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"Objective: The aim of this study was to provide a review that gives a general perspective of legionellosis and the different factors associated with this disease, such as the incidence, causal agents, treatment, control and prevention methods used globally in order to safeguard public health. Methodology: To develop this document, the search and analysis of pertinent information was carried out in different scientific and academic databases such as Scielo, Scopus, Latindex, Redalyc, Google Scholar, among others. Results: Legionellosis is caused by species of the genus Legionella spp., with L. pneumophila being commonly associated to clinical cases. Analytical methods have been developed for their detection, as well as sanitary regulations for water and hydraulic facilities for human use, in order to mitigate their impact on the population. Implications in the study: The causal agents of legionellosis inhabit aquatic ecosystems, and are capable of resisting diverse physicochemical conditions; therefore, they have been detected in hydraulic systems and equipment for human use, thus generating their dispersion and potential infection when inhaled through small drops of water (sprays). Conclusions: Legionella spp. is an emerging pathogen of importance in public health mainly in developed countries, due to its incidence, complications and mortality. It has been established that the prevention and control of legionellosis require joint actions in the microbiological control of water, development, dissemination, implementation and monitoring of the application of regular cleaning and disinfection programs by governmental entities, international health organizations, academia, industry and the general population." ; "Objetivo: Brindar una revisión que aporte una perspectiva general de la legionelosis y de los diferentes factores asociados a esta enfermedad tales como la incidencia, agentes causales, terapéutica, métodos de control y prevención utilizados a nivel global a fin de salvaguardar la salud pública. Metodología: Para el desarrollo del presente documento se realizó la búsqueda y análisis de información pertinente en diferentes bases de datos científicas y académicas como Scielo, Scopus, Latindex, Redalyc, Google Académico entre otras. Resultados: La legionelosis es causada por especies del género Legionella spp., siendo L. pneumophila comúnmente asociada a casos clínicos. Se han desarrollado métodos analíticos para su detección, así como regulaciones sanitarias al agua e instalaciones hidráulicas para uso humano, a fin de mitigar su incidencia en la población. Implicaciones en el estudio: Los agentes causales de legionelosis habitan los ecosistemas acuáticos, y son capaces de resistir diversas condiciones fisicoquímicas por ende se han detectado en sistemas y equipos hidráulicos de uso humano, generando así su dispersión y potencial infección al ser inhaladas a través de pequeñas gotas de agua (aerosoles)."

AbstractAn increase in the number of reports of legionellosis in the European Union and the European Economic Area have been recorded in recent years. The increase in cases is significant: from 6947 reports in 2015 to 11,298 in 2019. This is alarming as genus Legionella, which comprises a large group of bacteria inhabiting various aquatic systems, poses a serious threat to human health and life, since more than 20 species can cause legionellosis, with L. pneumophila being responsible for the majority of cases. The ability to colonize diverse ecosystems makes the eradication of these microorganisms difficult. A detailed understanding of the Legionella habitat may be helpful in the effective control of this pathogen. This paper provides an overview of Legionella environments in Europe: natural (lakes, groundwater, rivers, compost, soil) and anthropogenic (fountains, air humidifiers, water supply systems), and the role of Legionella spp. in nosocomial infections, which are potentially fatal for children, the elderly and immunocompromised patients.
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AbstractBased on biomolecular methods, rapid and selective identification of human pathogenic water organisms becomes an important issue. Legionella spp., are pathogenic water bacteria with worldwide significance. Prevalent detection methods for these microorganisms are time and/or cost intensive. We describe a detection setup and relating DNA assay. A miniaturized real‐time polymerase chain reaction (real‐time PCR) for direct on‐line discrimination of Legionella pneumophila and Legionella spp. was established and integrated into a real‐time PCR‐chip‐system. The PCR‐chip device combines a temperature controlling unit and a fluorescence intensity measurement. It was designed to achieve rapid amplification, using an approach of real‐time fluorescence read out with the intercalating dye EvaGreen® and melting curve analysis, without requiring multiple probes. The presented results exhibit reproducibility and good sensitivity, showing that the setup is suitable for robust, rapid and cost‐efficient detection and monitoring of a variety of Legionella spp.in urban water samples.

Legionnaires' disease (LD) outbreaks are often traced to colonized potable water systems. We collected water samples from potable water systems of 96 buildings in Pinellas County, Florida, between January and April 2002, during a time when chlorine was the primary residual disinfectant, and from the same buildings between June and September 2002, immediately after monochloramine was introduced into the municipal water system. Samples were cultured for legionellae and amoebae using standard methods. We determined predictors of Legionella colonization of individual buildings and of individual sampling sites. During the chlorine phase, 19 (19.8%) buildings were colonized with legionellae in at least one sampling site. During the monochloramine phase, six (6.2%) buildings were colonized. In the chlorine phase, predictors of Legionella colonization included water source (source B compared to all others, adjusted odds ratio [aOR], 6.7; 95% confidence interval [CI], 2.0 to 23) and the presence of a system with continuously circulating hot water (aOR, 9.8; 95% CI, 1.9 to 51). In the monochloramine phase, there were no predictors of individual building colonization, although we observed a trend toward greater effectiveness of monochloramine in hotels and single-family homes than in county government buildings. The presence of amoebae predicted Legionella colonization at individual sampling sites in both phases (OR ranged from 15 to 46, depending on the phase and sampling site). The routine introduction of monochloramine into a municipal drinking water system appears to have reduced colonization by Legionella spp. in buildings served by the system. Monochloramine may hold promise as community-wide intervention for the prevention of LD.

AbstractOpportunistic pathogens, such as several species of Legionella, are a growing concern globally. This is especially true in building plumbing. Plumbing design guidance has not been updated to reflect changes in use, leading to increased hydraulic retention time and exacerbating pathogen risks. While the effects of several water quality variables on Legionella spp. concentrations are well‐studied at bench‐scale, little is known about the strength of, or interactions between, these relationships in full‐scale plumbing. The influence of water quality variables and water use metrics on Legionella spp. concentrations was evaluated with several statistical tools from a data‐driven perspective. The results add to the weight of evidence required to develop systematic risk management strategies like monitoring. Variables related to Legionella and logistically more feasible to measure in full scale buildings, such as dissolved oxygen, heterotrophic plate count, total organic carbon, and water age, were identified.

AbstractMethods for recovery and identification of Legionella spp. in water have not been improved significantly since the traditional culture method using buffered charcoal yeast extract (BCYE) agar was developed in 1979. Variations to the BCYE method include sample concentration techniques, acid and heat treatment of samples, and inclusions of antibiotics and dyes in the medium to improve Legionella recovery. A new culture method—Legiolert—was developed and is targeted specifically for recovery and enumeration of Legionella pneumophila, the pathogen responsible for >97% of Legionella pneumonia cases. This study assessed the performance of the Legiolert and BCYE methods in water samples. A total of 247 potable water samples were collected and analyzed using both methods. Mean recoveries in reagent water were similar for both methods (~70%), while Legiolert was more likely than BCYE to detect L. pneumophila when it is present in low numbers.Article Impact StatementThe Legiolert method for enumeration of Legionella pneumophila in water is a significant improvement over the buffered charcoal yeast extract method and should be adopted.

This presentation will summarise the experiences gained from a Legionella project within Nordic Sugar which emphasises risk evaluation, modern DNA analysis methods, control strategies and water treatment methods. The project started in 2002 with yearly campaign screenings for Legionella spp and Legionella pneumophila. Initially an ISO Legionella method for quantification was used, but this was replaced with a modern, rapid DNA-based Real Time Polymerase Chain Reaction assay in 2005. The assay time for quantitative results using the Real Time PCR is approximately 3 hours compared to between 10 and 14 days for the ISO-method. All Nordic Sugar factories equipped with cooling towers are screened on a weekly or bi-weekly basis during every sugar campaign. Only one sugar factory has shown consistently positive results for Legionella pneumophila on a moderate level. A multiple biocide approach combined with a dispersing agent was successfully used to control the Legionella. In 2010 a non-chemical treatment method, Wallenius AOT-system was installed to eliminate an annual high cost for biocides. The system successfully controlled the L. pneumophila even when the cooling water was partially exchanged with fresh lake water.

Legionellosis is a collection of infections that are caused by Legionella pneumophila and related Legionella bacteria. The severity of legionellosis varies from mild febrile illness (Pontiac fever) to a potentially fatal form of pneumonia (Legionnaires' disease) that can affect anyone, but principally affects those who are susceptible due to age, illness, immunosuppression or other risk factors, such as smoking. Legionella spp. are heterotrophic bacteria found in a wide range of water environments and proliferate at temperatures between 25°C and 45°C. These bacteria are members of the natural flora of many freshwater environments, such as rivers, streams and impoundments, where they occur in relatively low numbers. Bacteria of the genus Legionella are ubiquitous, they can proliferate in certain human-made water environments, such as water cooling devices associated with air conditioning systems, hot water, spas, distribution systems, on the inside surfaces of shower heads especially in warm waters. Legionellae can be ingested by certain amoebae which play an important role in their persistence in water environments. Devices that support multiplication of Legionella have been associated with outbreaks of Legionnaires'disease. Nosocomial cases usually make up a small proportion of reported cases of legionellosis. However, the proportion of cases that are fatal tends to be much higher with nosocomial infections than with community-acquired infections. Health-care facilities may include environments that support the proliferation and dissemination of Legionella and must be monitored. In Portugal only exists legislation for air conditioning systems and thermal waters. It is important to be aware of the need to develop specific rules for the detection of Legionella in water intended for human consumption in order to act more for the prevention of the disease than to act only in the monitoring of an outbreak. In recent years there has been an increasing incidence of disease caused by this bacterium, atypical pneumonia, and a large variety of water systems are different sources of contamination.

Background: Currently, to our knowledge, quality of output water of dental chair units is not covered by specific regulations in the European Union, and national recommendations are heterogeneous. In Germany, water used in dental chair units must follow drinking water quality. In the United States of America, testing for aerobic heterotrophic bacteria is recommended. The present study was performed to evaluate whether the counts of aerobic heterotrophic bacteria correlate with the presence of potentially pathogenic bacteria such as Legionella spp. or Pseudomonas aeruginosa. Methods: 71 samples were collected from 26 dental chair units with integrated disinfection device and 31 samples from 15 outlets of the water distribution pipework within the department were examined. Samples were tested for aerobic heterotrophic bacteria at 35°C and 22°C using different culture media and for Legionella spp. and for Pseudomonas aeruginosa . Additionally, strains of Legionella pneumophila serogroup 1 were typed with monoclonal antibodies and representative samples of Legionella pneumophila serogroup 1 were typed by sequence based typing.Results: Our results showed a correlation between different agars for aerobic heterotrophic bacteria but no correlation for the count of aerobic heterotrophic bacteria and the presence of Legionella spp. or Pseudomonas aeruginosa. Conclusion: Testing for aerobic heterotrophic bacteria in output water or water distribution pipework within the departments alone is without any value for predicting whether the water is contaminated with potentially pathogenic bacteria like Legionella spp. or Pseudomonas aeruginosa. ; Hintergrund: Entsprechend unserer Kenntnis sind die Anforderungen an austretendes Wasser in Wasser führenden Elementen von Dentaleinheiten in keiner Europäischen Richtlinie geregelt. Nationale Empfehlungen sind heterogen. In Deutschland muss in Detaleinheiten eingespeistes Wasser der Trinkwasserverordnung entsprechen. In den Vereinigten Staaten wird die Überprüfung auf aerobe ...

AbstractSignificant seasonal changes in chemical and microbiological water quality can occur in buildings at different fixture locations due to temperature and time dependent reaction rates. Here, a series of calibrated plumbing hydraulic‐water quality models were developed for the extensively monitored Retrofitted Net‐zero Energy, Water & Waste (ReNEWW) house in West Lafayette, Indiana, USA. The eight new models predict the absolute level of free chlorine, total trihalomethanes, copper, iron, lead, NO3− (nitrate‐nitrogen), heterotrophic plate count (HPC), and Legionella spp. concentration at each fixture for plumbing use, operational characteristics, and design layouts of the plumbing system. Model development revealed that the carrying capacity to describe Legionella spp. growth (and other organisms) under water usage and plumbing design conditions is lacking in the literature. Reducing simulated building water use by 25% prompted increased absolute concentrations of HPC and Legionella spp., each increasing by a factor of about 105. When the simulated service line length was increased, Legionella spp. concentrations increased by up to 106 gene copies /L in the Summer season. The proposed modeling framework can be used to support better planning, design, analysis, and operational decision‐making.

Introduction: Legionella spp. is a potential pneumonia causing pathogen, which can be transmitted to humans from water-supplying systems. Immunocompromised but also healthy individuals can be vitally threatened. Both, hot and cold-water supplying systems must be considered as transmission sources and therefore a periodic surveillance has to be performed in public buildings according to local legislations. During a routine surveillance, a hazardous colonization was detected within the cold-water supplying system at University Hospital Knappschaftskrankenhaus Bochum, Germany. Applied architectural measures remained unsatisfying in the reduction of legionella contamination of the cold-water distributing system. Methods: Adapted to an analysis of risks, effort and benefit, the superheat and flush procedure was applied twice with a time interval of 6 months. Results were evaluated concerning the efficiency and the sustainability and statistically analyzed. Results: While 33 out of 70 samples had a higher legionella count than the legal threshold of 100 CFU/100 mL (CFU - Colony Forming Units) before the first disinfection was carried out, this number could be reduced to 1 out of 202 samples after the first intervention. Additionally, in contrast to previously published studies, the effect was long-lasting, as no relevant limit exceedance occurred during the following observation period of more than two years. Conclusion: The superheat and flush disinfection can provide an economic and highly effective measure in case of legionella contamination and should be shortlisted for an eradication attempt of affected water-supplying systems in hospitals.

Recently in Australia concerns have been raised regarding the contamination of municipal drinking water supplies with lead. This is of particular concern to children due to the impact of lead exposure on cognitive development and as such these findings have received much media attention. The response from legislators has been swift, and The Victorian School Building Authority has announced that all new schools and school upgrade works will only use lead-free tapware and piping systems. However, while the immediate replacement of lead-containing brass fittings may seem a logical and obvious response, it does not consider the potential implications on microbial contamination. This is particularly concerning given the increasing public health threat posed by opportunistic premise plumbing pathogens (OPPPs). This commentary explores this public health risk of lead exposure from plumbing materials compared to the potential public health risks from OPPPs. Non-tuberculous mycobacterium was chosen as the example OPPP, and the influence on plumbing material and its public health burden in Australia is explored. This commentary highlights the need for future research into the influence of plumbing material on OPPPs prior to any changes in legislation regarding plumbing material.