Specialized cleaning associated with antimicrobial coatings for reduction of hospital-acquired infection: opinion of the COST Action Network AMiCI (CA15114).

Recognized issues with poor hand hygiene compliance among healthcare workers and reports of recontamination of previously chemically disinfected surfaces through hand contact emphasize the need for novel hygiene methods in addition to those currently available. One such approach involves antimicrobial (nano) coatings (AMCs), whereby integrated active ingredients are responsible for elimination of micro-organisms that come into contact with treated surfaces. While widely studied under laboratory conditions with promising results, studies under real-life healthcare conditions are scarce. The views of 75 contributors from 30 European countries were collated regarding specialized cleaning associated with AMCs for reduction of healthcare-associated infection. There was unanimous agreement that generation of scientific guidelines for cleaning of AMCs, using traditional or new processes, is needed. Specific topics included: understanding mechanisms of action of cleaning materials and their physical interactions with conventional coatings and AMCs; that assessments mimic the life cycle of coatings to determine the impact of repetitive cleaning and other aspects of ageing (e.g. exposure to sunlight); determining concentrations of AMC-derived biocides in effluents; and development of effective de-activation and sterilization treatments for cleaning effluents. Further, the consensus opinion was that, prior to widespread implementation of AMCs, there is a need for clarification of the varying responsibilities of involved clinical, healthcare management, cleaning services and environmental safety stakeholders.

Surface modifications for antimicrobial effects in the healthcare setting: a critical overview.

The spread of infections in healthcare environments is a persistent and growing problem in most countries, aggravated by the development of microbial resistance to antibiotics and disinfectants. In addition to indwelling medical devices (e.g. implants, catheters), such infections may also result from adhesion of microbes either to external solid-water interfaces such as shower caps, taps, drains, etc., or to external solid-gas interfaces such as door handles, clothes, curtains, computer keyboards, etc. The latter are the main focus of the present work, where an overview of antimicrobial coatings for such applications is presented. This review addresses well-established and novel methodologies, including chemical and physical functional modification of surfaces to reduce microbial contamination, as well as the potential risks associated with the implementation of such anticontamination measures. Different chemistry-based approaches are discussed, for instance anti-adhesive surfaces (e.g. superhydrophobic, zwitterions), contact-killing surfaces (e.g. polymer brushes, phages), and biocide-releasing surfaces (e.g. triggered release, quorum sensing-based systems). The review also assesses the impact of topographical modifications at distinct dimensions (micrometre and nanometre orders of magnitude) and the importance of applying safe-by-design criteria (e.g. toxicity, contribution for unwanted acquisition of antimicrobial resistance, long-term stability) when developing and implementing antimicrobial surfaces.

Bacterial community changes in copper and PEX drinking water pipeline biofilms under extra disinfection and magnetic water treatment.

AIMS: To study the stability of biofilms and water quality in pilot scale drinking water copper and PEX pipes in changing conditions (extra disinfection, magnetic water treatment, MWT). METHODS AND RESULTS: Next-generation sequencing (NGS) of 16S ribosomal RNA genes (rDNA) to describe total bacterial community and ribosomal RNA (rRNA) to describe active bacterial members in addition to traditional microbiological methods were applied. Biofilms from control copper and PEX pipes shared same most abundant bacteria (Methylobacterium spp., Sphingomonas spp., Zymomonas spp.) and average species diversities (Shannon 3·8-4·2) in rDNA and rRNA libraries, whereas few of the taxa differed by their abundance such as lower total Mycobacterium spp. occurrence in copper (<0·02%) to PEX (<0·2%) pipes. Extra disinfection (total chlorine increase from c. 0·5 to 1 mg l-1 ) affected total and active population in biofilms seen as decrease in many bacterial species and diversity (Shannon 2·7, P < 0·01, rRNA) and increase in Sphingomonas spp. as compared to control samples. Furthermore, extra-disinfected copper and PEX samples formed separate clusters in unweighted non-metric multidimensional scaling plot (rRNA) similarly to MWT-treated biofilms of copper (but not PEX) pipes that instead showed higher species diversity (Shannon 4·8, P < 0·05 interaction). CONCLUSIONS: Minor chlorine dose addition increased selection pressure and many species were sensitive to chlorination. Pipe material seemed to affect mycobacteria occurrence, and bacterial communities with MWT in copper but not in PEX pipes. SIGNIFICANCE AND IMPACT OF THE STUDY: This study using rRNA showed that chlorination affects especially active fraction of bacterial communities. Copper and PEX differed by the occurrence of some bacterial members despite similar community profiles.

Copper as an antibacterial material in different facilities.

The present study was performed in real life settings in different facilities (hospital, kindergarten, retirement home, office building) with copper and copper alloy touch surface products (floor drain lids, toilet flush buttons, door handles, light switches, closet touch surfaces, corridor hand rails, front door handles and toilet support rails) in parallel to reference products. Pure copper surfaces supported lower total bacterial counts (16 ± 45 vs 105 ± 430 CFU cm-2 , n = 214, P < 0·001) and a lower occurrence of Staphylococcus aureus (2·6 vs 14%, n = 157, P < 0·01) and Gram-negatives (21 vs 34%, n = 214, P < 0·05) respectively than did reference surfaces, whereas the occurrence of enterococci (15%, n = 214, P > 0·05) was similar. The studied products could be assigned to three categories according to their bacterial loads as follows (P < 0·001): floor drain lids (300 ± 730 CFU cm-2 , n = 32), small area touch surfaces (8·0 ± 7·1 to 62 ± 160 CFU cm-2 , n = 90) and large area touch surfaces (1·1 ± 1·1 to 1·7 ± 2·4 CFU cm-2 , n = 92). In conclusion, copper touch surface products can function as antibacterial materials to reduce the bacterial load, especially on frequently touched small surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: The efficiency of copper as an antimicrobial material has been noted in laboratory studies and in the hospital environment. The present study further shows that copper exerted an antibacterial effect in different facilities, i.e. in a hospital, a kindergarten, an office building and in a retirement home for the elderly. The study suggests that copper has potential use as an antibacterial material and therefore might serve as a means to lower the incidence of transmission of infectious agents from inanimate surfaces in different facilities, with everyday functions.

Diversity of ribosomal 16S DNA- and RNA-based bacterial community in an office building drinking water system.

AIMS: Next-generation sequencing of 16S ribosomal RNA genes (rDNA) and ribosomal RNA (rRNA) was used to characterize water and biofilm microbiome collected from a drinking water distribution system of an office building after its first year of operation. METHODS AND RESULTS: The total bacterial community (rDNA) and active bacterial members (rRNA) sequencing databases were generated by Illumina MiSeq PE250 platform. As estimated by Chao1 index, species richness in cold water system was lower (180-260) in biofilms (Sphingomonas spp., Methylobacterium spp., Limnohabitans spp., Rhizobiales order) than in waters (250-580), (also Methylotenera spp.) (P = 0·005, n = 20). Similarly species richness (Chao1) was slightly higher (210-580) in rDNA libraries compared to rRNA libraries (150-400; P = 0·054, n = 24). Active Mycobacterium spp. was found in cross-linked polyethylene (PEX), but not in corresponding copper pipeline biofilm. Nonpathogenic Legionella spp. was found in rDNA libraries but not in rRNA libraries. CONCLUSIONS: Microbial communities differed between water and biofilms, between cold and hot water systems, locations in the building and between water rRNA and rDNA libraries, as shown by clear clusters in principal component analysis (PcoA). By using the rRNA method, we found that not all bacterial community members were active (e.g. Legionella spp.), whereas other members showed increased activity in some locations; for example, Pseudomonas spp. in hot water circulations' biofilm and order Rhizobiales and Limnohabitans spp. in stagnated locations' water and biofilm. SIGNIFICANCE AND IMPACT OF THE STUDY: rRNA-based methods may be better than rDNA-based methods for evaluating human health implications as rRNA methods can be used to describe the active bacterial fraction. This study indicates that copper as a pipeline material might have an adverse impact on the occurrence of Mycobacterium spp. The activity of Legionella spp. maybe questionable when detected solely by using DNA-based methods.

Personal exposures to particles and microbes in relation to microenvironmental concentrations.

UNLABELLED: The aim of this study was to compare the personal exposures of particles and microbes with the exposure being assessed by stationary samplers in the main microenvironments, i.e. home and the workplace. A random sample of 81 elementary school teachers in eastern Finland were selected to perform the two wintertime 24-h measurement periods. Particle mass concentration, black smoke (BS) concentration and concentrations of viable and total microorganisms on the sampled filters were determined using personal exposure sampling and microenvironmental measurements in homes and workplaces. In this paper, the correlations between different pollutants in each environment and correlations between personal exposures and home and work concentrations are presented. The results show that personal BS exposures correlated with both home and work BS concentrations. Furthermore, the concentrations of viable fungi and bacteria were related between personal and home concentrations. The time weighted microenvironmental model underestimated the personal exposures of particle mass, viable fungi, total fungi and total bacteria concentrations but the model might satisfactorily assess personal exposure to concentrations of BS and viable bacteria. The mass concentration of total fungi and bacteria was <1% of the total particle mass concentration. PRACTICAL IMPLICATIONS: Stationary samples are only surrogate measures of personal exposures. Personal exposure measurements conducted on individuals' breathing zone are needed to assess the exposure to particles and microbes. The time weighted microenvironmental model is a useful method to assess personal exposure to combustion related particles and viable bacteria concentrations but the model underestimates personal exposures of particle mass, viable fungi, total fungi and total bacteria concentrations.

Differences in inflammatory responses and cytotoxicity in RAW264.7 macrophages induced by Streptomyces Anulatus grown on different building materials.

Streptomyces anulatus, an indicator microbe of mold in buildings, was grown on different building materials in order to study the impact of growth conditions on the ability of the spores of this microbe to induce toxicity and inflammatory responses. The microbes were grown for 2 months on sterilized and unsterilized wood, chipboard, concrete, plaster board and mineral wool in tight glass vessels under humid conditions. The highest microbial spore concentration was detected on the sterilized mineral wool followed by the sterilized plaster board and the unsterilized mineral wool. Mouse RAW264.7 macrophages were exposed in vitro for 24 h to the spores of S. anulatus and the production of the inflammatory mediators, nitric oxide (NO), tumor necrosis factor alpha (TNF alpha), interleukin-6 (IL-6), interleukin-10 (IL-10) and cytotoxicity, were measured. The dose equivalent to 5 x 10(5) spores/ml of medium was used to compare the different materials. The most intense production of NO (11.6 microM), TNF alpha (560 pg/ml) and IL-6 (2800 pg/ml) in macrophages was induced by the spores grown on sterilized plaster board. They also caused the greatest loss of cell viability (39%). The spores grown on sterilized concrete induced significant production of NO (1.5 microM) and decreased cell viability (22%), and the spores grown on unsterilized and sterilized mineral wool increased production of NO (4.1 microM and 0.8 microM, respectively). The spores did not stimulate production of the anti-inflammatory cytokine IL-10. These results indicate that the ability of S. anulatus to induce inflammatory responses and cytotoxicity in macrophages is dependent on the growth conditions provided by different building materials.

Induction of cytotoxicity and production of inflammatory mediators in raw264.7 macrophages by spores grown on six different plasterboards.

Dampness and microbial growth in buildings are associated with respiratory symptoms in the occupants, but details of the phenomenon are not sufficiently understood. The current study examined the effects of growth conditions provided by six plasterboards on cytotoxicity and inflammatory potential of the spores of Streptomyces californicus, Penicillium spinulosum, Aspergillus versicolor, and Stachybotrys chartarum. The microbes were isolated from mold problem buildings and thereafter grown on six different plasterboards. The spores were harvested, applied to RAW264.7 macrophages (10(4), 10(5), 10(6) spores/10(6) cells), and evaluated 24 h after exposure for the ability to cause cytotoxicity and to stimulate production of nitric oxide (NO), interleukin-1 beta (IL-1beta), tumor necrosis factor alpha (TNFalpha) and interleukin-6 (IL-6). The data indicate clear differences between spores of different microbes in their ability to induce the production of these inflammatory mediators and to cause cell death in macrophages. Also, for each microbe, the induction ability specifically depended on the brand of plasterboard. The spores of Streptomyces californicus collected from all plasterboards were the most potent at inducing NO and cytokine production. Cytotoxicity caused by P. spinulosum and Streptomyces californicus spores was consistent with NO, IL-1beta and IL-6 production induced by those microbes. However, the production of these inflammatory mediators by the spores of Stachybotrys chartarum was not parallel to their ability to cause cell death. The low productions of NO and cytokines were associated with high cytotoxicity caused by the spores of the A. versicolor. These data suggest that growth condition of microbes on different plasterboards affect the ability of microbial spores to induce inflammatory responses and cytotoxicity in macrophages.

An approach to management of critical indoor air problems in school buildings.

This study was conducted in a school center that had been the focus of intense public concern over 2 years because of suspected mold and health problems. Because several attempts to find solutions to the problem within the community were not satisfactory, outside specialists were needed for support in solving the problem. The study group consisted of experts in civil engineering, indoor mycology, and epidemiology. The studies were conducted in close cooperation with the city administration. Structures at risk were opened, moisture and temperature were measured, and the causes of damage were analyzed. Microbial samples were taken from the air, surfaces, and materials. Health questionnaires were sent to the schoolchildren and personnel. Information on the measurements and their results was released regularly to school employees, students and their parents, and to the media. Repairs were designed on the basis of this information. Moisture damage was caused mainly by difficult moisture conditions at the building site, poor ventilation, and water leaks. Fungal genera (concentrations <200 colony-forming units (cfu)/m(3), <3000 cfu/cm(2)) typical to buildings with mold problems (e.g., Aspergillus versicolor, Eurotium) were collected from the indoor air and surfaces of the school buildings. Where moisture-prone structures were identified and visible signs of damage or elevated moisture content were recorded, the numbers of microbes also were high; thus microbial results from material samples supported the conclusions made in the structural studies. Several irritative and recurrent symptoms were common among the upper secondary and high school students. The prevalence of asthma was high (13%) among the upper secondary school students. During the last 4 years, the incidence of asthma was 3-fold that of the previous 4-year period.

Carpal tunnel syndrome. Anatomical and clinical investigation.

The anatomy of the carpal tunnel was studied by postmortem dissection of both wrists in ten adults with normal wrists. Preoperative clinical and EMG examinations were performed on 28 wrists in 23 patients suffering from carpal tunnel syndrome. Anatomical and histological studies were made in connection with operation, and postoperatively the condition was followed clinically and by EMG. Numbness, tingling, and pain of the hands were markedly relieved during 2 months of follow-up, whereas clumsiness and weakness showed no significant change. preoperatively, EMG showed sensory abnormalities in 96% of cases and motoric abnormalities in 82%. The diagnostic accuracy of EMG was good, in particular as regards the sensory aspect. The return to normal of EMg was slow. Pathoanatomical examination showed a normal tendon sheath and transverse carpal ligament in 52%, while rheuma was found in the specimens of 12%, fibrosis of the tendon sheath in 36%, and fibrosis of the transverse carpal ligament in 32%. No correlation was observed between the shape of the osseous carpal tunnel and the degree of clinical symptoms.