Legionella occurrence in municipal and industrial wastewater treatment plants and risks of reclaimed wastewater reuse: Review.

Wastewater treatment plants (WWTPs) have been identified as confirmed but until today underestimated sources of Legionella, playing an important role in local and community cases and outbreaks of Legionnaires' disease. In general, aerobic biological systems provide an optimum environment for the growth of Legionella due to high organic nitrogen and oxygen concentrations, ideal temperatures and the presence of protozoa. However, few studies have investigated the occurrence of Legionella in WWTPs, and many questions in regards to the interacting factors that promote the proliferation and persistence of Legionella in these treatment systems are still unanswered. This critical review summarizes the current knowledge about Legionella in municipal and industrial WWTPs, the conditions that might support their growth, as well as control strategies that have been applied. Furthermore, an overview of current quantification methods, guidelines and health risks associated with Legionella in reclaimed wastewater is also discussed in depth. A better understanding of the conditions promoting the occurrence of Legionella in WWTPs will contribute to the development of improved wastewater treatment technologies and/or innovative mitigation approaches to minimize future Legionella outbreaks.

Contact killing and antimicrobial properties of copper.

With the emergence of antibiotic resistance, the interest for antimicrobial agents has recently increased again in public health. Copper was recognized in 2008 by the United States Environmental Protection Agency (EPA) as the first metallic antimicrobial agent. This led to many investigations of the various properties of copper as an antibacterial, antifungal and antiviral agent. This review summarizes the latest findings about 'contact killing', the mechanism of action of copper nanoparticles and the different ways micro-organisms develop resistance to copper.

Harmonizing and supporting infection control training in Europe.

Healthcare-associated infection (HCAI), patient safety, and the harmonization of related policies and programmes are the focus of increasing attention and activity in Europe. Infection control training for healthcare workers (HCWs) is a cornerstone of all patient safety and HCAI prevention and control programmes. In 2009 the European Centre for Disease Prevention and Control (ECDC) commissioned an assessment of needs for training in infection control in Europe (TRICE), which showed a substantial increase in commitment to HCAI prevention. On the other hand, it also identified obstacles to the harmonization and promotion of training in infection control and hospital hygiene (IC/HH), mostly due to differences between countries in: (i) the required qualifications of HCWs, particularly nurses; (ii) the available resources; and (iii) the sustainability of IC/HH programmes. In 2013, ECDC published core competencies for infection control and hospital hygiene professionals in the European Union and a new project was launched ['Implementation of a training strategy for infection control in the European Union' (TRICE-IS)] that aimed to: define an agreed methodology and standards for the evaluation of IC/HH courses and training programmes; develop a flexible IC/HH taxonomy; and implement an easily accessible web tool in 'Wiki' format for IC/HH professionals. This paper reviews several aspects of the TRICE and the TRICE-IS projects.

Training infection control and hospital hygiene professionals in Europe, 2010: agreed core competencies among 33 European countries.

The harmonisation of training programmes for infection control and hospital hygiene (IC/HH) professionals in Europe is a requirement of the Council recommendation on patient safety. The European Centre for Disease Prevention and Control commissioned the 'Training Infection Control in Europe' project to develop a consensus on core competencies for IC/HH professionals in the European Union (EU). Core competencies were drafted on the basis of the Improving Patient Safety in Europe (IPSE) project's core curriculum (CC), evaluated by questionnaire and approved by National Representatives (NRs) for IC/HH training. NRs also re-assessed the status of IC/HH training in European countries in 2010 in comparison with the situation before the IPSE CC in 2006. The IPSE CC had been used to develop or update 28 of 51 IC/HH courses. Only 10 of 33 countries offered training and qualification for IC/HH doctors and nurses. The proposed core competencies are structured in four areas and 16 professional tasks at junior and senior level. They form a reference for standardisation of IC/HH professional competencies and support recognition of training initiatives.

Environmental impact of medical prescriptions: assessing the risks and hazards of persistence, bioaccumulation and toxicity of pharmaceuticals.

In the context of increasing concerns regarding sustainable development, healthcare workers must consider practices that are not harmful to the environment. 'Primum non nocere' is of great value for the residues of pharmaceuticals and biocides resulting from medical prescriptions. Stockholm County Council has developed a simple classification system covering both environmental risks and hazards of pharmaceuticals according to their persistence, bioaccumulation and toxicity. This classification, which is easy to understand and well accepted among Swedish medical doctors, could be a model for other countries and useful to general medical doctors wishing to be environmentally conscious in their prescribing. Limited information is available on both the fate and ecotoxicity of pharmaceuticals and biocides in the aquatic environment. The primary concern regarding the environmental impact of pharmaceuticals seems to be drug classes such as antibiotics, oestrogens, cytostatic agents, contrast agents and disinfectants. Performing a full ecological risk assessment of pharmaceuticals and biocides is difficult because of a lack of data on exposure scenarios, target aquatic species and dose-response relationships.

Dermal and pulmonary absorption of ethanol from alcohol-based hand rub.

BACKGROUND: Ethanol intoxication of healthcare workers (HCWs) using alcohol-based hand rubs (ABHRs) in the workplace is a potentially serious issue. This study quantified the level of ethanol absorption among HCWs after hygienic hand disinfection. METHODS: Eighty-six HCWs from Nancy University Hospital were tested before and after a 4-h shift. Participants used ABHR containing 70% ethanol. Levels of ethanol, acetaldehyde and acetate in blood and urine were determined using gas chromatography. A breathalyzer was used to measure the level of ethanol in expired air. RESULTS: Ethanol [mean concentration 0.076 (standard deviation 0.05) mg/L] was detected in the expired air of 28 HCWs 1-2 min post exposure. Ethanol, acetaldehyde and acetate were undetectable in blood after a 4-h shift, and urine tests were negative in all participants. CONCLUSION: Ethanol exposure from ABHR, particularly inhalation of vapours, resulted in positive breathalyzer readings 1-2 min after exposure. Dermal absorption of ethanol was not detected. Pulmonary absorption was detected but was below toxic levels.

Pontiac fever among retirement home nurses associated with airborne legionella.

The aim of this study was to ascertain incidence of symptoms compatible with Pontiac fever (PF) and to assess their association with exposure to legionella bacteria among retirement home nurses who help residents take their shower. Within a non-epidemic framework, 104 nurses of 19 retirement homes were followed up during an average period of four months. Data on symptoms, number and location of showers they attended were recorded daily by each participant. Water and aerosol bacterial quality was characterised at the end of follow-up using the culturable and the in-situ hybridisation techniques. Among 11 Pontiac-like episodes, eight cases complied with the study definition of PF. Water concentrations >10(3) cfu legionella per litre were associated with an increased risk of PF, with dose-response patterns. No association was established between the aerosol legionella concentrations and PF events. A threshold value of 103 cfu legionella per litre of water might be used with a view to protection from legionella-associated occupational conditions.

Legionellosis prevention in France.

Since 1997, both the prevention of legionellosis and the control of Legionella in water networks and cooling towers have greatly improved in France. The epidemiological surveillance of Legionnaires' disease showed an increase, which was followed by a decrease in the incidence after a maximum was reached in 2005 (incidence rate of 2.5 per 10(5)). A steady decrease in the incidence rate has been observed since 2006, mainly due to the efficacy of control measures both for cooling towers and hospital water networks. In hospitals, a proactive approach was proposed in 1998 and quantitative limit values with systematic survey were put into force in 2002. The percentage of nosocomial cases has decreased dramatically and is now around 6-7% of all cases recorded in France. No nosocomial outbreak has been reported in recent years. However, this is not the case for community cases linked to diverse exposure sources, including cooling towers.

An international trial of quantitative PCR for monitoring Legionella in artificial water systems.

AIMS: To perform an international trial to derive alert and action levels for the use of quantitative PCR (qPCR) in the monitoring of Legionella to determine the effectiveness of control measures against legionellae. METHODS AND RESULTS: Laboratories (7) participated from six countries. Legionellae were determined by culture and qPCR methods with comparable detection limits. Systems were monitored over ≥10 weeks. For cooling towers (232 samples), there was a significant difference between the log mean difference between qPCR (GU l(-1) ) and culture (CFU l(-1) ) for Legionella pneumophila (0·71) and for Legionella spp. (2·03). In hot and cold water (506 samples), the differences were less, 0·62 for Leg. pneumophila and 1·05 for Legionella spp. Results for individual systems depended on the nature of the system and its treatment. In cooling towers, Legionella spp. GU l(-1) always exceeded CFU l(-1) , and usually Legionella spp. were detected by qPCR when absent by culture. The pattern of results by qPCR for Leg. pneumophila followed the culture trend. In hot and cold water, culture and qPCR gave similar results, particularly for Leg. pneumophila. There were some marked exceptions with temperatures ≥50°C, or in the presence of supplementary biocides. Action and alert levels for qPCR were derived that gave results comparable to the application of the European Guidelines based on culture. Algorithms are proposed for the use of qPCR for routine monitoring. CONCLUSIONS: Action and alert levels for qPCR can be adjusted to ensure public health is protected with the benefit that remedial actions can be validated earlier with only a small increase in the frequency of action being required. SIGNIFICANCE AND IMPACT OF THE STUDY: This study confirms it is possible to derive guidelines on the use of qPCR for monitoring the control of legionellae with consequent improvement to response and public health protection.

[Control measures for a VRE outbreak in a haemodialysis unit]. / Mise en oeuvre de mesures visant à contrôler une épidémie de portage d'Entérocoques Résistants aux Glycopeptides dans un centre d'hémodialyse.

We report an outbreak of colonization with Vancomycin Resistant Enterococci (VRE) in the Haemodialysis unit of our hospital. From October 2004 to September 2008, 19 patients were found positive. The risk of acquiring this multi-resistant bacterium is extremely important in patients undergoing haemodialysis, heightened measures have gradually been set to control cross transmissions: first isolation, then geographic clustering of carriers and finally creating cohorting sectors with different staff for carriers, contacts and VRE free patients. This re-organization was supplemented by strengthening procedures for hand hygiene, active screening of patients and enhanced cleaning. Monitoring of the epidemic curve has allowed us to demonstrate the effectiveness of measures introduced. However, deleterious effects were observed in patients whose habits were changed; we could also highlight significant impact on the activity of the unit.

The case for re-evaluating the upper limit value for selenium in drinking water in Europe.

Selenium is an essential trace element for life, which can be toxic for humans when intakes reach a certain amount. Therefore, since the margin between healthy intake and toxic intake is narrow, the selenium concentration of tap water is a parameter that must be monitored because of its potential for increased intake. The present work gives an overview of the different approaches used to calculate safe limits for selenium. As recommended by WHO, the guidelines for drinking water form the basis of national legislated standards for drinking water. Before setting a maximum acceptable level in drinking water, it is necessary to take into account the total intake of selenium in both food and beverage. The limit value of 10 microg l(-1) for drinking water laid down in the European regulations for all countries should be adapted depending on geographic area, as previously recommended by WHO.

Overview of diagnostic and detection methods for legionellosis and Legionella spp.

Since 1977, the diagnostic tools for Legionnaires' disease have been based on culture and serological investigations. Both methods require considerable time to produce results and have 'low' to 'reasonable' sensitivity. Since the introduction of urinary antigen tests in the mid 1990s, underdiagnosis has diminished and mortality has declined, thanks to early diagnosis. To obtain the most accurate diagnosis, culture, serological investigation, and urinary antigen testing should all be performed. In the last decade, advances in polymerase chain reaction technology allowed the development of assays detecting Legionella nucleic acids in clinical and environmental samples. Thus far, only widely varying results with relatively small series have been reported. Furthermore, these assays which are still labour intensive and complicated are not yet practicable for the average medical and/or environmental microbiological laboratory.

Legionella bacteria in shower aerosols increase the risk of Pontiac fever among older people in retirement homes.

BACKGROUND: 828 elderly subjects residing in nursing homes were followed up during 4 months to ascertain incidence of symptoms associated with Pontiac fever (PF) in a non-epidemic setting. METHODS: The exposure situation was inhalation of Legionella bacteria while showering. An audit of the hot water system in all institutions allowed ascribing each subject to a water quality area wherefrom one shower was sampled for Legionella assays at the end of the follow-up period. Legionella were detected in water and aerosols using the culture (CFU, colony forming units) and in situ hybridization (FISH) techniques. RESULTS: Among 32 Pontiac-like episodes, 29 cases complied with the operational definition of PF elaborated for this study. Incidence density was 0.11 case/person-year (95% CI 0.07 to 0.15). Water concentrations greater than 105 Legionella FISH/l and 104 Legionella CFU/l were associated with an increased risk of PF (respectively RR 2.23, p = 0.05 and RR 2.39, p = 0.11, with significant dose-response patterns: p for trend <0.04). The condition also seems associated with aerosol concentrations above 103 Legionella FISH/l of air. A significantly higher risk of Pontiac-like episodes (RR 6.24, 95% CI 2.12 to 18.38) was seen for elderly subjects receiving corticosteroid therapy. CONCLUSION: The water and threshold values identified in this research could be used to inform guidance measures aimed at protecting institutionalised older people from Legionnaires' disease. Immunosuppressive therapy in the same population group can significantly enhance susceptibility to Legionella bacteria.

Use of genotypic selection to detect P53 codon 273 CGT>CTT transversion: application to an occupationally exposed population.

CGT>CTT transversion in codon 273 of the P53 tumor-suppressor gene is one of the major mutations detected in human tumors. Within an epidemiological framework, we investigated the use of a genotypic selection method to measure this point mutation. The allele-specific polymerase chain reaction (AS-PCR) that was developed was able to detect 10 mutant copies of the gene among a total of 5 x 10(5) wild-type copies. We used this assay to detect CGT>CTT transversions in buccal cell DNA of production workers (n=76) from a viscose factory exposed to carbon disulfide (amongst other pollutants) and in the DNA of non-exposed office workers (n=67). The mutation appeared more frequently in the exposed than in the non-exposed worker who were smokers. The results of the study indicate that occupational exposure results in a significant increase in P53 CGT>CTT transversions and more especially identified occupational exposure in combination with smoking as a significant risk factor for the mutation. We conclude that AS-PCR of the P53 273rd codon transversions is a suitable technique for studying the effects of occupational exposure.

[Intra-amoebal development of Legionella pneumophila and the potential role of amoebae in the transmission of Legionnaires' disease]. / Multiplication intra-amibienne de Legionella pneumophila et rôle potentiel des amibes dans la transmission de la légionellose.

Legionnaires' disease is one of the major infectious risks related to hospital water systems. It is commonly accepted, that the disease is transmitted to man mostly by inhalation of water aerosols contaminated by Legionella pneumophila. The ability of L. pneumophila to multiply intracellularly within some amoebae better explains the ecology, the pathogenicity, and the virulence of this bacterium against human alveolar macrophages. The presence of these amoebae in water systems located where cases of Legionnaire's disease broke out, partly explains the difficulty in eradicating Legionella. Some studies also show that amoebae can play a major role in the transmission of the disease to man. Some other studies point out that inhaled amoebae could be involved in the pathogenesis of Legionnaire's disease. Future strategies to prevent the transmission of Legionella will probably have to include efficient treatments against amoebae.

[Study of 12 epidemical cases of legionnaire's disease occurred in Meurthe-et-Moselle (France) between July and August 2004]. / Etude de douze cas épidémiques de légionellose survenus en Meurthe-et-Moselle en juillet-août 2004.

PATIENTS AND METHOD: To describe epidemiological, clinical, biological, radiological data and therapeutic features of legionnaire's disease during an outbreak occurring in Meurthe-et-Moselle between July-August 2004. RESULTS: 12 cases were recorded including 11 men, 6 smokers, 4 alcoholo-nicotinic, 3 diabetics, 3 with hemopathy, 1 with corticotherapy; in one case no risks factors were found; mean age was 68.5 years [minimum=48; maximum=96]. Nine cases had sudden symptoms. Nine cases had a fever up to 40 degrees C, 9 with dyspnoea, 7 with cough, 7 with a relative bradycardia, 3 with diarrhoea, 3 felt faint, 3 with confusion. Radiology: unilateral unilobe localisation in 10 cases. Biological data: cytolysis in 8 cases, CRP >300 mg/l in 8. The diagnosis confirmed with urinary antigen of Legionella pneumophila serogroup 1 (UrAgLp1) in 12 cases. In 2 cases, UrAgLp1 appeared negative between 3rd and 10th day after the beginning of a treatment although UrAgLp1 was positive before the treatment. In all cases, the first serology realised during first days following occurrence the first symptoms remained negative. Two serology of control in four were positive. One search of L. pneumophila serogroup 1 in sputum was positive in 7. Bitherapy was used in 7 cases with preferential association: fluoroquinolone+rifampicin. Two patients died. Origin of the contamination remains unknown. CONCLUSION: Culture of Legionella is essential, in epidemic context, to compare clinical and environmental Legionella and to locate the origin of contamination.

Prevention and control of health care-associated waterborne infections in health care facilities.

The current article is a review of the public health risks attributable to waterborne pathogens in health care. The consequences of health care-associated infections (HAIs) are discussed. Not only are Legionella spp involved in HAIs, but also Pseudomonas aeruginosa, other gram-negative microorganisms, fungi, and amoeba-associated bacteria. This is particularly noteworthy among immunocompromised patients. New prevention strategies and control measures brought about through advanced planning, facility remodelling and reconstruction, disinfection, and filtration have resulted in a significant reduction of the incidence of waterborne HAIs. The positive consequences of a comprehensive multibarrier approach including prevention and control programs in health care facilities are discussed. Environmental cultures are now integrated within the infection control program of some European countries. In high-risk areas, the application of disposable sterile point-of-use filters for faucets and shower heads appears to be the practice of choice to efficiently control waterborne pathogens and to prevent infections.

Escherichia coli behavior in the presence of organic matter released by algae exposed to water treatment chemicals.

When exposed to oxidation, algae release dissolved organic matter with significant carbohydrate (52%) and biodegradable (55 to 74%) fractions. This study examined whether algal organic matter (AOM) added in drinking water can compromise water biological stability by supporting bacterial survival. Escherichia coli (1.3 x 10(5) cells ml(-1)) was inoculated in sterile dechlorinated tap water supplemented with various qualities of organic substrate, such as the organic matter coming from chlorinated algae, ozonated algae, and acetate (model molecule) to add 0.2 +/- 0.1 mg of biodegradable dissolved organic carbon (BDOC) liter(-1). Despite equivalent levels of BDOC, E. coli behavior depended on the source of the added organic matter. The addition of AOM from chlorinated algae led to an E. coli growth equivalent to that in nonsupplemented tap water; the addition of AOM from ozonated algae allowed a 4- to 12-fold increase in E. coli proliferation compared to nonsupplemented tap water. Under our experimental conditions, 0.1 mg of algal BDOC was sufficient to support E. coli growth, whereas the 0.7 mg of BDOC liter(-1) initially present in drinking water and an additional 0.2 mg of BDOC acetate liter(-1) were not sufficient. Better maintenance of E. coli cultivability was also observed when AOM was added; cultivability was even increased after addition of AOM from ozonated algae. AOM, likely to be present in treatment plants during algal blooms, and thus potentially in the treated water may compromise water biological stability.

Mycobacterium xenopi and drinking water biofilms.

The ability of Mycobacterium xenopi to colonize an experimental drinking water distribution system (a Propella reactor) was investigated. M. xenopi was present in the biofilm within an hour following its introduction. After 9 weeks, it was always present in the outlet water (1 to 10 CFU 100 ml(-1)) and inside the biofilm (10(2) to 10(3) CFU cm(-2)). Biofilms may be considered reservoirs for the survival of M. xenopi.