Is a reduction in viability enough to determine biofilm susceptibility to a biocide?

Objective: The abundance and prevalence of dry-surface biofilms (DSBs) in hospitals constitute an emerging problem, yet studies rarely report the cleaning and disinfection efficacy against DSBs. Here, the combined impact of treatments on viability, transferability, and recovery of bacteria from DSBs has been investigated for the first time. Methods: Staphylococcus aureus DSBs were produced in alternating 48-hour wet–dry cycles for 12 days on AISI 430 stainless steel discs. The efficacy of 11 commercially available disinfectants, 4 detergents, and 2 contactless interventions were tested using a modified standardized product test. Reduction in viability, direct transferability, cross transmission (via glove intermediate), and DSB recovery after treatment were measured. Results: Of 11 disinfectants, 9 were effective in killing and removing bacteria from S. aureus DSBs with >4 log10 reduction. Only 2 disinfectants, sodium dichloroisocyanurate 1,000 ppm and peracetic acid 3,500 ppm, were able to lower both direct and cross transmission of bacteria (<2 compression contacts positive for bacterial growth). Of 11 disinfectants, 8 could not prevent DSB recovery for >2 days. Treatments not involving mechanical action (vaporized hydrogen peroxide and cold atmospheric plasma) were ineffective, producing <1 log10 reduction in viability, DSB regrowth within 1 day, and 100% transferability of DSB after treatment. Conclusions: Reduction in bacterial viability alone does not determine product performance against biofilm and might give a false sense of security to consumers, manufacturers and regulators. The ability to prevent bacterial transfer and biofilm recovery after treatment requires a better understanding of the effectiveness of biocidal products.

Is the hepatotoxicity of metamizole significant in clinical practice?

In December 2020 representatives of the responsible entities in consulation with European Medicines Agency and Office for Registration of Medicinal Products, Medical Devices and Biocidal Products published a safety communication on the possible occurrence of drug-induced liver injury (DILI) in the use of metamizolecontaining medicinal products. According to the message, metamizole should not be re-used in patients with a history of liver damage during treatment with metamizole, when no other cause that could lead to liver damage has been identified. Clinical practice, including spontaneous monitoring of side effects, shows that metamizole is still an effective and safe analgesic, which is included in the current recommendations for the treatment of acute, postoperative and cancer patients.

Investigation on Combined Inhalation Exposure Scenarios to Biocidal Mixtures: Biocidal and Household Chemical Products in South Korea

Global regulations of biocides have been continuously enhanced for protecting human health and the environment from potentially harmful biocidal products. Such regulations consider the combined toxicity caused by mixture components in a biocidal product of which approval and authorization are to be enhanced. Although the combined exposure scenarios of components in mixtures are firstly needed to conduct the mixture risk assessment, systematic combined exposure scenarios are still lacking. In this study, combined inhalation exposure scenarios of biocides in household chemical and biocidal products marketed in South Korea were investigated based on the European Union (EU) and Korean chemical product databases and various data sources integration. The information of 1058 biocidal products and 675 household chemical products that are likely to cause inhalation exposure with two or more biocides was collected, and mixture combination patterns were investigated. Binary mixtures occupied 72% in biocidal products. The most frequently appearing binary mixture was phthalthrin and d-phenothrin. Based on the frequency of use, we suggested a priority list of biocide mixture combinations which need to be firstly evaluated for identifying their combined toxicity for the mixture risk assessment. This study highlights that the derived combined inhalation exposure scenarios can support and facilitate further studies on priority settings for mixture risk assessment and management of potentially inhalable biocides.

Feasibility and safety of the new coronary noncompliant balloon catheter River NC®

Aim: In this preliminary study, we aimed to confirm the clinical utility and safety of the new noncompliant balloon catheter River NC (Balton, Poland). Materials & methods: The primary study endpoint was to verify balloon diameters calculated in quantitative coronary angiography (QCA) to diameters prespecified by the manufacturer and obtained at given pressures in subjects undergoing percutaneous coronary interventions. Results: Forty-two subjects were enrolled (73.8% multivessel disease; 40.5% type B1 lesions; 100% device success). No clinically significant differences between expected balloon diameters and QCA were registered in predilatation (2.36 ± 0.11 mm vs. 2.43 ± 0.07 mm) and postdilatation (3.18 ± 0.19 mm vs. 3.21 ± 0.31 mm). Conclusions: Our study results suggest that the River NC balloon is effective and safe. In the QCA evaluation, River NC balloon obtained prespecified diameters and lengths at applied pressures. Study registration: Office for Registration of Medicinal Products, Medical Devices and Biocidal Products (UR.D.WM.DNB.109.2019).

Novel Antibiofilm Non-Biocidal Strategies

Subaerial biofilm (SAB) formation on cultural heritage objects is often considered an undesirable process in which microorganisms and their by-products, e.g., enzymes and pigments, cause damage or alteration to a surface. Since biofilms are widespread phenomena, there has been a high demand for preventive and control strategies that resist their formation or reduce their negative effects once formed. Up to date, the main strategy to control biofilms has been the use of biocides. Because of their intrinsic properties, biocidal products can pose risks to humans, animals, and the environment. In this chapter, the authors call “green” only those alternative strategies to biocides able to prevent/control biofilms but that do not kill microorganisms, i.e., irrespective of the use of natural compounds. Here, we describe some of the methods that are most commonly used to test the effectiveness of antibiofilm compounds with multiple-species biofilm model systems. A unified terminology and well described protocols and guidelines are still required to compare and test the effectiveness of traditional or novel compounds against biofilms retrieved on heritage surfaces.

Higiena površin in pripomočkov za večkratno uporabo v domu starejših občanov

Biocidal products (disinfectants) are intensively used in nursing homes to control and prevent the spread of microorganisms and healthcare associated infections. We checked the hygiene of the surfaces intended for multiple use and the microbial population present on these surfaces. In three different areas, we noticed the working protocol and the biocidal products in use. The surfaces of the devices were sampled with swabbing before use, after use and after disinfection. Identification and quantification of microorganisms was performed using classical culture methods and MALDI-TOF method. The results showed that some devices were contaminated before use. Of particular concern is the fact that microorganisms remain on the devices even after disinfection in concentrations from 1 to 300 cfu/mL. In complex microbial communities on surfaces and with intensive use of disinfectants, the acquired bacterial resistance to disinfectants can develop, which can consequently lead to increased bacterial resistance to antibiotics.