as underlying mechanism. However, there is still little knowledge about photosensitizers at blue wavelength...

Touch screen displays are potential pathogen reservoirs and involved in the spread of hospital acquired infections. They emit visible light that is known for a weak but proven antimicrobial photoinactivation effect, so the question is whether displays have the potential to disinfect themselves. To test the antimicrobial capacity of touch screen dis...

Photoinactivation of bacteria with visible light has been reported in numerous studies. Radiation around 405 nm is absorbed by endogenous porphyrins and generates reactive oxygen species that destroy bacteria from within. Blue light in the spectral range of 450–470 nm also exhibits an antibacterial effect, but it is weaker than 405 nm radiation, an...

Legionella infections caused by contaminated water are a widespread problem worldwide. Discharge lamps like mercury vapor lamps are widely known for the disinfection properties of their radiation, but they suffer technical disadvantages, like high voltages and toxic content, and are, therefore, not suitable for some infection control applications....

A list of the globally most important pathogens is generated based on the causes of death statistics published in the Global Burden Disease study 2015. Pathogens are assigned to the specified diseases as far as possible. Difficulties arises because the death provoking pathogens are often unidentified or arise in mixed infections with more than one...

In this study, the photoinactivation of Legionella by visible light is investigated. The success of this approach would offer new prospects for technical water disinfection and maybe even for therapeutic measures in cases of Legionella infections. Therefore, Legionella rubrilucens was dispensed on buffered charcoal yeast extract medium agar plates...

Background: Despite the great health significance of Legionella, there is only little information on their UV sensitivity. Besides Legionella pneumophila only L. longbeachae has been investigated so far. Methods: In this study L. rubrilucens has been spread on buffered charcoal yeast extract agar and irradiated with the 254 nm UV-C emission of a me...

Background: Despite the great health significance of Legionella, there is only little information on their UV sensitivity. Besides Legionella pneumophila only L. longbeachae has been investigated so far. Methods: In this study L. rubrilucens has been spread on buffered charcoal yeast extract agar and irradiated with the 254 nm UV-C emission of a me...

Während die desinfizierende Wirkung von UV-Licht heutzutage zum Allgemeinwissen gehört, ist die bereits vor über 100 Jahren entdeckte keimabtötende Wirkung sichtbaren Lichts kaum bekannt. Ein Grund dafür könnte sein, dass die benötigten Bestrahlungsdosen für sinnvolle Anwendungen im besonders effektiven violetten und blauen Spektralbereich mit konv...

Das Verfahren dient der Desinfektion bzw. der Sterilisation von medizinischen Hilfsmitteln durch elektromagnetische Strahlung, insbesondere von Sehhilfen wie Kontaktlinsen. Hierzu erfolgt eine Bestrahlung im Wellenlängenbereich zwischen 390 nm und 420 nm.

Visible light has strong disinfectant properties, a fact which is not well known in comparison to the antibacterial properties of UV light. This review compiles the published data on bacterial inactivation caused by visible light and endogenous photosensitizers. It evaluates more than 100 published studies containing information on about 40 differe...

Generally contact lenses are transferred overnight into a cleaning and disinfecting solution. The applied chemical disinfectant on the one hand has to be aggressive enough to kill all bacteria but on the other hand must not affect the eye itself when reinserting the lens. This difficult balancing act is not always successful. Appliance of violet LE...

In der Regel werden Kontaktlinsen über Nacht in eine Reinigungs- und Desinfektionslösung gelegt. Das dabei eingesetzte chemische Desinfektionsmittel soll auf der einen Seite so aggressiv sein, dass es möglichst alle Keime abtötet, aber auf der anderen Seite darf das Auge beim Wiedereinsetzen der Linse nicht angegriffen werden. Dieser schwierige Spa...

Konventionelle Kontaktlinsendesinfektionsverfahren nutzen Lösungen mit meist aggressiven chemischen Inhaltsstoffen, die nicht nur Mikroorganismen reduzieren, sondern auch schädigend auf die epitheliale Augenoberfläche wirken. Ziel dieser Untersuchungen war die Evaluierung eines alternativen oder ergänzenden Desinfektionsverfahrens. Suspensionen der...

A small water disinfection system based on the combination of a strong single 25 mW LED with a wavelength of 285 nm and a short quartz tube with an outer rectangular cross section is presented. For the disinfection tests clear tap water and slightly turbid and yellow pond water are contaminated with high concentrations of Escherichia coli bacteria....

Background: Conventional procedures for contact lens disinfection, based on solutions with aggressive chemical ingredients, not only affect microorganisms but operate likewise damaging towards the epithelial eye surface. Objective: The aim of this study was to evaluate the applicability of an alternative or complementary disinfection procedure f...

A new approach is investigated utilizing light guidance capabilities of optical pure quartz glass in order to maximize drinking water disinfection efficiency with UVC-light-emitting diodes (LEDs). Two experimental setups consisting of soda-lime AR ® glass (VWR, Darmstadt, Germany) or HSQ ® 100 quartz glass (Heraeus, Wasserburg, Germany) reactors we...

Visible optical radiation generates bactericidal effect applicable for inactivation of health care associated germs demonstrated by inactivation of E. coli and B. subtilis using 405 nm and 460 nm light emitting diodes ABSTRACT The Ulm University of Applied Sciences is investigating a technique using visible optical radiation (405 nm and 460 nm) to...

An advanced prototype of an UVC and ultrasound based water disinfection system is developed. The aim is to deliver 5 to 10 l/h germfree water at any day and night time. A first prototype was presented at the 2013 InterSolar conference [1]. Since then almost all parts of the system have been improved. Aiming at an island system especially for rural...

A battery operated, energy- and cost-effective power ultrasound unit is developed. It is used for purification of contaminated water in combination with an UVC-LED based disinfection system by utilizing acoustic cavitation. Thus biofilm formation is prevented and synergistic effects with UVC-rays enhance disinfection efficiency. The ultrasound unit...