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Whapham CA, Walker JT. Too much ado about data: continuous remote monitoring of water temperatures, circulation and throughput can assist in the reduction of hospital-associated waterborne infections. J Hosp Infect 2024; 152:47-55. [PMID: 38960042 DOI: 10.1016/j.jhin.2024.05.023] [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: 04/01/2024] [Revised: 05/14/2024] [Accepted: 05/16/2024] [Indexed: 07/05/2024]
Abstract
BACKGROUND National and international guidance provides advice on maintenance and management of water systems in healthcare buildings; however, healthcare-associated waterborne infections (HAWIs) are increasing. AIM To identify parameters critical to water quality in healthcare buildings and to assess whether remote sensor monitoring can deliver safe water systems, thus reducing HAWIs. METHODS A narrative review was performed using the following search terms: (1) consistent water temperature AND waterborne pathogen control OR nosocomial infection; (2) water throughput AND waterborne pathogen control OR nosocomial infection; (3) remote monitoring of in-premises water systems AND continuous surveillance for temperature OR throughput OR flow OR use. Databases employed were PubMed, CDSR (Clinical Study Data Request) and DARE (Database of Abstracts of Reviews of Effects) from January 2013 to March 2024. FINDINGS Single ensuite-patient rooms, expansion of handwash basins, widespread glove use, alcohol gel and wipes have increased water system stagnancy resulting in amplification of waterborne pathogens and transmission risk of legionella, pseudomonas, and non-tuberculous mycobacteria. Manual monitoring does not represent temperatures across large complex water systems. This review deems that multiple-point continuous remote sensor monitoring is effective at identifying redundant and low use outlets, hydraulic imbalance and inconsistent temperature delivery across in-premises water systems. CONCLUSION As remote monitoring becomes more common there will be greater recognition of failures in temperature control, hydraulics, and balancing in water systems, and there remains much to learn as we adopt this developing technology within our hospitals.
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Affiliation(s)
- C A Whapham
- Independent Water Hygiene Consultant, Ludlow, UK.
| | - J T Walker
- Independent Microbiology Consultant, Walker on Water, Salisbury, UK
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Kanatani JI, Fujiyoshi S, Isobe J, Kimata K, Watahiki M, Maenishi E, Izumiyama S, Amemura-Maekawa J, Maruyama F, Oishi K. Correlation between bacterial microbiome and Legionella species in water from public bath facilities by 16S rRNA gene amplicon sequencing. Microbiol Spectr 2024; 12:e0345923. [PMID: 38363136 PMCID: PMC10986325 DOI: 10.1128/spectrum.03459-23] [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: 09/21/2023] [Accepted: 01/24/2024] [Indexed: 02/17/2024] Open
Abstract
Public bath facilities are a major source of Legionella infections in Japan. In this study, we performed 16S rRNA gene amplicon sequencing to characterize the bacterial community in bath and shower water from public bath facilities, along with chemical parameters, and investigated the effect of the bacterial microbiome on the presence of Legionella species. Although no significant difference in bacterial community richness was observed between bath and shower water samples, there was a remarkable difference in the bacterial community structure between them. Distance-based redundancy analysis revealed that several factors (free residual chlorine, pH, and conductivity) were correlated with the bacterial community in bath water. The most abundant bacterial genera in the samples were Pseudomonas (13.7%) in bath water and Phreatobacter (13.6%) in shower water, as indicated by the taxonomic composition, and the dominant bacteria differed between these environmental samples. Legionella pneumophila was the most frequently detected Legionella species, with additional 15 other Legionella species detected in water samples. In Legionella-positive water samples, several unassigned and uncultured bacteria were enriched together. In addition, the co-occurrence network showed that Legionella was strongly interconnected with two uncultured bacteria. Corynebacterium and Sphingomonas negatively correlated with Legionella species. The present study reveals the ecology of Legionella species, especially their interactions with other bacteria that are poorly understood to date. IMPORTANCE Public bath facilities are major sources of sporadic cases and outbreaks of Legionella infections. Recently, 16S rRNA gene amplicon sequencing has been used to analyze bacterial characteristics in various water samples from both artificial and natural environments, with a particular focus on Legionella bacterial species. However, the relationship between the bacterial community and Legionella species in the water from public bath facilities remains unclear. In terms of hygiene management, it is important to reduce the growth of Legionella species by disinfecting the water in public bath facilities. Our findings contribute to the establishment of appropriate hygiene management practices and provide a basis for understanding the potential health effects of using bath and shower water available in public bath facilities.
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Affiliation(s)
- Jun-ichi Kanatani
- Department of Bacteriology, Toyama Institute of Health, Imizu, Toyama, Japan
| | - So Fujiyoshi
- Section of Microbial Genomics and Ecology, Hiroshima University, Hiroshima, Japan
| | - Junko Isobe
- Department of Bacteriology, Toyama Institute of Health, Imizu, Toyama, Japan
| | - Keiko Kimata
- Department of Bacteriology, Toyama Institute of Health, Imizu, Toyama, Japan
| | - Masanori Watahiki
- Department of Bacteriology, Toyama Institute of Health, Imizu, Toyama, Japan
| | - Emi Maenishi
- Department of Bacteriology, Toyama Institute of Health, Imizu, Toyama, Japan
| | - Shinji Izumiyama
- Department of Parasitology, National Institute of Infectious Diseases, Toyama, Japan
| | - Junko Amemura-Maekawa
- Department of Bacteriology, National Institute of Infectious Diseases, Toyama, Japan
| | - Fumito Maruyama
- Section of Microbial Genomics and Ecology, Hiroshima University, Hiroshima, Japan
| | - Kazunori Oishi
- Department of Bacteriology, Toyama Institute of Health, Imizu, Toyama, Japan
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Cross J, Honnavar P, Quidet XLT, Butler T, Shivaprasad A, Christian L. Assessing Freshwater Microbiomes from Different Storage Sources in the Caribbean Using DNA Metabarcoding. Microorganisms 2023; 11:2945. [PMID: 38138089 PMCID: PMC10745428 DOI: 10.3390/microorganisms11122945] [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: 10/27/2023] [Revised: 11/23/2023] [Accepted: 11/28/2023] [Indexed: 12/24/2023] Open
Abstract
Next-generation sequencing (NGS) and the technique of DNA metabarcoding have provided more efficient and comprehensive options for testing water quality compared to traditional methods. Recent studies have shown the efficacy of DNA metabarcoding in characterizing the bacterial microbiomes of varied sources of drinking water, including rivers, reservoirs, wells, tanks, and lakes. We asked whether DNA metabarcoding could be used to characterize the microbiome of different private sources of stored freshwater on the Caribbean Island nation of Antigua and Barbuda. Two replicate water samples were obtained from three different private residential sources in Antigua: a well, an above-ground tank, and a cistern. The bacterial microbiomes of different freshwater sources were assessed using 16S rRNA metabarcoding. We measured both alpha diversity (species diversity within a sample) and beta diversity (species diversity across samples) and conducted a taxonomic analysis. We also looked for the presence of potentially pathogenic species. Major differences were found in the microbiome composition and relative abundances depending on the water source. A lower alpha diversity was observed in the cistern sample compared to the others, and distinct differences in the microbiome composition and relative abundance were noted between the samples. Notably, pathogenic species, or genera known to harbor such species, were detected in all the samples. We conclude that DNA metabarcoding can provide an effective and comprehensive assessment of drinking water quality and has the potential to identify pathogenic species overlooked using traditional methods. This method also shows promise for tracing the source of disease outbreaks due to waterborne microorganisms. This is the first study from small island countries in the Caribbean where metabarcoding has been applied for assessing freshwater water quality.
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Affiliation(s)
- Joseph Cross
- Department of Biochemistry, Cell Biology and Genetics, American University of Antigua College of Medicine, St. Johns 1451, Antigua and Barbuda;
- Department of Microbial Pathogenesis and Immunology, Texas A&M University School of Medicine, College Station, TX 77843, USA
| | - Prasanna Honnavar
- Department of Microbiology and Immunology, American University of Antigua College of Medicine, St. Johns 1451, Antigua and Barbuda;
| | - Xegfred Lou T. Quidet
- Basic Medical Sciences, American University of Antigua College of Medicine, St. Johns 1451, Antigua and Barbuda; (X.L.T.Q.); (T.B.)
| | - Travis Butler
- Basic Medical Sciences, American University of Antigua College of Medicine, St. Johns 1451, Antigua and Barbuda; (X.L.T.Q.); (T.B.)
| | - Aparna Shivaprasad
- Department of Microbiology and Immunology, American University of Antigua College of Medicine, St. Johns 1451, Antigua and Barbuda;
| | - Linroy Christian
- Department of Analytical Services, St. Johns 1451, Antigua and Barbuda;
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Liang J, Cameron G, Faucher SP. Development of heat-shock resistance in Legionella pneumophila modeled by experimental evolution. Appl Environ Microbiol 2023; 89:e0066623. [PMID: 37668382 PMCID: PMC10537758 DOI: 10.1128/aem.00666-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 06/29/2023] [Indexed: 09/06/2023] Open
Abstract
Because it can grow in buildings with complex hot water distribution systems (HWDS), healthcare facilities recognize the waterborne bacterium Legionella pneumophila as a major nosocomial infection threat and often try to clear the systems with a pasteurization process known as superheat-and-flush. After this treatment, many facilities find that the contaminating populations slowly recover, suggesting the possibility of in situ evolution favoring increased survival in high-temperature conditions. To mimic this process in a controlled environment, an adaptive laboratory evolution model was used to select a wild-type strain of L. pneumophila for survival to transient exposures to temperatures characteristic of routine hot water use or failed pasteurization processes in HWDS. Over their evolution, these populations became insensitive to exposure to 55°C and developed the ability to survive short exposures to 59°C heat shock. Heat-adapted lineages maintained a higher expression of heat-shock genes during low-temperature incubation in freshwater, suggesting a pre-adaptation to heat stress. Although there were distinct mutation profiles in each of the heat-adapted lineages, each acquired multiple mutations in the DnaJ/DnaK/ClpB disaggregase complex, as well as mutations in chaperone htpG and protease clpX. These mutations were specific to heat-shock survival and were not seen in control lineages included in the experimental model without exposure to heat shock. This study supports in situ observations of adaptation to heat stress and demonstrates the potential of L. pneumophila to develop resistance to control measures. IMPORTANCE As a bacterium that thrives in warm water ecosystems, Legionella pneumophila is a key factor motivating regulations on hot water systems. Two major measures to control Legionella are high circulating temperatures intended to curtail growth and the use of superheat-and-flush pasteurization processes to eliminate established populations. Facilities often suffer recolonization of their hot water systems; hospitals are particularly at risk due to the severe nosocomial pneumoniae caused by Legionella. To understand these long-term survivors, we have used an adaptive laboratory evolution model to replicate this process. We find major differences between the mutational profiles of heat-adapted and heat-naïve L. pneumophila populations including mutations in major heat-shock genes like chaperones and proteases. This model demonstrates that well-validated treatment protocols are needed to clear contaminated systems and-in an analog to antibiotic resistance-the importance of complete eradication of the resident population to prevent selection for more persistent bacteria.
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Affiliation(s)
- Jeffrey Liang
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, Québec, Canada
| | - Gillian Cameron
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, Québec, Canada
| | - Sébastien P. Faucher
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, Québec, Canada
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
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Cavallaro A, Rhoads WJ, Sylvestre É, Marti T, Walser JC, Hammes F. Legionella relative abundance in shower hose biofilms is associated with specific microbiome members. FEMS MICROBES 2023; 4:xtad016. [PMID: 37705999 PMCID: PMC10496943 DOI: 10.1093/femsmc/xtad016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 07/13/2023] [Accepted: 08/14/2023] [Indexed: 09/15/2023] Open
Abstract
Legionella are natural inhabitants of building plumbing biofilms, where interactions with other microorganisms influence their survival, proliferation, and death. Here, we investigated the associations of Legionella with bacterial and eukaryotic microbiomes in biofilm samples extracted from 85 shower hoses of a multiunit residential building. Legionella spp. relative abundance in the biofilms ranged between 0-7.8%, of which only 0-0.46% was L. pneumophila. Our data suggest that some microbiome members were associated with high (e.g. Chthonomonas, Vrihiamoeba) or low (e.g. Aquabacterium, Vannella) Legionella relative abundance. The correlations of the different Legionella variants (30 Zero-Radius OTUs detected) showed distinct patterns, suggesting separate ecological niches occupied by different Legionella species. This study provides insights into the ecology of Legionella with respect to: (i) the colonization of a high number of real shower hoses biofilm samples; (ii) the ecological meaning of associations between Legionella and co-occurring bacterial/eukaryotic organisms; (iii) critical points and future directions of microbial-interaction-based-ecological-investigations.
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Affiliation(s)
- Alessio Cavallaro
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zürich, Switzerland
| | - William J Rhoads
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Émile Sylvestre
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Thierry Marti
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zürich, Switzerland
| | - Jean-Claude Walser
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zürich, Switzerland
- Department of Environmental Systems Science, Genetic Diversity Centre (GDC), ETH Zurich, 8092 Zürich, Switzerland
| | - Frederik Hammes
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
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Bergman O, Be'eri-Shlevin Y, Ninio S. Sodium levels and grazing pressure shape natural communities of the intracellular pathogen Legionella. MICROBIOME 2023; 11:167. [PMID: 37518067 PMCID: PMC10388490 DOI: 10.1186/s40168-023-01611-0] [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: 01/29/2023] [Accepted: 06/30/2023] [Indexed: 08/01/2023]
Abstract
BACKGROUND Legionella are parasites of freshwater protozoa, responsible for Legionellosis. Legionella can be found in a variety of aquatic environments, including rivers, lakes, and springs, as well as in engineered water systems where they can potentially lead to human disease outbarks. Legionella are considered to be predominantly freshwater organisms with a limited ability to proliferate in saline environments. Exposure of Legionella to high sodium concentrations inhibits growth and virulence of laboratory strains, particularly under elevated temperatures. Nonetheless, Legionella have been identified in some saline environments where they likely interact with various protozoan hosts. In this work, we examine how these selection pressures, sodium and grazing, help shape Legionella ecology within natural environments. Utilizing Legionella-specific primers targeting a variable region of the Legionella 16S rRNA gene, we characterized Legionella abundance, diversity, and community composition in natural spring clusters of varying sodium concentrations, focusing on high sodium concentrations and elevated temperatures. RESULTS We observed the highest abundance of Legionella in spring clusters of high salinity, particularly in combination with elevated temperatures. Legionella abundance was strongly related to sodium concentrations. The Legionella community structure in saline environments was characterized by relatively low diversity, compared to spring clusters of lower salinity. The community composition in high salinity was characterized by few dominant Legionella genotypes, not related to previously described species. Protozoan microbial community structure and composition patterns resembled those of Legionella, suggesting a common response to similar selection pressures. We examined Legionella co-occurrence with potential protozoan hosts and found associations with Ciliophora and Amoebozoa representatives. CONCLUSIONS Our results indicate that selection forces in saline environments favor a small yet dominant group of Legionella species that are not closely related to known species. These novel environmental genotypes interact with various protozoan hosts, under environmental conditions of high salinity. Our findings suggest that alternative survival mechanisms are utilized by these species, representing mechanisms distinct from those of well-studied laboratory strains. Our study demonstrate how salinity can shape communities of opportunistic pathogens and their hosts, in natural environments, shedding light on evolutionary forces acting within these complex environments. Video Abstract.
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Affiliation(s)
- Oded Bergman
- Kinneret Limnological Laboratory (KLL), Israel Oceanographic and Limnological Research (IOLR), P.O. Box 447, 49500, Migdal, Israel
| | - Yaron Be'eri-Shlevin
- Kinneret Limnological Laboratory (KLL), Israel Oceanographic and Limnological Research (IOLR), P.O. Box 447, 49500, Migdal, Israel
| | - Shira Ninio
- Kinneret Limnological Laboratory (KLL), Israel Oceanographic and Limnological Research (IOLR), P.O. Box 447, 49500, Migdal, Israel.
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7
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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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Gleason JA, Newby R, Gaynor JJ, Lee LH, Chu T, Bliese AD, Taylor CW, Yoon P, DeLorenzo S, Pranitis D, Bella J. Legionella monitoring results by water quality characteristics in a large public water system. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:55974-55988. [PMID: 36913019 DOI: 10.1007/s11356-023-26198-9] [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: 06/29/2022] [Accepted: 02/25/2023] [Indexed: 06/18/2023]
Abstract
Legionella, the causative agent of Legionnaires' disease, is an emerging concern for water utilities. Passaic Valley Water Commission (PVWC) is a public drinking water supplier, which provides treated surface water to approximately 800,000 customers in New Jersey. To evaluate the occurrence of Legionella in the PVWC distribution system, swab, first draw, and flushed cold water samples were collected from total coliform sites (n = 58) during a summer and winter sampling event. Endpoint PCR detection methods were combined with culture for Legionella detection. Among 58 total coliform sites during the summer, 17.2% (10/58) of first draw samples were positive for 16S and mip Legionella DNA markers and 15.5% (9/58) in flushed samples. Across both summer and winter sampling, a total of four out of 58 sites had low-level culture detection of Legionella spp. (0.5-1.6 CFU/mL) among first draw samples. Only one site had both a first and flush draw detection (8.5 CFU/mL and 1.1 CFU/mL) for an estimated culture detection frequency of 0% in the summer and 1.7% in the winter among flushed draw samples. No L. pneumophila was detected by culture. Legionella DNA detection was significantly greater in the summer than in the winter, and detection was greater in samples collected from areas treated with phosphate. No statistical difference was found between first draw and flush sample detection. Total organic carbon, copper, and nitrate were significantly associated with Legionella DNA detection.
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Affiliation(s)
- Jessie A Gleason
- Environmental and Occupational Health Surveillance Program, New Jersey Department of Health, 135 East State Street, P.O. Box 369, Trenton, NJ, 08625, USA.
| | - Robert Newby
- Division of Science, New Jersey Department of Environmental Protection, 428 East State Street, P.O. Box 420, Trenton, NJ, 08625, USA
| | - John J Gaynor
- Department of Biology, Montclair State University, Montclair, NJ, 07043, USA
| | - Lee H Lee
- Department of Biology, Montclair State University, Montclair, NJ, 07043, USA
| | - Tinchun Chu
- Department of Biological Sciences, Seton Hall University, 400 South Orange Ave, South Orange, NJ, 07076, USA
| | - Alorah D Bliese
- Department of Biology, Montclair State University, Montclair, NJ, 07043, USA
| | - Calvin W Taylor
- Department of Biology, Montclair State University, Montclair, NJ, 07043, USA
| | - Paul Yoon
- Department of Biological Sciences, Seton Hall University, 400 South Orange Ave, South Orange, NJ, 07076, USA
| | - Suzanne DeLorenzo
- Passaic Valley Water Commission, 1525 Main Avenue, Totowa, NJ, 07512, USA
| | - David Pranitis
- Passaic Valley Water Commission, 1525 Main Avenue, Totowa, NJ, 07512, USA
| | - Joe Bella
- Passaic Valley Water Commission, 1525 Main Avenue, Totowa, NJ, 07512, USA
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9
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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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Comparative Genomics of Legionella pneumophila Isolates from the West Bank and Germany Support Molecular Epidemiology of Legionnaires' Disease. Microorganisms 2023; 11:microorganisms11020449. [PMID: 36838414 PMCID: PMC9965269 DOI: 10.3390/microorganisms11020449] [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: 12/31/2022] [Revised: 01/27/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023] Open
Abstract
Legionella pneumophila is an environmental bacterium and clinical pathogen that causes many life-threating outbreaks of an atypical pneumonia called Legionnaires' disease (LD). Studies of this pathogen have focused mainly on Europe and the United States. A shortage in L. pneumophila data is clearly observed for developing countries. To reduce this knowledge gap, L. pneumophila isolates were studied in two widely different geographical areas, i.e., the West Bank and Germany. For this study, we sequenced and compared the whole genome of 38 clinical and environmental isolates of L. pneumophila covering different MLVA-8(12) genotypes in the two areas. Sequencing was conducted using the Illumina HiSeq 2500 platform. In addition, two isolates (A194 and H3) were sequenced using a Pacific Biosciences (PacBio) RSII platform to generate complete reference genomes from each of the geographical areas. Genome sequences from 55 L. pneumophila strains, including 17 reference strains, were aligned with the genome sequence of the closest strain (L. pneumophila strain Alcoy). A whole genome phylogeny based on single nucleotide polymorphisms (SNPs) was created using the ParSNP software v 1.0. The reference genomes obtained for isolates A194 and H3 consisted of circular chromosomes of 3,467,904 bp and 3,691,263 bp, respectively. An average of 36,418 SNPs (min. 8569, max. 70,708 SNPs) against our reference strain L. pneumophila str. Alcoy, and 2367 core-genes were identified among the fifty-five strains. An analysis of the genomic population structure by SNP comparison divided the fifty-five L. pneumophila strains into six branches. Individual isolates in sub-lineages in these branches differed by less than 120 SNPs if they had the same MLVA genotype and were isolated from the same location. A bioinformatics analysis identified the genomic islands (GIs) for horizontal gene transfer and mobile genetic elements, demonstrating that L. pneumophila showed high genome plasticity. Four L. pneumophila isolates (H3, A29, A129 and L10-091) contained well-defined plasmids. On average, only about half of the plasmid genes could be matched to proteins in databases. In silico phage findings suggested that 43 strains contained at least one phage. However, none of them were found to be complete. BLASTp analysis of proteins from the type IV secretion Dot/Icm system showed those proteins highly conserved, with less than 25% structural differences in the new L. pneumophila isolates. Overall, we demonstrated that whole genome sequencing provides a molecular surveillance tool for L. pneumophila at the highest conceivable discriminatory level, i.e., two to eight SNPs were observed for isolates from the same location but several years apart.
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11
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Surveillance of Legionella spp. in Open Fountains: Does It Pose a Risk? Microorganisms 2022; 10:microorganisms10122458. [PMID: 36557711 PMCID: PMC9781103 DOI: 10.3390/microorganisms10122458] [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: 10/29/2022] [Revised: 11/21/2022] [Accepted: 12/03/2022] [Indexed: 12/14/2022] Open
Abstract
Clusters of outbreaks or cases of legionellosis have been linked to fountains. The function of fountains, along with their inadequate design and poor sanitation, in combination with the warm Mediterranean climate, can favor the proliferation of Legionella in water systems. Public fountains in Mediterranean cities may pose a significant risk for public health due to the aerosolization of water. Nevertheless, few studies have been conducted on Legionella and the risk of infection in humans through fountains. In our study, the presence and quantity of Legionella spp. in fifteen external public fountains were investigated. Two samplings were performed in two different periods (dry and wet). Sixty samples were collected, quantified and analyzed with a culture ISO method. The operation of all fountains was evaluated twice using a standardized checklist. In accordance with their operation, a ranking factor (R factor) was suggested. Finally, based on these results, a quantitative microbial risk assessment was performed. Thirty water samples taken from the fountains (100%) during the dry sampling period were positive for Legionella (mean log concentration: 3.64 ± 0.45 cfu/L), whereas 24 water samples taken from the fountains during the wet period were Legionella-positive (mean log concentration: 2.36 ± 1.23 cfu/L). All fountains were classified as unsatisfactory according to the checklist for the evaluation of their function. A statistically significant correlation was found between Legionella concentration and the assessment score. The risk of Legionella infection was estimated in both periods, with higher risk in the dry period. The surveillance and risk assessment of Legionella spp. in the fountains of Patras confirmed a high prevalence and a high risk to public health.
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Kanarek P, Bogiel T, Breza-Boruta B. Legionellosis risk-an overview of Legionella spp. habitats in Europe. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:76532-76542. [PMID: 36161570 PMCID: PMC9511453 DOI: 10.1007/s11356-022-22950-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 09/05/2022] [Indexed: 05/28/2023]
Abstract
An increase in the number of reports of legionellosis in the European Union and the European Economic Area have been recorded in recent years. The increase in cases is significant: from 6947 reports in 2015 to 11,298 in 2019. This is alarming as genus Legionella, which comprises a large group of bacteria inhabiting various aquatic systems, poses a serious threat to human health and life, since more than 20 species can cause legionellosis, with L. pneumophila being responsible for the majority of cases. The ability to colonize diverse ecosystems makes the eradication of these microorganisms difficult. A detailed understanding of the Legionella habitat may be helpful in the effective control of this pathogen. This paper provides an overview of Legionella environments in Europe: natural (lakes, groundwater, rivers, compost, soil) and anthropogenic (fountains, air humidifiers, water supply systems), and the role of Legionella spp. in nosocomial infections, which are potentially fatal for children, the elderly and immunocompromised patients.
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Affiliation(s)
- Piotr Kanarek
- Department of Microbiology and Food Technology, Faculty of Agriculture and Biotechnology, Bydgoszcz University of Science and Technology, 6 Bernardyńska Street, 85-029, Bydgoszcz, Poland
| | - Tomasz Bogiel
- Department of Microbiology, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, 9 Skłodowska-Curie Street, 85-094, Bydgoszcz, Poland
| | - Barbara Breza-Boruta
- Department of Microbiology and Food Technology, Faculty of Agriculture and Biotechnology, Bydgoszcz University of Science and Technology, 6 Bernardyńska Street, 85-029, Bydgoszcz, Poland.
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Treglia M, Pallocci M, Ricciardi Tenore G, Castellani P, Pizzuti F, Bianco G, Passalacqua P, De Luca L, Zanovello C, Mazzuca D, Gratteri S, Messineo A, Quintavalle G, Marsella LT. Legionella and Air Transport: A Study of Environmental Contamination. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19138069. [PMID: 35805725 PMCID: PMC9265378 DOI: 10.3390/ijerph19138069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/20/2022] [Accepted: 06/25/2022] [Indexed: 11/16/2022]
Abstract
Introduction: There is growing interest in the public health and transport sectors in research into exposure to biological hazards, considering not only the risks arising from inter-human contagion, but also those related to exposure to the flight environment itself. The aim of this paper is to report data from an investigation into the water and air-conditioning systems of commercial aircraft for the presence of Legionella contamination, with a total of 645 water samples taken during the period 2007−2021. Methods: The investigation involved 126 aircraft of six different commercial aircraft types: MD80, Airbus A320 F, Embraer 175/190, AIRBUS A330, Boeing 767 and Boeing 777. Water samples were taken from the water systems (toilet taps, galley and boilers). Each sample was preliminarily subjected to an evaluation of the following parameters: temperature, pH and residual chlorine. The ScanVit® Legionella kit was used for bacteria detection and enumeration. Results: Samples were considered positive if the number of colony-forming units/liter (CFU/L) was >100. For the entire observation period, 45% of the investigated aircraft tested positive. Regarding the overall number of samples analyzed, 68.4% (441/645) were below 100 CFU/L, and thus within the limits allowed by the Italian Guidelines. Conclusions: Water system contamination with Legionella in the air transport field is a real public health issue that should not be underestimated given the heavy passenger traffic. Infection should be considered an occupational risk to which crew members are exposed.
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Affiliation(s)
- Michele Treglia
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy; (M.T.); (P.P.); (L.D.L.); (C.Z.); (A.M.); (L.T.M.)
| | - Margherita Pallocci
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy; (M.T.); (P.P.); (L.D.L.); (C.Z.); (A.M.); (L.T.M.)
- Correspondence:
| | - Giorgio Ricciardi Tenore
- APSSP-Prevention, Safety & Health Association, Velletri, 00049 Rome, Italy; (G.R.T.); (P.C.); (F.P.); (G.B.)
| | - Paola Castellani
- APSSP-Prevention, Safety & Health Association, Velletri, 00049 Rome, Italy; (G.R.T.); (P.C.); (F.P.); (G.B.)
| | - Fabrizio Pizzuti
- APSSP-Prevention, Safety & Health Association, Velletri, 00049 Rome, Italy; (G.R.T.); (P.C.); (F.P.); (G.B.)
| | - Giovanna Bianco
- APSSP-Prevention, Safety & Health Association, Velletri, 00049 Rome, Italy; (G.R.T.); (P.C.); (F.P.); (G.B.)
| | - Pierluigi Passalacqua
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy; (M.T.); (P.P.); (L.D.L.); (C.Z.); (A.M.); (L.T.M.)
| | - Lucilla De Luca
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy; (M.T.); (P.P.); (L.D.L.); (C.Z.); (A.M.); (L.T.M.)
| | - Claudia Zanovello
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy; (M.T.); (P.P.); (L.D.L.); (C.Z.); (A.M.); (L.T.M.)
| | - Daniela Mazzuca
- Department of Surgical Sciences, University “Magna Græcia” of Catanzaro, 88100 Catanzaro, Italy; (D.M.); (S.G.)
| | - Santo Gratteri
- Department of Surgical Sciences, University “Magna Græcia” of Catanzaro, 88100 Catanzaro, Italy; (D.M.); (S.G.)
| | - Agostino Messineo
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy; (M.T.); (P.P.); (L.D.L.); (C.Z.); (A.M.); (L.T.M.)
| | | | - Luigi Tonino Marsella
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy; (M.T.); (P.P.); (L.D.L.); (C.Z.); (A.M.); (L.T.M.)
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Eriksson KIA, Thelaus J, Andersson A, Ahlinder J. Microbial Interactions - Underexplored Links Between Public Health Relevant Bacteria and Protozoa in Coastal Environments. Front Microbiol 2022; 13:877483. [PMID: 35770179 PMCID: PMC9235517 DOI: 10.3389/fmicb.2022.877483] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/23/2022] [Indexed: 12/13/2022] Open
Abstract
The co-existence of bacteria and protozoa in aquatic environments has led to the evolution of predation defense mechanisms by the bacteria. Some of the predation-resistant bacteria (PRB) are also pathogenic to humans and other mammals. The links between PRB and protozoa in natural aquatic systems are poorly known, but they are important in predicting outbreaks and determining the long-term consequences of a contamination event. To elucidate co-occurrence patterns between PRB (16S rRNA) and bacterivorous protozoa (18S rRNA), we performed a field study in a coastal area in the northern Baltic Sea. Interactions between bacteria and protozoa were explored by using two complementary statistical tools. We found co-occurrence patterns between specific PRB and protozoa, such as Legionella and Ciliophora, and we also found that the interactions are genotype-specific as, for example, Rickettsia. The PRB sequence diversity was larger in bays and freshwater inlets compared to offshore sites, indicating local adaptions. Considering the PRB diversity in the freshwater in combination with the large spring floods in the area, freshwater influxes should be considered a potential source of PRB in the coastal northern Baltic Sea. These findings are relevant for the knowledge of survival and dispersal of potential pathogens in the environment.
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Affiliation(s)
- Karolina I. A. Eriksson
- Department of Ecology and Environmental Sciences, Faculty of Science and Technology, Umeå University, Umeå, Sweden
| | - Johanna Thelaus
- Division of CBRN Defence and Security, Swedish Defence Research Agency (FOI), Umeå, Sweden
| | - Agneta Andersson
- Department of Ecology and Environmental Sciences, Faculty of Science and Technology, Umeå University, Umeå, Sweden
- Umeå Marine Sciences Centre, Umeå University, Hörnefors, Sweden
| | - Jon Ahlinder
- Division of CBRN Defence and Security, Swedish Defence Research Agency (FOI), Umeå, Sweden
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Girolamini L, Salaris S, Pascale MR, Mazzotta M, Cristino S. Dynamics of Legionella Community Interactions in Response to Temperature and Disinfection Treatment: 7 Years of Investigation. MICROBIAL ECOLOGY 2022; 83:353-362. [PMID: 34091718 PMCID: PMC8891097 DOI: 10.1007/s00248-021-01778-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/17/2021] [Indexed: 05/12/2023]
Abstract
In man-made water distribution systems, Legionella community interactions remain unknown, due to their ability to change from sessile to planktonic states or live in viable but non-culturable forms, in response to anthropic and environmental stress. During 7 years of hospital Legionella surveillance, in 191 hot water positive samples, the interactions among the Legionella species, temperature, and disinfection treatment were evaluated. Legionella was isolated following ISO 11731:2017, and identification was performed by mip gene sequencing and sequence-based typing (SBT) for L. anisa or L. rubrilucens and L. pneumophila, respectively. The species with the higher frequency of isolation was L. pneumophila serogroup 1 (78.53%; 4865.36 ± 25,479.11 cfu/L), followed by L. anisa (54.45%; 558.79 ± 2637.41 cfu/L) and L. rubrilucens (21.99%; 307.73 ± 1574.95 cfu/L), which were sometimes present together. Spearman's rho correlation test was conducted among the species with respect to temperature and disinfectant (H2O2/Ag+). The results showed a generally positive interaction among these species sharing the same environment, except for competition between L. anisa and L. rubrilucens. High temperature (48.83 ± 2.59 °C) and disinfection treatment (11.58 ± 4.99 mg/L) affected the presence of these species. An exception was observed with L. anisa, which showed disinfection treatment resistance. For the purposes of environmental surveillance, it is fundamental to better understand the interactions and dynamic of the Legionella community in man-made water systems in order to choose the proper physical or chemical treatments. The simultaneous presence of different Legionella species could result in an increased resistance to high temperature and disinfectant treatment, leading to changes in contamination level and species diversity.
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Affiliation(s)
- Luna Girolamini
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, via San Giacomo 12, 40126 Bologna, BO Italy
| | - Silvano Salaris
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, via San Giacomo 12, 40126 Bologna, BO Italy
| | - Maria Rosaria Pascale
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, via San Giacomo 12, 40126 Bologna, BO Italy
| | - Marta Mazzotta
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, via San Giacomo 12, 40126 Bologna, BO Italy
| | - Sandra Cristino
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, via San Giacomo 12, 40126 Bologna, BO Italy
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Talapko J, Frauenheim E, Juzbašić M, Tomas M, Matić S, Jukić M, Samardžić M, Škrlec I. Legionella pneumophila-Virulence Factors and the Possibility of Infection in Dental Practice. Microorganisms 2022; 10:microorganisms10020255. [PMID: 35208710 PMCID: PMC8879694 DOI: 10.3390/microorganisms10020255] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/08/2022] [Accepted: 01/21/2022] [Indexed: 02/07/2023] Open
Abstract
Legionella pneumophila is defined as a bacterium that can cause severe pneumonia. It is found in the natural environment and in water, and is often found in water tanks. It can be an integral part of biofilms in nature, and the protozoa in which it can live provide it with food and protect it from harmful influences; therefore, it has the ability to move into a sustainable but uncultured state (VBNC). L. pneumophila has been shown to cause infections in dental practices. The most common transmission route is aerosol generated in dental office water systems, which can negatively affect patients and healthcare professionals. The most common way of becoming infected with L. pneumophila in a dental office is through water from dental instruments, and the dental unit. In addition to these bacteria, patients and the dental team may be exposed to other harmful bacteria and viruses. Therefore, it is vital that the dental team regularly maintains and decontaminates the dental unit, and sterilizes all accessories that come with it. In addition, regular water control in dental offices is necessary.
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Affiliation(s)
- Jasminka Talapko
- Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, HR-31000 Osijek, Croatia; (J.T.); (E.F.); (M.J.); (M.T.); (S.M.); (M.J.); (M.S.)
| | - Erwin Frauenheim
- Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, HR-31000 Osijek, Croatia; (J.T.); (E.F.); (M.J.); (M.T.); (S.M.); (M.J.); (M.S.)
| | - Martina Juzbašić
- Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, HR-31000 Osijek, Croatia; (J.T.); (E.F.); (M.J.); (M.T.); (S.M.); (M.J.); (M.S.)
| | - Matej Tomas
- Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, HR-31000 Osijek, Croatia; (J.T.); (E.F.); (M.J.); (M.T.); (S.M.); (M.J.); (M.S.)
| | - Suzana Matić
- Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, HR-31000 Osijek, Croatia; (J.T.); (E.F.); (M.J.); (M.T.); (S.M.); (M.J.); (M.S.)
- Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, Josipa Huttlera 4, HR-31000 Osijek, Croatia
| | - Melita Jukić
- Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, HR-31000 Osijek, Croatia; (J.T.); (E.F.); (M.J.); (M.T.); (S.M.); (M.J.); (M.S.)
- General Hospital Vukovar, Županijska 35, HR-32000 Vukovar, Croatia
| | - Marija Samardžić
- Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, HR-31000 Osijek, Croatia; (J.T.); (E.F.); (M.J.); (M.T.); (S.M.); (M.J.); (M.S.)
| | - Ivana Škrlec
- Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, HR-31000 Osijek, Croatia; (J.T.); (E.F.); (M.J.); (M.T.); (S.M.); (M.J.); (M.S.)
- Correspondence:
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17
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Jiang L, Gu R, Li X, Song M, Huang X, Mu D. Multiple Cross Displacement Amplification Coupled with Lateral Flow Biosensor (MCDA-LFB) for rapid detection of Legionella pneumophila. BMC Microbiol 2022; 22:20. [PMID: 34996350 PMCID: PMC8742375 DOI: 10.1186/s12866-021-02363-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 10/15/2021] [Indexed: 06/26/2024] Open
Abstract
Background Legionella pneumophila is an opportunistic waterborne pathogen of significant public health problems, which can cause serious human respiratory diseases (Legionnaires’ disease). Multiple cross displacement amplification (MCDA), a isothermal nucleic acid amplification technique, has been applied in the rapid detection of several bacterial agents. In this report, we developed a MCDA coupled with Nanoparticles-based Lateral Flow Biosensor (MCDA-LFB) for the rapid detection of L. pneumophila. Results A set of 10 primers based on the L. pneumophila specific mip gene to specifically identify 10 different target sequence regions of L. pneumophila was designed. The optimal time and temperature for amplification are 57 min and 65 °C. The limit of detection (LoD) is 10 fg in pure cultures of L. pneumophila. No cross-reaction was obtained and the specificity of MCDA-LFB assay was 100%. The whole process of the assay, including 20 min of DNA preparation, 35 min of L. pneumophila-MCDA reaction, and 2 min of sensor strip reaction, took a total of 57 min (less than 1 h). Among 88 specimens for clinical evaluation, 5 (5.68%) samples were L. pneumophila-positive by MCDA-LFB and traditional culture method, while 4(4.55%) samples were L. pneumophila-positive by PCR method targeting mip gene. Compared with culture method, the diagnostic accuracy of MCDA-LFB method was higher. Conclusions In summary, the L. pneumophila-MCDA-LFB method we successfully developed is a simple, fast, reliable and sensitive diagnostic tool, which can be widely used in basic and clinical laboratories. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02363-3.
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Affiliation(s)
- Luxi Jiang
- Department of Respiratory Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, People's Republic of China
| | - Rumeng Gu
- Department of Respiratory Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, People's Republic of China.,Graduate School of Clinical Medicine, Bengbu Medical College, Bengbu, China
| | - Xiaomeng Li
- Department of Respiratory and Critical Care Medicine, Shanghai Fourth People's Hospital Affiliated to Tongji University, 1279 Sanmen Road, Shanghai, 200080, People's Republic of China
| | - Meijun Song
- Department of Respiratory Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, People's Republic of China
| | - Xiaojun Huang
- Department of Respiratory Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, People's Republic of China
| | - Deguang Mu
- Department of respiratory and critical care medicine, Xi'an Daxing Hospital, Xi'an, China.
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Water Age Effects on the Occurrence and Concentration of Legionella Species in the Distribution System, Premise Plumbing, and the Cooling Towers. Microorganisms 2021; 10:microorganisms10010081. [PMID: 35056530 PMCID: PMC8778510 DOI: 10.3390/microorganisms10010081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/24/2021] [Accepted: 12/29/2021] [Indexed: 11/30/2022] Open
Abstract
In this study, droplet digital PCRTM (ddPCRTM) was used to characterize total Legionella spp. and five specific Legionella species from source (groundwater) to exposure sites (taps and cooling towers). A total of 42–10 L volume water samples were analyzed during this study: 12 from a reservoir (untreated groundwater and treated water storage tanks), 24 from two buildings (influents and taps), and six from cooling towers, all part of the same water system. The approximate water age (time in the system) for all sample locations are as follows: ~4.5, 3.4, 9.2, 20.8, and 23.2 h (h) for the groundwater to the reservoir influent, reservoir influent to the reservoir effluent, reservoir effluent to building Fa (building names are abbreviated to protect the privacy of site location), building ERC and the cooling towers, respectively. Results demonstrated that gene copies of Legionella spp. (23S rRNA) were significantly higher in the cooling towers and ERC building (p < 0.05) relative to the reservoir and building Fa (closest to reservoir). Legionella spp. (23S rRNA) were found in 100% (42/42) of water samples at concentrations ranging from 2.2 to 4.5 Log10 GC/100 mL. More specifically, L. pneumophila was found in 57% (24/42) of the water samples, followed by L. bozemanii 52% (22/42), L. longbeachae 36% (15/42), L. micdadei 23% (10/42) and L. anisa 21% (9/42) with geometric mean concentrations of 1.7, 1.7, 1.4, 1.6 and 1.7 Log10 GC/100 mL, respectively. Based on this study, it is hypothesized that water age in the distribution system and the premise-plumbing system as well as building management plays a major role in the increase of Legionella spp., (23S rRNA) and the diversity of pathogenic species found as seen in the influent, and at the taps in the ERC building—where the building water quality was most comparable to the industrial cooling towers. Other pathogenic Legionella species besides L.pneumophila are also likely amplifying in the system; thus, it is important to consider other disease relevant species in the whole water supply system—to subsequently control the growth of pathogenic Legionella in the built water environment.
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Sevillano M, Vosloo S, Cotto I, Dai Z, Jiang T, Santiago Santana JM, Padilla IY, Rosario-Pabon Z, Velez Vega C, Cordero JF, Alshawabkeh A, Gu A, Pinto AJ. Spatial-temporal targeted and non-targeted surveys to assess microbiological composition of drinking water in Puerto Rico following Hurricane Maria. WATER RESEARCH X 2021; 13:100123. [PMID: 34704006 PMCID: PMC8524244 DOI: 10.1016/j.wroa.2021.100123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 09/28/2021] [Accepted: 09/30/2021] [Indexed: 05/05/2023]
Abstract
Loss of basic utilities, such as drinking water and electricity distribution, were sustained for months in the aftermath of Hurricane Maria's (HM) landfall in Puerto Rico (PR) in September 2017. The goal of this study was to assess if there was deterioration in biological quality of drinking water due to these disruptions. This study characterized the microbial composition of drinking water following HM across nine drinking water systems (DWSs) in PR and utilized an extended temporal sampling campaign to determine if changes in the drinking water microbiome were indicative of HM associated disturbance followed by recovery. In addition to monitoring water chemistry, the samples were subjected to culture independent targeted and non-targeted microbial analysis including quantitative PCR (qPCR) and genome-resolved metagenomics. The qPCR results showed that residual disinfectant was the major driver of bacterial concentrations in tap water with marked decrease in concentrations from early to late sampling timepoints. While Mycobacterium avium and Pseudomonas aeruginosa were not detected in any sampling locations and timepoints, genetic material from Leptospira and Legionella pneumophila were transiently detected in a few sampling locations. The majority of metagenome assembled genomes (MAGs) recovered from these samples were not associated with pathogens and were consistent with bacterial community members routinely detected in DWSs. Further, whole metagenome-level comparisons between drinking water samples collected in this study with samples from other full-scale DWS indicated no significant deviation from expected community membership of the drinking water microbiome. Overall, our results suggest that disruptions due to HM did not result in significant and sustained deterioration of biological quality of drinking water at our study sites.
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Affiliation(s)
- Maria Sevillano
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA, United States of America
| | - Solize Vosloo
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, United States of America
| | - Irmarie Cotto
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA, United States of America
| | - Zihan Dai
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Tao Jiang
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA, United States of America
| | - Jose M. Santiago Santana
- Department of Natural Sciences, University of Puerto Rico, Carolina, PR, United States of America
| | - Ingrid Y. Padilla
- Department of Civil Engineering and Surveying, University of Puerto Rico, Mayagüez, PR, United States of America
| | - Zaira Rosario-Pabon
- University of Puerto Rico—Medical Sciences Campus, San Juan, PR, United States of America
| | - Carmen Velez Vega
- University of Puerto Rico—Medical Sciences Campus, San Juan, PR, United States of America
| | - José F. Cordero
- Department of Epidemiology and Biostatistics, University of Georgia, Athens, Georgia, United States of America
| | - Akram Alshawabkeh
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA, United States of America
| | - April Gu
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, United States of America
| | - Ameet J. Pinto
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, United States of America
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Zhang C, Lu J. Legionella: A Promising Supplementary Indicator of Microbial Drinking Water Quality in Municipal Engineered Water Systems. FRONTIERS IN ENVIRONMENTAL SCIENCE 2021; 9:1-22. [PMID: 35004706 PMCID: PMC8740890 DOI: 10.3389/fenvs.2021.684319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Opportunistic pathogens (OPs) are natural inhabitants and the predominant disease causative biotic agents in municipal engineered water systems (EWSs). In EWSs, OPs occur at high frequencies and concentrations, cause drinking-water-related disease outbreaks, and are a major factor threatening public health. Therefore, the prevalence of OPs in EWSs represents microbial drinking water quality. Closely or routinely monitoring the dynamics of OPs in municipal EWSs is thus critical to ensuring drinking water quality and protecting public health. Monitoring the dynamics of conventional (fecal) indicators (e.g., total coliforms, fecal coliforms, and Escherichia coli) is the customary or even exclusive means of assessing microbial drinking water quality. However, those indicators infer only fecal contamination due to treatment (e.g., disinfection within water utilities) failure and EWS infrastructure issues (e.g., water main breaks and infiltration), whereas OPs are not contaminants in drinking water. In addition, those indicators appear in EWSs at low concentrations (often absent in well-maintained EWSs) and are uncorrelated with OPs. For instance, conventional indicators decay, while OPs regrow with increasing hydraulic residence time. As a result, conventional indicators are poor indicators of OPs (the major aspect of microbial drinking water quality) in EWSs. An additional or supplementary indicator that can well infer the prevalence of OPs in EWSs is highly needed. This systematic review argues that Legionella as a dominant OP-containing genus and natural inhabitant in EWSs is a promising candidate for such a supplementary indicator. Through comprehensively comparing the behavior (i.e., occurrence, growth and regrowth, spatiotemporal variations in concentrations, resistance to disinfectant residuals, and responses to physicochemical water quality parameters) of major OPs (e.g., Legionella especially L. pneumophila, Mycobacterium, and Pseudomonas especially P. aeruginosa), this review proves that Legionella is a promising supplementary indicator for the prevalence of OPs in EWSs while other OPs lack this indication feature. Legionella as a dominant natural inhabitant in EWSs occurs frequently, has a high concentration, and correlates with more microbial and physicochemical water quality parameters than other common OPs. Legionella and OPs in EWSs share multiple key features such as high disinfectant resistance, biofilm formation, proliferation within amoebae, and significant spatiotemporal variations in concentrations. Therefore, the presence and concentration of Legionella well indicate the presence and concentrations of OPs (especially L. pneumophila) and microbial drinking water quality in EWSs. In addition, Legionella concentration indicates the efficacies of disinfectant residuals in EWSs. Furthermore, with the development of modern Legionella quantification methods (especially quantitative polymerase chain reactions), monitoring Legionella in ESWs is becoming easier, more affordable, and less labor-intensive. Those features make Legionella a proper supplementary indicator for microbial drinking water quality (especially the prevalence of OPs) in EWSs. Water authorities may use Legionella and conventional indicators in combination to more comprehensively assess microbial drinking water quality in municipal EWSs. Future work should further explore the indication role of Legionella in EWSs and propose drinking water Legionella concentration limits that indicate serious public health effects and require enhanced treatment (e.g., booster disinfection).
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Affiliation(s)
- Chiqian Zhang
- Pegasus Technical Services, Inc., Cincinnati, OH, United States
| | - Jingrang Lu
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH, United States
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Zhang C, Struewing I, Mistry JH, Wahman DG, Pressman J, Lu J. Legionella and other opportunistic pathogens in full-scale chloraminated municipal drinking water distribution systems. WATER RESEARCH 2021; 205:117571. [PMID: 34628111 PMCID: PMC8629321 DOI: 10.1016/j.watres.2021.117571] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 08/02/2021] [Accepted: 08/13/2021] [Indexed: 05/06/2023]
Abstract
Water-based opportunistic pathogens (OPs) are a leading cause of drinking-water-related disease outbreaks, especially in developed countries such as the United States (US). Physicochemical water quality parameters, especially disinfectant residuals, control the (re)growth, presence, colonization, and concentrations of OPs in drinking water distribution systems (DWDSs), while the relationship between OPs and those parameters remain unclear. This study aimed to quantify how physicochemical parameters, mainly monochloramine residual concentration, hydraulic residence time (HRT), and seasonality, affected the occurrence and concentrations of four common OPs (Legionella, Mycobacterium, Pseudomonas, and Vermamoeba vermiformis) in four full-scale DWDSs in the US. Legionella as a dominant OP occurred in 93.8% of the 64 sampling events and had a mean density of 4.27 × 105 genome copies per liter. Legionella positively correlated with Mycobacterium, Pseudomonas, and total bacteria. Multiple regression with data from the four DWDSs showed that Legionella had significant correlations with total chlorine residual level, free ammonia concentration, and trihalomethane concentration. Therefore, Legionella is a promising indicator of water-based OPs, reflecting microbial water quality in chloraminated DWDSs. The OP concentrations had strong seasonal variations and peaked in winter and/or spring possibly because of reduced water usage (i.e., increased water stagnation or HRT) during cold seasons. The OP concentrations generally increased with HRT presumably because of disinfectant residual decay, indicating the importance of well-maintaining disinfectant residuals in DWDSs for OP control. The concentrations of Mycobacterium, Pseudomonas, and V. vermiformis were significantly associated with total chlorine residual concentration, free ammonia concentration, and pH and trihalomethane concentration, respectively. Overall, this study demonstrates how the significant spatiotemporal variations of OP concentrations in chloraminated DWDSs correlated with critical physicochemical water quality parameters such as disinfectant residual levels. This work also indicates that Legionella is a promising indicator of OPs and microbial water quality in chloraminated DWDSs.
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Affiliation(s)
- Chiqian Zhang
- Pegasus Technical Services, Inc., Cincinnati, Ohio, USA
| | - Ian Struewing
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Jatin H Mistry
- United States Environmental Protection Agency, Region 6, Dallas, Texas, USA
| | - David G Wahman
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Jonathan Pressman
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Jingrang Lu
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio, USA.
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Han Z, Lu J, An W, Zhang Y, Yang M. Removal efficacy of opportunistic pathogen gene markers in drinking water supply systems: an in situ and large-scale molecular investigation. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:54153-54160. [PMID: 34389952 DOI: 10.1007/s11356-021-15744-y] [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: 03/25/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
The prevalence and interactions with biofilm and disinfectant of opportunistic pathogens in drinking water supply systems (DWSSs) have been extensively interpreted. In contrast, the large geographical distribution and in situ removal of opportunistic pathogens are overlooked aspects. Here, paired source and tap water samples of 36 parallel DWSSs across China were collected, with five common waterborne pathogens characterized by qPCR. From source to tap, the removal of bacterial biomass (16S rRNA gene copy number) was 1.10 log, and gene marker removal of five opportunistic pathogens ranged from 0.66 log to 2.27 log, with the order of Escherichia coli > Mycobacterium spp. > Clostridium perfringens > Bacillus cereus > Aeromonas hydrophila. Different with bacterial community, geographical location and source water types (river or reservoir) were not key contributor to variation of opportunistic pathogens. Gene marker removal efficacies of E. coli, Mycobacterium spp., and C. perfringens from source to tap were restricted to removal efficacy of overall bacterial biomass, while abundance of B. cereus in tap water linked to the input of B. cereus from source water. Although culture-dependent approach is important for pathogen enumeration in drinking water, qPCR-based molecular survey shows advantages of quantifiable high-throughput and easy operation, providing abundant and timely information on pathogen occurrence in water. This study provides the in situ, molecular-level evidence toward differential propagation features of multiple opportunistic pathogens in DWSSs and suggests the source protection and early warning of treatment-resistant pathogens.
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Affiliation(s)
- Ziming Han
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Junying Lu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Wei An
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Yu Zhang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Min Yang
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
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Zhang C, Qin K, Struewing I, Buse H, Santo Domingo J, Lytle D, Lu J. The Bacterial Community Diversity of Bathroom Hot Tap Water Was Significantly Lower Than That of Cold Tap and Shower Water. Front Microbiol 2021; 12:625324. [PMID: 33967975 PMCID: PMC8102780 DOI: 10.3389/fmicb.2021.625324] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/12/2021] [Indexed: 12/17/2022] Open
Abstract
Microbial drinking water quality in premise plumbing systems (PPSs) strongly affects public health. Bacterial community structure is the essential aspect of microbial water quality. Studies have elucidated the microbial community structure in cold tap water, while the microbial community structures in hot tap and shower water are poorly understood. We sampled cold tap, hot tap, and shower water from a simulated PPS monthly for 16 consecutive months and assessed the bacterial community structures in those samples via high-throughput sequencing of bacterial 16S rRNA genes. The total relative abundance of the top five most abundant phyla (Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, and Firmicutes) was greater than 90% among the 24 identified phyla. The most abundant families were Burkholderiaceae, Sphingomonadaceae, unclassified Alphaproteobacteria, unclassified Corynebacteriales, and Mycobacteriaceae. A multiple linear regression suggests that the bacterial community diversity increased with water temperature and the age of the simulated PPS, decreased with total chlorine residual concentration, and had a limited seasonal variation. The bacterial community in hot tap water had significantly lower Shannon and Inverse Simpson diversity indices (p < 0.05) and thus a much lower diversity than those in cold tap and shower water. The paradoxical results (i.e., diversity increased with water temperature, but hot tap water bacterial community was less diverse) were presumably because (1) other environmental factors made hot tap water bacterial community less diverse, (2) the diversity of bacterial communities in all types of water samples increased with water temperature, and (3) the first draw samples of hot tap water could have a comparable or even lower temperature than shower water samples and the second draw samples of cold tap water. In both a three-dimensional Non-metric multidimensional scaling ordination plot and a phylogenetic dendrogram, the samples of cold tap and shower water cluster and are separate from hot tap water samples (p < 0.05). In summary, the bacterial community in hot tap water in the simulated PPS had a distinct structure from and a much lower diversity than those in cold tap and shower water.
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Affiliation(s)
- Chiqian Zhang
- Pegasus Technical Services, Inc., Cincinnati, OH, United States
| | - Ke Qin
- Oak Ridge Institute for Science and Education Participation Program, Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH, United States
| | - Ian Struewing
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH, United States
| | - Helen Buse
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH, United States
| | - Jorge Santo Domingo
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH, United States
| | - Darren Lytle
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH, United States
| | - Jingrang Lu
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH, United States
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The Tail-Specific Protease Is Important for Legionella pneumophila To Survive Thermal Stress in Water and inside Amoebae. Appl Environ Microbiol 2021; 87:AEM.02975-20. [PMID: 33608288 DOI: 10.1128/aem.02975-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 02/09/2021] [Indexed: 12/26/2022] Open
Abstract
Legionella pneumophila (Lp) is an inhabitant of natural and human-made water systems, where it replicates within amoebae and ciliates and survives within biofilms. When Lp-contaminated aerosols are breathed in, Lp can enter the lungs and may infect human alveolar macrophages, causing severe pneumonia known as Legionnaires' disease. Lp is often found in hot water distribution systems (HWDS), which are linked to nosocomial outbreaks. Heat treatment is used to disinfect HWDS and reduce the concentration of Lp However, Lp is often able to recolonize these water systems, indicating an efficient heat shock response. Tail-specific proteases (Tsp) are typically periplasmic proteases implicated in degrading aberrant proteins in the periplasm and important for surviving thermal stress. In Lp Philadelphia-1, Tsp is encoded by the lpg0499 gene. In this paper, we show that Tsp is important for surviving thermal stress in water and for optimal infection of amoeba when a shift in temperature occurs during intracellular growth. We also demonstrate that Tsp is expressed in the postexponential phase but repressed in the exponential phase and that the cis-encoded small regulatory RNA Lpr17 shows the opposite expression, suggesting that it represses translation of tsp In addition, our results show that tsp is regulated by CpxR, a major regulator in Lp, in an Lpr17-independent manner. Deletion of CpxR also reduced the ability of Lp to survive heat shock. In conclusion, our study shows that Tsp is likely an important factor for the survival and growth of Lp in water systems.IMPORTANCE Lp is a major cause of nosocomial and community-acquired pneumonia. Lp is found in water systems, including hot water distribution systems. Heat treatment is a method of disinfection often used to limit the presence of Lp in such systems; however, the benefit is usually short term, as Lp is able to quickly recolonize these systems. Presumably, Lp responds efficiently to thermal stress, but so far, not much is known about the genes involved. In this paper, we show that the Tsp and the two-component system CpxRA are required for resistance to thermal stress when Lp is free in water and when it is inside host cells. Our study identifies critical systems for the survival of Lp in its natural environment under thermal stress.
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Cytotoxicity, Intracellular Replication, and Contact-Dependent Pore Formation of Genotyped Environmental Legionella pneumophila Isolates from Hospital Water Systems in the West Bank, Palestine. Pathogens 2021; 10:pathogens10040417. [PMID: 33915921 PMCID: PMC8066006 DOI: 10.3390/pathogens10040417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/15/2021] [Accepted: 03/28/2021] [Indexed: 12/02/2022] Open
Abstract
Legionella pneumophila is the causative agent of Legionnaires’ disease. Due to the hot climate and intermittent water supply, the West Bank, Palestine, can be considered a high-risk area for this often fatal atypical pneumonia. L. pneumophila occurs in biofilms of natural and man-made freshwater environments, where it infects and replicates intracellularly within protozoa. To correlate the genetic diversity of the bacteria in the environment with their virulence properties for protozoan and mammalian host cells, 60 genotyped isolates from hospital water systems in the West Bank were analyzed. The L. pneumophila isolates were previously genotyped by high resolution Multi Locus Variable Number of Tandem Repeat Analysis (MLVA-8(12)) and sorted according to their relationship in clonal complexes (VACC). Strains of relevant genotypes and VACCs were compared according to their capacity to infect Acanthamoeba castellanii and THP-1 macrophages, and to mediate pore-forming cytotoxicity in sheep red blood cells (sRBCs). Based on a previous detailed analysis of the biogeographic distribution and abundance of the MLVA-8(12)-genotypes, the focus of the study was on the most abundant L. pneumophila- genotypes Gt4(17), Gt6 (18) and Gt10(93) and the four relevant clonal complexes [VACC1, VACC2, VACC5 and VACC11]. The highly abundant genotypes Gt4(17) and Gt6(18) are affiliated with VACC1 and sequence type (ST)1 (comprising L. pneumophila str. Paris), and displayed seroroup (Sg)1. Isolates of these two genotypes exhibited significantly higher virulence potentials compared to other genotypes and clonal complexes in the West Bank. Endemic for the West Bank was the clonal complex VACC11 (affiliated with ST461) represented by three relevant genotypes that all displayed Sg6. These genotypes unique for the West Bank showed a lower infectivity and cytotoxicity compared to all other clonal complexes and their affiliated genotypes. Interestingly, the L. pneumophila serotypes ST1 and ST461 were previously identified by in situ-sequence based typing (SBT) as main causative agents of Legionnaires’ disease (LD) in the West Bank at a comparable level. Overall, this study demonstrates the site-specific regional diversity of L. pneumophila genotypes in the West Bank and suggests that a combination of MLVA, cellular infection assays and hierarchical agglomerative cluster analysis allows an improved genotype-based risk assessment.
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Sciuto EL, Laganà P, Filice S, Scalese S, Libertino S, Corso D, Faro G, Coniglio MA. Environmental Management of Legionella in Domestic Water Systems: Consolidated and Innovative Approaches for Disinfection Methods and Risk Assessment. Microorganisms 2021; 9:577. [PMID: 33799845 PMCID: PMC8001549 DOI: 10.3390/microorganisms9030577] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 12/31/2022] Open
Abstract
Legionella is able to remain in water as free-living planktonic bacteria or to grow within biofilms that adhere to the pipes. It is also able to enter amoebas or to switch into a viable but not culturable (VBNC) state, which contributes to its resistance to harsh conditions and hinders its detection in water. Factors regulating Legionella growth, such as environmental conditions, type and concentration of available organic and inorganic nutrients, presence of protozoa, spatial location of microorganisms, metal plumbing components, and associated corrosion products are important for Legionella survival and growth. Finally, water treatment and distribution conditions may affect each of these factors. A deeper comprehension of Legionella interactions in water distribution systems with the environmental conditions is needed for better control of the colonization. To this purpose, the implementation of water management plans is the main prevention measure against Legionella. A water management program requires coordination among building managers, health care providers, and Public Health professionals. The review reports a comprehensive view of the state of the art and the promising perspectives of both monitoring and disinfection methods against Legionella in water, focusing on the main current challenges concerning the Public Health sector.
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Affiliation(s)
- Emanuele Luigi Sciuto
- Azienda Ospedaliero Universitaria Policlinico “G. Rodolico-San Marco”, Via Sofia 78, 95123 Catania, Italy;
| | - Pasqualina Laganà
- Regional Reference Laboratory of Clinical and Environmental Surveillance of Legionellosis, Messina, Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Torre Biologica 3p, AOU ‘G. Martino, Via C. Valeria, s.n.c., 98125 Messina, Italy;
| | - Simona Filice
- Istituto per la Microelettronica e Microsistemi–Consiglio Nazionale delle Ricerche (CNR-IMM), Ottava Strada 5, 95121 Catania, Italy; (S.F.); (S.S.); (S.L.); (D.C.)
| | - Silvia Scalese
- Istituto per la Microelettronica e Microsistemi–Consiglio Nazionale delle Ricerche (CNR-IMM), Ottava Strada 5, 95121 Catania, Italy; (S.F.); (S.S.); (S.L.); (D.C.)
| | - Sebania Libertino
- Istituto per la Microelettronica e Microsistemi–Consiglio Nazionale delle Ricerche (CNR-IMM), Ottava Strada 5, 95121 Catania, Italy; (S.F.); (S.S.); (S.L.); (D.C.)
| | - Domenico Corso
- Istituto per la Microelettronica e Microsistemi–Consiglio Nazionale delle Ricerche (CNR-IMM), Ottava Strada 5, 95121 Catania, Italy; (S.F.); (S.S.); (S.L.); (D.C.)
| | - Giuseppina Faro
- Azienda Sanitaria Provinciale di Catania, Via S. Maria La Grande 5, 95124 Catania, Italy;
| | - Maria Anna Coniglio
- Azienda Ospedaliero Universitaria Policlinico “G. Rodolico-San Marco”, Via Sofia 78, 95123 Catania, Italy;
- Regional Reference Laboratory of Clinical and Environmental Surveillance of Legionellosis, Catania, Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”, University of Catania, Via Sofia 87, 95123 Catania, Italy
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Papagianeli SD, Aspridou Z, Didos S, Chochlakis D, Psaroulaki A, Koutsoumanis K. Dynamic modelling of Legionella pneumophila thermal inactivation in water. WATER RESEARCH 2021; 190:116743. [PMID: 33352528 DOI: 10.1016/j.watres.2020.116743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 06/12/2023]
Abstract
A predictive mathematical model describing the effect of temperature on the inactivation of Legionella pneumophila in water was developed. Thermal inactivation of L. pneumophila was monitored under isothermal conditions (51 - 61°C). A primary log-linear model was fitted to the inactivation data and the estimated D values ranged from 0.23 to 25.31 min for water temperatures from 61 to 51°C, respectively. The effect of temperature on L. pneumophila inactivation was described using a secondary model, and the model parameters z value and Dref (D-value at 55°C) were estimated at 5.54°C and 3.47 min, respectively. The developed model was further validated under dynamic temperature conditions mimicking various conditions of water thermal disinfection in plumbing systems. The results indicated that the model can satisfactorily predict thermal inactivation of the pathogen at dynamic temperature environments and effectively translate water temperature profiles to cell number reduction. The application of the model in combination with effective temperature monitoring could provide the basis of an integrated preventive approach for the effective control of L. pneumophila in plumbing systems.
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Affiliation(s)
- Styliani Dimitra Papagianeli
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Zafeiro Aspridou
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Spyros Didos
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Dimosthenis Chochlakis
- Laboratory of Clinical Microbiology and Microbial Pathogenesis, Unit of Water, Food and Environmental Microbiology, School of Medicine, University of Crete, Heraklion, 71110, Greece
| | - Anna Psaroulaki
- Laboratory of Clinical Microbiology and Microbial Pathogenesis, Unit of Water, Food and Environmental Microbiology, School of Medicine, University of Crete, Heraklion, 71110, Greece
| | - Konstantinos Koutsoumanis
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.
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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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How Molecular Typing Can Support Legionella Environmental Surveillance in Hot Water Distribution Systems: A Hospital Experience. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17228662. [PMID: 33233464 PMCID: PMC7700474 DOI: 10.3390/ijerph17228662] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/27/2020] [Accepted: 11/18/2020] [Indexed: 12/12/2022]
Abstract
In this study, we aimed to associate the molecular typing of Legionella isolates with a culture technique during routine Legionella hospital environmental surveillance in hot water distribution systems (HWDSs) to develop a risk map able to be used to prevent nosocomial infections and formulate appropriate preventive measures. Hot water samples were cultured according to ISO 11731:2017. The isolates were serotyped using an agglutination test and genotyped by sequence-based typing (SBT) for Legionella pneumophila or macrophage infectivity potentiator (mip) gene sequencing for non-pneumophila Legionella species. The isolates' relationship was phylogenetically analyzed. The Legionella distribution and level of contamination were studied in relation to temperature and disinfectant residues. The culture technique detected 62.21% of Legionella positive samples, characterized by L. pneumophila serogroup 1, Legionella non-pneumophila, or both simultaneously. The SBT assigned two sequence types (STs): ST1, the most prevalent in Italy, and ST104, which had never been isolated before. The mip gene sequencing detected L. anisa and L. rubrilucens. The phylogenetic analysis showed distinct clusters for each species. The distribution of Legionella isolates showed significant differences between buildings, with a negative correlation between the measured level of contamination, disinfectant, and temperature. The Legionella molecular approach introduced in HWDSs environmental surveillance permits (i) a risk map to be outlined that can help formulate appropriate disinfection strategies and (ii) rapid epidemiological investigations to quickly identify the source of Legionella infections.
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Buse HY, Morris BJ, Gomez-Alvarez V, Szabo JG, Hall JS. Legionella Diversity and Spatiotemporal Variation in The Occurrence of Opportunistic Pathogens within a Large Building Water System. Pathogens 2020; 9:E567. [PMID: 32668779 PMCID: PMC7400177 DOI: 10.3390/pathogens9070567] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 01/22/2023] Open
Abstract
Understanding Legionella survival mechanisms within building water systems (BWSs) is challenging due to varying engineering, operational, and water quality characteristics unique to each system. This study aimed to evaluate Legionella, mycobacteria, and free-living amoebae occurrence within a BWS over 18-28 months at six locations differing in plumbing material and potable water age, quality, and usage. A total of 114 bulk water and 57 biofilm samples were analyzed. Legionella culturability fluctuated seasonally with most culture-positive samples being collected during the winter compared to the spring, summer, and fall months. Positive and negative correlations between Legionella and L. pneumophila occurrence and other physiochemical and microbial water quality parameters varied between location and sample types. Whole genome sequencing of 19 presumptive Legionella isolates, from four locations across three time points, identified nine isolates as L. pneumophila serogroup (sg) 1 sequence-type (ST) 1; three as L. pneumophila sg5 ST1950 and ST2037; six as L. feeleii; and one as Ochrobactrum. Results showed the presence of a diverse Legionella population with consistent and sporadic occurrence at four and two locations, respectively. Viewed collectively with similar studies, this information will enable a better understanding of the engineering, operational, and water quality parameters supporting Legionella growth within BWSs.
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Affiliation(s)
- Helen Y. Buse
- Homeland Security and Materials Management Division, Center for Environmental Solutions & Emergency Response (CESER), Office of Research and Development (ORD), US Environmental Protection Agency (USEPA), Cincinnati, OH 45268, USA; (J.G.S.); (J.S.H.)
| | - Brian J. Morris
- Pegasus Technical Services, Inc c/o US EPA, Cincinnati, OH 45268, USA;
| | - Vicente Gomez-Alvarez
- Water Infrastructure Division, Center for Environmental Solutions & Emergency Response (CESER), US Environmental Protection Agency (USEPA), Office of Research and Development (ORD), Cincinnati, OH 45268, USA;
| | - Jeffrey G. Szabo
- Homeland Security and Materials Management Division, Center for Environmental Solutions & Emergency Response (CESER), Office of Research and Development (ORD), US Environmental Protection Agency (USEPA), Cincinnati, OH 45268, USA; (J.G.S.); (J.S.H.)
| | - John S. Hall
- Homeland Security and Materials Management Division, Center for Environmental Solutions & Emergency Response (CESER), Office of Research and Development (ORD), US Environmental Protection Agency (USEPA), Cincinnati, OH 45268, USA; (J.G.S.); (J.S.H.)
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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: 33] [Impact Index Per Article: 8.3] [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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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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Graells T, Ishak H, Larsson M, Guy L. The all-intracellular order Legionellales is unexpectedly diverse, globally distributed and lowly abundant. FEMS Microbiol Ecol 2019; 94:5110392. [PMID: 30973601 PMCID: PMC6167759 DOI: 10.1093/femsec/fiy185] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 09/08/2018] [Indexed: 12/14/2022] Open
Abstract
Legionellales is an order of the Gammaproteobacteria, only composed of host-adapted, intracellular bacteria, including the accidental human pathogens Legionella pneumophila and Coxiella burnetii. Although the diversity in terms of lifestyle is large across the order, only a few genera have been sequenced, owing to the difficulty to grow intracellular bacteria in pure culture. In particular, we know little about their global distribution and abundance. Here, we analyze 16/18S rDNA amplicons both from tens of thousands of published studies and from two separate sampling campaigns in and around ponds and in a silver mine. We demonstrate that the diversity of the order is much larger than previously thought, with over 450 uncultured genera. We show that Legionellales are found in about half of the samples from freshwater, soil and marine environments and quasi-ubiquitous in man-made environments. Their abundance is low, typically 0.1%, with few samples up to 1%. Most Legionellales OTUs are globally distributed, while many do not belong to a previously identified species. This study sheds a new light on the ubiquity and diversity of one major group of host-adapted bacteria. It also emphasizes the need to use metagenomics to better understand the role of host-adapted bacteria in all environments.
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Affiliation(s)
- Tiscar Graells
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Box 582, 75123 Uppsala, Sweden.,Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Edifici C, Carrer de la Vall Moronta, 08193 Bellaterra, Spain
| | - Helena Ishak
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Box 582, 75123 Uppsala, Sweden
| | - Madeleine Larsson
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Box 582, 75123 Uppsala, Sweden
| | - Lionel Guy
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Box 582, 75123 Uppsala, Sweden
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Cervero-Aragó S, Schrammel B, Dietersdorfer E, Sommer R, Lück C, Walochnik J, Kirschner A. Viability and infectivity of viable but nonculturable Legionella pneumophila strains induced at high temperatures. WATER RESEARCH 2019; 158:268-279. [PMID: 31048196 PMCID: PMC6520252 DOI: 10.1016/j.watres.2019.04.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/05/2019] [Accepted: 04/06/2019] [Indexed: 06/09/2023]
Abstract
Thermal disinfection is commonly used to prevent the proliferation of culturable Legionella in engineered water systems (EWS). In response to such stress, culturable Legionella populations can switch into a viable but nonculturable (VBNC) state. The importance of such VBNC Legionella cells is currently hotly debated. Here, we investigated the stress response patterns and transitions of the bacteria to the VBNC state at 55 °C, 60 °C and 70 °C on two L. pneumophila strains for >80 days using a combination of cell-based viability indicators. Complete loss of culturability at 55 °C, 60 °C and 70 °C occurred after 3-8 h, 60 min and <2 min, respectively. In contrast, L. pneumophila strains required 9 days at 55 °C, 8 h at 60 °C and 20 min at 70 °C to achieve a 2 log reduction in cells with intact membranes and high esterase activity; a 4 log reduction was achieved only after 150, 8-15 and 1-4 days, respectively. In parallel, the presence of diagnostic outer-membrane epitopes (OMEs) and changes in the infectivity patterns of the two strains towards amoebae and THP-1 cells were assessed. OMEs were more persistent than viability indicators, showing their potential as targets for VBNC Legionella detection. L. pneumophila strains infected amoebae and THP-1 cells for at least 85 days at 55 °C and 60 °C and for up to 8 days at 70 °C. However, they did so with reduced efficiency, requiring prolonged co-incubation times with the hosts and higher Legionella cell numbers in comparison to culturable cells. Consequently, infection of amoebae by thermally induced VBNC L. pneumophila with lowered virulence can be expected in EWS. Although the gold standard method cannot detect VBNC Legionella, it provides important information about the most virulent bacterial subpopulations. Our results indicate that a prolonged thermal regime ≥60 °C at the central parts of warm water systems is not only effective against culturable L. pneumophila but in the long run even against VBNC cells.
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Affiliation(s)
- Sílvia Cervero-Aragó
- Medical University of Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090, Vienna, Austria; Interuniversity Cooperation Centre for Water & Health, Vienna, Austria.
| | - Barbara Schrammel
- Medical University of Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090, Vienna, Austria
| | - Elisabeth Dietersdorfer
- Medical University of Vienna, Institute of Specific Prophylaxis and Tropical Medicine, Kinderspitalgasse 15, A-1090, Vienna, Austria
| | - Regina Sommer
- Medical University of Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090, Vienna, Austria; Interuniversity Cooperation Centre for Water & Health, Vienna, Austria
| | - Christian Lück
- Technical University Dresden, Institute for Medical Microbiology and Hygiene, Medical Faculty "Carl Gustav Carus", Helmholtzstr. 10, D 01069, Dresden, Germany
| | - Julia Walochnik
- Medical University of Vienna, Institute of Specific Prophylaxis and Tropical Medicine, Kinderspitalgasse 15, A-1090, Vienna, Austria
| | - Alexander Kirschner
- Medical University of Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090, Vienna, Austria; Interuniversity Cooperation Centre for Water & Health, Vienna, Austria; Karl Landsteiner University of Health Sciences, Division Water Quality and Health, Dr. Karl Dorrekstraße 30, A-3400, Krems, Austria
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Caicedo C, Rosenwinkel KH, Exner M, Verstraete W, Suchenwirth R, Hartemann P, Nogueira R. Legionella occurrence in municipal and industrial wastewater treatment plants and risks of reclaimed wastewater reuse: Review. WATER RESEARCH 2019; 149:21-34. [PMID: 30445393 DOI: 10.1016/j.watres.2018.10.080] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/26/2018] [Accepted: 10/27/2018] [Indexed: 05/22/2023]
Abstract
Wastewater treatment plants (WWTPs) have been identified as confirmed but until today underestimated sources of Legionella, playing an important role in local and community cases and outbreaks of Legionnaires' disease. In general, aerobic biological systems provide an optimum environment for the growth of Legionella due to high organic nitrogen and oxygen concentrations, ideal temperatures and the presence of protozoa. However, few studies have investigated the occurrence of Legionella in WWTPs, and many questions in regards to the interacting factors that promote the proliferation and persistence of Legionella in these treatment systems are still unanswered. This critical review summarizes the current knowledge about Legionella in municipal and industrial WWTPs, the conditions that might support their growth, as well as control strategies that have been applied. Furthermore, an overview of current quantification methods, guidelines and health risks associated with Legionella in reclaimed wastewater is also discussed in depth. A better understanding of the conditions promoting the occurrence of Legionella in WWTPs will contribute to the development of improved wastewater treatment technologies and/or innovative mitigation approaches to minimize future Legionella outbreaks.
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Affiliation(s)
- C Caicedo
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany.
| | - K-H Rosenwinkel
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany
| | - M Exner
- University of Bonn, Institute for Hygiene and Public Health, Bonn, Germany
| | - W Verstraete
- Ghent University, CMET, Ghent, and Avecom, Wondelgem, Belgium
| | - R Suchenwirth
- Public Health Office of Lower Saxony, Hannover, Germany
| | - P Hartemann
- Faculty of Medicine, Department of Environment and Public Health, Nancy University-CHU Nancy, Vandoeuvre Les Nancy, France
| | - R Nogueira
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany.
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Wang H, Xu J, Tang W, Li H, Xia S, Zhao J, Zhang W, Yang Y. Removal Efficacy of Opportunistic Pathogens and Bacterial Community Dynamics in Two Drinking Water Treatment Trains. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1804436. [PMID: 30536542 DOI: 10.1002/smll.201804436] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 11/16/2018] [Indexed: 06/09/2023]
Abstract
Drinking water treatment processes (DWTPs) impact pathogen colonization and microbial communities in finished water; however, their efficacies against opportunistic pathogens are not fully understood. In this study, the effects of treatment steps on the removal of Legionella spp., Legionella pneumophila, nontuberculous mycobacteria, Mycobacterium avium, and two amoeba hosts (Vermamoeba vermiformis, Acanthamoeba) are evaluated in two parallel trains of DWTPs equipped with different pretreatment units. Quantitative polymerase chain reaction analysis demonstrates significantly reduced numbers of total bacteria, Legionella, and mycobacteria during ozonation, followed by a rebound in granular activated carbon (GAC) filtration, whereas sand filtration exerts an overarching effect in removing microorganisms in both treatment trains. V. vermiformis is more prevalent in biofilm (34%) than water samples (7.7%), while Acanthamoeba is not found in the two trains of DWTPs. Illumina sequencing of bacterial 16S rRNA genes reveals significant community shifts at different treatment steps, as well as distinct bacterial community structures in water and biofilm samples in parallel units (e.g., ozonation, GAC, sand filtration) between the two trains (analysis of similarities (ANOSIM), p < 0.05), implying the potential influence of different pretreatment steps in shaping the downstream microbiome. Overall, the results provide insights to mitigation of opportunistic pathogens and engineer approaches for managing bacterial communities in DWTPs.
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Affiliation(s)
- Hong Wang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Jiajiong Xu
- Shanghai Municipal Engineering Design Institute (Group) CO., LTD, Shanghai, 200092, China
| | - Wei Tang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Huan Li
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Siqing Xia
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Jianfu Zhao
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Weixian Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Yang Yang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University, Shanghai, 200433, China
- Institute for Advanced Study, Tongji University, 1239 Siping Road, Shanghai, 200430, China
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Dai D, Rhoads WJ, Edwards MA, Pruden A. Shotgun Metagenomics Reveals Taxonomic and Functional Shifts in Hot Water Microbiome Due to Temperature Setting and Stagnation. Front Microbiol 2018; 9:2695. [PMID: 30542327 PMCID: PMC6277882 DOI: 10.3389/fmicb.2018.02695] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 10/23/2018] [Indexed: 12/20/2022] Open
Abstract
Hot water premise plumbing has emerged as a critical nexus of energy, water, and public health. The composition of hot water microbiomes is of special interest given daily human exposure to resident flora, especially opportunistic pathogens (OPs), which rely on complex microbial ecological interactions for their proliferation. Here, we applied shotgun metagenomic sequencing to characterize taxonomic and functional shifts in microbiomes as a function of water heater temperature setting, stagnation in distal pipes, and associated shifts in water chemistry. A cross-section of samples from controlled, replicated, pilot-scale hot water plumbing rigs representing different temperature settings (39, 42, and 51°C), stagnation periods (8 h vs. 7 days), and time-points, were analyzed. Temperature setting exhibited an overarching impact on taxonomic and functional gene composition. Further, distinct taxa were selectively enriched by specific temperature settings (e.g., Legionella at 39°C vs. Deinococcus at 51°C), while relative abundances of genes encoding corresponding cellular functions were highly consistent with expectations based on the taxa driving these shifts. Stagnation in distal taps diminished taxonomic and functional differences induced by heating the cold influent water to hot water in recirculating line. In distal taps relative to recirculating hot water, reads annotated as being involved in metabolism and growth decreased, while annotations corresponding to stress response (e.g., virulence disease and defense, and specifically antibiotic resistance) increased. Reads corresponding to OPs were readily identified by metagenomic analysis, with L. pneumophila reads in particular correlating remarkably well with gene copy numbers measured by quantitative polymerase chain reaction. Positive correlations between L. pneumophila reads and those of known protozoan hosts were also identified. Elevated proportions of genes encoding metal resistance and hydrogen metabolism were noted, which was consistent with elevated corrosion-induced metal concentrations and hydrogen generation. This study provided new insights into real-world factors influencing taxonomic and functional compositions of hot water microbiomes. Here metagenomics is demonstrated as an effective tool for screening for potential presence, and even quantities, of pathogens, while also providing diagnostic capabilities for assessing functional responses of microbiomes to various operational conditions. These findings can aid in informing future monitoring and intentional control of hot water microbiomes.
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Affiliation(s)
| | | | | | - Amy Pruden
- Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
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Highlighting the Potency of Biosurfactants Produced by Pseudomonas Strains as Anti- Legionella Agents. BIOMED RESEARCH INTERNATIONAL 2018; 2018:8194368. [PMID: 30426015 PMCID: PMC6217892 DOI: 10.1155/2018/8194368] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 09/12/2018] [Accepted: 09/27/2018] [Indexed: 12/18/2022]
Abstract
Legionella pneumophila, the causative agent of Legionnaires' disease, is a waterborne bacterium mainly found in man-made water systems in close association with free-living amoebae and multispecies biofilms. Pseudomonas strains, originating from various environments including freshwater systems or isolated from hospitalized patients, were tested for their antagonistic activity towards L. pneumophila. A high amount of tested strains was thus found to be active. This antibacterial activity was correlated to the presence of tensioactive agents in culture supernatants. As Pseudomonas strains were known to produce biosurfactants, these compounds were specifically extracted and purified from active strains and further characterized using reverse-phase HPLC and mass spectrometry methods. Finally, all biosurfactants tested (lipopeptides and rhamnolipids) were found active and this activity was shown to be higher towards Legionella strains compared to various other bacteria. Therefore, described biosurfactants are potent anti-Legionella agents that could be used in the water treatment industry although tests are needed to evaluate how effective they would be under field conditions.
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40
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Pereira RPA, Peplies J, Mushi D, Brettar I, Höfle MG. Pseudomonas-Specific NGS Assay Provides Insight Into Abundance and Dynamics of Pseudomonas Species Including P. aeruginosa in a Cooling Tower. Front Microbiol 2018; 9:1958. [PMID: 30186269 PMCID: PMC6110898 DOI: 10.3389/fmicb.2018.01958] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 08/02/2018] [Indexed: 12/23/2022] Open
Abstract
Pseudomonas species are frequent inhabitants of freshwater environments and colonizers of water supply networks via bioadhesion and biofilm formation. P. aeruginosa is the species most commonly associated with human disease, causing a wide variety of infections with links to its presence in freshwater systems. Though several other Pseudomonas species are of ecological and public health importance, little knowledge exists regarding environmental abundances of these species. In the present study, an Illumina-based next-generation sequencing (NGS) approach using Pseudomonas-specific primers targeting the 16S rRNA gene was evaluated and applied to a set of freshwater samples from different environments including a cooling tower sampled monthly during 2 years. Our approach showed high in situ specificity and accuracy. NGS read counts revealed a precise quantification of P. aeruginosa and a good correlation with the absolute number of Pseudomonas genome copies in a validated genus-specific qPCR assay, demonstrating the ability of the NGS approach to determine both relative and absolute abundances of Pseudomonas species and P. aeruginosa. The characterization of Pseudomonas communities in cooling tower water allowed us to identify 43 phylotypes, with P. aeruginosa being the most abundant. A shift existed within each year from a community dominated by phylotypes belonging to P. fluorescens and P. oleovorans phylogenetic groups to a community where P. aeruginosa was highly abundant. Co-occurrence was observed between P. aeruginosa and other phylotypes of P. aeruginosa group as well as the potentially pathogenic species P. stutzeri, but not with phylotypes of the P. fluorescens group, indicating the need to further investigate the metabolic networks and ecological traits of Pseudomonas species. This study demonstrates the potential of deep sequencing as a valuable tool in environmental diagnostics and surveillance of health-related pathogens in freshwater environments.
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Affiliation(s)
- Rui P A Pereira
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Douglas Mushi
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Department of Biological Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Ingrid Brettar
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Manfred G Höfle
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany
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41
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Waak MB, LaPara TM, Hallé C, Hozalski RM. Occurrence of Legionella spp. in Water-Main Biofilms from Two Drinking Water Distribution Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:7630-7639. [PMID: 29902377 DOI: 10.1021/acs.est.8b01170] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The maintenance of a chlorine or chloramine residual to suppress waterborne pathogens in drinking water distribution systems is common practice in the United States but less common in Europe. In this study, we investigated the occurrence of Bacteria and Legionella spp. in water-main biofilms and tap water from a chloraminated distribution system in the United States and a system in Norway with no residual using real-time quantitative polymerase chain reaction (qPCR). Despite generally higher temperatures and assimilable organic carbon levels in the chloraminated system, total Bacteria and Legionella spp. were significantly lower in water-main biofilms and tap water of that system ( p < 0.05). Legionella spp. were not detected in the biofilms of the chloraminated system (0 of 35 samples) but were frequently detected in biofilms from the no-residual system (10 of 23 samples; maximum concentration = 7.8 × 104 gene copies cm-2). This investigation suggests water-main biofilms may serve as a source of Legionella for tap water and premise plumbing systems, and residual chloramine may aid in reducing their abundance.
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Affiliation(s)
- Michael B Waak
- Department of Civil, Environmental, and Geo-Engineering , University of Minnesota , 500 Pillsbury Drive Southeast , Minneapolis , Minnesota 55455 , United States
| | - Timothy M LaPara
- Department of Civil, Environmental, and Geo-Engineering , University of Minnesota , 500 Pillsbury Drive Southeast , Minneapolis , Minnesota 55455 , United States
- BioTechnology Institute , University of Minnesota , 1479 Gortner Avenue , Saint Paul , Minnesota 55108 , United States
| | - Cynthia Hallé
- Department of Civil and Environmental Engineering , Norwegian University of Science and Technology , S.P. Andersens veg 5 , Trondheim NO-7491 , Norway
| | - Raymond M Hozalski
- Department of Civil, Environmental, and Geo-Engineering , University of Minnesota , 500 Pillsbury Drive Southeast , Minneapolis , Minnesota 55455 , United States
- BioTechnology Institute , University of Minnesota , 1479 Gortner Avenue , Saint Paul , Minnesota 55108 , United States
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Quantitative Microbial Risk Assessment and Opportunist Waterborne Infections⁻Are There Too Many Gaps to Fill? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15061150. [PMID: 29865180 PMCID: PMC6025005 DOI: 10.3390/ijerph15061150] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 01/14/2023]
Abstract
Quantitative microbial risk assessment (QMRA) is a relatively new approach in identifying health risks associated with the ubiquitous presence of pathogens and opportunists in the human environment. The methodology builds on experimental and meta-analytical data to identify measurable factors that contribute to, and can quantify, the likely extent of disease given a particular exposure. Early modelling was particularly focused on food-borne disease, and subsequently water-borne disease, with the emphasis focused on ingestion and its role in enteric disease. More recently, there has been a focus on translating these principles to opportunist waterborne infections (OWI) with primary focus on Legionella spp. Whereas dose and susceptibility are well documented via the ingestion route of exposure there is considerably less certainty regarding both factors when understanding Legionella spp. and other OWI. Many OWI can arise through numerous routes of transmission with greatly differing disease presentations. Routes of Legionella spp. infection do not include ingestion, but rather aspiration and inhalation of contaminated water are the routes of exposure. The susceptible population for OWI is a vulnerable sub-set of the population unlike those associated with enteric disease pathogens. These variabilities in dose, exposure and susceptibility call in to question whether QMRA can be a useful tool in managing risks associated with OWI. Consideration of Legionella spp. as a well-documented subject of research calls into question whether QMRA of OWI is likely to be a useful tool in developing risk management strategies.
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Virulence Traits of Environmental and Clinical Legionella pneumophila Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) Genotypes. Appl Environ Microbiol 2018. [PMID: 29523542 DOI: 10.1128/aem.00429-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Legionella pneumophila causes water-based infections resulting in severe pneumonia. Recently, we showed that different MLVA-8 (multilocus variable-number tandem-repeat analysis using 8 loci) genotypes dominated different sites of a drinking-water distribution system. Each genotype displayed a unique temperature-dependent growth behavior. Here we compared the pathogenicity potentials of different MLVA-8 genotypes of environmental and clinical strains. The virulence traits studied were hemolytic activity and cytotoxicity toward amoebae and macrophages. Clinical strains were significantly more hemolytic than environmental strains, while their cytotoxicity toward amoebae was significantly lower at 30°C. No significant differences were detected between clinical and environmental strains in cytotoxicity toward macrophages. Significant differences in virulence were observed between the environmental genotypes (Gt). Gt15 strains showed a significantly higher hemolytic activity. In contrast, Gt4 and Gt6 strains were more infective toward Acanthamoeba castellanii Moreover, Gt4 strains exhibited increased cytotoxicity toward macrophages and demonstrated a broader temperature range of amoebal lysis than Gt6 and Gt15 strains. Understanding the virulence traits of Legionella genotypes may improve the assessment of public health risks of Legionella in drinking water.IMPORTANCELegionella pneumophila is the causative agent of a severe form of pneumonia. Here we demonstrated that clinical strains were significantly more cytotoxic toward red blood cells than environmental strains, while their cytotoxicity toward macrophages was similar. Genotype 4 (Gt4) strains were highly cytotoxic toward amoebae and macrophages and lysed amoebae in a broader temperature range than to the other studied genotypes. The results can explain the relatively high success of Gt4 in the environment and in clinical samples; thus, Gt4 strains should be considered a main factor for the assessment of public health risks of Legionella in drinking water. Our findings shed light on the ecology, virulence, and pathogenicity potential of different L. pneumophila genotypes, which can be a valuable parameter for future modeling and quantitative microbial risk assessment of Legionella in drinking-water systems.
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Liu J, Li C, Jing J, Zhao P, Luo Z, Cao M, Ma Z, Jia T, Chai B. Ecological patterns and adaptability of bacterial communities in alkaline copper mine drainage. WATER RESEARCH 2018; 133:99-109. [PMID: 29367051 DOI: 10.1016/j.watres.2018.01.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/31/2017] [Accepted: 01/05/2018] [Indexed: 06/07/2023]
Abstract
Environmental gradient have strong effects on community assembly processes. In order to reveal the effects of alkaline mine drainage (AlkMD) on bacterial and denitrifying bacterial community compositions and diversity in tailings reservoir, here we conducted an experiment to examine all and core bacterial taxa and denitrifying functional genes's (nirS, nirK, nosZΙ) abundance along a chemical gradient in tailings water in Shibahe copper tailings in Zhongtiaoshan, China. Differences in bacterial and denitrifying bacterial community compositions in different habitats and their relationships with environmental parameters were analyzed. The results showed that the richness and diversity of bacterial community in downstream seeping water (SDSW) were the largest, while that in upstream tailings water (STW1) were the lowest. The diversity and abundance of bacterial communities tended to increase from STW1 to SDSW. The variation of bacterial community diversity was significantly related to electroconductibility (EC), nitrate (NO3-), nitrite (NO2-), total carbon (TC), inorganic carbon (IC) and sulfate (SO42-), but was not correlated with geographic distance in local scale. Core taxa from class to genus were all significantly related to NO3- and NO2-. Core taxa Rhodobacteraceae, Rhodobacter, Acinetobacter and Hydrogenophaga were typical denitrifying bacteria. The variation trends of these groups were consistent with the copy number of nirS, nirK and nosZΙ, demonstrating their importance in the process of nitrogen reduction. The copy number of nirK, nosZΙ and nirS/16S rDNA, nirK/16Sr DNA correlated strongly with NO3-, NO2- and IC, but nirS and nosZI/16SrDNA had no significant correlation with NO3- and NO2-. The copy numbers of denitrifying functional genes (nirS, nirK and nosZΙ) were negatively correlated with heavy metal plumbum (Pb) and zinc (Zn). It showed that heavy metal contamination was an important factor affecting the structure of denitrifying bacterial community in AlkMD. In this study we have identified the distribution pattern of bacterial community along physiochemical gradients in alkaline tailings reservoir and displayed the driving force of shaping the structure of bacterial community. The influence of NO3-, NO2-, IC and heavy metal Pb and Zn on bacterial community might via their influence on the functional groups involving nitrogen, carbon and metal metabolisms.
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Affiliation(s)
- Jinxian Liu
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Cui Li
- Faculty of Environment Economics, Shanxi University of Finance and Economics, Taiyuan, 030006, China
| | - Juhui Jing
- Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Pengyu Zhao
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Zhengming Luo
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Miaowen Cao
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Zhuanzhuan Ma
- Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Tong Jia
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Baofeng Chai
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China.
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Stüken A, Haverkamp THA, Dirven HAAM, Gilfillan GD, Leithaug M, Lund V. Microbial Community Composition of Tap Water and Biofilms Treated with or without Copper-Silver Ionization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3354-3364. [PMID: 29461810 DOI: 10.1021/acs.est.7b05963] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Copper-silver ionization (CSI) is an in-house water disinfection method primarily installed to eradicate Legionella bacteria from drinking water distribution systems (DWDS). Its effect on the abundance of culturable Legionella and Legionella infections has been documented in several studies. However, the effect of CSI on other bacteria in DWDS is largely unknown. To investigate these effects, we characterized drinking water and biofilm communities in a hospital using CSI, in a neighboring building without CSI, and in treated drinking water at the local water treatment plant. We used 16S rDNA amplicon sequencing and Legionella culturing. The sequencing results revealed three distinct water groups: (1) cold-water samples (no CSI), (2) warm-water samples at the research institute (no CSI), and (3) warm-water samples at the hospital (after CSI; ANOSIM, p < 0.001). Differences between the biofilm communities exposed and not exposed to CSI were less clear (ANOSIM, p = 0.022). No Legionella were cultured, but limited numbers of Legionella sequences were recovered from all 25 water samples (0.2-1.4% relative abundance). The clustering pattern indicated local selection of Legionella types (Kruskal-Wallis, p < 0.001). Furthermore, one unclassified Betaproteobacteria OTU was highly enriched in CSI-treated warm water samples at the hospital (Kruskal-Wallis, p < 0.001).
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Affiliation(s)
- Anke Stüken
- Dept. Zoonotic, Food and Waterborne Infections , Norwegian Institute of Public Health , Oslo , Norway
| | - Thomas H A Haverkamp
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences , University of Oslo , Blindern, Oslo , Norway
| | - Hubert A A M Dirven
- Dept. Toxicology and Risk Assessment , Norwegian Institute of Public Health , Oslo , Norway
| | - Gregor D Gilfillan
- Dept. Medical Genetics , Oslo University Hospital and University of Oslo , Oslo , Norway
| | - Magnus Leithaug
- Dept. Medical Genetics , Oslo University Hospital and University of Oslo , Oslo , Norway
| | - Vidar Lund
- Dept. Zoonotic, Food and Waterborne Infections , Norwegian Institute of Public Health , Oslo , Norway
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Ji P, Rhoads WJ, Edwards MA, Pruden A. Effect of heat shock on hot water plumbing microbiota and Legionella pneumophila control. MICROBIOME 2018; 6:30. [PMID: 29426363 PMCID: PMC5807837 DOI: 10.1186/s40168-018-0406-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 01/18/2018] [Indexed: 05/25/2023]
Abstract
BACKGROUND Heat shock is a potential control strategy for Legionella pneumophila in hot water plumbing systems. However, it is not consistently effective, with little understanding of its influence on the broader plumbing microbiome. Here, we employed a lab-scale recirculating hot water plumbing rig to compare the pre- and post-"heat shock" (i.e., 40 → 60 → 40 °C) microbiota at distal taps. In addition, we used a second plumbing rig to represent a well-managed system at 60 °C and conducted a "control" sampling at 60 °C, subsequently reducing the temperature to 40 °C to observe the effects on Legionella and the microbiota under a simulated "thermal disruption" scenario. RESULTS According to 16S rRNA gene amplicon sequencing, in the heat shock scenario, there was no significant difference or statistically significant, but small, difference in the microbial community composition at the distal taps pre- versus post-heat shock (both biofilm and water; weighted and unweighted UniFrac distance matrices). While heat shock did lead to decreased total bacteria numbers at distal taps, it did not measurably alter the richness or evenness of the microbiota. Quantitative PCR measurements demonstrated that L. pneumophila relative abundance at distal taps also was not significantly different at 2-month post-heat shock relative to the pre-heat shock condition, while relative abundance of Vermamoeba vermiformis, a known Legionella host, did increase. In the thermal disruption scenario, relative abundance of planktonic L. pneumophila (quantitative PCR data) increased to levels comparable to those observed in the heat shock scenario within 2 months of switching long-term operation at 60 to 40 °C. Overall, water use frequency and water heater temperature set point exhibited a stronger effect than one-time heat shock on the microbial composition and Legionella levels at distal taps. CONCLUSIONS While heat shock may be effective for instantaneous Legionella control and reduction in total bacteria numbers, water heater temperature set point and water use frequency are more promising factors for long-term Legionella and microbial community control, illustrating the importance of maintaining consistent elevated temperatures in the system relative to short-term heat shock.
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Affiliation(s)
- Pan Ji
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - William J Rhoads
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Marc A Edwards
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Amy Pruden
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA.
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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: 54] [Impact Index Per Article: 7.7] [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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Whiley H, Bentham R, Brown MH. Legionella Persistence in Manufactured Water Systems: Pasteurization Potentially Selecting for Thermal Tolerance. Front Microbiol 2017; 8:1330. [PMID: 28769899 PMCID: PMC5515819 DOI: 10.3389/fmicb.2017.01330] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 06/30/2017] [Indexed: 01/13/2023] Open
Abstract
Legionella is an opportunistic waterborne pathogen of increasing public health significance. Pasteurization, otherwise known as super-heat and flush (increasing water temperature to above 70°C and flushing all outlets), has been identified as an important mechanism for the disinfection of Legionella in manufactured water systems. However, several studies have reported that this procedure was ineffective at remediating water distribution systems as Legionella was able to maintain long term persistent contamination. Up to 25% of L. pneumophila cells survived heat treatment of 70°C, but all of these were in a viable but non-culturable state. This demonstrates the limitations of the culture method of Legionella detection currently used to evaluate disinfection protocols. In addition, it has been demonstrated that pasteurization and nutrient starvation can select for thermal tolerant strains, where L. pneumophila was consistently identified as having greater thermal tolerance compared to other Legionella species. This review demonstrates that further research is needed to investigate the effectiveness of pasteurization as a disinfection method. In particular, it focuses on the potential for pasteurization to select for thermal tolerant L. pneumophila strains which, as the primary causative agent of Legionnaires disease, have greater public health significance compared to other Legionella species.
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Affiliation(s)
- Harriet Whiley
- College of Science and Engineering, Flinders University, Bedford ParkSA, Australia
| | - Richard Bentham
- College of Science and Engineering, Flinders University, Bedford ParkSA, Australia
| | - Melissa H Brown
- College of Science and Engineering, Flinders University, Bedford ParkSA, Australia
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Pereira RPA, Peplies J, Brettar I, Höfle MG. Development of a genus-specific next generation sequencing approach for sensitive and quantitative determination of the Legionella microbiome in freshwater systems. BMC Microbiol 2017; 17:79. [PMID: 28359254 PMCID: PMC5374610 DOI: 10.1186/s12866-017-0987-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 03/21/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Next Generation Sequencing (NGS) has revolutionized the analysis of natural and man-made microbial communities by using universal primers for bacteria in a PCR based approach targeting the 16S rRNA gene. In our study we narrowed primer specificity to a single, monophyletic genus because for many questions in microbiology only a specific part of the whole microbiome is of interest. We have chosen the genus Legionella, comprising more than 20 pathogenic species, due to its high relevance for water-based respiratory infections. METHODS A new NGS-based approach was designed by sequencing 16S rRNA gene amplicons specific for the genus Legionella using the Illumina MiSeq technology. This approach was validated and applied to a set of representative freshwater samples. RESULTS Our results revealed that the generated libraries presented a low average raw error rate per base (<0.5%); and substantiated the use of high-fidelity enzymes, such as KAPA HiFi, for increased sequence accuracy and quality. The approach also showed high in situ specificity (>95%) and very good repeatability. Only in samples in which the gammabacterial clade SAR86 was present more than 1% non-Legionella sequences were observed. Next-generation sequencing read counts did not reveal considerable amplification/sequencing biases and showed a sensitive as well as precise quantification of L. pneumophila along a dilution range using a spiked-in, certified genome standard. The genome standard and a mock community consisting of six different Legionella species demonstrated that the developed NGS approach was quantitative and specific at the level of individual species, including L. pneumophila. The sensitivity of our genus-specific approach was at least one order of magnitude higher compared to the universal NGS approach. Comparison of quantification by real-time PCR showed consistency with the NGS data. Overall, our NGS approach can determine the quantitative abundances of Legionella species, i. e. the complete Legionella microbiome, without the need for species-specific primers. CONCLUSIONS The developed NGS approach provides a new molecular surveillance tool to monitor all Legionella species in qualitative and quantitative terms if a spiked-in genome standard is used to calibrate the method. Overall, the genus-specific NGS approach opens up a new avenue to massive parallel diagnostics in a quantitative, specific and sensitive way.
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Affiliation(s)
- Rui P A Pereira
- Department of Vaccinology and Applied Microbiology, RG Microbial Diagnostics, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, 38124, Braunschweig, Germany.,Present address: School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Jörg Peplies
- Ribocon GmbH, Fahrenheitstraße 1, 28359, Bremen, Germany
| | - Ingrid Brettar
- Department of Vaccinology and Applied Microbiology, RG Microbial Diagnostics, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Manfred G Höfle
- Department of Vaccinology and Applied Microbiology, RG Microbial Diagnostics, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, 38124, Braunschweig, Germany.
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Whiley H. Legionella Risk Management and Control in Potable Water Systems: Argument for the Abolishment of Routine Testing. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 14:E12. [PMID: 28029126 PMCID: PMC5295263 DOI: 10.3390/ijerph14010012] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 12/20/2016] [Accepted: 12/22/2016] [Indexed: 01/05/2023]
Abstract
Legionella is an opportunistic pathogen of public health significance. One of the main sources of Legionella is potable water systems. As a consequence of aging populations there is an increasing demographic considered at high risk for Legionellosis and, as such, a review of the guidelines is required. Worldwide, Legionella has been detected from many potable water sources, suggesting it is ubiquitous in this environment. Previous studies have identified the limitations of the current standard method for Legionella detection and the high possibility of it returning both false negative and false positive results. There is also huge variability in Legionella test results for the same water sample when conducted at different laboratories. However, many guidelines still recommend the testing of water systems. This commentary argues for the removal of routine Legionella monitoring from all water distribution guidelines. This procedure is financially consuming and false negatives may result in managers being over-confident with a system or a control mechanism. Instead, the presence of the pathogen should be assumed and focus spent on managing appropriate control measures and protecting high-risk population groups.
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Affiliation(s)
- Harriet Whiley
- Health and the Environment, School of the Environment, Flinders University, GPO Box 2100, Adelaide 5001, Australia.
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