Organic Photo-antimicrobials: Principles, Molecule Design, and Applications.

The emergence of multi-drug-resistant pathogens threatens the healthcare systems world-wide. Recent advances in phototherapy (PT) approaches mediated by photo-antimicrobials (PAMs) provide new opportunities for the current serious antibiotic resistance. During the PT treatment, reactive oxygen species or heat produced by PAMs would react with the cell membrane, consequently leaking cytoplasm components and effectively eradicating different pathogens like bacteria, fungi, viruses, and even parasites. This Perspective will concentrate on the development of different organic photo-antimicrobials (OPAMs) and their application as practical therapeutic agents into therapy for local infections, wound dressings, and removal of biofilms from medical devices. We also discuss how to design highly efficient OPAMs by modifying the chemical structure or conjugating with a targeting component. Moreover, this Perspective provides a discussion of the general challenges and direction for OPAMs and what further needs to be done. It is hoped that through this overview, OPAMs can prosper and will be more widely used for microbial infections in the future, especially at a time when the global COVID-19 epidemic is getting more serious.

Environmental detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from medical equipment in long-term care facilities undergoing COVID-19 outbreaks.

Environmental sampling was conducted at long-term care facilities to determine the extent of surface contamination with severe acute respiratory syndrome coronavirus 2 virus. Medical equipment used throughout the facility was determined to be contaminated.

COVID-19: ensuring our medical equipment can meet the challenge.

To predict the spread of coronavirus disease globally and consequently prepare the hospital facilities with the required technology is a challenge. The availability of essential medical equipment to support patients affected by Covid-19 is globally limited. Areas covered This perspective gives a technical view of the pandemic focusing on the main actions taken by regulatory agencies to cope with the shortage of devices. The risk/benefit assessment and the main infection control policies in the clinical practices are also looked at. Expert opinion Regulatory agencies have amended their medical devices directives to address the pandemic, but each in a different way. In this exceptional situation scientist and technology experts in collaboration with medical specialists should work together to re-assess the risk analysis on medical equipment management and their use and re-use in this context with the aim to improve global health care Every effort must be made to provide the necessary devices at least with the minimum acceptable performances for Covid-19 patients while maintaining a high standard of safety for users. The aim of the present manuscript is to highlight the technical challenges in order to prevent, through targeted actions, operating standards from falling below the standards of care due to a lack of medical devices. Abbreviations AKI: acute Kidney Injury; ARGMD: Australian Regulatory Guidelines for Medical Devices; Covid-19: Coronavirus disease; FDA: Food and Drug Administration; ECMO: Extracorporeal Membrane Oxygenation; EU: European Union; ICU: Intensive Care Unit; WHO: World Health Organization; MHRA: Medicines and Healthcare products Regulatory Agency; MDR: Medical Device Regulation; SARI: Severe Acute Respiratory Infection.

The ability of two chlorine dioxide chemistries to inactivate human papillomavirus-contaminated endocavitary ultrasound probes and nasendoscopes.

Sexual transmission is the most common pathway for the spread of Human papillomavirus (HPV). However, the potential for iatrogenic HPV infections is also real. Even though cleared by the Food and Drug Administration and recommended by the World Federation for Ultrasound in Medicine and Biology, several disinfectants including glutaraldehyde and o-phthalaldehyde have shown a lack of efficacy for inactivating HPV. Other methods such as ultraviolet C and concentrated hydrogen peroxide have been shown highly effective at inactivating infectious HPV. In this study, two chlorine dioxide systems are also shown to be highly efficacious at inactivating HPV. An important difference in these present studies is that as opposed to testing in suspension or using a carrier, we dried the infectious virus directly onto endocavitary ultrasound probes and nasendoscopes, therefore, validating a more realistic system to demonstrate disinfectant efficacy.

A qualitative risk assessment of cleansing and disinfection requirements after an avian influenza outbreak in commercial poultry.

1. During an avian influenza (AI) outbreak in the United Kingdom, the joint aim of the poultry industry and the Government is to eliminate and prevent the spread of infection, through control measures based on the current European Union (EU) Council Directive (2005/94/EC). An essential part of these measures is the cleansing and disinfection (C&D) of infected premises.2. This risk assessment assessed the differences in re-infection in a repopulated flock if the EU Directive is interpreted to permit secondary C&D to be undertaken either with or without dismantling complex equipment. The assessment estimated the probability of virus survival on different types of equipment in a depopulated contaminated poultry house before and after preliminary and secondary C&D procedures. A risk matrix spreadsheet tool was used to carry out the assessment and concluded that, provided secondary C&D is carried out with due diligence (i.e. carried out to a defined code of practice as agreed by both industry and policymakers), the risk of re-infection from equipment is negligible, both with and without dismantling complex equipment in all farm types considered.3. By considering the equipment types individually, the assessment identified those areas of the house which may still contain viable virus post-preliminary C&D and on which attention should be focussed during secondary C&D. The generic risk pathway and matrix spreadsheet tool have the potential to be used for other pathogens and species, given appropriate data.

Hepatitis B outbreak in a nursing home associated with reusable lancet devices for blood glucose monitoring, Northern Germany 2010.

In September 2010, an outbreak of acute hepatitis B virus (HBV) infections in a nursing home was notified to public health authorities in Northern Germany. To identify the route of transmission and prevent further cases a retrospective cohort study was conducted. Blood samples of residents were tested for serologic markers of HBV infection and HBV subgenotypes and sequences were analyzed. Outbreak-related cases were defined as residents of the nursing home with detection of hepatitis B surface antigen (HBsAg) and the HBV DNA sequence of the outbreak strain in 2010. Information on possible risk factors as patient care, invasive diagnostic, and therapeutical procedures was collected using a standardized questionnaire. Risk ratios (RR) and 95% confidence intervals (CI) were estimated with exact Poisson regression and binomial regression. Sixty-four residents were included in the study, 5 of them were outbreak-related cases, 12 had a past HBV infection. The outbreak strain belonged to HBV genotype D2 (HBsAg subtype ayw3, Ala118) which is not prevalent in Germany but in Eastern Europe. All cases (median age 81) were female, had diabetes, blood glucose monitoring, and chiropody. In multivariable analysis only blood glucose monitoring was associated with HBV infection (RR = 22, 95%CI 3.0-∞). Blood glucose monitoring was reported to be done by nursing home staff with patient-based reusable lancet devices. In nursing home settings the use of single use lancets for blood glucose monitoring is recommended strongly to prevent transmission. National guidelines on the handling of point-of-care devices and reusable equipment in long-term care facilities should be developed.

Evaluation of an automated high-level disinfection technology for ultrasound transducers.

BACKGROUND: Ultrasound transducer reprocessing is required to prevent the transmission of infections between patients. In some regions, reprocessing practices are not sufficient to achieve high-level disinfection (HLD), which can result in contaminated probes. Furthermore, current manual HLD methods use toxic chemicals and are prone to operator error/variability. The development of automated, non-toxic HLD disinfection devices may reduce the risk of transmission and reduce safety risks for operators and patients. This study investigated the disinfection efficacy of a hydrogen peroxide-based, automated HLD device, the Trophon(®) EPR, against a range of international standards. METHODS: Disinfection efficacy was assessed in carrier and simulated use tests against 21 different species of bacteria, fungi and viruses. Carrier tests were performed by placing carriers throughout the disinfection chamber and measuring the log reduction in viable organisms following disinfection. These tests were performed according to Association of Analytical Communities International Official Methods and European and ASTM International Standards for bactericidal, fungicidal, mycobactericidal, sporicidal and virucidal disinfection. Simulated use tests involving the disinfection of six widely used ultrasound probe models were conducted according to ASTM-E1837-96 using Mycobacterium terrae as a test organism. RESULTS: The device satisfied criteria for HLD and sporicidal disinfection efficacy under all standards tested. CONCLUSIONS: Automated, hydrogen peroxide-based disinfection devices offer an alternative to manual ultrasound probe disinfection technologies. Such devices reduce the risks of operator error and can improve patient and operator safety by preventing exposure to toxic chemicals. The adoption of next-generation disinfection devices may help to decrease infection risk and improve patient safety.

Reducing infectivity of HIV upon exposure to surfaces coated with N,N-dodecyl, methyl-polyethylenimine.

The infectivity of high-titer, cell-free HIV in culture media and human milk is rapidly reduced upon exposure to polyethylene slides painted with the linear hydrophobic polycation N,N-dodecyl,methyl-polyethylenimine (DMPEI). Accompanying viral p24 protein and free viral RNA analysis of solutions exposed to DMPEI-coated surfaces suggests that virion attachment to the polycationic surface and its subsequent inactivation are the likely mechanism of this phenomenon.

Use of UV-C radiation to disinfect non-critical patient care items: a laboratory assessment of the Nanoclave Cabinet.

BACKGROUND: The near-patient environment is often heavily contaminated, yet the decontamination of near-patient surfaces and equipment is often poor. The Nanoclave Cabinet produces large amounts of ultraviolet-C (UV-C) radiation (53 W/m2) and is designed to rapidly disinfect individual items of clinical equipment. Controlled laboratory studies were conducted to assess its ability to eradicate a range of potential pathogens including Clostridium difficile spores and Adenovirus from different types of surface. METHODS: Each test surface was inoculated with known levels of vegetative bacteria (10(6) cfu/cm(2)), C. difficile spores (10(2)-10(6) cfu/cm(2)) or Adenovirus (10(9) viral genomes), placed in the Nanoclave Cabinet and exposed for up to 6 minutes to the UV-C light source. Survival of bacterial contaminants was determined via conventional cultivation techniques. Degradation of viral DNA was determined via PCR. Results were compared to the number of colonies or level of DNA recovered from non-exposed control surfaces. Experiments were repeated to incorporate organic soils and to compare the efficacy of the Nanoclave Cabinet to that of antimicrobial wipes. RESULTS: After exposing 8 common non-critical patient care items to two 30-second UV-C irradiation cycles, bacterial numbers on 40 of 51 target sites were consistently reduced to below detectable levels (≥ 4.7 log10 reduction). Bacterial load was reduced but still persisted on other sites. Objects that proved difficult to disinfect using the Nanoclave Cabinet (e.g. blood pressure cuff) were also difficult to disinfect using antimicrobial wipes. The efficacy of the Nanoclave Cabinet was not affected by the presence of organic soils. Clostridium difficile spores were more resistant to UV-C irradiation than vegetative bacteria. However, two 60-second irradiation cycles were sufficient to reduce the number of surface-associated spores from 10(3) cfu/cm(2) to below detectable levels. A 3 log10 reduction in detectable Adenovirus DNA was achieved within 3 minutes; after 6 minutes, viral DNA was undetectable. CONCLUSION: The results of this study suggest that the Nanoclave Cabinet can provide rapid and effective disinfection of some patient-related equipment. However, laboratory studies do not necessarily replicate 'in-use' conditions and further tests are required to assess the usability, acceptability and relative performance of the Nanoclave Cabinet when used in situ.

Disinfection: is it time to reconsider Spaulding?

The Spaulding classification, originally proposed in 1957, is a widely used system for matching the disinfection and sterilization of surfaces, particularly those of re-usable medical/surgical devices, with available processes. It presents a ranking, from simple disinfection through to sterilization, that should be considered in the reprocessing of devices, based on the risks associated with their use, ranging from 'critical' (presenting a high risk), through 'semi-critical' to 'non-critical' (presenting a low risk). The different levels of disinfection are based on demonstrating antimicrobial activity against established marker micro-organisms representing a range of pathogens. Although this classification system is probably as valid today as it was in 1957, the understanding of microbiology and micro-organisms has changed. This article discusses some examples of disinfection studies with viruses, bacteria, protozoa and prions that challenge the current definitions and expectations of high-, intermediate- and low-level disinfection. In many of these examples, the test micro-organisms demonstrate atypical tolerance or resistance profiles to disinfection processes. In addition to laboratory-based studies, there is now clinical evidence for at least some of these micro-organisms that biocide resistance can lead to infection outbreaks due to unexpected disinfection failure. These reports should encourage the reader to challenge current dogma, and reconsider the expectations of disinfection and sterilization practices.