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Chemical disinfection is an indispensable means of preventing infection. This holds true for healthcare settings, but also for all other settings where transmission of pathogens poses a potential health risk to humans and/or animals. Research on how to ensure effectiveness of disinfectants and the process of disinfection, as well as on when, how and where to implement disinfection precautions is an ongoing challenge requiring an interdisciplinary team effort. The valuable resources of active substances used for disinfection must be used wisely and their interaction with the target organisms and the environment should be evaluated and monitored closely, if we are to reliable reap the benefits of disinfection in future generations. In view of the global threat of communicable diseases and emerging and re-emerging pathogens and multidrug-resistant pathogens, the relevance of chemical disinfection is continually increasing. Although this consensus paper pinpoints crucial aspects for strategies of chemical disinfection in terms of the properties of disinfectant agents and disinfection practices in a particularly vulnerable group and setting, i.e., patients in healthcare settings, it takes a comprehensive, holistic approach to do justice to the complexity of the topic of disinfection.

In the past years infections caused by multidrug-resistant Gram-negative bacteria have dramatically increased in all parts of the world. This consensus paper is based on presentations, subsequent discussions and an appraisal of current literature by a panel of international experts invited by the Rudolf Schülke Stiftung, Hamburg. It deals with the epidemiology and the inherent properties of Gram-negative bacteria, elucidating the patterns of the spread of antibiotic resistance, highlighting reservoirs as well as transmission pathways and risk factors for infection, mortality, treatment and prevention options as well as the consequences of their prevalence in livestock. Following a global, One Health approach and based on the evaluation of the existing knowledge about these pathogens, this paper gives recommendations for prevention and infection control measures as well as proposals for various target groups to tackle the threats posed by Gram-negative bacteria and prevent the spread and emergence of new antibiotic resistances.

In developing hygiene strategies, in recent years, the major focus has been on the hands as the key route of infection transmission. However, there is a multitude of lesser-known and underestimated reservoirs for microorganisms which are the triggering sources and vehicles for outbreaks or sporadic cases of infection. Among those are water reservoirs such as sink drains, fixtures, decorative water fountains and waste-water treatment plants, frequently touched textile surfaces such as private curtains in hospitals and laundry, but also transvaginal ultrasound probes, parenteral drug products, and disinfectant wipe dispensers. The review of outbreak reports also reveals Gram-negative and multiple-drug resistant microorganisms to have become an increasingly frequent and severe threat in medical settings. In some instances, the causative organisms are particularly difficult to identify because they are concealed in biofilms or in a state referred to as viable but nonculturable, which eludes conventional culture media-based detection methods. There is an enormous preventative potential in these insights, which has not been fully tapped. New and emerging pathogens, novel pathogen detection methods, and hidden reservoirs of infection should hence be given special consideration when designing the layout of buildings and medical devices, but also when defining the core competencies for medical staff, establishing programmes for patient empowerment and education of the general public, and when implementing protocols for the prevention and control of infections in medical, community and domestic settings.

[english] Background: The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed “The Role of Surface Disinfection in Infection Prevention”. The most important findings and conclusions of this meeting are summarised in the present consensus paper.Aim: Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges.Methods and findings: After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects.Conclusions: Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection.

The antimicrobial efficacy of antiseptics used in wound management is tested in vitro under standardised conditions according to DIN EN 13727, with albumin and sheep erythrocytes used as organic challenge. However, these testing conditions do not adequately simulate the wound bed environment. Thus, the aim of this study was to compare the efficacy of different antiseptics such as octenidine dihydrochloride (OCT), chlorhexidine digluconate (CHX), polyhexamethylene biguanide (PHMB), and povidone‐iodine under challenge with human wound exudate instead of standardised organic load in an in vitro setting according to DIN EN 13727. Moreover, protein contents, pH, and temperature were compared with standardised testing conditions. The tested antiseptic agents were reduced to different extents based on their bactericidal efficacy, when challenged with human wound exudate compared with standardised conditions. Overall, 0.10% OCT showed the highest effects reaching full efficacy after 30 seconds. CHX and PHMB were the least efficient. Next to the protein content, other components of wound exudate, such as the microflora, seem to influence the efficacy of antiseptics. In summary, the optimisation of in vitro testing conditions in future applications, to more adequately simulate the wound bed environment, will allow a more realistic picture on the potential performance of antiseptics in clinical practice. [ABSTRACT FROM AUTHOR]

An assay is described that has allowed rapid determination of the dosage and contact times in the presence of organic soiling, as demanded by the EN 14564 standard, by using an optimized variant of the green fluorescent protein (Gfp). The [gfp.sub.m.sup.2+]-expressing Mycobacterium terrace is established as a new reporter strain for evaluating mycobactericidal activities of disinfectants with a superior sensitivity and in a shorter time.

Quantitative carrier tests were carried out with monodispersed cells of Mycobacterium terrae using ortho-phthaldialdehyde (OPA) and coco fatty aminoxethylate as biocides. In contrast to OPA, with coco fatty aminoxethylate the reductions obtained with freshly homogenized mycobacteria were significantly higher than those obtained with mycobacteria kept in the refrigerator for four days.

Preservatives are added to cosmetics to protect the consumers from infections and prevent product spoilage. The concentration of preservatives should be kept as low as possible and this can be achieved by adding potentiating agents. The aim of the study was to investigate the mechanisms behind potentiation of the bactericidal effect of a commonly used preservative, 2-phenoxyethanol (PE), by the potentiating agent ethylhexylglycerin (EHG). Sub-lethal concentrations of EHG (0.075%) and PE (0.675%) in combination led to rapid killing of E. coli (> 5 log reduction of cfu after 30 min), leakage of cellular constituents, disruption of the energy metabolism, morphological deformities of cells and condensation of DNA. Used alone, EHG disrupted the membrane integrity even at low concentrations. In conclusion, sub-lethal concentrations of EHG potentiate the effect of PE through damage of the cell membrane integrity. Thus, adding EHG to PE in a 1:9 ratio has a similar effect on membrane damage and bacterial viability as doubling the concentration of PE. This study provides insight about the mechanism of action of a strong potentiating agent, EHG, which is commonly used in cosmetics together with PE. [ABSTRACT FROM AUTHOR]

The first barrier for cationic molecules attacking gram-positive microorganisms is the cell wall and its amount of net negative charge. Modification of the cell wall by esterification of teichoic acids provides a very effective mechanism to resist such attacks up to a certain degree. Our data demonstrates that also for the cationic octenidine dihydrochloride association with the cell wall of gram-positive bacteria is dependent on the negative net charge of the cell wall. However, even though this provides some protection our data proves, that the penetration of the biocide through the peptidoglycan layers cannot be prevented at increasing concentrations as shown by LIVE/DEAD staining, thus resulting in a lethal damage of the bacterial cells. In addition it could be demonstrated, that interaction of octenidine dihydrochloride with the bacterial cell wall results in a significantly enhanced phagocytosis by neutrophils in human blood. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the influence of culturing Staphylococcus aureus and Pseudomonas aeruginosa under different growth conditions on their inactivation by the cationic active compounds benzalkonium chloride, chlorhexidine digluconate and octenidine dihydrochloride was investigated. Cells were grown in non-agitated tryptone soya broth as well as on tryptone soya agar according to national and international standards for evaluating chemical disinfectants. In quantitative suspension tests, cells of both test organisms grown on agar were significantly more sensitive to all three biocides than cells grown in broth. The differences in antimicrobial activity were greater in the case of S. aureus than in the case of P. aeruginosa. With S. aureus cultures, differences in the reduction factor of up to 5log steps were found, with P. aeruginosa up to 2.5log steps. The results of our uptake tests performed with S. aureus and octenidine dihydrochloride indicated that the growth conditions and the associated different stress factors either had an influence on the composition of the cell surface of this test organism or induced the formation of an efflux system. Cells of S. aureus cultured in broth took up only one-fifth of the amount of biocide molecules compared to cells from agar cultures. These data correlated with the results of the suspension tests. A low uptake of biocides apparently led to a reduced killing rate. In contrast to S. aureus, no significant differences in the uptake of octenidine dihydrochloride by cells of P. aeruginosa could be observed. These cells took up the same amount of the antimicrobial substance, whether on agar or in broth. In view of these results, possible consequences should be considered prior to changing test regulations. [Copyright &y& Elsevier]

Background: Human norovirus (NoV) causes more than 80% of nonbacterial gastroenteritis in Europe and the United States. NoV transmission via contaminated surfaces may be significant for the spread of viruses. Therefore, measures for prevention and control, such as surface disinfection, are necessary to interrupt the dissemination of human NoV. Murine norovirus (MNV) as a surrogate for human NoV was used to study the efficacy of active ingredients of chemical disinfectants for virus inactivation on inanimate surfaces.Methods: The inactivating properties of different chemical biocides were tested in a quantitative carrier test with stainless steel discs without mechanical action. Vacuum-dried MNV was exposed to different concentrations of alcohols, peracetic acid (PAA) or glutaraldehyde (GDA) for 5 minutes exposure time. Detection of residual virus was determined by endpoint-titration on RAW 264.7 cells.Results: PAA [1000 ppm], GDA [2500 ppm], ethanol [50% (v/v)] and 1-propanol [30% (v/v)] were able to inactivate MNV under clean conditions (0.03% BSA) on the carriers by > or = 4 log10 within 5 minutes exposure time, whereas 2-propanol showed a reduced effectiveness even at 60% (v/v). Furthermore, there were no significant differences in virus reduction whatever interfering substances were used. When testing with ethanol, 1- and 2-propanol, results under clean conditions were nearly the same as in the presence of dirty conditions (0.3% BSA plus 0.3% erythrocytes).Conclusion: Products based upon PAA, GDA, ethanol and 1-propanol should be used for NoV inactivation on inanimate surfaces. Our data provide valuable information for the development of strategies to control NoV transmission via surfaces. [ABSTRACT FROM AUTHOR]

Abstract Background Human norovirus (NoV) causes more than 80% of nonbacterial gastroenteritis in Europe and the United States. NoV transmission via contaminated surfaces may be significant for the spread of viruses. Therefore, measures for prevention and control, such as surface disinfection, are necessary to interrupt the dissemination of human NoV. Murine norovirus (MNV) as a surrogate for human NoV was used to study the efficacy of active ingredients of chemical disinfectants for virus inactivation on inanimate surfaces. Methods The inactivating properties of different chemical biocides were tested in a quantitative carrier test with stainless steel discs without mechanical action. Vacuum-dried MNV was exposed to different concentrations of alcohols, peracetic acid (PAA) or glutaraldehyde (GDA) for 5 minutes exposure time. Detection of residual virus was determined by endpoint-titration on RAW 264.7 cells. Results PAA [1000 ppm], GDA [2500 ppm], ethanol [50% (v/v)] and 1-propanol [30% (v/v)] were able to inactivate MNV under clean conditions (0.03% BSA) on the carriers by ≥ 4 log10 within 5 minutes exposure time, whereas 2-propanol showed a reduced effectiveness even at 60% (v/v). Furthermore, there were no significant differences in virus reduction whatever interfering substances were used. When testing with ethanol, 1- and 2-propanol, results under clean conditions were nearly the same as in the presence of dirty conditions (0.3% BSA plus 0.3% erythrocytes). Conclusion Products based upon PAA, GDA, ethanol and 1-propanol should be used for NoV inactivation on inanimate surfaces. Our data provide valuable information for the development of strategies to control NoV transmission via surfaces.