Search

International audience; Legionella pneumophila is frequently detected in hot water distribution systems and thermal control is a common measure implemented by health care facilities. A risk assessment based on water temperature profiling and temperature distribution within the network is proposed, to guide effective monitoring strategies and allow the identification of high risk areas. Temperature and heat loss at control points (water heater, recirculation, representative points-of-use) were monitored in various sections of five health care facilities hot water distribution systems and results used to develop a temperature-based risk assessment tool. Detailed investigations show that defective return valves in faucets can cause widespread temperature losses because of hot and cold water mixing. Systems in which water temperature coming out of the water heaters was kept consistently above 60 °C and maintained above 55 °C across the network were negative for Legionella by culture or qPCR. For systems not meeting these temperature criteria, risk areas for L. pneumophila were identified using temperature profiling and system's characterization; higher risk was confirmed by more frequent microbiological detection by culture and qPCR. Results confirmed that maintaining sufficiently high temperatures within hot water distribution systems suppressed L. pneumophila culturability. However, the risk remains as shown by the persistence of L. pneumophila by qPCR.

International audience; Due to their high surface-volume ratio, their laminar flow and frequent stagnation periods, dental unit waterlines (DUWL) foster the attachment of microorganisms and the development of biofilm, resulting in the continuous contamination of the outlet water from dental units; this contamination may be responsible for a potential risk of infection due to the exposure of patients and medical staff to droplet inhalation or splashed water. In this study, the anti-biofilm activity of three disinfectants recommended by dental unit manufacturers -Calbenium(©), Oxygenal 6(©) and Sterispray(©) - was evaluated. A dynamic model simulating DUWL conditions was developed and polymicrobial biofilms containing bacteria (Pseudomonas aeruginosa), fungi (Candida albicans) and Free Living Amoeba (FLA: Vermamoeba vermiformis) were allowed to form. The ability of disinfectants to reduce biofilm formation or to eradicate an already formed biofilm was evaluated. Results showed the various effects of the tested disinfectants according to their composition, concentration and the targeted species. V. vermiformis was resistant to disinfectants, regardless of the tested concentrations and the concentrations recommended by manufacturers were not the most appropriate. Results also showed that Calbenium(©) was the most effective disinfectant to reduce already formed biofilms; its maximum efficiency was observed from 0.5% on both P. aeruginosa and C. albicans compared to 2 and 3% respectively for Sterispray(©). The maximum efficiency of Oxygenal(©) was observed from 3% on P. aeruginosa but Oxygenal(©) was unable to totally eliminate C. albicans in the tested conditions, contrary to other disinfectants. Calbenium(©) was able to prevent biofilm formation efficiently even if it displayed no prophylactic activity against V. vermiformis. Overall, the FLA survival may contribute to maintaining other species. Finally the tested disinfectants were partially active against sessile microorganisms and more suitable concentrations could be used to increase their efficacy. Their use in a prophylactic rather than curative way should be recommended.

International audience; The HIWATE (Health Impacts of long-term exposure to disinfection byproducts in drinking WATEr) project was a systematic analysis that combined the epidemiology on adverse pregnancy outcomes and other health effects with long-term exposure to low levels of drinking water disinfection byproducts (DBPs) in the European Union. The present study focused on the relationship of the occurrence and concentration of DBPs with in vitro mammalian cell toxicity. Eleven drinking water samples were collected from five European countries. Each sampling location corresponded with an epidemiological study for the HIWATE program. Over 90 DBPs were identified; the range in the number of DBPs and their levels reflected the diverse collection sites, different disinfection processes, and the different characteristics of the source waters. For each sampling site, chronic mammalian cell cytotoxicity correlated highly with the numbers of DBPs identified and the levels of DBP chemical classes. Although there was a clear difference in the genotoxic responses among the drinking waters, these data did not correlate as well with the chemical analyses. Thus, the agents responsible for the genomic DNA damage observed in the HIWATE samples may be due to unresolved associations of combinations of identified DBPs, unknown emerging DBPs that were not identified, or other toxic water contaminants. This study represents the first to integrate quantitative in vitro toxicological data with analytical chemistry and human epidemiologic outcomes for drinking water DBPs.

International audience; Municipal sewage effluents are complex mixtures that are known to compromise the health condition of aquatic organisms. The aim of this study was to evaluate the impacts of various wastewater disinfection processes on the immune system of juvenile rainbow trout (Oncorhynchus mykiss). The trout were exposed to a primary-treated effluent for 28 days before and after one of each of the following treatments: ultraviolet (UV) radiation, ozonation and peracetic acid. Immune function was characterized in leucocytes from the anterior head kidney by the following three parameters: phagocytosis activity, natural cytotoxic cells (NCC) function and lymphocyte (B and T) proliferation assays. The results show that the fish mass to length ratio was significantly decreased for the primary-treated and all three disinfection processes. Exposure to the primary-treated effluent led to a significant increase in macrophage-related phagocytosis; the addition of a disinfection step was effective in removing this effect. Both unstimulated and mitogen-stimulated T lymphocyte proliferation in fish decreased dramatically in fish exposed to the ozonated effluent compared to fish exposed to either the primary-treated effluent or to aquarium water. Stimulation of T lymphocytes proliferation was observed with the peracetic acid treatment group. In conclusion, the disinfection strategy used can modify the immune system in fish at the level of T lymphocyte proliferation but was effective to remove the effects on phagocytosis activity.

International audience; Cleaning products may cause work-related asthma, but information regarding the specific exposures involved is scarce. We aimed to determine the associations between asthma and occupational exposure to cleaning agents in hospital workers. Analyses were conducted in 179 (136 women) hospital workers and a reference population of 545 subjects (18-79 years) from the French case-control and familial Epidemiological study on the Genetics and Environment of Asthma (2003-2007). Exposures to cleaning agents were estimated using three methods: self-report, expert assessment and an asthma-specific job-exposure matrix (JEM). Associations between cleaning products and current asthma were evaluated by logistic regressions, stratified by sex and adjusted for age and smoking status. According to expert assessment, 55% of male and 81% of female hospital workers were exposed to cleaning/disinfecting tasks weekly (p

International audience; Drosophila melanogaster is a robust model to investigate many biological problems. It is however prone to some infections, which may endanger fly stocks if left unchecked for. One such infection is caused by an obligate fungal intracellular parasite, Tubulinosema ratisbonensis, which can be found in laboratory stocks. Here, we identify and briefly characterize a T. ratisbonensis strain that was infesting our Drosophila cultures and that required intensive measures to contain and eradicate the infection. We describe the phenotypes of infested stocks. We also report PCR-based techniques that allow the detection of infested stocks with a high sensitivity. We have developed a high-throughput qPCR assay that allows the efficient parallel screening of a large number of potentially-infested stocks. We also have investigated several prophylactic measures to prevent the further contamination of stocks, namely UV-exposure, ethanol treatment, bleaching, and desiccation. Bleaching was found to kill all spores. Other treatments were less effective but were found to be sufficient to prevent further contamination of noninfested stocks. Two treatments were efficacious in curing infested stocks (1) bleaching of eggs and subsequent raising of the larvae in clean vials; (2) fumagillin treatment. These cures only work on stocks that have not become too weak to withstand the procedures.

International audience; Water and air quality of fifteen swimming pools using chlorine disinfection was measured during eight sampling campaigns in Rennes, France. Concentrations of trihalomethanes (THMs) and trichloramine (NCl(3)) in air as well as concentrations of parameters, including total organic carbon (TOC), chlorine (free, combined and total), pH, Kjeldhal nitrogen (KN), chloride ions and THMs in water and air temperature, were measured. Water and air samples were collected during 3h in the morning and afternoon, during high and low attendance days, in summer and winter. Data analysis was perfomed by multivariate ordinary least square (OLS) and quantile (QR) regressions, from both data quality and other parameters such as the ratio between the number of visitors and the volume of water available V/W, the proportion of air re-circulated and the number of swimmers during sampling. The geometric means (GM±95% CIs) of the sum of THMs (TTHM) and NCl(3) in air were 74.9±6.7 μg/m(3) and 190±10 μg/m(3), respectively. As expected, concentrations of TTHM in air were correlated to concentrations of TTHM in water. Concentrations of TTHM and NCl(3) in air measured in winter were significantly higher than in summer, depicting that low air exchange rate in winter lead to accumulation of pollutants. NCl(3) (especially at higher quantiles) and TTHM concentrations in air were associated to the number of swimmers. NCl(3) was also linked to air temperature and pH. Moreover TTHM and NCl(3) in air seemed to be affected by additional determinants including the volume of hall and the ratio V/W. In a process of reducing exposure, the OLS regression provides useful information on key parameters influencing concentrations of THMs and NCl(3) in indoor swimming pools. In addition, QR allows identifying factors associated to elevated levels of contamination.

International audience; Several epidemiological studies suggested an association between the risk of bladder cancer and the exposure to trihalomethanes (THMs), the main disinfection by-products (DBPs) of chlorinated water. A previous pooled analysis of case-control studies from North America and Europe estimated a summarized dose-response relation. For policy guidance of drinking water disinfection in Europe and because major differences exist in water disinfection practices and DBPs occurrence between both continents, specific risk estimates for bladder cancer in relation to DBPs exposure for European populations were needed. We conducted a pooled and a two-stage random-effect meta-analyses of three European case-control studies from France, Finland, and Spain (5467 individuals: 2381 cases and 3086 controls). Individual exposure to THMs was calculated combining information on residential history, estimates of the average total THMs (TTHM) level in tap water at the successive residences and personal water consumption. A significant odds-ratio was observed for men exposed to an average residential TTHM level > 50 μg/l (OR = 1.47 (1.05; 2.05)) when compared to men exposed to levels ≤ 5 μg/l. The linear trend of the exposure-risk association was significant (p = 0.01). Risks increased significantly for exposure levels above 25 μg/l and with more than 30 years of exposure to chlorinated water, but were mainly driven by the level rather than the duration of exposure. No significant association was found among women or with cumulative exposure through ingestion. There was no evidence of a differential exposure-response relation for TTHM and bladder cancer in Europe and North America. Consequently, a global exposure-risk relation based on 4351 cases and 7055 controls is now available.

BACKGROUND: Most studies of corneal donor contamination concentrate on postenucleation contamination of the eyeball. The purpose of the present study was to evaluate the relative contamination of in situ excised corneal tissue and relevance to final success or rejection by recipients of the corneal grafts. METHODS: Ninety-three donors underwent anterior chamber puncture (ACP) and corneal epithelium scarification (CS) before and after disinfection with 5% povidone-iodine. Following in situ excision, corneas were preserved in culture medium at +35 degrees C. Morphological and bacteriological assessment was carried out after culture, and recipients were followed up over a 2-year period. RESULTS: Samples taken by ACP, CS before disinfection, CS after disinfection and a culture medium sample were contaminated by bacteria in, respectively, 8 (8.6%), 23 (24.7%) 4 (4.3%) and 5 (5.4%) donors. Contamination of aqueous humor was significantly associated with age, death-to-sample time and premortem systemic infection. Contamination of epithelium significantly increased culture medium contamination. CONCLUSION: External bacteria on donor cornea are mainly skin bacteria (especially Staphylococcus) and can be partially eliminated by a povidone-iodine wash. Internal bacteria are mainly gut bacteria and may be due to perimortem bacteriemia. However, bacterial infection at the time of death appears to have no effect on the incidence of endophthalmitis in recipients and should no longer prevent use of such corneal tissue in grafts.