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Mahieux M, Richard C, Aemig Q, Delgenès JP, Juge M, Trably E, Escudié R. Archaeal community composition as key driver of H2 consumption rates at the start-up of the biomethanation process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 931:172922. [PMID: 38701927 DOI: 10.1016/j.scitotenv.2024.172922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/03/2024] [Accepted: 04/29/2024] [Indexed: 05/05/2024]
Abstract
The performance of hydrogen consumption by various inocula derived from mesophilic anaerobic digestion plants was evaluated under ex situ biomethanation. A panel of 11 mesophilic inocula was operated at a concentration of 15 gVS.L-1 at a temperature of 35 °C in batch system with two successive injections of H2:CO2 (4:1 mol:mol). Hydrogen consumption and methane production rates were monitored from 44 h to 72 h. Hydrogen consumption kinetics varies significantly based on the inoculum origin, with no accumulation of volatile fatty acids. Microbial community analyses revealed that microbial indicators such as the increase in Methanosarcina sp. abundance and the increase of the Archaea/Bacteria ratio were associated to high initial hydrogen consumption rates. The improvement in the hydrogen consumption rate between the two injections was correlated with the enrichment in hydrogenotrophic methanogens. This work provides new insights into the early response of microbial communities to hydrogen injection and on the microbial structures that may favor their adaptation to the biomethanation process.
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Affiliation(s)
- M Mahieux
- INRAE, Univ. Montpellier, LBE, 102 Avenue des étangs, F-11100 Narbonne, France; ENGIE, Lab CRIGEN, 4 Rue Joséphine Baker, 93240 Stains, France
| | - C Richard
- ENGIE, Lab CRIGEN, 4 Rue Joséphine Baker, 93240 Stains, France
| | - Q Aemig
- ENGIE, Lab CRIGEN, 4 Rue Joséphine Baker, 93240 Stains, France
| | - J-P Delgenès
- INRAE, Univ. Montpellier, LBE, 102 Avenue des étangs, F-11100 Narbonne, France
| | - M Juge
- ENGIE, Lab CRIGEN, 4 Rue Joséphine Baker, 93240 Stains, France
| | - E Trably
- INRAE, Univ. Montpellier, LBE, 102 Avenue des étangs, F-11100 Narbonne, France
| | - R Escudié
- INRAE, Univ. Montpellier, LBE, 102 Avenue des étangs, F-11100 Narbonne, France.
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Buultjens AH, Vandelannoote K, Mercoulia K, Ballard S, Sloggett C, Howden BP, Seemann T, Stinear TP. High performance Legionella pneumophila source attribution using genomics-based machine learning classification. Appl Environ Microbiol 2024; 90:e0129223. [PMID: 38289130 PMCID: PMC10952463 DOI: 10.1128/aem.01292-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/30/2023] [Indexed: 02/08/2024] Open
Abstract
Fundamental to effective Legionnaires' disease outbreak control is the ability to rapidly identify the environmental source(s) of the causative agent, Legionella pneumophila. Genomics has revolutionized pathogen surveillance, but L. pneumophila has a complex ecology and population structure that can limit source inference based on standard core genome phylogenetics. Here, we present a powerful machine learning approach that assigns the geographical source of Legionnaires' disease outbreaks more accurately than current core genome comparisons. Models were developed upon 534 L. pneumophila genome sequences, including 149 genomes linked to 20 previously reported Legionnaires' disease outbreaks through detailed case investigations. Our classification models were developed in a cross-validation framework using only environmental L. pneumophila genomes. Assignments of clinical isolate geographic origins demonstrated high predictive sensitivity and specificity of the models, with no false positives or false negatives for 13 out of 20 outbreak groups, despite the presence of within-outbreak polyclonal population structure. Analysis of the same 534-genome panel with a conventional phylogenomic tree and a core genome multi-locus sequence type allelic distance-based classification approach revealed that our machine learning method had the highest overall classification performance-agreement with epidemiological information. Our multivariate statistical learning approach maximizes the use of genomic variation data and is thus well-suited for supporting Legionnaires' disease outbreak investigations.IMPORTANCEIdentifying the sources of Legionnaires' disease outbreaks is crucial for effective control. Current genomic methods, while useful, often fall short due to the complex ecology and population structure of Legionella pneumophila, the causative agent. Our study introduces a high-performing machine learning approach for more accurate geographical source attribution of Legionnaires' disease outbreaks. Developed using cross-validation on environmental L. pneumophila genomes, our models demonstrate excellent predictive sensitivity and specificity. Importantly, this new approach outperforms traditional methods like phylogenomic trees and core genome multi-locus sequence typing, proving more efficient at leveraging genomic variation data to infer outbreak sources. Our machine learning algorithms, harnessing both core and accessory genomic variation, offer significant promise in public health settings. By enabling rapid and precise source identification in Legionnaires' disease outbreaks, such approaches have the potential to expedite intervention efforts and curtail disease transmission.
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Affiliation(s)
- Andrew H. Buultjens
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Center for Pathogen Genomics, University of Melbourne, Melbourne, Victoria, Australia
| | - Koen Vandelannoote
- Bacterial Phylogenomics Group, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Karolina Mercoulia
- Department of Microbiology and Immunology, Microbiology Diagnostic Unit, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Susan Ballard
- Department of Microbiology and Immunology, Microbiology Diagnostic Unit, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Clare Sloggett
- Department of Microbiology and Immunology, Microbiology Diagnostic Unit, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Benjamin P. Howden
- Center for Pathogen Genomics, University of Melbourne, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology, Microbiology Diagnostic Unit, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Department of Infectious Diseases, Austin Health, Heidelberg, Victoria, Australia
| | - Torsten Seemann
- Department of Microbiology and Immunology, Microbiology Diagnostic Unit, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Timothy P. Stinear
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Center for Pathogen Genomics, University of Melbourne, Melbourne, Victoria, Australia
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Jimoh AA, Booysen E, van Zyl L, Trindade M. Do biosurfactants as anti-biofilm agents have a future in industrial water systems? Front Bioeng Biotechnol 2023; 11:1244595. [PMID: 37781531 PMCID: PMC10540235 DOI: 10.3389/fbioe.2023.1244595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/04/2023] [Indexed: 10/03/2023] Open
Abstract
Biofilms are bacterial communities embedded in exopolymeric substances that form on the surfaces of both man-made and natural structures. Biofilm formation in industrial water systems such as cooling towers results in biofouling and biocorrosion and poses a major health concern as well as an economic burden. Traditionally, biofilms in industrial water systems are treated with alternating doses of oxidizing and non-oxidizing biocides, but as resistance increases, higher biocide concentrations are needed. Using chemically synthesized surfactants in combination with biocides is also not a new idea; however, these surfactants are often not biodegradable and lead to accumulation in natural water reservoirs. Biosurfactants have become an essential bioeconomy product for diverse applications; however, reports of their use in combating biofilm-related problems in water management systems is limited to only a few studies. Biosurfactants are powerful anti-biofilm agents and can act as biocides as well as biodispersants. In laboratory settings, the efficacy of biosurfactants as anti-biofilm agents can range between 26% and 99.8%. For example, long-chain rhamnolipids isolated from Burkholderia thailandensis inhibit biofilm formation between 50% and 90%, while a lipopeptide biosurfactant from Bacillus amyloliquefaciens was able to inhibit biofilms up to 96% and 99%. Additionally, biosurfactants can disperse preformed biofilms up to 95.9%. The efficacy of antibiotics can also be increased by between 25% and 50% when combined with biosurfactants, as seen for the V9T14 biosurfactant co-formulated with ampicillin, cefazolin, and tobramycin. In this review, we discuss how biofilms are formed and if biosurfactants, as anti-biofilm agents, have a future in industrial water systems. We then summarize the reported mode of action for biosurfactant molecules and their functionality as biofilm dispersal agents. Finally, we highlight the application of biosurfactants in industrial water systems as anti-fouling and anti-corrosion agents.
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Affiliation(s)
| | | | | | - Marla Trindade
- Department of Biotechnology, Institute for Microbial Biotechnology and Metagenomics (IMBM), University of the Western Cape, Cape Town, South Africa
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Gumá M, Drasar V, Santandreu B, Cano R, Afshar B, Nicolau A, Bennassar M, del Barrio J, Crespi P, Crespi S. A community outbreak of Legionnaires' disease caused by outdoor hot tubs for private use in a hotel. Front Microbiol 2023; 14:1137470. [PMID: 37180254 PMCID: PMC10167275 DOI: 10.3389/fmicb.2023.1137470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 03/30/2023] [Indexed: 05/16/2023] Open
Abstract
During the period October-November 2017, an outbreak of Legionnaires' disease involving 27 cases occurred in the tourist area of Palmanova (Mallorca, Spain). The majority of cases were reported by the European Centre of Disease Prevention and Control (ECDC) as travel associated cases of Legionnaires' disease (TALD). Most cases belonged to different hotel cluster alerts. No cases were reported among the local population residing in the area. All tourist establishments associated with one or more TALD cases were inspected and sampled by public health inspectors. All relevant sources of aerosol emission detected were investigated and sampled. The absence of active cooling towers in the affected area was verified, by documents and on-site. Samples from hot tubs for private use located on the terraces of the penthouse rooms of a hotel in the area were included in the study. Extremely high concentrations (> 106 CFU/l) of Legionella pneumophila, including the outbreak strain, were found in the hot tubs of vacant rooms of this hotel thus identifying the probable source of infection. Meteorological situation may have contributed to the geographical distribution pattern of this outbreak. In conclusion, hot tubs for private use located outdoors should be considered when investigating community outbreaks of Legionnaires' disease of unclear origin.
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Affiliation(s)
- Mercedes Gumá
- Conselleria de Salut i Consum, Govern Balear, Palma de Mallorca, Spain
| | - Vladimir Drasar
- Public Health Institute Ostrava, National Legionella Reference Laboratory, Ostrava, Czechia
| | - Beatriz Santandreu
- Environmental Health and Laboratory Services, Biolinea Int., Palma de Mallorca, Spain
| | - Rosa Cano
- Centro Nacional de Epidemiología and CIBERESP, Instituto de Salud Carlos III, Madrid, Spain
| | - Baharak Afshar
- Respiratory and Vaccine Preventable Bacteria Reference Unit (RVPBRU), UK Health Security Agency (UKHSA), London, United Kingdom
| | - Antonio Nicolau
- Conselleria de Salut i Consum, Govern Balear, Palma de Mallorca, Spain
| | - Magdalena Bennassar
- Environmental Health and Laboratory Services, Biolinea Int., Palma de Mallorca, Spain
| | - Jorge del Barrio
- Environmental Health and Laboratory Services, Biolinea Int., Palma de Mallorca, Spain
| | - Pau Crespi
- Environmental Health and Laboratory Services, Biolinea Int., Palma de Mallorca, Spain
| | - Sebastian Crespi
- Environmental Health and Laboratory Services, Biolinea Int., Palma de Mallorca, Spain
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Kim T, Zhao X, LaPara TM, Hozalski RM. Flushing Temporarily Improves Microbiological Water Quality for Buildings Supplied with Chloraminated Surface Water but Has Little Effect for Groundwater Supplies. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5453-5463. [PMID: 36952669 DOI: 10.1021/acs.est.2c08123] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Microbial communities in premise plumbing systems were investigated after more than 2 months of long-term stagnation, during a subsequent flushing event, and during post-flush stagnation. Water samples were collected from showers in buildings supplied with chlorinated groundwater, untreated groundwater, and chloraminated surface water. The building supplied with chlorinated groundwater generally had the lowest bacterial concentrations across all sites (ranging from below quantification limit to 5.2 log copies/L). For buildings supplied with untreated groundwater, bacterial concentrations (5.0 to 7.6 log copies/L) and microbial community diversity index (ACE) values were consistent throughout sampling. Nontuberculous mycobacteria (NTM) and Legionella pneumophila were not detected in any groundwater-supplied buildings. Total bacteria, Legionella spp., and NTM were abundant in the surface water-supplied buildings following long-term stagnation (up to 7.6, 6.2, and 7.6 log copies/L, respectively). Flushing decreased these concentrations by ∼1 to >4 log units and reduced microbial community diversity, but the communities largely recovered within a week of post-flush stagnation. The results suggest that buildings supplied with disinfected surface water are more likely than buildings supplied with treated or untreated groundwater to experience deleterious changes in microbiological water quality during stagnation and that the water quality improvements from flushing with chloraminated water, while substantial, are short-lived.
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Affiliation(s)
- Taegyu Kim
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota Twin Cities, 500 Pillsbury Drive S.E., Minneapolis, Minnesota 55455, United States
| | - Xiaotian Zhao
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota Twin Cities, 500 Pillsbury Drive S.E., Minneapolis, Minnesota 55455, United States
| | - Timothy M LaPara
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota Twin Cities, 500 Pillsbury Drive S.E., Minneapolis, Minnesota 55455, United States
- Biotechnology Institute, University of Minnesota Twin Cities, 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
| | - Raymond M Hozalski
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota Twin Cities, 500 Pillsbury Drive S.E., Minneapolis, Minnesota 55455, United States
- Biotechnology Institute, University of Minnesota Twin Cities, 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
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Persistent contamination of a hospital hot water network by Legionellapneumophila. Int J Hyg Environ Health 2023; 250:114143. [PMID: 36907106 DOI: 10.1016/j.ijheh.2023.114143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/20/2023] [Accepted: 02/20/2023] [Indexed: 03/12/2023]
Abstract
OBJECTIVES We assessed the contamination with Legionella pneumophila (Lp) of the hot water network (HWN) of a hospital, mapped the risk of contamination, and evaluated the relatedness of isolates. We further validated phenotypically the biological features that could account for the contamination of the network. METHODS We collected 360 water samples from October 2017 to September 2018 in 36 sampling points of a HWN of a building from a hospital in France. Lp were quantified and identified with culture-based methods and serotyping. Lp concentrations were correlated with water temperature, date and location of isolation. Lp isolates were genotyped by pulsed-field gel electrophoresis and compared to a collection of isolates retrieved in the same HWN two years later, or in other HWN from the same hospital. RESULTS 207/360 (57.5%) samples were positive with Lp. In the hot water production system, Lp concentration was negatively associated with water temperature. In the distribution system, the risk of recovering Lp decreased when temperature was >55 °C (p < 10-3), the proportion of samples with Lp increased with distance from the production network (p < 10-3), and the risk of finding high loads of Lp increased 7.96 times in summer (p = 0.001). All Lp isolates (n = 135) were of serotype 3, and 134 (99.3%) shared the same pulsotype which is found two years later (Lp G). In vitro competition experiments showed that a 3-day culture of Lp G on agar inhibited the growth of a different pulsotype of Lp (Lp O) contaminating another HWN of the same hospital (p = 0.050). We also found that only Lp G survived to a 24h-incubation in water at 55 °C (p = 0.014). CONCLUSION We report here a persistent contamination with Lp of a hospital HWN. Lp concentrations were correlated with water temperature, season, and distance from the production system. Such persistent contamination could be due to biotic parameters such as intra-Legionella inhibition and tolerance to high temperature, but also to the non-optimal configuration of the HWN that prevented the maintenance of high temperature and optimal water circulation.
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Radziminski C, White P. Cooling tower Legionella pneumophila surveillance results: Vancouver, Canada, 2021. JOURNAL OF WATER AND HEALTH 2023; 21:313-328. [PMID: 37338312 PMCID: wh_2023_154 DOI: 10.2166/wh.2023.154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
Cooling towers have been linked to Legionnaires' disease cases and outbreaks. Legionella pneumophila results (from a culture-based method) are presented for 557 cooling towers across the City of Vancouver, Canada for 2021. Results of 10 CFU/mL or greater (defined as exceedances) were reported for 30 cooling towers (5.4%), including six >1,000 CFU/mL, and L. pneumophila serogroup 1 (sg1) was identified in 17 of these cooling towers (out of 28 with serogroup-level analysis). The data indicate highly localised Legionella issues, with exceedances concentrated within 16 facilities, including two hospitals. In the 3 months preceding each cooling tower exceedance, the nearest municipal water sampling station had a free chlorine residual of at least 0.46 mg/L and a temperature of <20 °C. There was not a statistically significant correlation between the L. pneumophila concentration of a cooling tower in exceedance and the municipal water free chlorine residual, temperature, pH, turbidity or conductivity. There was a statistically significant negative correlation between the concentrations of L. pneumophila sg1 and other L. pneumophila serogroups in cooling towers. This unique dataset underscores the pivotal role of building owners and managers in preventing the growth of Legionella bacteria and the value of regulations to verify operations and maintenance practices.
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Affiliation(s)
- Christopher Radziminski
- City of Vancouver, Development, Buildings & Licensing, 515 W 10th Avenue, Vancouver, BC V5Z 4A8, Canada E-mail:
| | - Phillip White
- City of Vancouver, Development, Buildings & Licensing, 515 W 10th Avenue, Vancouver, BC V5Z 4A8, Canada E-mail:
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Campaña M, Del Hoyo R, Monleón-Getino A, Checa J. Predicting Legionella contamination in cooling towers and evaporative condensers from microbiological and physicochemical parameters. Int J Hyg Environ Health 2023; 248:114117. [PMID: 36708652 DOI: 10.1016/j.ijheh.2023.114117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 12/30/2022] [Accepted: 01/22/2023] [Indexed: 01/27/2023]
Abstract
BACKGROUND Inhalation of Legionella-containing aerosols generated by cooling towers (CT) and evaporative condensers (EC) where water risk management is not performed correctly has been linked to a high percentage of community outbreaks of Legionnaires' disease (LD). Likewise, microbiological and physicochemical characteristics of the water in these facilities have been associated with this bacterium. The main aim of this study was to assess the risk of Legionella colonization in CT and EC based on the data for microbiological and physicochemical water quality provided by the Environmental Health Department and Laboratory of the City Council of L'Hospitalet de Llobregat (Barcelona, Spain). METHODS Legionella was analysed in 789 samples collected from 127 CT and EC in 46 companies in Catalonia from 2002 to 2019. A two-step logistic regression analysis was carried out to assess the risk of colonization by Legionella in the studied facilities according to the microbiological (aerobic heterotrophic bacteria) and physicochemical (pH, alkalinity, hardness, turbidity, conductivity, total iron and Langelier Index) water parameters. The optimal cut-off points for the water parameters predictive of Legionella contamination were defined as the values on the receiver operating characteristic (ROC) curve where sensitivity and specificity were jointly maximized. RESULTS Legionella was isolated in 8.49% of the 789 analysed samples, 22.39% of which were heavily contaminated (with counts higher than 1.0 × 104 CFU/l). L. pneumophila was isolated in 82.09% of the samples, with 41.82% belonging to serogroup 1. Logistic regression analysis revealed that aerobic heterotrophic bacteria concentrations ≥6.90 × 102 CFU/ml [Odds ratios (OR) (95% CI) = 3.56 (1.39-9.43), p = 0.01], a pH ≥ 8.70 [OR (95% CI) = 3.60 (1.34-10.09), p = 0.01], and water hardness ≥5.72 × 102 mg/l [OR (95% CI) = 6.30 (2.34-18.56), p < 0.001] were each independently associated with a higher risk of CT and EC colonization by Legionella. CONCLUSIONS The present study shows the importance of risk assessment for improving the control measures aimed at preventing or reducing Legionella populations in CT and EC, thus minimizing potential dangers for public health.
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Affiliation(s)
- María Campaña
- BIOST(3). GRBIO. Department of Genetics, Microbiology and Statistics (Section of Statistics), Faculty of Biology, University of Barcelona, Diagonal 645, 08028, Barcelona, Spain.
| | - Rafael Del Hoyo
- Environmental Health Department and Laboratory, City Council of L'Hospitalet de Llobregat, Cobalt Building. Cobalt Street, 57-59, 2nd Floor, 08907, L'Hospitalet de Llobregat, Barcelona, Spain.
| | - Antonio Monleón-Getino
- BIOST(3). GRBIO. Department of Genetics, Microbiology and Statistics (Section of Statistics), Faculty of Biology, University of Barcelona, Diagonal 645, 08028, Barcelona, Spain.
| | - Javier Checa
- Environmental Health Department and Laboratory, City Council of L'Hospitalet de Llobregat, Cobalt Building. Cobalt Street, 57-59, 2nd Floor, 08907, L'Hospitalet de Llobregat, Barcelona, Spain.
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Four-Year Environmental Surveillance Program of Legionella spp. in One of Palermo’s Largest Hospitals. Microorganisms 2022; 10:microorganisms10040764. [PMID: 35456814 PMCID: PMC9030258 DOI: 10.3390/microorganisms10040764] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/25/2022] [Accepted: 03/28/2022] [Indexed: 02/05/2023] Open
Abstract
Legionella is a ubiquitous bacterium that lives in freshwater environments and colonizes human-made water systems. Legionella pneumophila is the most virulent species, and risk factors for Legionnaires’ disease include increasing age, smoking, chronic diseases, and immunodeficiency. For this reason, it is very important to assess and monitor hospital water systems in order to prevent legionellosis. We have monitored a large hospital in Palermo for four years. To determine the presence of microorganisms, according to national guidelines, we used the culture method, which is considered the gold standard for Legionella detection. Sampling was divided into five macro-areas, and a total of 251 samples were collected during the period of investigation, 49% of which were Legionella spp.-positive and 51% were Legionella spp.-negative. Positive samples with L. pneumophila. sgr 2-15 were most frequent in the Underground (55.6%, p = 0.0184), Medicine (42.9%, p = 0.0184) and Other (63.2%, p = 0.002) areas; while positive samples for L. pneumophila sgr 1 were less frequent in the Underground (0.0%, p = 0.0184) and Surgery areas (4.5%, p = 0.033), and for Legionella anisa, were less frequent in the Medicine (4.1%, p = 0.021), Oncohematology (0.0%, p = 0.0282), and Other (0.0%, p = 0.016) areas. Finally, no significant differences were observed among the areas for each isolate considered. The surveillance carried out in these years demonstrates the importance of monitoring, which allows us to analyze the conditions of hospital facilities and, therefore, prevent Legionella spp. infections.
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Salinas MB, Fenoy S, Magnet A, Vaccaro L, Gomes TD, Hurtado C, Ollero D, Valdivieso E, Del Águila C, Pozuelo MJ, Izquierdo F. Are pathogenic Legionella non-pneumophila a common bacteria in Water Distribution Networks? WATER RESEARCH 2021; 196:117013. [PMID: 33813251 DOI: 10.1016/j.watres.2021.117013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/16/2021] [Accepted: 03/04/2021] [Indexed: 05/22/2023]
Abstract
The present study analyzes at the national level, the presence of circulating Legionella in the artificial aquatic systems of different facilities of all of them state-owned centers throughout Spain for 12 months. 1754 water samples from various state-owned centers were collected from January to December 2014. Samples were collected from the cooling towers and evaporative condensers (CTC), and water distribution networks such as domestic hot water (DHW), cold water for human consumption (CW), sprinkler irrigation systems (SIS), fire sprinkler systems (FSS), and water from decorative fountains (DF). All these facilities are considered, according to current regulations, as potential amplifying systems for bacteria and possible sources of infection by the generation of droplets and aerosols. The isolation and counting of Legionella in water samples was carried out using microbiological culture following the international normative UNE-EN-ISO 11,731:2007 (ISO 11,731:1998) and UNE-EN ISO 8199:2008 (ISO 8199:2005).The quantification of Legionella colonization, the annual distribution, and the geographical distribution of the Legionella isolates recovered in the water were analyzed. Besides, molecular techniques were used for the characterization of the Legionella non-pneumophila isolates. Legionella was recovered from 15.79% of the analyzed water samples. High colonization was more frequently detected in water samples from CTC, DHW, CW, and DF. Regarding the geographic distribution, positive samples of Legionella were obtained in 14 of the 18 Spanish locations analyzed. Legionella non-pneumophila was the most prevalent and was isolated from water samples from 13 different geographical locations (72%). Legionella anisa and Legionella jordanis were the most frequently non-pneumophila species isolated. Legionella donaldsonii was isolated for the first time in the water distribution networks in Spain. Legionella pneumophila sg 2-14 was detected in 13 locations and Legionella pneumophila sg 1 in 11 locations. Therefore, our study concludes that the presence of Legionella pneumophila and Legionella non-pneumophila species in these systems can be a potential threat to public health and should be examined thoroughly with complementary techniques, such as molecular techniques as a screen for routine diagnosis.
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Affiliation(s)
- Mireya Beatriz Salinas
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Madrid, España
| | - Soledad Fenoy
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Madrid, España
| | - Angela Magnet
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Madrid, España
| | - Lucianna Vaccaro
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Madrid, España
| | - Thiago Ds Gomes
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Madrid, España
| | - Carolina Hurtado
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Madrid, España
| | - Dolores Ollero
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Madrid, España
| | - Elizabeth Valdivieso
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Madrid, España
| | - Carmen Del Águila
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Madrid, España
| | - María José Pozuelo
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Madrid, España
| | - Fernando Izquierdo
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660 Boadilla del Monte, Madrid, España.
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Chasing Waterborne Pathogens in Antarctic Human-Made and Natural Environments, with Special Reference to Legionella spp. Appl Environ Microbiol 2021; 87:AEM.02247-20. [PMID: 33097517 DOI: 10.1128/aem.02247-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 10/18/2020] [Indexed: 12/21/2022] Open
Abstract
Waterborne pathogenic diseases are public health issues, especially for people staying in remote environments, such as Antarctica. After repeated detection of Legionella by PCR from the shower room of Syowa Station, the Japanese Antarctic research station, we wanted to understand the occurrence of waterborne pathogens, especially Legionella, in the station and their potential sources. In this study, we analyzed water and biofilm samples collected from the water facilities of Syowa Station, as well as water samples from surrounding glacier lakes, by 16S rRNA gene-based amplicon sequencing. For Legionella spp., we further attempted to obtain a detailed community structure by using genus-specific primers. The results showed that potentially pathogenic genera were mostly localized in the station, while Legionella spp., Pseudomonas spp., and Mycobacterium spp. were also widely distributed in lakes. Genus-specific analysis of Legionella spp. within the lake environments confirmed the presence of diverse Legionella amplicon sequence variants (ASVs) that were distinctly different from the Legionella ASVs detected in the station. The majority of the Legionella ASVs inhabiting Antarctic lake habitats were phylogenetically distinct from known Legionella species, whereas the ASVs detected in the human-made station tended to contain ASVs highly similar to well-described mesophilic species with human pathogenicity. These data suggest that unexpected Legionella diversity exists in remote Antarctic cold environments and that environmental differences (e.g., temperature) in and around the station affect the community structure.IMPORTANCE We comprehensively examined the localization of potential waterborne pathogens in the Antarctic human-made and natural aquatic environment with special focus on Legionella spp. Some potential pathogenic genera were detected with low relative abundance in the natural environment, but most detections of these genera occurred in the station. Through detailed community analysis of Legionella spp., we revealed that a variety of Legionella spp. was widely distributed in the Antarctic environment and that they were phylogenetically distinct from the described species. This fact indicates that there are still diverse unknown Legionella spp. in Antarctica, and this genus encompasses a greater variety of species in low-temperature environments than is currently known. In contrast, amplicon sequence variants closely related to known Legionella spp. with reported pathogenicity were almost solely localized in the station, suggesting that human-made environments alter the Legionella community.
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12
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Brigmon RL, Turick CE, Knox AS, Burckhalter CE. The Impact of Storms on Legionella pneumophila in Cooling Tower Water, Implications for Human Health. Front Microbiol 2020; 11:543589. [PMID: 33362725 PMCID: PMC7758282 DOI: 10.3389/fmicb.2020.543589] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 11/02/2020] [Indexed: 12/03/2022] Open
Abstract
At the U.S. Department of Energy’s Savannah River Site (SRS) in Aiken, SC, cooling tower water is routinely monitored for Legionella pneumophila concentrations using a direct fluorescent antibody (DFA) technique. Historically, 25–30 operating SRS cooling towers have varying concentrations of Legionella in all seasons of the year, with patterns that are unpredictable. Legionellosis, or Legionnaires’ disease (LD), is a pneumonia caused by Legionella bacteria that thrive both in man-made water distribution systems and natural surface waters including lakes, streams, and wet soil. Legionnaires’ disease is typically contracted by inhaling L. pneumophila, most often in aerosolized mists that contain the bacteria. At the SRS, L. pneumophila is typically found in cooling towers ranging from non-detectable up to 108 cells/L in cooling tower water systems. Extreme weather conditions contributed to elevations in L. pneumophila to 107–108 cells/L in SRS cooling tower water systems in July–August 2017. L. pneumophila concentrations in Cooling Tower 785-A/2A located in SRS A-Area, stayed in the 108 cells/L range despite biocide addition. During this time, other SRS cooling towers did not demonstrate this L. pneumophila increase. No significant difference was observed in the mean L. pneumophila mean concentrations for the towers (p < 0.05). There was a significant variance observed in the 285-2A/A Tower L. pneumophila results (p < 0.05). Looking to see if we could find “effects” led to model development by analyzing 13 months of water chemistry and microbial data for the main factors influencing the L. pneumophila concentrations in five cooling towers for this year. It indicated chlorine and dissolved oxygen had a significant impact (p < 0.0002) on cooling tower 785A/2A. Thus, while the variation in the log count data for the A-area tower is statistically greater than that of the other four towers, the average of the log count data for the A-Area tower was in line with that of the other towers. It was also observed that the location of 785A/2A and basin resulted in more debris entering the system during storm events. Our results suggest that future analyses should evaluate the impact of environmental conditions and cooling tower design on L. pneumophila water concentrations and human health.
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Affiliation(s)
- Robin L Brigmon
- Savannah River National Laboratory, Environmental Science and Biotechnology Group, Aiken, SC, United States
| | - Charles E Turick
- Savannah River National Laboratory, Environmental Science and Biotechnology Group, Aiken, SC, United States
| | - Anna S Knox
- Savannah River National Laboratory, Environmental Science and Biotechnology Group, Aiken, SC, United States
| | - Courtney E Burckhalter
- Savannah River National Laboratory, Environmental Science and Biotechnology Group, Aiken, SC, United States
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13
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Li M, Matouš K, Nerenberg R. Predicting biofilm deformation with a viscoelastic phase‐field model: Modeling and experimental studies. Biotechnol Bioeng 2020; 117:3486-3498. [DOI: 10.1002/bit.27491] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/18/2020] [Accepted: 07/10/2020] [Indexed: 01/27/2023]
Affiliation(s)
- Mengfei Li
- Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame Notre Dame Indiana
| | - Karel Matouš
- Department of Aerospace and Mechanical Engineering University of Notre Dame Notre Dame Indiana
| | - Robert Nerenberg
- Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame Notre Dame Indiana
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14
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Wüthrich D, Gautsch S, Spieler-Denz R, Dubuis O, Gaia V, Moran-Gilad J, Hinic V, Seth-Smith HM, Nickel CH, Tschudin-Sutter S, Bassetti S, Haenggi M, Brodmann P, Fuchs S, Egli A. Air-conditioner cooling towers as complex reservoirs and continuous source of Legionella pneumophila infection evidenced by a genomic analysis study in 2017, Switzerland. ACTA ACUST UNITED AC 2020; 24. [PMID: 30696527 PMCID: PMC6351994 DOI: 10.2807/1560-7917.es.2019.24.4.1800192] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Introduction Water supply and air-conditioner cooling towers (ACCT) are potential sources of Legionella pneumophila infection in people. During outbreaks, traditional typing methods cannot sufficiently segregate L. pneumophila strains to reliably trace back transmissions to these artificial water systems. Moreover, because multiple L. pneumophila strains may be present within these systems, methods to adequately distinguish strains are needed. Whole genome sequencing (WGS) and core genome multilocus sequence typing (cgMLST), with their higher resolution are helpful in this respect. In summer 2017, the health administration of the city of Basel detected an increase of L. pneumophila infections compared with previous months, signalling an outbreak. Aim We aimed to identify L. pneumophila strains populating suspected environmental sources of the outbreak, and to assess the relations between these strains and clinical outbreak strains. Methods An epidemiological and WGS-based microbiological investigation was performed, involving isolates from the local water supply and two ACCTs (n = 60), clinical outbreak and non-outbreak related isolates from 2017 (n = 8) and historic isolates from 2003–2016 (n = 26). Results In both ACCTs, multiple strains were found. Phylogenetic analysis of the ACCT isolates showed a diversity of a few hundred allelic differences in cgMLST. Furthermore, two isolates from one ACCT showed no allelic differences to three clinical isolates from 2017. Five clinical isolates collected in the Basel area in the last decade were also identical in cgMLST to recent isolates from the two ACCTs. Conclusion Current outbreak-related and historic isolates were linked to ACCTs, which form a complex environmental habitat where strains are conserved over years.
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Affiliation(s)
- Daniel Wüthrich
- Swiss Institute of Bioinformatics, Basel, Switzerland.,Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland.,Division of Clinical Microbiology, University Hospital Basel, Basel, Switzerland
| | | | - Ruth Spieler-Denz
- Department of Health, Medical Services, Canton of Basel-Stadt, Basel, Switzerland
| | | | - Valeria Gaia
- National Reference Center for Legionella, Department of Laboratory medicine, Ente Ospedaliero Cantonale, Bellinzona, Switzerland
| | - Jacob Moran-Gilad
- Public Health Services, Ministry of Health, Jerusalem, Israel.,Department of Health Systems Management, School of Public Health, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Vladimira Hinic
- Division of Clinical Microbiology, University Hospital Basel, Basel, Switzerland
| | - Helena Mb Seth-Smith
- Swiss Institute of Bioinformatics, Basel, Switzerland.,Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland.,Division of Clinical Microbiology, University Hospital Basel, Basel, Switzerland
| | - Christian H Nickel
- Division of Emergency Medicine, University Hospital Basel, Basel, Switzerland
| | - Sarah Tschudin-Sutter
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland
| | - Stefano Bassetti
- Division of Internal Medicine, University Hospital Basel, Basel, Switzerland
| | - Monika Haenggi
- Department of Health, Medical Services, Canton of Basel-Country, Liestal, Switzerland
| | | | - Simon Fuchs
- Department of Health, Medical Services, Canton of Basel-Stadt, Basel, Switzerland
| | - Adrian Egli
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland.,Division of Clinical Microbiology, University Hospital Basel, Basel, Switzerland
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15
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Hasni I, Jarry A, Quelard B, Carlino A, Eberst JB, Abbe O, Demanèche S. Intracellular Behaviour of Three Legionella pneumophila Strains within Three Amoeba Strains, Including Willaertia magna C2c Maky. Pathogens 2020; 9:pathogens9020105. [PMID: 32041369 PMCID: PMC7168187 DOI: 10.3390/pathogens9020105] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/04/2020] [Accepted: 02/05/2020] [Indexed: 12/12/2022] Open
Abstract
Legionella pneumophila is a facultative intracellular pathogen found in aquatic environments as planktonic cells within biofilms and as intracellular parasites of free-living amoebae such as Acanthamoeba castellanii. This pathogen bypasses the elimination mechanism to replicate within amoebae; however, not all amoeba species support the growth of L. pneumophila. Willaertia magna C2c Maky, a non-pathogenic amoeba, was previously demonstrated to possess the ability to eliminate the L. pneumophila strain Paris. Here, we study the intracellular behaviour of three L. pneumophila strains (Paris, Philadelphia, and Lens) within W. magna C2c Maky and compare this strain to A. castellanii and W. magna Z503, which are used as controls. We observe the intracellular growth of strain Lens within W. magna Z503 and A. castellanii at 22 °C and 37 °C. Strain Paris grows within A. castellanii at any temperature, while it only grows at 22 °C within W. magna Z503. Strain Philadelphia proliferates only within A. castellanii at 37 °C. Within W. magna C2c Maky, none of the three legionella strains exhibit intracellular growth. Additionally, the ability of W. magna C2c Maky to decrease the number of internalized L. pneumophila is confirmed. These results support the idea that W. magna C2c Maky possesses unique behaviour in regard to L. pneumophila strains.
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Affiliation(s)
- Issam Hasni
- Microbes, Evolution, Phylogeny and Infection Department, Institut de Recherche pour le Développement IRD 198, Institut Hospitalo-Universitaire (IHU), Aix-Marseille Université, 13007 Marseille, France;
- R&D Department, Amoéba, 38 Avenue des Frères Montgolfier, 69680 Chassieu, France; (A.J.); (B.Q.); (A.C.); (J.-B.E.); (O.A.)
| | - Antoine Jarry
- R&D Department, Amoéba, 38 Avenue des Frères Montgolfier, 69680 Chassieu, France; (A.J.); (B.Q.); (A.C.); (J.-B.E.); (O.A.)
| | - Benjamin Quelard
- R&D Department, Amoéba, 38 Avenue des Frères Montgolfier, 69680 Chassieu, France; (A.J.); (B.Q.); (A.C.); (J.-B.E.); (O.A.)
| | - Antoine Carlino
- R&D Department, Amoéba, 38 Avenue des Frères Montgolfier, 69680 Chassieu, France; (A.J.); (B.Q.); (A.C.); (J.-B.E.); (O.A.)
| | - Jean-Baptiste Eberst
- R&D Department, Amoéba, 38 Avenue des Frères Montgolfier, 69680 Chassieu, France; (A.J.); (B.Q.); (A.C.); (J.-B.E.); (O.A.)
| | - Olivier Abbe
- R&D Department, Amoéba, 38 Avenue des Frères Montgolfier, 69680 Chassieu, France; (A.J.); (B.Q.); (A.C.); (J.-B.E.); (O.A.)
| | - Sandrine Demanèche
- R&D Department, Amoéba, 38 Avenue des Frères Montgolfier, 69680 Chassieu, France; (A.J.); (B.Q.); (A.C.); (J.-B.E.); (O.A.)
- Correspondence:
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16
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Paranjape K, Bédard É, Whyte LG, Ronholm J, Prévost M, Faucher SP. Presence of Legionella spp. in cooling towers: the role of microbial diversity, Pseudomonas, and continuous chlorine application. WATER RESEARCH 2020; 169:115252. [PMID: 31726393 DOI: 10.1016/j.watres.2019.115252] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 10/23/2019] [Accepted: 10/27/2019] [Indexed: 05/25/2023]
Abstract
Legionnaires' disease (LD) is a severe pneumonia caused by several species of the genus Legionella, most frequently by Legionella pneumophila. Cooling towers are the most common source for large community-associated outbreaks. Colonization, survival, and proliferation of L. pneumophila in cooling towers are necessary for outbreaks to occur. These steps are affected by the chemical and physical parameters of the cooling tower environment. We hypothesize that the bacterial community residing in the cooling tower could also affect the presence of L. pneumophila. A 16S rRNA gene targeted amplicon sequencing approach was used to study the bacterial community of cooling towers and its relationship with the Legionella spp. and L. pneumophila communities. The results indicated that the water source shaped the bacterial community of cooling towers. Several taxa were enriched and positively correlated with Legionella spp. and L. pneumophila. In contrast, Pseudomonas showed a strong negative correlation with Legionella spp. and several other genera. Most importantly, continuous chlorine application reduced microbial diversity and promoted the presence of Pseudomonas creating a non-permissive environment for Legionella spp. This suggests that disinfection strategies as well as the resident microbial population influences the ability of Legionella spp. to colonize cooling towers.
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Affiliation(s)
- Kiran Paranjape
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Émilie Bédard
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada; Department of Civil Engineering, Polytechnique Montréal, Montréal, QC, Canada
| | - Lyle G Whyte
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Jennifer Ronholm
- Department of Food Science and Agricultural Chemistry, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada; Department of Animal Science, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Michèle Prévost
- Department of Civil Engineering, Polytechnique Montréal, Montréal, QC, Canada
| | - Sébastien P Faucher
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada.
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17
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Bayle S, Martinez-Arribas B, Jarraud S, Giannoni P, Garrelly L, Roig B, Cadière A. Development of a DGGE method to explore Legionella communities. Heliyon 2020; 6:e03149. [PMID: 31922052 PMCID: PMC6948247 DOI: 10.1016/j.heliyon.2019.e03149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 03/18/2019] [Accepted: 12/30/2019] [Indexed: 11/26/2022] Open
Abstract
Legionella risk assessment is nowadays based on the presence and concentration of either Legionella pneumophila or Legionella spp. Many species of Legionella can cause Legionnaires' disease, indeed about half of the known species have been associated with infection. The aim of this work was to develop a method to assess the composition of the Legionella species community in an environmental sample in order to have a better understanding of the contamination of the ecosystem by pathogenic strains. The method is based on the comparison of PCR-DGGE profile of DNA sample with a database consisting in DGGE profiles of Legionella species. Such a database includes all pathogenic Legionella strains. In order to homogenize and normalize the different DGGE fingerprint, a reference marker has been built and added during DGGE gel analysis. This study gives a valuable advance in the methods available for the understanding of Legionella contamination of water environments.
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Affiliation(s)
- S Bayle
- Laboratoire Génie de l'Environnement Industriel, IMT- Mines Alès, Université de Montpellier, Alès, 30100, France
| | - B Martinez-Arribas
- EA7352 CHROME, Rue du Dr G. Salan, University of Nîmes, 30021 Nîmes cedex 1, France
| | - S Jarraud
- Hospices Civils de Lyon, Groupement Hospitalier Nord, Institut des Agents Infectieux, France
| | - P Giannoni
- EA7352 CHROME, Rue du Dr G. Salan, University of Nîmes, 30021 Nîmes cedex 1, France
| | - L Garrelly
- GL Biocontrol, 9, avenue de l'Europe, Cap Alpha, 34830, Clapiers, France
| | - B Roig
- EA7352 CHROME, Rue du Dr G. Salan, University of Nîmes, 30021 Nîmes cedex 1, France
| | - A Cadière
- EA7352 CHROME, Rue du Dr G. Salan, University of Nîmes, 30021 Nîmes cedex 1, France
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18
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Inoue H, Agata K, Ohta H. Phylogenetic Characterization of Viable but-not-yet Cultured Legionella Groups Grown in Amoebic Cocultures: A Case Study using Various Cooling Tower Water Samples. Biocontrol Sci 2019; 24:39-45. [PMID: 30880312 DOI: 10.4265/bio.24.39] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Legionella spp. exist naturally in association with amoeba in water environments and are known to be the etiological agent of a severe form of pneumonia. To detect diverse Legionella populations in cooling tower water systems, amoebic coculturing was performed for 15 water samples obtained from five different kinds of facilities in six geographically different locations. The growth of Legionella in coculture with Acanthamoeba sp. cells was monitored by quantitative PCR targeting Legionella-specific 16S rRNA genes. Seven out of the 15 samples were positive for Legionella growth and subjected to clone library analysis. A total of 333 clones were classified into 14 operational taxonomic units composed of seven known species and seven previously undescribed groups. Four of the seven Legionella-growth-positive samples harbored detectable levels of free-living amoeba and were predominated by either L. drozanskii or L. lytica, by both L. bozemanii and L. longbeachae, or by a not-yet-described group named OTU 4. The Legionella-growth- positive samples contained higher ATP levels (>980 pM) than the growth-negative samples (<160 pM) , suggesting that ATP content would be a good indicator of the presence of viable but nonculturable Legionella populations able to grow with amoeba.
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Affiliation(s)
- Hiroaki Inoue
- Tsukuba Research Laboratories, Aquas Corporation.,Ibaraki University College of Agriculture
| | - Kunio Agata
- Tsukuba Research Laboratories, Aquas Corporation
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19
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Sharaby Y, Rodríguez-Martínez S, Höfle MG, Brettar I, Halpern M. Quantitative microbial risk assessment of Legionella pneumophila in a drinking water supply system in Israel. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 671:404-410. [PMID: 30933796 DOI: 10.1016/j.scitotenv.2019.03.287] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 03/13/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
Legionella pneumophila cause human infections via inhalation of contaminated water aerosols, resulting in severe pneumonia. Legionella spp. prevalence was monitored in a drinking-water distribution system (DWDS) in Northern Israel. Five points (toilet faucets and showers) were sampled seasonally along a three years period. Toilet faucets and shower use, both generating aerosols, are known transmission routes for this pathogen and thus, present a potential health risk. Quantitative Microbial Risk Assessment (QMRA) was applied in order to assess the health risks posed by Legionella for these two exposure scenarios, while considering Legionella seasonality. The obtained results were compared with estimated tolerable risk levels of infection and of disease set by the USEPA and WHO. Both limits were expressed as Disability-Adjusted Life Years index (DALY) being 1 × 10-4 and 1 × 10-6, respectively. The QMRA revealed that the annual risk levels for both faucets and showers use exceeded the acceptable risk of infection with an average of 5.52 × 10-4 and 2.37 × 10-3 DALY'S per person per year, respectively. Annual risk levels were stable with no significant differences between the three years. Risk levels varied significantly between seasons by up to three orders of magnitude. Risk levels were highest during summer, autumn, and lowest during winter. The highest seasonal infection risk values were found in summer for both faucets and showers, which corresponded to 8.09 × 10-4 and 2.75 × 10-3 DALY'S per person per year, respectively. In conclusion, during summer and autumn there is a significant increase of the infection risk associated with exposure to Legionella-contaminated aerosols, in the studied water system. Public health assessment and prevention measures should focus on these seasons.
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Affiliation(s)
- Y Sharaby
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
| | - S Rodríguez-Martínez
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - M G Höfle
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - I Brettar
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - M Halpern
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel; Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Tivon, Israel
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20
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Levin TC, Goldspiel BP, Malik HS. Density-dependent resistance protects Legionella pneumophila from its own antimicrobial metabolite, HGA. eLife 2019; 8:46086. [PMID: 31134893 PMCID: PMC6598767 DOI: 10.7554/elife.46086] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/16/2019] [Indexed: 01/01/2023] Open
Abstract
To persist in microbial communities, the bacterial pathogen Legionella pneumophila must withstand competition from neighboring bacteria. Here, we find that L. pneumophila can antagonize the growth of other Legionella species using a secreted inhibitor: HGA (homogentisic acid). Unexpectedly, L. pneumophila can itself be inhibited by HGA secreted from neighboring, isogenic strains. Our genetic approaches further identify lpg1681 as a gene that modulates L. pneumophila susceptibility to HGA. We find that L. pneumophila sensitivity to HGA is density-dependent and cell intrinsic. Resistance is not mediated by the stringent response nor the previously described Legionella quorum-sensing pathway. Instead, L. pneumophila cells secrete HGA only when they are conditionally HGA-resistant, which allows these bacteria to produce a potentially self-toxic molecule while restricting the opportunity for self-harm. We propose that established Legionella communities may deploy molecules such as HGA as an unusual public good that can protect against invasion by low-density competitors. In the environment, bacteria frequently compete with each other for resources and space. These battles often involve the bacteria releasing toxins, antibiotics or other molecules that make it more difficult for their neighbors to grow. The bacteria also carry specific resistance genes that protect them from the effects of the molecules that they produce. Legionella pneumophila is a species of bacteria that infects people and causes a severe form of pneumonia known as Legionnaires’ disease. The bacteria spread in droplets of water from contaminated water systems such as sink faucets, cooling towers, water tanks, and other plumbing systems. In these water systems, L. pneumophila cells live within communities known as biofilms, which contain many different species of bacteria. These communities often include other species of Legionella that compete with L. pneumophila for similar nutrients. However, L. pneumophila was not known to produce any toxins or antibiotics, so it was not clear how it is able to survive in biofilms. Levin et al. used genetic approaches to investigate how L. pneumophila competes with other species of Legionella. The experiments found that this bacterium released a molecule called homogentisic acid (HGA) that reduced the growth of neighboring Legionella bacteria. Unexpectedly, L. pneumophila was not always resistant to HGA, despite secreting large quantities of this molecule. Instead, L. pneumophila cells were only resistant to HGA when the bacteria were living in crowded conditions. Previous studies have shown that HGA is widely produced by bacteria and other organisms – including humans – but this is the first time it has been shown that this molecule limits the ability of bacteria to grow. The work of Levin et al. suggests that HGA may help L. pneumophila bacteria to persist in biofilms, but more work needs to be done to test this idea. A possible next step is to test whether drugs that inhibit the production of HGA can eliminate Legionella bacteria from water systems. If so, similar treatments could potentially be used to stop and prevent outbreaks of Legionnaires’ disease in the future.
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Affiliation(s)
- Tera C Levin
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Brian P Goldspiel
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Harmit S Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States.,Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, United States
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21
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Di Pippo F, Di Gregorio L, Congestri R, Tandoi V, Rossetti S. Biofilm growth and control in cooling water industrial systems. FEMS Microbiol Ecol 2019; 94:4935158. [PMID: 29596620 DOI: 10.1093/femsec/fiy044] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/13/2018] [Indexed: 12/18/2022] Open
Abstract
Matrix-embedded, surface-attached microbial communities, known as biofilms, profusely colonise industrial cooling water systems, where the availability of nutrients and organic matter favours rapid microbial proliferation and their adhesion to surfaces in the evaporative fill material, heat exchangers, water reservoir and cooling water sections and pipelines. The extensive growth of biofilms can promote micro-biofouling and microbially induced corrosion (MIC) as well as pose health problems associated with the presence of pathogens like Legionella pneumophila. This review examines critically biofilm occurrence in cooling water systems and the main factors potentially affecting biofilm growth, biodiversity and structure. A broad evaluation of the most relevant biofilm monitoring and control strategies currently used or potentially useful in cooling water systems is also provided.
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Affiliation(s)
- F Di Pippo
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy.,CNR-IAMC, National Research Council, Institute for Coastal Marine Environment, Località Sa Mardini, Torregrande, 09170 Oristano, Italy
| | - L Di Gregorio
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy.,University of Rome Tor Vergata, Department of Biology, Via Cracovia 1, 00133 Rome, Italy
| | - R Congestri
- University of Rome Tor Vergata, Department of Biology, Via Cracovia 1, 00133 Rome, Italy
| | - V Tandoi
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy
| | - S Rossetti
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy
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Di Gregorio L, Congestri R, Tandoi V, Neu TR, Rossetti S, Di Pippo F. Biofilm diversity, structure and matrix seasonality in a full-scale cooling tower. BIOFOULING 2018; 34:1093-1109. [PMID: 30663885 DOI: 10.1080/08927014.2018.1541454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 10/23/2018] [Accepted: 10/24/2018] [Indexed: 06/09/2023]
Abstract
Biofilms commonly colonise cooling water systems, causing equipment damage and interference with the operational requirements of the systems. In this study, next-generation sequencing (NGS), catalysed reporter deposition fluorescence in situ hybridisation (CARD-FISH), lectin staining and microscopy were used to evaluate temporal dynamics in the diversity and structure of biofilms collected seasonally over one year from an open full-scale cooling tower. Water samples were analysed to evaluate the contribution of the suspended microorganisms to the biofilm composition and structure. Alphaproteobacteria dominated the biofilm communities along with Beta- and Gammaproteobacteria. The phototrophic components were mainly cyanobacteria, diatoms and green algae. Bacterial biodiversity decreased from winter to autumn, concurrently with an increase in cyanobacterial and microalgal richness. Differences in structure, spatial organisation and glycoconjugates were observed among assemblages during the year. Overall, microbial variation appeared to be mostly affected by irradiance and water temperature rather than the source of the communities. Variations in biofilms over seasons should be evaluated to develop specific control strategies.
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Affiliation(s)
- L Di Gregorio
- a CNR-IRSA , Water Research Institute , Rome , Italy
- b Department of Biology , University of Rome Tor Vergata , Rome , Italy
| | - R Congestri
- b Department of Biology , University of Rome Tor Vergata , Rome , Italy
| | - V Tandoi
- a CNR-IRSA , Water Research Institute , Rome , Italy
| | - T R Neu
- c Department of River Ecology , Helmholtz Centre for Environmental Research - UFZ , Magdeburg , Germany
| | - S Rossetti
- a CNR-IRSA , Water Research Institute , Rome , Italy
| | - F Di Pippo
- a CNR-IRSA , Water Research Institute , Rome , Italy
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23
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Shen Y, Huang PC, Huang C, Sun P, Monroy GL, Wu W, Lin J, Espinosa-Marzal RM, Boppart SA, Liu WT, Nguyen TH. Effect of divalent ions and a polyphosphate on composition, structure, and stiffness of simulated drinking water biofilms. NPJ Biofilms Microbiomes 2018; 4:15. [PMID: 30038792 PMCID: PMC6052100 DOI: 10.1038/s41522-018-0058-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 05/24/2018] [Accepted: 06/01/2018] [Indexed: 02/04/2023] Open
Abstract
The biofilm chemical and physical properties in engineered systems play an important role in governing pathogen transmission, fouling facilities, and corroding metal surfaces. Here, we investigated how simulated drinking water biofilm chemical composition, structure, and stiffness responded to the common scale control practice of adjusting divalent ions and adding polyphosphate. Magnetomotive optical coherence elastography (MM-OCE), a tool developed for diagnosing diseased tissues, was used to determine biofilm stiffness in this study. MM-OCE, together with atomic force microscopy (AFM), revealed that the biofilms developed from a drinking water source with high divalent ions were stiffer compared to biofilms developed either from the drinking water source with low divalent ions or the water containing a scale inhibitor (a polyphosphate). The higher stiffness of biofilms developed from the water containing high divalent ions was attributed to the high content of calcium carbonate, suggested by biofilm composition examination. In addition, by examining the biofilm structure using optical coherence tomography (OCT), the highest biofilm thickness was found for biofilms developed from the water containing the polyphosphate. Compared to the stiff biofilms developed from the water containing high divalent ions, the soft and thick biofilms developed from the water containing polyphosphate will be expected to have higher detachment under drinking water flow. This study suggested that water chemistry could be used to predict the biofilm properties and subsequently design the microbial safety control strategies. A variety of analytical techniques are revealing the complex influences of ions in drinking water supplies on the structure of biofilms. Such biofilms often contaminate water supply pipes and machinery. Yun Shen and colleagues at the University of Illinois at Urbana-Champaign in the USA investigated the effects of ions with a double positive charge – ‘divalent cations’ – and polyphosphate ions. Divalent cations, especially calcium and magnesium ions, are abundant in drinking water in many regions, promoting the formation of limescale deposits. Polyphosphates are commonly added to water supplies to reduce limescale formation, inhibit corrosion and discourage biofilm formation. The research revealed that divalent cations increase biofilm stiffness, while polyphosphates promote softer but thicker biofilms that are more easily removed. The results will help optimize water treatment procedures to control both microbial contamination and limescale problems.
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Affiliation(s)
- Yun Shen
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA.,4Present Address: University of Michigan, 1351 Beal Ave., 219 EWRE Bldg, Ann Arbor, MI 48109-2125 USA
| | - Pin Chieh Huang
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Conghui Huang
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Peng Sun
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Guillermo L Monroy
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Wenjing Wu
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Jie Lin
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Rosa M Espinosa-Marzal
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Stephen A Boppart
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA.,3Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Wen-Tso Liu
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Thanh H Nguyen
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
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24
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Caicedo C, Rosenwinkel KH, Nogueira R. Temperature-driven growth of Legionella in lab-scale activated sludge systems and interaction with protozoa. Int J Hyg Environ Health 2018; 221:315-322. [DOI: 10.1016/j.ijheh.2017.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 12/07/2017] [Accepted: 12/10/2017] [Indexed: 12/14/2022]
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25
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Llewellyn AC, Lucas CE, Roberts SE, Brown EW, Nayak BS, Raphael BH, Winchell JM. Distribution of Legionella and bacterial community composition among regionally diverse US cooling towers. PLoS One 2017; 12:e0189937. [PMID: 29261791 PMCID: PMC5738086 DOI: 10.1371/journal.pone.0189937] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 12/05/2017] [Indexed: 11/19/2022] Open
Abstract
Cooling towers (CTs) are a leading source of outbreaks of Legionnaires' disease (LD), a severe form of pneumonia caused by inhalation of aerosols containing Legionella bacteria. Accordingly, proper maintenance of CTs is vital for the prevention of LD. The aim of this study was to determine the distribution of Legionella in a subset of regionally diverse US CTs and characterize the associated microbial communities. Between July and September of 2016, we obtained aliquots from water samples collected for routine Legionella testing from 196 CTs located in eight of the nine continental US climate regions. After screening for Legionella by PCR, positive samples were cultured and the resulting Legionella isolates were further characterized. Overall, 84% (164) were PCR-positive, including samples from every region studied. Of the PCR-positive samples, Legionella spp were isolated from 47% (78), L. pneumophila was isolated from 32% (53), and L. pneumophila serogroup 1 (Lp1) was isolated from 24% (40). Overall, 144 unique Legionella isolates were identified; 53% (76) of these were Legionella pneumophila. Of the 76 L. pneumophila isolates, 51% (39) were Lp1. Legionella were isolated from CTs in seven of the eight US regions examined. 16S rRNA amplicon sequencing was used to compare the bacterial communities of CT waters with and without detectable Legionella as well as the microbiomes of waters from different climate regions. Interestingly, the microbial communities were homogenous across climate regions. When a subset of seven CTs sampled in April and July were compared, there was no association with changes in corresponding CT microbiomes over time in the samples that became culture-positive for Legionella. Legionella species and Lp1 were detected frequently among the samples examined in this first large-scale study of Legionella in US CTs. Our findings highlight that, under the right conditions, there is the potential for CT-related LD outbreaks to occur throughout the US.
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Affiliation(s)
- Anna C. Llewellyn
- Laboratory Leadership Service, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
- Pneumonia Response and Surveillance Laboratory, Respiratory Disease Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Claressa E. Lucas
- Pneumonia Response and Surveillance Laboratory, Respiratory Disease Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Sarah E. Roberts
- Pneumonia Response and Surveillance Laboratory, Respiratory Disease Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Ellen W. Brown
- Pneumonia Response and Surveillance Laboratory, Respiratory Disease Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Bina S. Nayak
- Water Quality Division, Pinellas County Utilities, Largo, FL, United States of America
| | - Brian H. Raphael
- Pneumonia Response and Surveillance Laboratory, Respiratory Disease Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Jonas M. Winchell
- Pneumonia Response and Surveillance Laboratory, Respiratory Disease Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
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26
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Prussin AJ, Schwake DO, Marr LC. Ten Questions Concerning the Aerosolization and Transmission of Legionella in the Built Environment. BUILDING AND ENVIRONMENT 2017; 123:684-695. [PMID: 29104349 PMCID: PMC5665586 DOI: 10.1016/j.buildenv.2017.06.024] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Legionella is a genus of pathogenic Gram-negative bacteria responsible for a serious disease known as legionellosis, which is transmitted via inhalation of this pathogen in aerosol form. There are two forms of legionellosis: Legionnaires' disease, which causes pneumonia-like symptoms, and Pontiac fever, which causes influenza-like symptoms. Legionella can be aerosolized from various water sources in the built environment including showers, faucets, hot tubs/swimming pools, cooling towers, and fountains. Incidence of the disease is higher in the summertime, possibly because of increased use of cooling towers for air conditioning systems and differences in water chemistry when outdoor temperatures are higher. Although there have been decades of research related to Legionella transmission, many knowledge gaps remain. While conventional wisdom suggests that showering is an important source of exposure in buildings, existing measurements do not provide strong support for this idea. There has been limited research on the potential for Legionella transmission through heating, ventilation, and air conditioning (HVAC) systems. Epidemiological data suggest a large proportion of legionellosis cases go unreported, as most people who are infected do not seek medical attention. Additionally, controlled laboratory studies examining water-to-air transfer and source tracking are still needed. Herein, we discuss ten questions that spotlight current knowledge about Legionella transmission in the built environment, engineering controls that might prevent future disease outbreaks, and future research that is needed to advance understanding of transmission and control of legionellosis.
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Affiliation(s)
- Aaron J. Prussin
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
- Corresponding Author:
| | - David Otto Schwake
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Linsey C. Marr
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
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27
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Moscoviz R, de Fouchécour F, Santa-Catalina G, Bernet N, Trably E. Cooperative growth of Geobacter sulfurreducens and Clostridium pasteurianum with subsequent metabolic shift in glycerol fermentation. Sci Rep 2017; 7:44334. [PMID: 28287150 PMCID: PMC5347079 DOI: 10.1038/srep44334] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 01/26/2017] [Indexed: 02/03/2023] Open
Abstract
Interspecies electron transfer is a common way to couple metabolic energy balances between different species in mixed culture consortia. Direct interspecies electron transfer (DIET) mechanism has been recently characterised with Geobacter species which couple the electron balance with other species through physical contacts. Using this mechanism could be an efficient and cost-effective way to directly control redox balances in co-culture fermentation. The present study deals with a co-culture of Geobacter sulfurreducens and Clostridium pasteurianum during glycerol fermentation. As a result, it was shown that Geobacter sulfurreducens was able to grow using Clostridium pasteurianum as sole electron acceptor. C. pasteurianum metabolic pattern was significantly altered towards improved 1,3-propanediol and butyrate production (+37% and +38% resp.) at the expense of butanol and ethanol production (−16% and −20% resp.). This metabolic shift was clearly induced by a small electron uptake that represented less than 0.6% of the electrons consumed by C. pasteurianum. A non-linear relationship was found between G. sulfurreducens growth (i.e the electrons transferred between the two species) and the changes in C. pasteurianum metabolite distribution. This study opens up new possibilities for controlling and increasing specificity in mixed culture fermentation.
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Affiliation(s)
- Roman Moscoviz
- LBE, INRA, 102 Avenue des étangs, 11100 Narbonne, France
| | | | | | - Nicolas Bernet
- LBE, INRA, 102 Avenue des étangs, 11100 Narbonne, France
| | - Eric Trably
- LBE, INRA, 102 Avenue des étangs, 11100 Narbonne, France
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28
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Saur T, Morin E, Habouzit F, Bernet N, Escudié R. Impact of wall shear stress on initial bacterial adhesion in rotating annular reactor. PLoS One 2017; 12:e0172113. [PMID: 28207869 PMCID: PMC5312967 DOI: 10.1371/journal.pone.0172113] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 01/31/2017] [Indexed: 12/02/2022] Open
Abstract
The objective of this study was to investigate the bacterial adhesion under different wall shear stresses in turbulent flow and using a diverse bacterial consortium. A better understanding of the mechanisms governing microbial adhesion can be useful in diverse domains such as industrial processes, medical fields or environmental biotechnologies. The impact of wall shear stress—four values ranging from 0.09 to 7.3 Pa on polypropylene (PP) and polyvinyl chloride (PVC)—was carried out in rotating annular reactors to evaluate the adhesion in terms of morphological and microbiological structures. A diverse inoculum consisting of activated sludge was used. Epifluorescence microscopy was used to quantitatively and qualitatively characterize the adhesion. Attached bacterial communities were assessed by molecular fingerprinting profiles (CE-SSCP). It has been demonstrated that wall shear stress had a strong impact on both quantitative and qualitative aspects of the bacterial adhesion. ANOVA tests also demonstrated the significant impact of wall shear stress on all three tested morphological parameters (surface coverage, number of objects and size of objects) (p-values < 2.10−16). High wall shear stresses increased the quantity of attached bacteria but also altered their spatial distribution on the substratum surface. As the shear increased, aggregates or clusters appeared and their size grew when increasing the shears. Concerning the microbiological composition, the adhered bacterial communities changed gradually with the applied shear.
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29
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Halotolerant bioanodes: The applied potential modulates the electrochemical characteristics, the biofilm structure and the ratio of the two dominant genera. Bioelectrochemistry 2016; 112:24-32. [DOI: 10.1016/j.bioelechem.2016.06.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 06/21/2016] [Accepted: 06/24/2016] [Indexed: 11/17/2022]
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30
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Kirschner AK. Determination of viable legionellae in engineered water systems: Do we find what we are looking for? WATER RESEARCH 2016; 93:276-288. [PMID: 26928563 PMCID: PMC4913838 DOI: 10.1016/j.watres.2016.02.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 02/06/2016] [Accepted: 02/09/2016] [Indexed: 05/06/2023]
Abstract
In developed countries, legionellae are one of the most important water-based bacterial pathogens caused by management failure of engineered water systems. For routine surveillance of legionellae in engineered water systems and outbreak investigations, cultivation-based standard techniques are currently applied. However, in many cases culture-negative results are obtained despite the presence of viable legionellae, and clinical cases of legionellosis cannot be traced back to their respective contaminated water source. Among the various explanations for these discrepancies, the presence of viable but non-culturable (VBNC) Legionella cells has received increased attention in recent discussions and scientific literature. Alternative culture-independent methods to detect and quantify legionellae have been proposed in order to complement or even substitute the culture method in the future. Such methods should detect VBNC Legionella cells and provide a more comprehensive picture of the presence of legionellae in engineered water systems. However, it is still unclear whether and to what extent these VBNC legionellae are hazardous to human health. Current risk assessment models to predict the risk of legionellosis from Legionella concentrations in the investigated water systems contain many uncertainties and are mainly based on culture-based enumeration. If VBNC legionellae should be considered in future standard analysis, quantitative risk assessment models including VBNC legionellae must be proven to result in better estimates of human health risk than models based on cultivation alone. This review critically evaluates current methods to determine legionellae in the VBNC state, their potential to complement the standard culture-based method in the near future, and summarizes current knowledge on the threat that VBNC legionellae may pose to human health.
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Affiliation(s)
- Alexander K.T. Kirschner
- Medical University Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090 Vienna, Austria
- Interuniversity Cooperation Centre for Water & Health, Austria
- Medical University Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene Kinderspitalgasse 16, A-1090 Vienna, Austria . URL: http://www.waterandhealth.at
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31
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Godon JJ, Arulazhagan P, Steyer JP, Hamelin J. Vertebrate bacterial gut diversity: size also matters. BMC Ecol 2016; 16:12. [PMID: 27008566 PMCID: PMC4804487 DOI: 10.1186/s12898-016-0071-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 03/10/2016] [Indexed: 12/21/2022] Open
Abstract
Background One of the central issues in microbial ecology is to understand the parameters that drive diversity. Among these parameters, size has often been considered to be the main driver in many different ecosystems. Surprisingly, the influence of size on gut microbial diversity has not yet been investigated, and so far in studies reported in the literature only the influences of age, diet, phylogeny and digestive tract structures have been considered. This study explicitly challenges the underexplored relationship connecting gut volume and bacterial diversity. Results The bacterial diversity of 189 faeces produced by 71 vertebrate species covering a body mass range of 5.6 log. The animals comprised mammals, birds and reptiles. The diversity was evaluated based on the Simpson Diversity Index extracted from 16S rDNA gene fingerprinting patterns. Diversity presented an increase along with animal body mass following a power law with a slope z of 0.338 ± 0.027, whatever the age, phylogeny, diet or digestive tract structure. Conclusions The results presented here suggest that gut volume cannot be neglected as a major driver of gut microbial diversity. The characteristics of the gut microbiota follow general principles of biogeography that arise in many ecological systems. Electronic supplementary material The online version of this article (doi:10.1186/s12898-016-0071-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jean-Jacques Godon
- UR0050, Laboratoire de Biotechnologie de l'Environnement, INRA, 102 avenue des étangs, 11100, Narbonne, France.
| | - Pugazhendi Arulazhagan
- UR0050, Laboratoire de Biotechnologie de l'Environnement, INRA, 102 avenue des étangs, 11100, Narbonne, France.,Centre of Excellence in Environmental Studies, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Jean-Philippe Steyer
- UR0050, Laboratoire de Biotechnologie de l'Environnement, INRA, 102 avenue des étangs, 11100, Narbonne, France
| | - Jérôme Hamelin
- UR0050, Laboratoire de Biotechnologie de l'Environnement, INRA, 102 avenue des étangs, 11100, Narbonne, France
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32
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Wunderlich A, Torggler C, Elsässer D, Lück C, Niessner R, Seidel M. Rapid quantification method for Legionella pneumophila in surface water. Anal Bioanal Chem 2016; 408:2203-13. [DOI: 10.1007/s00216-016-9362-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/15/2016] [Accepted: 01/25/2016] [Indexed: 01/08/2023]
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33
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Moscoviz R, Trably E, Bernet N. Consistent 1,3-propanediol production from glycerol in mixed culture fermentation over a wide range of pH. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:32. [PMID: 26855671 PMCID: PMC4744455 DOI: 10.1186/s13068-016-0447-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 01/20/2016] [Indexed: 05/28/2023]
Abstract
BACKGROUND Glycerol is currently an over-produced chemical that can be used as substrate for the production of high value products such as 1,3-propanediol (1,3-PDO) in fermentation processes. The aim of this study was to investigate the effect of initial pH on a batch mixed culture fermentation of glycerol, considering both the bacterial community composition and the fermentation patterns. RESULTS For pH values between 5 and 9, 1,3-PDO production yields ranged from 0.52 ± 0.01 to 0.64 ± 0.00 [Formula: see text], with the highest values obtained at pH 7 and 8. An Enterobacteriaceae member closely related to Citrobacter freundii was strongly enriched at all pH values. Within the less dominant bacterial species, two different microbial community structures were found, one at acid pH values and another at neutral to basic pH values. CONCLUSIONS 1,3-PDO production was improved at pH values over 7. It was anti-correlated with lactate and ethanol production but positively correlated with acetate production. No direct correlation between 1,3-PDO production and a specific family of bacteria was found, suggesting functional redundancies in the microbial community. However, 1,3-PDO production yield remained high over the range of pH studied and was comparable to the best obtained in the same conditions in the literature.
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Affiliation(s)
- Roman Moscoviz
- INRA, UR0050, Laboratoire de Biotechnologie de L’Environnement (LBE), Avenue des étangs, 11100 Narbonne, France
| | - Eric Trably
- INRA, UR0050, Laboratoire de Biotechnologie de L’Environnement (LBE), Avenue des étangs, 11100 Narbonne, France
| | - Nicolas Bernet
- INRA, UR0050, Laboratoire de Biotechnologie de L’Environnement (LBE), Avenue des étangs, 11100 Narbonne, France
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34
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Lu J, Struewing I, Vereen E, Kirby AE, Levy K, Moe C, Ashbolt N. Molecular Detection of Legionella
spp. and their associations with Mycobacterium
spp., Pseudomonas aeruginosa
and amoeba hosts in a drinking water distribution system. J Appl Microbiol 2016; 120:509-21. [DOI: 10.1111/jam.12996] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/08/2015] [Accepted: 10/27/2015] [Indexed: 01/12/2023]
Affiliation(s)
- J. Lu
- U.S. EPA National Exposure Research Laboratory; Cincinnati OH USA
| | | | - E. Vereen
- Center for Global Safe Water; Sanitation and Hygiene; Emory University; Atlanta GA USA
| | - A. E. Kirby
- Center for Global Safe Water; Sanitation and Hygiene; Emory University; Atlanta GA USA
| | - K. Levy
- Center for Global Safe Water; Sanitation and Hygiene; Emory University; Atlanta GA USA
| | - C. Moe
- Center for Global Safe Water; Sanitation and Hygiene; Emory University; Atlanta GA USA
| | - N. Ashbolt
- School of Public Health; University of Alberta; Edmonton AB Canada
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35
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Pierra M, Carmona-Martínez AA, Trably E, Godon JJ, Bernet N. Specific and efficient electrochemical selection of Geoalkalibacter subterraneus and Desulfuromonas acetoxidans in high current-producing biofilms. Bioelectrochemistry 2015; 106:221-5. [DOI: 10.1016/j.bioelechem.2015.02.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/30/2015] [Accepted: 02/13/2015] [Indexed: 01/27/2023]
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36
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Cazier EA, Trably E, Steyer JP, Escudie R. Biomass hydrolysis inhibition at high hydrogen partial pressure in solid-state anaerobic digestion. BIORESOURCE TECHNOLOGY 2015; 190:106-113. [PMID: 25935390 DOI: 10.1016/j.biortech.2015.04.055] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 04/15/2015] [Accepted: 04/16/2015] [Indexed: 06/04/2023]
Abstract
In solid-state anaerobic digestion, so-called ss-AD, biogas production is inhibited at high total solids contents. Such inhibition is likely caused by a slow diffusion of dissolved reaction intermediates that locally accumulate. In this study, we investigated the effect of H2 and CO2 partial pressure on ss-AD. Partial pressure of H2 and/or CO2 was artificially fixed, from 0 to 1 557mbars for H2 and from 0 to 427mbars for CO2. High partial pressure of H2 showed a significant effect on methanogenesis, while CO2 had no impact. At high [Formula: see text] , the overall substrate degradation decreased with no accumulation of metabolites from acidogenic bacteria, indicating that the hydrolytic activity was specifically impacted. Interestingly, such inhibition did not occur when CO2 was added with H2. This result suggests that CO2 gas transfer is probably a key factor in ss-AD from biomass.
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Affiliation(s)
- E A Cazier
- INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, 11100 Narbonne, France
| | - E Trably
- INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, 11100 Narbonne, France.
| | - J P Steyer
- INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, 11100 Narbonne, France
| | - R Escudie
- INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, 11100 Narbonne, France
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Shen SM, Chou MY, Hsu BM, Ji WT, Hsu TK, Tsai HF, Huang YL, Chiu YC, Kao ES, Kao PM, Fan CW. Assessment of Legionella pneumophila in recreational spring water with quantitative PCR (Taqman) assay. Pathog Glob Health 2015; 109:236-41. [PMID: 26184706 DOI: 10.1179/2047773215y.0000000023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Legionella spp. are common in various natural and man-made aquatic environments. Recreational hot spring is frequently reported as an infection hotspot because of various factors such as temperature and humidity. Although polymerase chain reaction (PCR) had been used for detecting Legionella, several inhibitors such as humic substances, calcium, and melanin in the recreational spring water may interfere with the reaction thus resulting in risk underestimation. The purpose of this study was to compare the efficiencies of conventional and Taqman quantitative PCR (qPCR) on detecting Legionella pneumophila in spring facilities and in receiving water. In the results, Taqman PCR had much better efficiency on specifying the pathogen in both river and spring samples. L. pneumophila was detected in all of the 27 river water samples and 45 of the 48 hot spring water samples. The estimated L. pneumophela concentrations ranged between 1.0 × 10(2) and 3.3 × 10(5) cells/l in river water and 72.1-5.7 × 10(6) cells/l in hot spring water. Total coliforms and turbidity were significantly correlated with concentrations of L. pneumophila in positive water samples. Significant difference was also found in water temperature between the presence/absence of L. pneumophila. Our results suggest that conventional PCR may be not enough for detecting L. pneumophila particularly in the aquatic environments full of reaction inhibitors.
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Bioaerosol emissions from open microalgal processes and their potential environmental impacts: what can be learned from natural and anthropogenic aquatic environments? Curr Opin Biotechnol 2015; 33:279-86. [DOI: 10.1016/j.copbio.2015.03.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 03/13/2015] [Accepted: 03/17/2015] [Indexed: 10/23/2022]
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Inoue H, Fujimura R, Agata K, Ohta H. Molecular characterization of viable Legionella spp. in cooling tower water samples by combined use of ethidium monoazide and PCR. Microbes Environ 2015; 30:108-12. [PMID: 25736979 PMCID: PMC4356457 DOI: 10.1264/jsme2.me14115] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Viable Legionella spp. in environmental water samples were characterized phylogenetically by a clone library analysis combining the use of ethidium monoazide and quantitative PCR. To examine the diversity of Legionella spp., six cooling tower water samples and three bath water samples were collected and analyzed. A total of 617 clones were analyzed for their 16S rRNA gene sequences and classified into 99 operational taxonomic units (OTUs). The majority of OTUs were not clustered with currently described Legionella spp., suggesting the wide diversity of not-yet-cultured Legionella groups harbored in cooling tower water environments.
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Affiliation(s)
- Hiroaki Inoue
- Tsukuba Research Laboratories, Aquas Corporation, 4–4 Midorigahara, Tsukuba, Ibaraki 300–2646, Japan; Ibaraki University College of Agriculture, 3–21–1 Chuou, Ami-machi, Ibaraki 300–0393, Japan
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Dunyach-Remy C, Cadière A, Richard JL, Schuldiner S, Bayle S, Roig B, Sotto A, Lavigne JP. Polymerase chain reaction–denaturing gradient gel electrophoresis (PCR–DGGE): A promising tool to diagnose bacterial infections in diabetic foot ulcers. DIABETES & METABOLISM 2014; 40:476-80. [DOI: 10.1016/j.diabet.2014.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 03/03/2014] [Accepted: 03/06/2014] [Indexed: 11/28/2022]
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Thomas JM, Thomas T, Stuetz RM, Ashbolt NJ. Your garden hose: a potential health risk due to Legionella spp. growth facilitated by free-living amoebae. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:10456-10464. [PMID: 25075763 DOI: 10.1021/es502652n] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Common garden hoses may generate aerosols of inhalable size (≤10 μm) during use. If humans inhale aerosols containing Legionella bacteria, Legionnaires' disease or Pontiac fever may result. Clinical cases of these illnesses have been linked to garden hose use. The hose environment is ideal for the growth and interaction of Legionella and free-living amoebae (FLA) due to biofilm formation, elevated temperatures, and stagnation of water. However, the microbial densities and hose conditions necessary to quantify the human health risks have not been reported. Here we present data on FLA and Legionella spp. detected in water and biofilm from two types of garden hoses over 18 months. By culturing and qPCR, two genera of FLA were introduced via the drinking water supply and reached mean densities of 2.5 log10 amoebae·mL(-1) in garden hose water. Legionella spp. densities (likely including pathogenic L. pneumophila) were significantly higher in one type of hose (3.8 log10 cells·mL(-1), p < 0.0001). A positive correlation existed between Vermamoebae vermiformis densities and Legionella spp. densities (r = 0.83, p < 0.028). The densities of Legionella spp. identified in the hoses were similar to those reported during legionellosis outbreaks in other situations. Therefore, we conclude that there is a health risk to susceptible users from the inhalation of garden hose aerosols.
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Affiliation(s)
- Jacqueline M Thomas
- School of Civil and Environmental Engineering, The University of New South Wales , Sydney, NSW 2052, Australia
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Rousseau R, Santaella C, Achouak W, Godon JJ, Bonnafous A, Bergel A, Délia ML. Correlation of the Electrochemical Kinetics of High-Salinity-Tolerant Bioanodes with the Structure and Microbial Composition of the Biofilm. ChemElectroChem 2014. [DOI: 10.1002/celc.201402153] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Rico L, Ogaya R, Terradas J, Peñuelas J. Community structures of N2 -fixing bacteria associated with the phyllosphere of a Holm oak forest and their response to drought. PLANT BIOLOGY (STUTTGART, GERMANY) 2014; 16:586-93. [PMID: 23952768 DOI: 10.1111/plb.12082] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 06/26/2013] [Indexed: 05/22/2023]
Abstract
Biological nitrogen (N) fixation is a key pathway in terrestrial ecosystems and is therefore critical for understanding the responses of ecosystems to global environmental changes. The free-living diazotrophic community is distributed along the canopy-to-soil profile, but the ecological significance of epiphyllic N2 fixers, despite their functional relevance, on plant foliar surfaces remains very poorly understood compared with the N2 -fixing community in forest litter and soils. We assessed the community structure of N2 fixers and overall bacteria by genetic fingerprinting (t-RFLP) to explore the seasonal successional patterns of the microbial community in the natural phyllosphere of a Holm oak (Quercus ilex) forest submitted to 12-year field experiment of rain exclusion mimicking the conditions of drought projected for the coming decades. Leaves of Holm oak were analysed in different seasons over a period of 1.5 years. The bacterial community of the phyllosphere did not correspond to the surrounding soil biome in the same area. These analyses provided field evidence for the presence of free-living diazotrophs associated with the tissues of leaves of Holm oak, the dominant tree species of many Mediterranean forests. The results also revealed that the community composition is affected seasonally and inter-annually by the environment, and that the composition shifts in response to climate change. Drought treatment increased the richness of the epiphyllic microbial community, especially during the summer. These changes were associated with higher C:N ratios of leaves observed in response to drought in semiarid areas. This epiphyllic microbiota that can potentially fix N2 extends the capacity of plants to adapt to the environment.
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Affiliation(s)
- L Rico
- CSIC, Global Ecology Unit CREAF-CEAB-UAB, Cerdanyola del Vallès, Catalonia, Spain; CREAF, Cerdanyola del Vallès, Catalonia, Spain
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Lin W, Yu Z, Zhang H, Thompson IP. Diversity and dynamics of microbial communities at each step of treatment plant for potable water generation. WATER RESEARCH 2014; 52:218-30. [PMID: 24268295 DOI: 10.1016/j.watres.2013.10.071] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 10/27/2013] [Accepted: 10/29/2013] [Indexed: 05/08/2023]
Abstract
The dynamics of bacterial and eukaryotic community associated with each step of a water purification plant in China was investigated using 454 pyrosequencing and qPCR based approaches. Analysis of pyrosequencing revealed that a high degree diversity of bacterial and eukaryotic communities is present in the drinking water treatment process before sand filtration. In addition, the microbial compositions of the biofilm in the sand filters and those of the water of the putatively clear tanks were distinct, suggesting that sand filtration and chlorination treatments played primary roles in removing exposed microbial communities. Potential pathogens including Acinetobacter, Clostridium, Legionella, and Mycobacterium, co-occurred with protozoa such as Rhizopoda (Hartmannellidae), and fungi such as Penicillium and Aspergillus. Furthermore, this study supported the ideas based on molecular level that biofilm communities were different from those in corresponding water samples, and that the concentrations of Mycobacterium spp., Legionella spp., and Naegleria spp. in the water samples declined with each step of the water treatment process by qPCR. Overall, this study provides the first detailed evaluation of bacterial and eukaryotic diversity at each step of an individual potable water treatment process located in China.
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Affiliation(s)
- Wenfang Lin
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Shijingshan District, Beijing 100049, PR China
| | - Zhisheng Yu
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Shijingshan District, Beijing 100049, PR China; Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK.
| | - Hongxun Zhang
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Shijingshan District, Beijing 100049, PR China
| | - Ian P Thompson
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
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Mehta CM, Palni U, Franke-Whittle IH, Sharma AK. Compost: its role, mechanism and impact on reducing soil-borne plant diseases. WASTE MANAGEMENT (NEW YORK, N.Y.) 2014; 34:607-22. [PMID: 24373678 DOI: 10.1016/j.wasman.2013.11.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 11/28/2013] [Accepted: 11/28/2013] [Indexed: 05/14/2023]
Abstract
Soil-borne plant pathogens are responsible for causing many crop plant diseases, resulting in significant economic losses. Compost application to agricultural fields is an excellent natural approach, which can be taken to fight against plant pathogens. The application of organic waste products is also an environmentally friendly alternative to chemical use, which unfortunately is the most common approach in agriculture today. This review analyses pioneering and recent compost research, and also the mechanisms and mode of action of compost microbial communities for reducing the activity of plant pathogens in agricultural crops. In addition, an approach for improving the quality of composts through the microbial communities already present in the compost is presented. Future agricultural practices will almost definitely require integrated research strategies to help combat plant diseases.
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Affiliation(s)
- C M Mehta
- Department of Biological Sciences, College of Basic Science and Humanities, G. B. P. U. A. & T. Pantnagar, U.S. Nagar, Uttarakhand, India; Department of Botany, D.S.B. Campus, Kumaun University Nainital, Uttarakhand, India
| | - Uma Palni
- Department of Botany, D.S.B. Campus, Kumaun University Nainital, Uttarakhand, India
| | - I H Franke-Whittle
- Leopold-Franzens University, Institute of Microbiology, Technikerstraße 25, 6020 Innsbruck, Austria
| | - A K Sharma
- Department of Biological Sciences, College of Basic Science and Humanities, G. B. P. U. A. & T. Pantnagar, U.S. Nagar, Uttarakhand, India.
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Abdel-Nour M, Duncan C, Low DE, Guyard C. Biofilms: the stronghold of Legionella pneumophila. Int J Mol Sci 2013; 14:21660-75. [PMID: 24185913 PMCID: PMC3856027 DOI: 10.3390/ijms141121660] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/07/2013] [Accepted: 10/14/2013] [Indexed: 11/28/2022] Open
Abstract
Legionellosis is mostly caused by Legionella pneumophila and is defined as a severe respiratory illness with a case fatality rate ranging from 5% to 80%. L. pneumophila is ubiquitous in natural and anthropogenic water systems. L. pneumophila is transmitted by inhalation of contaminated aerosols produced by a variety of devices. While L. pneumophila replicates within environmental protozoa, colonization and persistence in its natural environment are also mediated by biofilm formation and colonization within multispecies microbial communities. There is now evidence that some legionellosis outbreaks are correlated with the presence of biofilms. Thus, preventing biofilm formation appears as one of the strategies to reduce water system contamination. However, we lack information about the chemical and biophysical conditions, as well as the molecular mechanisms that allow the production of biofilms by L. pneumophila. Here, we discuss the molecular basis of biofilm formation by L. pneumophila and the roles of other microbial species in L. pneumophila biofilm colonization. In addition, we discuss the protective roles of biofilms against current L. pneumophila sanitation strategies along with the initial data available on the regulation of L. pneumophila biofilm formation.
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Affiliation(s)
- Mena Abdel-Nour
- Ontario Agency for Health Protection and Promotion (OAHPP), Toronto, ON M9P 3T1, Canada; E-Mails: (M.A.-N.); (C.D.)
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Carla Duncan
- Ontario Agency for Health Protection and Promotion (OAHPP), Toronto, ON M9P 3T1, Canada; E-Mails: (M.A.-N.); (C.D.)
| | - Donald E. Low
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Cyril Guyard
- Ontario Agency for Health Protection and Promotion (OAHPP), Toronto, ON M9P 3T1, Canada; E-Mails: (M.A.-N.); (C.D.)
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-416-880-1339; Fax: +1-416-235-6281
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Jakubek D, Le Brun M, Leblon G, DuBow M, Binet M. The impact of monochloramine on the diversity and dynamics ofLegionella pneumophilasubpopulations in a nuclear power plant cooling circuit. FEMS Microbiol Ecol 2013; 85:302-12. [DOI: 10.1111/1574-6941.12121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 03/19/2013] [Accepted: 03/20/2013] [Indexed: 11/28/2022] Open
Affiliation(s)
| | | | - Gerard Leblon
- Institut de Génétique et de Microbiologie; CNRS UMR 8621; Univ Paris-Sud; Orsay Cedex; France
| | - Michael DuBow
- Institut de Génétique et de Microbiologie; CNRS UMR 8621; Univ Paris-Sud; Orsay Cedex; France
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Bedrina B, Macián S, Solís I, Fernández-Lafuente R, Baldrich E, Rodríguez G. Fast immunosensing technique to detect Legionella pneumophila in different natural and anthropogenic environments: comparative and collaborative trials. BMC Microbiol 2013; 13:88. [PMID: 23601924 PMCID: PMC3637370 DOI: 10.1186/1471-2180-13-88] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 04/16/2013] [Indexed: 12/05/2022] Open
Abstract
Background Legionellosis is an uncommon form of pneumonia. After a clinical encounter, the necessary antibiotic treatment is available if the diagnosis is made early in the illness. Before the clinical encounter, early detection of the main pathogen involved, Legionella pneumophila, in hazardous environments is important in preventing infectious levels of this bacterium. In this study a qualitative test based on combined magnetic immunocapture and enzyme-immunoassay for the fast detection of Legionella pneumophila in water samples was compared with the standard method, in both comparative and collaborative trials. The test was based on the use of anti-Legionella pneumophila antibodies immobilized on magnetic microspheres. The final protocol included concentration by filtration, resuspension and immunomagnetic capture. The whole assay took less than 1 hour to complete. Results A comparative trial was performed against the standard culture method (ISO 11731) on both artificially and naturally contaminated water samples, for two matrices: chlorinated tap water and cooling tower water. Performance characteristics of the test used as screening with culture confirmation resulted in sensitivity, specificity, false positive, false negative, and efficiency of 96.6%, 100%, 0%, 3.4%, and 97.8%, respectively. The detection limit at the level under which the false negative rate increases to 50% (LOD50) was 93 colony forming units (CFU) in the volume examined for both tested matrices. The collaborative trial included twelve laboratories. Water samples spiked with certified reference materials were tested. In this study the coincidence level between the two methods was 95.8%. Conclusion Results demonstrate the applicability of this immunosensing technique to the rapid, simple, and efficient detection of Legionella pneumophila in water samples. This test is not based on microbial growth, so it could be used as a rapid screening technique for the detection of L. pneumophila in waters, maintaining the performance of conventional culture for isolation of the pathogen and related studies.
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Affiliation(s)
- Begoña Bedrina
- Biótica, Bioquímica Analítica, S.L, Science and Technology Park of Jaume I University, Campus Riu Sec - Espaitec 2, planta baja, E12071, Castellón de la Plana, Spain
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Fykse EM, Aarskaug T, Thrane I, Blatny JM. Legionellaand non-Legionellabacteria in a biological treatment plant. Can J Microbiol 2013; 59:102-9. [DOI: 10.1139/cjm-2012-0166] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Legionella pneumophila were previously identified in the aeration ponds (up to 1010CFU/L) of a biological wastewater treatment plant at Borregaard Ind. Ltd., Sarpsborg, Norway, and in air samples (up to 3300 CFU/m3) collected above the aeration ponds. After 3 outbreaks of Legionnaires’ disease reported in this area in 2005 and 2008, the aeration ponds of the plant were shut down by the Norwegian authorities in September 2008. The aim of the present work was to analyze the Legionella and non-Legionella bacterial communities in the aeration ponds before and during the shutdown process and to identify potential human pathogens. The non-Legionella bacterial community was investigated in selected samples during the shutdown process by 16S rDNA sequencing of clone libraries (400 clones) and growth analysis. The concentration of L. pneumophila and Pseudomonas spp. DNA were monitored by quantitative PCR. Results showed a decrease in the concentration of L. pneumophila and Pseudomonas spp. during the shutdown. This was accompanied by a significant change in the composition of the bacterial community in the aeration ponds. This study demonstrated that several advanced analytical methods are necessary to characterize the bacterial population in complex environments, such as the industrial aeration ponds.
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Affiliation(s)
- Else Marie Fykse
- Norwegian Defence Research Establishment, P.O. Box 25, N-2027 Kjeller, Norway
| | - Tone Aarskaug
- Norwegian Defence Research Establishment, P.O. Box 25, N-2027 Kjeller, Norway
| | - Ingjerd Thrane
- Norwegian Defence Research Establishment, P.O. Box 25, N-2027 Kjeller, Norway
| | - Janet Martha Blatny
- Norwegian Defence Research Establishment, P.O. Box 25, N-2027 Kjeller, Norway
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Perendeci NA, Ekinci FY, Godon JJ. Monitoring the performance and microbial diversity dynamics of a full scale anaerobic wastewater treatment plant treating sugar factory wastewater. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2013; 15:494-502. [PMID: 25208715 DOI: 10.1039/c2em30597f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Microbial community dynamics and the overall system performance of a real scale anaerobic wastewater treatment plant treating sugar industry wastewater were studied. Dominant bacterial and archaeal communities were monitored by 16S rRNA gene targeted PCR amplification and single strand conformation polymorphism analysis (SSCP). Chemical oxygen demand (COD) removal efficiency and operational parameters such as pH, temperature, alkalinity, volatile fatty acids in the methanogenic reactor remained within respective optimal ranges. All bacterial profiles in acidogenic and methanogenic reactors and in the lamella separator presented complex patterns; and the bacterial diversity, measured as SSCP profile richness and structure, was quite chaotic. In contrast to the results obtained for the bacterial community, archaeal 16S rDNA patterns in acidogenic and methanogenic reactors and the lamella separator remained relatively stable over the whole operation period of the anaerobic wastewater treatment plant. Evaluation of microbial community dynamics and overall system performance using the Mantel test revealed that there was no correlation between the dynamics of the microbial communities and the abiotic parameters.
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Affiliation(s)
- N Altınay Perendeci
- Akdeniz University, Engineering Faculty, Environmental Engineering Department, 07058 Antalya, Turkey.
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