Interventions for preventing hospital-acquired legionnaires' disease

Background Legionnaires’ Disease (LD) has been recognized as a significant source of morbidity and mortality in many hospitals worldwide. Legionella in the hospital water distribution system has been epidemiologically linked to hospital-acquired LD. Despite the several disinfection methods available the optimal method to control hospital-acquired LD has not been established yet. Objectives To assess the efficacy of interventions for preventing hospital-acquired LD in hospitalized patients at high risk of developing the disease and the effect on environmental colonization associated to the risk of developing hospital-acquired LD. Search Methods We searched The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library and MEDLINE (PubMed). We also handsearched the reference lists of all primary studies identified by the initial search. Selection Criteria All controlled studies investigating the efficacy of interventions for the prevention of hospital-acquired LD, in hospitalized patients at high-risk for developing LD, were eligible for inclusion. Data collection and analysis Two authors independently assessed the trials and extracted data. Data was analysed using statistical software, Review Manager 5.2. Results Three controlled trials, two assessing copper-silver ionization and one assessing ultraviolet light (UVL), met the inclusion criteria. The meta-analysis showed a significant benefit in using copper-silver ionization rather than no intervention for Legionella positivity in distal sites, with RR = 0.04 (95% CI Fixed Effects 0.001, 0.29). One study demonstrated benefit of UVL versus no intervention with a RR = 0.03 (95% CI 0.00, 0.41) for Legionella positivity in water samples. Authors’ conclusions Our review demonstrates that copper-silver ionization and UVL are beneficial, compared with no treatment, to prevent hospital-acquired LD. However the quality of the body of evidence identified does not allow a robust conclusion regarding the effectiveness of interventions for preventing hospital-acquired LD. Further research with well design and high quality studies is needed

Outbreaks of Disease: Current European Reporting

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Assessing Hotel Employee Knowledge on Risk Factors and Risk Management Procedures for Microbial Contamination of Hotel Water Distribution Systems

Background: Compromised hotel water supply lines by neglect or by physical and structural damage can lead to exposure of harmful pathogens to guests and staff. To reduce the risk of having contaminated water in a hotel plumbing system, some facilities may incorporate a water safety plan (WSP). WSPs are not mandatory for hotels in many US states, including the state of Georgia. As such, many hotel personnel are uninformed of WSPs and the precautions to take if their hotel water system is compromised. The purpose of this study was to identify hotel personnel’s knowledge and practices of WSPs through a survey incorporating the Health Belief Model (HBM). Methods: Data were collected from 59 hotels within Fulton County, Georgia, through a questionnaire, and questions were developed tailored to the HBM. Results: Significant associations were found between the perceived susceptibility of contracting a waterborne illness and WMP for hotel personnel as well as between cues to action and having a WMP in general linear models (pConclusions: Our study concluded that many key personnel are not aware of WSPs. Many hotel facilities do not have a plan in place, and some facilities are unaware of a current plan is in place. This study provides insight into the importance of WSP and the risk factors associated with microbial contamination in a hotel building’s plumbing system. Future research and potential law change should be emphasized due to employees’ and owners’ lack of knowledge and for the continuation of waterborne outbreaks in hotel facilities

Increase in Legionnaires' disease cases associated with travel to Dubai among travellers from the United Kingdom, Sweden and the Netherlands, October 2016 to end August 2017.

Between 1 October 2016 and 31 August 2017, 51 Legionnaires' disease (LD) cases from the United Kingdom, Sweden and the Netherlands were identified with associated travel to Dubai. Cases did not all stay in the same accommodation, indicating that no single accommodation could be the source for all these infections. While local investigations continue into other potential sources, clinicians should remain alert to the possibility of LD among travellers returning from Dubai with respiratory illness

Effect of Common Oxidative Water Treatments on Acanthamoeba Internalized Legionella

Legionella pneumophila can cause pneumonic and non-pneumonic disease in humans. Infections occur from aerosolized contaminated water. This bacterium is an opportunistic intracellular pathogen able to infect both protozoans, such as Acanthamoeba polyphaga, and human macrophages. Both L. pneumophila and A. polyphaga resist commonly used water treatments, such as chlorination, but L. pneumophila has displayed greater resistance in the presence of A. polyphaga. Therefore, there is concern that L. pneumophila could become established in plumbing systems after water treatment, leading to infections. The objective of this study was to show the effect of chlorine and chlorine dioxide exposures on the survival of A. polyphaga internalized L. pneumophila. Gentamicin was used to kill extracellular L. pneumophila and samples were exposed to the oxidants, then the reactions were quenched and incubated at 30°C. The concentration of L. pneumophila was determined by culture analysis following lysis of Acanthamoeba on days 0, 7, and 14. Chlorine achieved ~1 log reduction at a concentration of 56.7 mg.min/L and ~2 log reduction at 376.3 mg.min/L. Chlorine dioxide achieved ~1 log reduction at a concentration of 74.21 mg.min/L and ~2 log reduction at 249.4 mg.min/L. All but one ClO2 concentration tested showed increasing log reduction throughout the 14-day monitoring period. This project addresses a concern of water treatment facilities and public health officials regarding the survival of intracellular Legionella. The results of this study show the need for greater understanding of other microorganisms’ impact on Legionella control and will be useful to water treatment in determining oxidant levels needed for ensuring that potable water does not pose a delayed threat to the public

Rapid Pathogen-Induced Apoptosis: A Mechanism Used by Dendritic Cells to Limit Intracellular Replication of Legionella pneumophila

Dendritic cells (DCs) are specialized phagocytes that internalize exogenous antigens and microbes at peripheral sites, and then migrate to lymphatic organs to display foreign peptides to naïve T cells. There are several examples where DCs have been shown to be more efficient at restricting the intracellular replication of pathogens compared to macrophages, a property that could prevent DCs from enhancing pathogen dissemination. To understand DC responses to pathogens, we investigated the mechanisms by which mouse DCs are able to restrict replication of the intracellular pathogen Legionella pneumophila. We show that both DCs and macrophages have the ability to interfere with L. pneumophila replication through a cell death pathway mediated by caspase-1 and Naip5. L. pneumophila that avoided Naip5-dependent responses, however, showed robust replication in macrophages but remained unable to replicate in DCs. Apoptotic cell death mediated by caspase-3 was found to occur much earlier in DCs following infection by L. pneumophila compared to macrophages infected similarly. Eliminating the pro-apoptotic proteins Bax and Bak or overproducing the anti-apoptotic protein Bcl-2 were both found to restore L. pneumophila replication in DCs. Thus, DCs have a microbial response pathway that rapidly activates apoptosis to limit pathogen replication

Guidelines for prevention of nosocomial pneumonia

"This document updates and replaces CDC's previously published "Guideline for Prevention of Nosocomial Pneumonia" (Infect Control 1982;3:327-33, Respir Care 1983;28:221-32, and Am J Infect Control 1983;11:230-44). This revised guideline is designed to reduce the incidence of nosocomial pneumonia and is intended for use by personnel who are responsible for surveillance and control of infections in acute-care hospitals; the information may not be applicable in long-term-care facilities because of the unique characteristics of such settings. This revised guideline addresses common problems encountered by infection-control practitioners regarding the prevention and control of nosocomial pneumonia in U.S. hospitals. Sections on the prevention of bacterial pneumonia in mechanically ventilated and/or critically ill patients, care of respiratory-therapy devices, prevention of cross-contamination, and prevention of viral lower respiratory tract infections (e.g., respiratory syncytial virus [RSV] and influenza infections) have been expanded and updated. New sections on Legionnaires disease and pneumonia caused by Aspergillus sp. have been included. Lower respiratory tract infection caused by Mycobacterium tuberculosis is not addressed in this document. Part I, "An Overview of the Prevention of Nosocomial Pneumonia, 1994, provides the background information for the consensus recommendations of the Hospital Infection Control Practices Advisory Committee (HICPAC) in Part II, Recommendations for Prevention of Nosocomial Pneumonia." Pneumonia is the second most common nosocomial infection in the United States and is associated with substantial morbidity and mortality."Includes bibliographical references (p. 67-72)."The following CDC staff members prepared this report:: Ofelia C. Tablan, Larry J. Anderson, Nancy H. Arden, Robert F. Breiman, Jay C. Butler, Michael M. McNeil, Michele L. Pearson, National Center for Infectious Diseases, in collaboration with theHospital Infection Control Practices Advisory Committee." p. v.Part 1. An Overview of the Prevention of Nosocomial Pneumonia, 1994 -- Part II. Recommendations for Preventing Nosocomial Pneumonia -- Appendix A: Examples of Semicritical Items Used on the Respiratory Tract -- Appendix B: Maintenance Procedures Used to Decrease Survival and Multiplication of Legionella sp. in Potable-Water Distribution Systems -- Appendix C: Culturing Environmental Specimens for Legionella sp -- Appendix D: Procedure for Cleaning Cooling Towers and Related Equipment.1997SupersededHICPACPrevention and ControlInfectious Disease903630

State of the art: public health and passenger ships

Background. The purpose of this report is to describe issues relevant to public health and to review all passenger ship associated diseases and outbreaks. Moreover, legislation and practices on sanitation and diseases surveillance related to ships internationally were also reviewed. Some relevant historical information about infections on merchant ships is provided as well. Material and methods. The methods used to develop the state-of-the-art report included a scientific literature review and an extensive and thorough search of the websites of organisations and government departments. A considerable effort was made to capitalise on previous experience in the field. In particular, for the literature review, a total of 158 scientific articles were used including 91 full papers and 67 abstracts, 7 guidelines published by the WHO, and 13 guideline documents published by other organisations. Moreover, 5 international conventions relevant to passenger ships were identified. Results. At the international level, public health issues related to ships are regulated by the revised International Health Regulations (2005). Other conventions of the International Maritime Organization regulate safety on board ships and waste and ballast water management, while conventions of the International Labour Organization regulates issues related to working conditions on board ships. Guidelines for preventing and controlling public health threats on board ships can be found in seven Guidelines published by the World Health Organization, including the WHO Guide to Ship Sanitation, which provides a framework for policy making and local decision making. The literature review results revealed that the infections/outbreaks that occur on passenger ships include Norovirus, Legionella spp., Salmonella spp., E. coli, Vibrio spp., and influenza A and B virus. The modes of transmission include person to person, waterborne, foodborne, airborne, and vectorborne, and shore excursions are responsible for some outbreaks. Conclusions. The industry (especially the ferry industry) and sanitary organisations can enhance collaboration in order to implement integrated hygiene programmes and prevent the occurrence of communicable diseases aboard passenger ships

Legionella control in the water system of antiquated hospital buildings by shock and continuous hyperchlorination: 5 years experience

To control the presence of Legionella in an old hospital water system, an integrated strategy of water disinfection-filtration was implemented in the university hospital Umberto I in Rome. Due to antiquated buildings, hospital water system design and hospital extension (38 buildings), shock hyperchlorination (sodium hypochlorite, 20-50 ppm of free chlorine at distal points for 1-2 h) followed by continuous hyperchlorination (0.5-1.0 mg/L at distal points) were adopted, and microbiological and chemical monitoring of the water supply was carried out in the university hospital (December 2006-December 2011). Overall, 1308 samples of cold 45°C (17.8%) water were collected, determining residual free chlorine (0.43 ± 0.44 mg/L), pH (7.43 ± 0.29) and trihalomethanes (8.97 ± 18.56 μg/L). Legionella was isolated in 102 (9.8%) out of 1.041 water samples without filters (L. pneumophila sg 1 17.6%, L. pneumophila sg 2-14 28.4%, L. non pneumophila 53.9%), and in none of the 267 samples with filters. Legionella was recovered in 23 buildings out of 38 and 29 samples (28.4%) exceeded 103 cfu/L. When considering the disinfection treatment Legionella was isolated: before shock hyperchlorination (21.1%), 15 days after shock hyperchlorination (7.8%), 30 days after shock hyperchlorination (3.5%), during continuous hyperchlorination (5.5%) and without continuous hyperchlorination (27.3%). Continuous hyperchlorination following the shock treatment achieved >70% reduction of positive samples, whereas no continuous hyperchlorination after shock treatment was more frequently associated to Legionella isolation (OR 6.41; 95% CI 3.10-13.26; p 0.5 < 1.0 mg/L) deteriorated water quality (organoleptic and chemical). However, shock and continuous hyperchlorination remains a valid-term option in old buildings with no water system rational design, managing problems due to hospital extension and absence of a proper hot water recirculation system