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Schwake DO, Alum A, Abbaszadegan M. Legionella Occurrence beyond Cooling Towers and Premise Plumbing. Microorganisms 2021; 9:microorganisms9122543. [PMID: 34946143 PMCID: PMC8706379 DOI: 10.3390/microorganisms9122543] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 11/27/2021] [Accepted: 12/06/2021] [Indexed: 11/18/2022] Open
Abstract
Legionella is an environmental pathogen that is responsible for respiratory disease and is a common causative agent of water-related outbreaks. Due to their ability to survive in a broad range of environments, transmission of legionellosis is possible from a variety of sources. Unfortunately, a disproportionate amount of research that is devoted to studying the occurrence of Legionella in environmental reservoirs is aimed toward cooling towers and premise plumbing. As confirmed transmission of Legionella has been linked to many other sources, an over-emphasis on the most common sources may be detrimental to increasing understanding of the spread of legionellosis. This review aims to address this issue by cataloguing studies which have examined the occurrence of Legionella in less commonly investigated environments. By summarizing and discussing reports of Legionella in fresh water, ground water, saltwater, and distribution system drinking water, future environmental and public health researchers will have a resource to aid in investigating these pathogens in relevant sources.
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Affiliation(s)
- David Otto Schwake
- Department of Natural Sciences, Middle Georgia State University, 100 University Pkwy, Macon, GA 31206, USA;
| | - Absar Alum
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ 85287, USA;
| | - Morteza Abbaszadegan
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ 85287, USA;
- Correspondence: ; Tel.: +1-480-965-3868
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Logan-Jackson A, Rose JB. Cooccurrence of Five Pathogenic Legionella spp. and Two Free-Living Amoebae Species in a Complete Drinking Water System and Cooling Towers. Pathogens 2021; 10:pathogens10111407. [PMID: 34832563 PMCID: PMC8619718 DOI: 10.3390/pathogens10111407] [Citation(s) in RCA: 3] [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: 09/24/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 12/13/2022] Open
Abstract
Pathogenic Legionella species grow optimally inside free-living amoebae to concentrations that increase risks to those who are exposed. The aim of this study was to screen a complete drinking water system and cooling towers for the occurrence of Acanthamoeba spp. and Naegleria fowleri and their cooccurrence with Legionella pneumophila, Legionella anisa, Legionella micdadei, Legionella bozemanii, and Legionella longbeachae. A total of 42 large-volume water samples, including 12 from the reservoir (water source), 24 from two buildings (influents to the buildings and exposure sites (taps)), and six cooling towers were collected and analyzed using droplet digital PCR (ddPCR). N. fowleri cooccurred with L. micdadei in 76 (32/42) of the water samples. In the building water system, the concentrations of N. fowleri and L. micdadei ranged from 1.5 to 1.6 Log10 gene copies (GC)/100 mL, but the concentrations of species increased in the cooling towers. The data obtained in this study illustrate the ecology of pathogenic Legionella species in taps and cooling towers. Investigating Legionella’s ecology in drinking and industrial waters will hopefully lead to better control of these pathogenic species in drinking water supply systems and cooling towers.
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Affiliation(s)
- Alshae Logan-Jackson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
- Correspondence:
| | - Joan B. Rose
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA;
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Falzone L, Gattuso G, Lombardo C, Lupo G, Grillo CM, Spandidos DA, Libra M, Salmeri M. Droplet digital PCR for the detection and monitoring of Legionella pneumophila. Int J Mol Med 2020; 46:1777-1782. [PMID: 33000184 PMCID: PMC7521553 DOI: 10.3892/ijmm.2020.4724] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 09/14/2020] [Indexed: 02/07/2023] Open
Abstract
Legionella pneumophila(L. pneumophila is a harmful pathogen often found in water systems. In hospitals, the absence of L. pneumophila in water systems is mandatory by law, therefore, frequent and effective monitoring of water is of fundamental importance. Molecular methods based on reverse transcription-quantitative polymerase chain reaction (RT-qPCR) have been proposed for the detection of L. pneumophila, however, the sensitivity and accuracy of these methods have not been validated yet. Therefore, it is important to evaluate other strategies able to overcome the limits of culture-based and RT-qPCR methods. On these bases, we compared the sensitivity and accuracy of droplet digital PC (ddPCR) and RT-qPCR in water samples with known concentrations of L. pneumophila and in an in vitro model of water heat treatments. ddPCR showed a higher sensitivity rate and accuracy compared to RT-qPCR in detecting low bacterial load. In addition, ddPCR is not affected by the presence of fragmented DNA and showed higher accuracy than RT-qPC in monitoring the efficacy of heat shock treatments. In conclusion, ddPCR represents an innovative strategy to effectively detect L. pneumophila in water samples. Thanks to its high robustness, ddPCR could be applied also for the detection of L. pneumophila in patients with suspected legionellosis.
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Affiliation(s)
- Luca Falzone
- Epidemiology Unit, IRCCS Istituto Nazionale Tumori 'Fondazione G. Pascale', I‑80131 Naples, Italy
| | - Giuseppe Gattuso
- Department of Biomedical and Biotechnological Sciences, Section of General Pathology, University of Catania, I‑95123 Catania, Italy
| | - Cinzia Lombardo
- Department of Biomedical and Biotechnological Sciences, Section of Microbiology, University of Catania, I‑95123 Catania, Italy
| | - Gabriella Lupo
- Department of Biomedical and Biotechnological Sciences, Section of Biochemistry, University of Catania, I‑95123 Catania, Italy
| | - Caterina Maria Grillo
- Department of Medical Sciences, Surgical and Advanced Technologies, GF Ingrassia, University of Catania, I‑95123 Catania, Italy
| | - Demetrios A Spandidos
- Laboratory of Clinical Virology, Medical School, University of Crete, 71003 Heraklion, Greece
| | - Massimo Libra
- Department of Biomedical and Biotechnological Sciences, Section of General Pathology, University of Catania, I‑95123 Catania, Italy
| | - Mario Salmeri
- Department of Biomedical and Biotechnological Sciences, Section of Microbiology, University of Catania, I‑95123 Catania, Italy
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Korajkic A, McMinn BR, Harwood VJ. Relationships between Microbial Indicators and Pathogens in Recreational Water Settings. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:E2842. [PMID: 30551597 PMCID: PMC6313479 DOI: 10.3390/ijerph15122842] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 11/16/2022]
Abstract
Fecal pollution of recreational waters can cause scenic blight and pose a threat to public health, resulting in beach advisories and closures. Fecal indicator bacteria (total and fecal coliforms, Escherichia coli, and enterococci), and alternative indicators of fecal pollution (Clostridium perfringens and bacteriophages) are routinely used in the assessment of sanitary quality of recreational waters. However, fecal indicator bacteria (FIB), and alternative indicators are found in the gastrointestinal tract of humans, and many other animals and therefore are considered general indicators of fecal pollution. As such, there is room for improvement in terms of their use for informing risk assessment and remediation strategies. Microbial source tracking (MST) genetic markers are closely associated with animal hosts and are used to identify fecal pollution sources. In this review, we examine 73 papers generated over 40 years that reported the relationship between at least one indicator and one pathogen group or species. Nearly half of the reports did not include statistical analysis, while the remainder were almost equally split between those that observed statistically significant relationships and those that did not. Statistical significance was reported less frequently in marine and brackish waters compared to freshwater, and the number of statistically significant relationships was considerably higher in freshwater (p < 0.0001). Overall, significant relationships were more commonly reported between FIB and pathogenic bacteria or protozoa, compared to pathogenic viruses (p: 0.0022⁻0.0005), and this was more pronounced in freshwater compared to marine. Statistically significant relationships were typically noted following wet weather events and at sites known to be impacted by recent fecal pollution. Among the studies that reported frequency of detection, FIB were detected most consistently, followed by alternative indicators. MST markers and the three pathogen groups were detected least frequently. This trend was mirrored by reported concentrations for each group of organisms (FIB > alternative indicators > MST markers > pathogens). Thus, while FIB, alternative indicators, and MST markers continue to be suitable indicators of fecal pollution, their relationship with waterborne pathogens, particularly viruses, is tenuous at best and influenced by many different factors such as frequency of detection, variable shedding rates, differential fate and transport characteristics, as well as a broad range of site-specific factors such as the potential for the presence of a complex mixture of multiple sources of fecal contamination and pathogens.
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Affiliation(s)
- Asja Korajkic
- National Exposure Research Laboratory, Office of Research and Development, United States Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Brian R McMinn
- National Exposure Research Laboratory, Office of Research and Development, United States Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Valerie J Harwood
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Ave, SCA 110, Tampa, FL 33620, USA.
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Ghilamicael AM, Boga HI, Anami SE, Mehari T, Budambula NLM. Potential human pathogenic bacteria in five hot springs in Eritrea revealed by next generation sequencing. PLoS One 2018; 13:e0194554. [PMID: 29566040 PMCID: PMC5864021 DOI: 10.1371/journal.pone.0194554] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 03/06/2018] [Indexed: 01/15/2023] Open
Abstract
Human pathogens can survive and grow in hot springs. For water quality assessment, Escherichia coli or Enterococci are the main thermotolerant enteric bacteria commonly used to estimate the load of pathogenic bacteria in water. However, most of the environmental bacteria are unculturable thus culture methods may cause bias in detection of most pathogens. Illumina sequencing can provide a more comprehensive and accurate insight into environmental bacterial pathogens, which can be used to develop better risk assessment methods and promote public health awareness. In this study, high-throughput Illumina sequencing was used to identify bacterial pathogens from five hot springs; Maiwooi, Akwar, Garbanabra, Elegedi and Gelti, in Eritrea. Water samples were collected from the five hot springs. Total community DNA was extracted from samples using the phenol-chloroform method. The 16S rRNA gene variable region (V4—V7) of the extracted DNA was amplified and library construction done according to Illumina sequencing protocol. The sequence reads (length >200 bp) from Illumina sequencing libraries ranged from 22,091 sequences in the wet sediment sample from Garbanabra to 155,789 sequences in the mat sample from Elegedi. Taxonomy was assigned to each OTU using BLASTn against a curated database derived from GreenGenes, RDPII, SILVA SSU Reference 119 and NCBI. The proportion of potential pathogens from the water samples was highest in Maiwooi (17.8%), followed by Gelti (16.7%), Akwar (13.6%) and Garbanabra (10.9%). Although the numbers of DNA sequence reads from Illumina sequencing were very high for the Elegedi (104,328), corresponding proportion of potential pathogens very low (3.6%). Most of the potential pathogenic bacterial sequences identified were from Proteobacteria and Firmicutes. Legionella and Clostridium were the most common detected genera with different species. Most of the potential pathogens were detected from the water samples. However, sequences belonging to Clostridium were observed more abundantly from the mat samples. This study employed high-throughput sequencing technologies to determine the presence of pathogenic bacteria in the five hot springs in Eritrea.
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Affiliation(s)
- Amanuel Menghs Ghilamicael
- Institute for Biotechnology Research, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
- * E-mail:
| | | | - Sylvester Elikana Anami
- Institute for Biotechnology Research, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Tadesse Mehari
- National Commission for Higher Education in Eritrea, Asmara, Eritrea
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Huang WC, Tsai HC, Tao CW, Chen JS, Shih YJ, Kao PM, Huang TY, Hsu BM. Approach to determine the diversity of Legionella species by nested PCR-DGGE in aquatic environments. PLoS One 2017; 12:e0170992. [PMID: 28166249 PMCID: PMC5293244 DOI: 10.1371/journal.pone.0170992] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/13/2017] [Indexed: 12/02/2022] Open
Abstract
In this study, we describe a nested PCR-DGGE strategy to detect Legionella communities from river water samples. The nearly full-length 16S rRNA gene was amplified using bacterial primer in the first step. After, the amplicons were employed as DNA templates in the second PCR using Legionella specific primer. The third round of gene amplification was conducted to gain PCR fragments apposite for DGGE analysis. Then the total numbers of amplified genes were observed in DGGE bands of products gained with primers specific for the diversity of Legionella species. The DGGE patterns are thus potential for a high-throughput preliminary determination of aquatic environmental Legionella species before sequencing. Comparative DNA sequence analysis of excised DGGE unique band patterns showed the identity of the Legionella community members, including a reference profile with two pathogenic species of Legionella strains. In addition, only members of Legionella pneumophila and uncultured Legionella sp. were detected. Development of three step nested PCR-DGGE tactic is seen as a useful method for studying the diversity of Legionella community. The method is rapid and provided sequence information for phylogenetic analysis.
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Affiliation(s)
- Wen-Chien Huang
- Department of Medicine, Mackay Medicine College, Taipei, Taiwan, ROC
- Department of Thoracic Surgery, Mackay Memorial Hospital, Taipei, Taiwan, ROC
- Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan, ROC
| | - Hsin-Chi Tsai
- School of Medicine Tzu-Chi University, Hualien, Taiwan, ROC
- Department of Psychiatry, Tzu-Chi General Hospital, Hualien, Taiwan, ROC
| | - Chi-Wei Tao
- Section of Respiratory Therapy, Cheng Hsin General Hospital, Taipei, Taiwan, ROC
| | - Jung-Sheng Chen
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, ROC
| | - Yi-Jia Shih
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Po-Min Kao
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Tung-Yi Huang
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Bing-Mu Hsu
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
- * E-mail:
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