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Karsenti N, Purssell A, Lau R, Ralevski F, Bhasker S, Raheel H, Boggild AK. Surveillance of Amoebic Keratitis-Causing Acanthamoebae for Potential Bacterial Endosymbionts in Ontario, Canada. Pathogens 2022; 11:pathogens11060661. [PMID: 35745515 PMCID: PMC9230791 DOI: 10.3390/pathogens11060661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/02/2022] [Accepted: 06/07/2022] [Indexed: 02/04/2023] Open
Abstract
Acanthamoeba spp. are the causative pathogens of several infections, including amoebic keratitis (AK), a vision-threatening infection. Acanthamoebae from corneal specimens of patients with AK harbor bacterial endosymbionts, which may increase virulence. We sought to understand the spectrum of bacterial endosymbionts present in clinical isolates of Acanthamoeba spp. identified in our reference parasitology laboratory. Isolates of Acanthamoeba spp. obtained from our biobank of anonymized corneal scrapings were screened for potential endosymbionts by PCR using primer pairs detecting bacteria belonging to orders Chlamydiales, Rickettsiales, or Legionellales and pan16S primers. Three primer pairs specific to the 18s rRNA gene of Acanthamoeba spp. were used for the amplification of Acanthamoeba DNA used for sequencing. Sanger sequencing of all PCR products was performed, followed by BLAST analysis for species identification. We screened 26 clinical isolates of Acanthamoeba spp. for potential endosymbionts. Five isolates (19%) were found to contain bacterial DNA belonging to Legionellales. Three (11%) contained members of the Rickettsiales and Pseudomonas genticulata was detected in a Rickettsia-positive sample. One strain (4%) contained Neochlamydia hartmannellae, a member of the Chlamydiales order. Bacterial endosymbionts are prevalent in clinical strains of Acanthamoeba causing AK isolated from corneal scrapings. The demonstration of these organisms in clinical Acanthamoeba isolates supports a potential exploration of anti-endosymbiont therapeutics as an adjuvant therapy in the treatment of AK.
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Affiliation(s)
- Nessika Karsenti
- Schulich School of Medicine & Dentistry, London, ON N6A 5C1, Canada; (N.K.); (H.R.)
| | - Andrew Purssell
- Faculty of Medicine, University of Ottawa, Ottawa, ON K1N 6N5, Canada;
| | - Rachel Lau
- Public Health Ontario Laboratories, Public Health Ontario, Toronto, ON M5G 1M1, Canada; (R.L.); (F.R.)
| | - Filip Ralevski
- Public Health Ontario Laboratories, Public Health Ontario, Toronto, ON M5G 1M1, Canada; (R.L.); (F.R.)
| | - Shveta Bhasker
- Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, ON M5S 1A1, Canada;
| | - Hira Raheel
- Schulich School of Medicine & Dentistry, London, ON N6A 5C1, Canada; (N.K.); (H.R.)
| | - Andrea K. Boggild
- Tropical Disease Unit, Division of Infectious Diseases, UHN-Toronto General Hospital, Toronto, ON M5G 2C4, Canada
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A1, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A1, Canada
- Correspondence: ; Tel.: +1-416-340-3675
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Akbar A, Hameed A, Alouffi AS, Almutairi MM, Tanveer T, Matin A. First report of successful Naegleria detection from environmental resources of some selected areas of Rawlakot, Azad Jammu and Kashmir, Pakistan. ACTA PROTOZOOL 2022. [DOI: 10.4467/16890027ap.21.005.15379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Naegleria belongs to the free-living amoeba family and is well-known as a human pathogen. It is recognized as etiological agent of primary amoebic meningoencephalitis involving central nervous system which always leads to death. To date, there is not a single report demonstrating Naegleria isolation and identification from environmental sources of Rawlakot, Azad Jammu and Kashmir Pakistan, and thus the aim of this study. Naegleria was isolated on non-nutrient agar plates seeded with heat killed E. coli and confirmed by morphological properties of the both stages of cyst or trophozoites. Furthermore, PCR was conducted along with direct sequencing of the PCR product for molecular identification. PCR and sequencing data verified the amplification of Naegleria sp. (07) and Vahlkampfia sp. (01) from both water and soil samples. Interestingly two species were successfully isolated and cultured on both 30 and 45°C. To the best of our knowledge this is the first report demonstrating the Naegleria isolation and molecular characterization from environmental sources of Rawlakot, Azad Jammu and Kashmir, Pakistan. The author is anxious for further evaluation of the pathogenic potential of the identified species and explores drinking water across Pakistan to investigate its quality and frequency of FLA, which might be a possible human hazard in future.
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Affiliation(s)
- Abida Akbar
- Department of Biological Science, Faculty of Natural and Health Sciences, University of Baltistan, Skardu, Gilgit-Baltistan, Pakistan; Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
| | - Abdul Hameed
- Institute of Biomedical and Genetic Engineering, 24 Mauve Area, G-9/1, Islamabad, Pakistan
| | | | - Mashal M. Almutairi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Tania Tanveer
- Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
| | - Abdul Matin
- Department of Biological Science, Faculty of Natural and Health Sciences, University of Baltistan, Skardu, Gilgit-Baltistan, Pakistan; Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
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Ecoepidemiology and Potential Transmission of Vibrio cholerae among Different Environmental Niches: An Upcoming Threat in Egypt. Pathogens 2021; 10:pathogens10020190. [PMID: 33578663 PMCID: PMC7916367 DOI: 10.3390/pathogens10020190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 12/04/2022] Open
Abstract
Cholera is a negative public health event caused by Vibrio cholerae. Although V. cholerae is abundant in natural environments, its pattern and transmission between different niches remain puzzling and interrelated. Our study aimed to investigate the occurrence of nonpathogenic V. cholerae in the natural environment during endemicity periods. It also aimed to highlight the role of molecular ecoepidemiology in mapping the routes of spread, transmission, and prevention of possible future cholera outbreaks. V. cholerae was detected in different aquatic environments, waterfowl, and poultry farms located along the length of the Nile River in Giza, Cairo, and Delta provinces, Egypt. After polymerase chain reaction amplification of the specific target outer membrane gene (Omp W) of suspected isolates, we performed sequence analysis, eventually using phylogenetic tree analysis to illustrate the possible epidemiological relationships between different sequences. Data revealed a significant variation in the physicochemical conditions of the examined Nile districts related to temporal, spatial, and anthropogenic activities. Moreover, data showed an evident association between V. cholerae and the clinically diseased Synodontis schall fish. We found that the environmental distress triggered by the salinity shift and elevated temperature in the Middle Delta of the Nile River affects the pathogenesis of V. cholerae, in addition to the characteristics of fish host inhabiting the Rosetta Branch at Kafr El-Zayat, El-Gharbia province, Egypt. In addition, we noted a significant relationship between V. cholerae and poultry sources that feed on the Nile dikes close to the examined districts. Sequence analysis revealed clustering of the waterfowl and broiler chicken isolates with human and aquatic isolated sequences retrieved from the GenBank databases. From the obtained data, we hypothesized that waterfowl act as a potential vector for the intermediate transmission of cholera. Therefore, continuous monitoring of Nile water quality and mitigation of Nile River pollution, in addition to following good managemental practices (GMPs), general hygienic guidelines, and biosecurity in the field of animal production and industry, might be the way to break this cyclic transmission between human, aquatic, and animal sectors.
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Ibekwe AM, Murinda SE. Linking Microbial Community Composition in Treated Wastewater with Water Quality in Distribution Systems and Subsequent Health Effects. Microorganisms 2019; 7:microorganisms7120660. [PMID: 31817873 PMCID: PMC6955928 DOI: 10.3390/microorganisms7120660] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/04/2019] [Accepted: 12/05/2019] [Indexed: 12/12/2022] Open
Abstract
The increases in per capita water consumption, coupled in part with global climate change have resulted in increased demands on available freshwater resources. Therefore, the availability of safe, pathogen-free drinking water is vital to public health. This need has resulted in global initiatives to develop sustainable urban water infrastructure for the treatment of wastewater for different purposes such as reuse water for irrigation, and advanced waste water purification systems for domestic water supply. In developed countries, most of the water goes through primary, secondary, and tertiary treatments combined with disinfectant, microfiltration (MF), reverse osmosis (RO), etc. to produce potable water. During this process the total bacterial load of the water at different stages of the treatment will decrease significantly from the source water. Microbial diversity and load may decrease by several orders of magnitude after microfiltration and reverse osmosis treatment and falling to almost non-detectable levels in some of the most managed wastewater treatment facilities. However, one thing in common with the different end users is that the water goes through massive distribution systems, and the pipes in the distribution lines may be contaminated with diverse microbes that inhabit these systems. In the main distribution lines, microbes survive within biofilms which may contain opportunistic pathogens. This review highlights the role of microbial community composition in the final effluent treated wastewater, biofilms formation in the distribution systems as the treated water goes through, and the subsequent health effects from potential pathogens associated with poorly treated water. We conclude by pointing out some basic steps that may be taken to reduce the accumulation of biofilms in the water distribution systems.
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Affiliation(s)
- Abasiofiok Mark Ibekwe
- US Salinity Laboratory, USDA-ARS, 450 W. Big Springs Rd., Riverside, CA 92507, USA
- Correspondence: ; Tel.: +951-369-4828
| | - Shelton E. Murinda
- Animal and Veterinary Sciences Department, Center for Antimicrobial Research and Food Safety, California State Polytechnic University, Pomona, CA 91768, USA;
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Tsao HF, Scheikl U, Herbold C, Indra A, Walochnik J, Horn M. The cooling tower water microbiota: Seasonal dynamics and co-occurrence of bacterial and protist phylotypes. WATER RESEARCH 2019; 159:464-479. [PMID: 31128471 PMCID: PMC6554697 DOI: 10.1016/j.watres.2019.04.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 04/04/2019] [Accepted: 04/13/2019] [Indexed: 05/30/2023]
Abstract
Cooling towers for heating, ventilation and air conditioning are ubiquitous in the built environment. Often located on rooftops, their semi-open water basins provide a suitable environment for microbial growth. They are recognized as a potential source of bacterial pathogens and have been associated with disease outbreaks such as Legionnaires' disease. While measures to minimize public health risks are in place, the general microbial and protist community structure and dynamics in these systems remain largely elusive. In this study, we analysed the microbiome of the bulk water from the basins of three cooling towers by 16S and 18S rRNA gene amplicon sequencing over the course of one year. Bacterial diversity in all three towers was broadly comparable to other freshwater systems, yet less diverse than natural environments; the most abundant taxa are also frequently found in freshwater or drinking water. While each cooling tower had a pronounced site-specific microbial community, taxa shared among all locations mainly included groups generally associated with biofilm formation. We also detected several groups related to known opportunistic pathogens, such as Legionella, Mycobacterium, and Pseudomonas species, albeit at generally low abundance. Although cooling towers represent a rather stable environment, microbial community composition was highly dynamic and subject to seasonal change. Protists are important members of the cooling tower water microbiome and known reservoirs for bacterial pathogens. Co-occurrence analysis of bacteria and protist taxa successfully captured known interactions between amoeba-associated bacteria and their hosts, and predicted a large number of additional relationships involving ciliates and other protists. Together, this study provides an unbiased and comprehensive overview of microbial diversity of cooling tower water basins, establishing a framework for investigating and assessing public health risks associated with these man-made freshwater environments.
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Affiliation(s)
- Han-Fei Tsao
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Ute Scheikl
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Craig Herbold
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Alexander Indra
- Department of Mycobacteriology and Clinical Molecular Biology, AGES, Vienna, Austria
| | - Julia Walochnik
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria.
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Chamberlain NB, Mehari YT, Hayes BJ, Roden CM, Kidane DT, Swehla AJ, Lorenzana-DeWitt MA, Farone AL, Gunderson JH, Berk SG, Farone MB. Infection and nuclear interaction in mammalian cells by 'Candidatus Berkiella cookevillensis', a novel bacterium isolated from amoebae. BMC Microbiol 2019; 19:91. [PMID: 31072343 PMCID: PMC6507137 DOI: 10.1186/s12866-019-1457-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 04/15/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND 'Candidatus Berkiella cookevillensis' and 'Ca. Berkiella aquae' have previously been described as intranuclear bacteria of amoebae. Both bacteria were isolated from amoebae and were described as appearing within the nuclei of Acanthamoeba polyphaga and ultimately lysing their host cells within 4 days. Both bacteria are Gammaproteobacteria in the order Legionellales with the greatest similarity to Coxiella burnetii. Neither bacterium grows axenically in artificial culture media. In this study, we further characterized 'Ca. B. cookevillensis' by demonstrating association with nuclei of human phagocytic and nonphagocytic cell lines. RESULTS Transmission electron microscopy (TEM) and confocal microscopy were used to confirm nuclear co-localization of 'Ca. B. cookevillensis' in the amoeba host A. polyphaga with 100% of cells having bacteria co-localized with host nuclei by 48 h. TEM and confocal microscopy demonstrated that the bacterium was also observed to be closely associated with nuclei of human U937 and THP-1 differentiated macrophage cell lines and nonphagocytic HeLa human epithelial-like cells. Immunofluorescent staining revealed that the bacteria-containing vacuole invaginates the nuclear membranes and appears to cross from the cytoplasm into the nucleus as an intact vacuole. CONCLUSION Results of this study indicate that a novel coccoid bacterium isolated from amoebae can infect human cell lines by associating with the host cell nuclei, either by crossing the nuclear membranes or by deeply invaginating the nuclear membranes. When associated with the nuclei, the bacteria appear to be bound within a vacuole and replicate to high numbers by 48 h. We believe this is the first report of such a process involving bacteria and human cell lines.
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Affiliation(s)
- Nicholas B Chamberlain
- Molecular Biosciences Program, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA.,Department of Biology, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA
| | - Yohannes T Mehari
- Molecular Biosciences Program, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA.,Department of Biology, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA
| | - B Jason Hayes
- Department of Biology, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA
| | - Colleen M Roden
- Department of Biology, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA
| | - Destaalem T Kidane
- Molecular Biosciences Program, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA.,Department of Biology, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA
| | - Andrew J Swehla
- Department of Biology, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA
| | - Mario A Lorenzana-DeWitt
- Department of Biology, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA
| | - Anthony L Farone
- Molecular Biosciences Program, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA.,Department of Biology, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA
| | - John H Gunderson
- Department of Biology, Tennessee Technological University, 1 William L Jones Dr, Cookeville, TN, 38505, USA
| | - Sharon G Berk
- Department of Biology, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA
| | - Mary B Farone
- Molecular Biosciences Program, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA. .,Department of Biology, Middle Tennessee State University, 1301 E. Main St, Murfreesboro, TN, 37130, USA.
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Abu Khweek A, Amer AO. Factors Mediating Environmental Biofilm Formation by Legionella pneumophila. Front Cell Infect Microbiol 2018. [PMID: 29535972 PMCID: PMC5835138 DOI: 10.3389/fcimb.2018.00038] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Legionella pneumophila (L. pneumophila) is an opportunistic waterborne pathogen and the causative agent for Legionnaires' disease, which is transmitted to humans via inhalation of contaminated water droplets. The bacterium is able to colonize a variety of man-made water systems such as cooling towers, spas, and dental lines and is widely distributed in multiple niches, including several species of protozoa In addition to survival in planktonic phase, L. pneumophila is able to survive and persist within multi-species biofilms that cover surfaces within water systems. Biofilm formation by L. pneumophila is advantageous for the pathogen as it leads to persistence, spread, resistance to treatments and an increase in virulence of this bacterium. Furthermore, Legionellosis outbreaks have been associated with the presence of L. pneumophila in biofilms, even after the extensive chemical and physical treatments. In the microbial consortium-containing L. pneumophila among other organisms, several factors either positively or negatively regulate the presence and persistence of L. pneumophila in this bacterial community. Biofilm-forming L. pneumophila is of a major importance to public health and have impact on the medical and industrial sectors. Indeed, prevention and removal protocols of L. pneumophila as well as diagnosis and hospitalization of patients infected with this bacteria cost governments billions of dollars. Therefore, understanding the biological and environmental factors that contribute to persistence and physiological adaptation in biofilms can be detrimental to eradicate and prevent the transmission of L. pneumophila. In this review, we focus on various factors that contribute to persistence of L. pneumophila within the biofilm consortium, the advantages that the bacteria gain from surviving in biofilms, genes and gene regulation during biofilm formation and finally challenges related to biofilm resistance to biocides and anti-Legionella treatments.
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Affiliation(s)
- Arwa Abu Khweek
- Department of Biology and Biochemistry, Birzeit University, West Bank, Palestine
| | - Amal O Amer
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, College of Medicine, Ohio State University, Columbus, OH, United States
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Mehari YT, Jason Hayes B, Redding KS, Mariappan PVG, Gunderson JH, Farone AL, Farone MB. Description of ' Candidatus Berkiella aquae' and ' Candidatus Berkiella cookevillensis', two intranuclear bacteria of freshwater amoebae. Int J Syst Evol Microbiol 2015; 66:536-541. [PMID: 26556637 DOI: 10.1099/ijsem.0.000750] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two novel bacteria of the phylum Proteobacteria were isolated during searches for amoeba-resistant micro-organisms in natural and constructed water systems. Strain HT99 was isolated from amoebae found in the biofilm of an outdoor hot tub in Cookeville, Tennessee, USA, and strain CC99 was isolated from amoebae in the biofilm of a cooling tower in the same city. Both bacteria were Gram-stain-negative cocci to coccobacilli, unculturable on conventional laboratory media, and were found to be intranuclear when maintained in Acanthamoeba polyphaga. The genomes of both isolates were completely sequenced. The genome of CC99 was found to be 3.0 Mbp with a 37.9 mol% DNA G+C content, while the genome of HT99 was 3.6 Mbp with a 39.5 mol% DNA G+C content. The 16S rRNA gene sequences of the two isolates were 94 % similar to each other. Phylogenetic comparisons of the 16S rRNA, mip and rpoB genes, the DNA G+C content and the fatty acid composition demonstrated that both bacteria are members of the order Legionellales, and are most closely related to Coxiella burnetii. The phenotypic and genetic evidence supports the proposal of novel taxa to accommodate these strains; however, because strains HT99 and CC99 cannot be cultured outside of the amoeba host, the respective names 'Candidatus Berkiella aquae' and 'Candidatus Berkiella cookevillensis' are proposed.
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Affiliation(s)
- Yohannes T Mehari
- Biology Department, Middle Tennessee State University, Murfreesboro, TN, USA
| | - B Jason Hayes
- Biology Department, Middle Tennessee State University, Murfreesboro, TN, USA
| | - Katherine S Redding
- Center for the Management, Utilization, and Protection of Water Resources, Tennessee Technological University, Cookeville, TN, USA
| | | | - John H Gunderson
- Department of Biology, Tennessee Technological University, Cookeville, TN, USA
| | - Anthony L Farone
- Biology Department, Middle Tennessee State University, Murfreesboro, TN, USA
| | - Mary B Farone
- Biology Department, Middle Tennessee State University, Murfreesboro, TN, USA
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Abstract
Vibrio cholerae is widely known to be the etiological agent of the life-threatening diarrheal disease cholera. Cholera remains a major scourge in many developing countries, infecting hundreds of thousands every year. Remarkably, V. cholerae is a natural inhabitant of brackish riverine, estuarine, and coastal waters, and only a subset of strains are known to be pathogenic to humans. Recent studies have begun to uncover a very complex network of relationships between V. cholerae and other sea dwellers, and the mechanisms associated with the occurrence of seasonal epidemics in regions where cholera is endemic are beginning to be elucidated. Many of the factors required for the organism's survival and persistence in its natural environment have been revealed, as well as the ubiquitous presence of horizontal gene transfer in the emergence of pathogenic strains of V. cholerae. In this article, we will focus on the environmental stage of pathogenic V. cholerae and the interactions of the microorganism with other inhabitants of aquatic environments. We will discuss the impact that its environmental reservoirs have on disease transmission and the distinction between reservoirs of V. cholerae and the vectors that establish cholera as a zoonosis.
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van Heijnsbergen E, Schalk JAC, Euser SM, Brandsema PS, den Boer JW, de Roda Husman AM. Confirmed and Potential Sources of Legionella Reviewed. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:4797-815. [PMID: 25774976 DOI: 10.1021/acs.est.5b00142] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Legionella bacteria are ubiquitous in natural matrices and man-made systems. However, it is not always clear if these reservoirs can act as source of infection resulting in cases of Legionnaires' disease. This review provides an overview of reservoirs of Legionella reported in the literature, other than drinking water distribution systems. Levels of evidence were developed to discriminate between potential and confirmed sources of Legionella. A total of 17 systems and matrices could be classified as confirmed sources of Legionella. Many other man-made systems or natural matrices were not classified as a confirmed source, since either no patients were linked to these reservoirs or the supporting evidence was weak. However, these systems or matrices could play an important role in the transmission of infectious Legionella bacteria; they might not yet be considered in source investigations, resulting in an underestimation of their importance. To optimize source investigations it is important to have knowledge about all the (potential) sources of Legionella. Further research is needed to unravel what the contribution is of each confirmed source, and possibly also potential sources, to the LD disease burden.
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Affiliation(s)
- Eri van Heijnsbergen
- †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
| | - Johanna A C Schalk
- †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
| | - Sjoerd M Euser
- ‡Regional Public Health Laboratory Kennemerland, Haarlem, Boerhaavelaan 26, 2035 RC Haarlem, The Netherlands
| | - Petra S Brandsema
- †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
| | - Jeroen W den Boer
- ‡Regional Public Health Laboratory Kennemerland, Haarlem, Boerhaavelaan 26, 2035 RC Haarlem, The Netherlands
| | - Ana Maria de Roda Husman
- †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
- §Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3584 CM Utrecht, The Netherlands
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Prevalence of protozoa species in drinking and environmental water sources in Sudan. BIOMED RESEARCH INTERNATIONAL 2015; 2015:345619. [PMID: 25789313 PMCID: PMC4348585 DOI: 10.1155/2015/345619] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 01/30/2015] [Accepted: 02/02/2015] [Indexed: 11/23/2022]
Abstract
Protozoa are eukaryotic cells distributed worldwide in nature and are receiving increasing attention as reservoirs and potential vectors for the transmission of pathogenic bacteria. In the environment, on the other hand, many genera of the protozoa are human and animal pathogens. Only limited information is available on these organisms in developing countries and so far no information on their presence is available from Sudan. It is necessary to establish a molecular identification of species of the protozoa from drinking and environmental water. 600 water samples were collected from five states (Gadarif, Khartoum, Kordofan, Juba, and Wad Madani) in Sudan and analysed by polymerase chain reaction (PCR) and sequencing. 57 out of 600 water samples were PCR positive for protozoa. 38 out of the 57 positive samples were identified by sequencing to contain 66 protozoa species including 19 (28.8%) amoebae, 17 (25.7%) Apicomplexa, 25 (37.9%) ciliates, and 5 (7.6%) flagellates. This study utilized molecular methods identified species belonging to all phyla of protozoa and presented a fast and accurate molecular detection and identification of pathogenic as well as free-living protozoa in water uncovering hazards facing public health.
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12
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Ravva SV, Sarreal CZ, Mandrell RE. Strain differences in fitness of Escherichia coli O157:H7 to resist protozoan predation and survival in soil. PLoS One 2014; 9:e102412. [PMID: 25019377 PMCID: PMC4097067 DOI: 10.1371/journal.pone.0102412] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 06/18/2014] [Indexed: 11/19/2022] Open
Abstract
Escherichia coli O157:H7 (EcO157) associated with the 2006 spinach outbreak appears to have persisted as the organism was isolated, three months after the outbreak, from environmental samples in the produce production areas of the central coast of California. Survival in harsh environments may be linked to the inherent fitness characteristics of EcO157. This study evaluated the comparative fitness of outbreak-related clinical and environmental strains to resist protozoan predation and survive in soil from a spinach field in the general vicinity of isolation of strains genetically indistinguishable from the 2006 outbreak strains. Environmental strains from soil and feral pig feces survived longer (11 to 35 days for 90% decreases, D-value) with Vorticella microstoma and Colpoda aspera, isolated previously from dairy wastewater; these D-values correlated (P<0.05) negatively with protozoan growth. Similarly, strains from cow feces, feral pig feces, and bagged spinach survived significantly longer in soil compared to clinical isolates indistinguishable by 11-loci multi-locus variable-number tandem-repeat analysis. The curli-positive (C+) phenotype, a fitness trait linked with attachment in ruminant and human gut, decreased after exposure to protozoa, and in soils only C− cells remained after 7 days. The C+ phenotype correlated negatively with D-values of EcO157 exposed to soil (rs = −0.683; P = 0.036), Vorticella (rs = −0.465; P = 0.05) or Colpoda (rs = −0.750; P = 0.0001). In contrast, protozoan growth correlated positively with C+ phenotype (Vorticella, rs = 0.730, P = 0.0004; Colpoda, rs = 0.625, P = 0.006) suggesting a preference for consumption of C+ cells, although they grew on C− strains also. We speculate that the C− phenotype is a selective trait for survival and possibly transport of the pathogen in soil and water environments.
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Affiliation(s)
- Subbarao V. Ravva
- Produce Safety and Microbiology Research Unit, U.S. Department of Agriculture, Agriculture Research Service, Western Regional Research Center, Albany, California, United States of America
- * E-mail:
| | - Chester Z. Sarreal
- Produce Safety and Microbiology Research Unit, U.S. Department of Agriculture, Agriculture Research Service, Western Regional Research Center, Albany, California, United States of America
| | - Robert E. Mandrell
- Produce Safety and Microbiology Research Unit, U.S. Department of Agriculture, Agriculture Research Service, Western Regional Research Center, Albany, California, United States of America
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Torvinen E, Suomalainen S, Paulin L, Kusnetsov J. Mycobacteria in Finnish cooling tower waters. APMIS 2013; 122:353-8. [PMID: 23937212 DOI: 10.1111/apm.12153] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 06/16/2013] [Indexed: 11/30/2022]
Abstract
Evaporative cooling towers are water systems used in, e.g., industry and telecommunication to remove excess heat by evaporation of water. Temperatures of cooling waters are usually optimal for mesophilic microbial growth and cooling towers may liberate massive amounts of bacterial aerosols. Outbreaks of legionellosis associated with cooling towers have been known since the 1980's, but occurrences of other potentially pathogenic bacteria in cooling waters are mostly unknown. We examined the occurrence of mycobacteria, which are common bacteria in different water systems and may cause pulmonary and other soft tissue infections, in cooling waters containing different numbers of legionellae. Mycobacteria were isolated from all twelve cooling systems and from 92% of the 24 samples studied. Their numbers in the positive samples varied from 10 to 7.3 × 10(4) cfu/L. The isolated species included M. chelonae/abscessus, M. fortuitum, M. mucogenicum, M. peregrinum, M. intracellulare, M. lentiflavum, M. avium/nebraskense/scrofulaceum and many non-pathogenic species. The numbers of mycobacteria correlated negatively with the numbers of legionellae and the concentration of copper. The results show that cooling towers are suitable environments for potentially pathogenic mycobacteria. Further transmission of mycobacteria from the towers to the environment needs examination.
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Affiliation(s)
- Eila Torvinen
- Department of Environmental Science, University of Eastern Finland, Kuopio, Finland
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Ravva SV, Sarreal CZ, Mandrell RE. Altered protozoan and bacterial communities and survival of Escherichia coli O157:H7 in monensin-treated wastewater from a dairy lagoon. PLoS One 2013; 8:e54782. [PMID: 23349969 PMCID: PMC3551901 DOI: 10.1371/journal.pone.0054782] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 12/18/2012] [Indexed: 02/03/2023] Open
Abstract
Surviving predation is a fitness trait of Escherichia coli O157:H7 (EcO157) that provides ample time for the pathogen to be transported from reservoirs (e.g. dairies and feedlots) to farm produce grown in proximity. Ionophore dietary supplements that inhibit rumen protozoa may provide such a selective advantage for EcO157 to proliferate in lagoons as the pathogen is released along with the undigested supplement as manure washings. This study evaluated the fate of an outbreak strain of EcO157, protozoan and bacterial communities in wastewater treated with monensin. Although total protozoa and native bacteria were unaffected by monensin, the time for 90% decrease in EcO157 increased from 0.8 to 5.1 days. 18S and 16S rRNA gene sequencing of wastewater samples revealed that monensin eliminated almost all colpodean and oligohymenophorean ciliates, probably facilitating the extended survival of EcO157. Total protozoan numbers remained high in treated wastewater as monensin enriched 94% of protozoan sequences undetected with untreated wastewater. Monensin stimulated 30-fold increases in Cyrtohymena citrina, a spirotrichean ciliate, and also biflagellate bicosoecids and cercozoans. Sequences of gram-negative Proteobacteria increased from 1% to 46% with monensin, but gram-positive Firmicutes decreased from 93% to 46%. It is noteworthy that EcO157 numbers increased significantly (P<0.01) in Sonneborn medium containing monensin, probably due to monensin-inhibited growth of Vorticella microstoma (P<0.05), a ciliate isolated from wastewater. We conclude that dietary monensin inhibits ciliate protozoa that feed on EcO157. Feed supplements or other methods that enrich these protozoa in cattle manure could be a novel strategy to control the environmental dissemination of EcO157 from dairies to produce production environments.
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Affiliation(s)
- Subbarao V Ravva
- Produce Safety and Microbiology Research Unit, U.S. Department of Agriculture, Agriculture Research Service, Western Regional Research Center, Albany, California, USA.
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Abstract
Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri are mitochondria-bearing, free-living eukaryotic amebae that have been known to cause infections of the central nervous system (CNS) of humans and other animals. Several species of Acanthamoeba belonging to several different genotypes cause an insidious and chronic disease, granulomatous amebic encephalitis (GAE), principally in immunocompromised hosts including persons infected with HIV/AIDS. Acanthamoeba spp., belonging to mostly group 2, also cause infection of the human cornea, Acanthamoeba keratitis. Balamuthia mandrillaris causes GAE in both immunocompromised and immunocompetent hosts mostly in the very young or very old individuals. Both Acanthamoeba spp. and B. mandrillaris also cause a disseminated disease including the lungs, skin, kidneys, and uterus. Naegleria fowleri, on the other hand, causes an acute and fulminating, necrotizing infection of the CNS called primary amebic meningoencephalitis (PAM) in children and young adults with a history of recent exposure to warm fresh water. Additionally, another free-living ameba Sappinia pedata, previously described as S. diploidea, also has caused a single case of amebic meningoencephalitis. In this review the biology of these amebae, clinical manifestations, molecular and immunological diagnosis, and epidemiological features associated with GAE and PAM are discussed.
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Affiliation(s)
- Govinda S Visvesvara
- Division of Foodborne, Waterborne & Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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Akya A, Pointon A, Thomas C. Listeria monocytogenes does not survive ingestion by Acanthamoeba polyphaga. MICROBIOLOGY-SGM 2009; 156:809-818. [PMID: 19892759 DOI: 10.1099/mic.0.031146-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Listeria monocytogenes is a ubiquitous bacterium capable of infecting humans, particularly pregnant women and immunocompromised individuals. Although the intracellular invasion and pathogenesis of listeriosis in mammalian tissues has been well studied, little is known about the ecology of L. monocytogenes , and in particular the environmental reservoir for this bacterium has not been identified. This study used short-term co-culture at 15, 22 and 37 degrees C to examine the interaction of L. monocytogenes strains with Acanthamoeba polyphaga ACO12. Survival of L. monocytogenes cells phagocytosed by monolayers of trophozoites was assessed by culture techniques and microscopy. A. polyphaga trophozoites eliminated bacterial cells within a few hours post-phagocytosis, irrespective of the incubation temperature used. Wild-type L. monocytogenes and a phenotypic listeriolysin O mutant were unable to either multiply or survive within trophozoites. By contrast, Salmonella enterica serovar Typhimurium C5 cells used as controls were able to survive and multiply within A. polyphaga trophozoites. The data presented indicate that A. polyphaga ACO12 is unlikely to harbour L. monocytogenes, or act as an environmental reservoir for this bacterium.
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Affiliation(s)
- Alisha Akya
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide 5005, Australia
| | - Andrew Pointon
- South Australian Research and Development Institute, Glenside, South Australia
| | - Connor Thomas
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide 5005, Australia
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Yli-Pirilä T, Kusnetsov J, Hirvonen MR, Seuri M, Nevalainen A. Survival of amoebae on building materials. INDOOR AIR 2009; 19:113-121. [PMID: 19076736 DOI: 10.1111/j.1600-0668.2008.00567.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
UNLABELLED Moisture damage and concurrent microbial growth in buildings are associated with adverse health effects among the occupants. However, the causal agents for the symptoms are unclear although microbes are assumed to play a major role. Fungi and bacteria are not the only microbes inhabiting moist building materials; it was recently revealed that amoebae are also present. As amoebae have the potential to harbor many pathogens and to modulate the characteristics of growing microbes, a better appreciation of the growth and survival of amoebae in moisture damage conditions will add to the understanding of their effects on health outcomes. In this study, we investigated the ability of amoebae to survive on six building materials. Furthermore, both aged and unused materials were tested. Amoebae survived on gypsum board and mineral wool for the whole 2 months experiment even without additional sustenance. When sustenance (heat-killed bacteria) was available, aged pine wood and birch wood also allowed their survival. In contrast, amoebae were quickly killed on fresh pine wood and they did not survive on concrete or linoleum. In conclusion, our data show that amoebae can persist on several common building materials once these materials become wet. PRACTICAL IMPLICATIONS Amoebae are able to survive on many building materials should the materials become wet. Amoebae have the potential to increase growth, cytotoxicity, and pathogenicity of other microbes present in moisture damages, and they may carry potentially pathogenic bacteria as endosymbionts and thus introduce them into the indoor air. Therefore, amoebae may have a prominent role in the microbial exposures occurring in moisture-damaged buildings. The presence of amoebae could be usefully included in reporting the microbial damage of material samples.
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Affiliation(s)
- T Yli-Pirilä
- Department of Environmental Health, National Public Health Institute, Kuopio, Finland.
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Critchley M, Bentham R. The efficacy of biocides and other chemical additives in cooling water systems in the control of amoebae. J Appl Microbiol 2009; 106:784-9. [DOI: 10.1111/j.1365-2672.2008.04044.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Liu Y, Zhang W, Sileika T, Warta R, Cianciotto NP, Packman A. Role of bacterial adhesion in the microbial ecology of biofilms in cooling tower systems. BIOFOULING 2009; 25:241-53. [PMID: 19177226 PMCID: PMC2723952 DOI: 10.1080/08927010802713414] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The fate of the three heterotrophic biofilm forming bacteria, Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. in pilot scale cooling towers was evaluated both by observing the persistence of each species in the recirculating water and the formation of biofilms on steel coupons placed in each cooling tower water reservoir. Two different cooling tower experiments were performed: a short-term study (6 days) to observe the initial bacterial colonization of the cooling tower, and a long-term study (3 months) to observe the ecological dynamics with repeated introduction of the test strains. An additional set of batch experiments (6 days) was carried out to evaluate the adhesion of each strain to steel surfaces under similar conditions to those found in the cooling tower experiments. Substantial differences were observed in the microbial communities that developed in the batch systems and cooling towers. P. aeruginosa showed a low degree of adherence to steel surfaces both in batch and in the cooling towers, but grew much faster than K. pneumoniae and Flavobacterium in mixed-species biofilms and ultimately became the dominant organism in the closed batch systems. However, the low degree of adherence caused P. aeruginosa to be rapidly washed out of the open cooling tower systems, and Flavobacterium became the dominant microorganism in the cooling towers in both the short-term and long-term experiments. These results indicate that adhesion, retention and growth on solid surfaces play important roles in the bacterial community that develops in cooling tower systems.
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Affiliation(s)
- Yang Liu
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA
| | - Wei Zhang
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA
| | - Tadas Sileika
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA
| | - Richard Warta
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA
| | - Nicholas P. Cianciotto
- Department of Microbiology-Immunology, Northwestern University Medical School, Chicago, IL, USA
| | - Aaron Packman
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA
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Bastian F, Alabouvette C, Saiz-Jimenez C. Bacteria and free-living amoeba in the Lascaux Cave. Res Microbiol 2008; 160:38-40. [PMID: 18977432 DOI: 10.1016/j.resmic.2008.10.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Accepted: 10/02/2008] [Indexed: 10/21/2022]
Abstract
The Lascaux Cave was discovered in 1940, and by 1960 it had received up to 1800 daily visitors. In 1963, the cave was closed and in 2001 it was invaded by a Fusarium solani species complex which was treated for four years with benzalkonium chloride. However, Lascaux Cave bacteria have only been poorly investigated. Here we show that the cave is now a reservoir of potential pathogenic bacteria and protozoa which can be found in outbreaks linked to air-conditioning systems and cooling towers in community hospitals and public buildings.
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Affiliation(s)
- Fabiola Bastian
- Université de Bourgogne, Microbiologie du Sol et de l'Environnement, BP 86510, 21065 Dijon Cedex, France
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Carvalho FRS, Vazoller RF, Foronda AS, Pellizari VH. Phylogenetic study of legionella species in pristine and polluted aquatic samples from a tropical Atlantic forest ecosystem. Curr Microbiol 2007; 55:288-93. [PMID: 17700986 DOI: 10.1007/s00284-006-0589-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Accepted: 02/01/2007] [Indexed: 10/23/2022]
Abstract
Legionella species are ubiquitous bacteria in aquatic environments. To examine the effect of anthropogenic impacts and physicochemical characteristics on the Legionellaceae population, we collected water from two sites in the Itanhaém River system in the Atlantic Forest of Brazil. One sample was collected from an upstream pristine region, the other from a downstream estuarine region moderately affected by untreated domestic sewage. Cultures on a selective medium failed to isolate Legionella species. Culture-independent methods showed that water from the estuarine aquatic habitat contained DNA sequences homologous to the 16S ribosomal DNA gene of Legionella pneumophila and non-pneumophila species. In pristine water, only two sequences related to L. pneumophila were detected. The results suggest that salinity and anthropogenic factors, such as wastewater discharge, favor a diversity of Legionella species, whereas pristine freshwater selects for Legionella pneumophila.
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Affiliation(s)
- Fábio R S Carvalho
- Laboratory of Environmental Microbiology, Department of Microbiology, Institute of Biomedical Science, University of São Paulo, Room 148 Lineu Prestes avenue, 1374, Cidade Universitária São Paulo, SP, Brazil.
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Långmark J, Storey MV, Ashbolt NJ, Stenström TA. The effects of UV disinfection on distribution pipe biofilm growth and pathogen incidence within the greater Stockholm area, Sweden. WATER RESEARCH 2007; 41:3327-36. [PMID: 17588636 DOI: 10.1016/j.watres.2007.04.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Revised: 04/13/2007] [Accepted: 04/24/2007] [Indexed: 05/16/2023]
Abstract
An assessment of the effects of the transition from conventional chlorination to UV disinfection on potable water biofilm growth and pathogen incidence was made. Two hydraulic systems were tested, one a 1.0 km polyethylene pilot-scale system within the Lovö waterworks, Stockholm, Sweden, as well as Hässelby and Nockeby municipal distribution systems within the greater Stockholm area. Biofilms were propagated on coupons and the amount of biomass analysed by standard culture and molecular methods. There was no measurable difference in biofilm biomass or pathogen incidence in the transition from conventional chlorination to UV-treatment in any system examined. With the exception of aeromonads, frank (salmonellae, enterobacteria) and opportunistic (legionellae) pathogens as well as indicator bacteria (E. coli, coliforms, enterococci) could not be detected within biofilms in either the pilot-scale or large-scale municipal system. Free-living protozoa were detected almost ubiquitously in biofilm samples in either experimental system though their exact significance and impact remains unknown and warrants further investigation.
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Affiliation(s)
- Jonas Långmark
- Department of Parasitology, Mycology, Water and Environmental Microbiology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden.
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Visvesvara GS, Moura H, Schuster FL. Pathogenic and opportunistic free-living amoebae: Acanthamoeba spp., Balamuthia mandrillaris, Naegleria fowleri, and Sappinia diploidea. ACTA ACUST UNITED AC 2007; 50:1-26. [PMID: 17428307 DOI: 10.1111/j.1574-695x.2007.00232.x] [Citation(s) in RCA: 776] [Impact Index Per Article: 45.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Among the many genera of free-living amoebae that exist in nature, members of only four genera have an association with human disease: Acanthamoeba spp., Balamuthia mandrillaris, Naegleria fowleri and Sappinia diploidea. Acanthamoeba spp. and B. mandrillaris are opportunistic pathogens causing infections of the central nervous system, lungs, sinuses and skin, mostly in immunocompromised humans. Balamuthia is also associated with disease in immunocompetent children, and Acanthamoeba spp. cause a sight-threatening infection, Acanthamoeba keratitis, mostly in contact-lens wearers. Of more than 30 species of Naegleria, only one species, N. fowleri, causes an acute and fulminating meningoencephalitis in immunocompetent children and young adults. In addition to human infections, Acanthamoeba, Balamuthia and Naegleria can cause central nervous system infections in animals. Because only one human case of encephalitis caused by Sappinia diploidea is known, generalizations about the organism as an agent of disease are premature. In this review we summarize what is known of these free-living amoebae, focusing on their biology, ecology, types of disease and diagnostic methods. We also discuss the clinical profiles, mechanisms of pathogenesis, pathophysiology, immunology, antimicrobial sensitivity and molecular characteristics of these amoebae.
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Affiliation(s)
- Govinda S Visvesvara
- Division of Parasitic Diseases, National Center for Infectious Diseases, Atlanta, Georgia 30341-3724, USA.
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Yli-Pirilä T, Kusnetsov J, Hirvonen MR, Seuri M, Nevalainen A. Effects of amoebae on the growth of microbes isolated from moisture-damaged buildings. Can J Microbiol 2006; 52:383-90. [PMID: 16699589 DOI: 10.1139/w05-131] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dampness, moisture, and mold in buildings are associated with adverse health outcomes. In addition to fungi and bacteria, amoebae have been found in moisture-damaged building materials. Amoebae and a growing list of bacteria have been shown to have mutual effects on each other's growth, but the interactions between amoebae and microbes common in moisture-damaged buildings have not been reported. We co-cultivated the amoeba Acanthamoeba polyphaga with bacteria and fungi isolated from moisture-damaged buildings in laboratory conditions for up to 28 days. The microbes selected were the bacteria Streptomyces californicus, Bacillus cereus, and Pseudomonas fluorescens, and the fungi Stachybotrys chartarum, Aspergillus versicolor, and Penicillium spinulosum. Fungi and bacteria generally benefited from the presence of the amoebae, whereas the growth of amoebae was hindered by Streptomyces californicus, Stachybotrys chartarum, and Bacillus cereus. Pseudomonas fluorescens slightly enhanced amoebae viability. Amoebae were indifferent to the presence of Aspergillus versicolor and Penicillium spinulosum. Thus, our results show that amoebae can alter the survival and growth of some microbes in moisture-damaged buildings.Key words: moisture-damaged buildings, free-living amoebae, bacteria, fungi, co-culture.
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Affiliation(s)
- Terhi Yli-Pirilä
- National Public Health Institute, Department of Environmental Health, Kuopio, Finland.
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Mura M, Bull TJ, Evans H, Sidi-Boumedine K, McMinn L, Rhodes G, Pickup R, Hermon-Taylor J. Replication and long-term persistence of bovine and human strains of Mycobacterium avium subsp. paratuberculosis within Acanthamoeba polyphaga. Appl Environ Microbiol 2006; 72:854-9. [PMID: 16391127 PMCID: PMC1352277 DOI: 10.1128/aem.72.1.854-859.2006] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Free-living protists are ubiquitous in the environment and form a potential reservoir for the persistence of animal and human pathogens. Mycobacterium avium subsp. paratuberculosis is the cause of Johne's disease, a systemic infection accompanied by chronic inflammation of the intestine that affects many animals, including primates. Most humans with Crohn's disease are infected with this chronic enteric pathogen. Subclinical infection with M. avium subsp. paratuberculosis is widespread in domestic livestock. Infected animals excrete large numbers of robust organisms into the environment, but little is known about their ability to replicate and persist in protists. In the present study we fed laboratory cultures of Acanthamoeba polyphaga with bovine and human strains of M. avium subsp. paratuberculosis. Real-time PCR showed that the numbers of the pathogens fell over the first 4 to 8 days and recovered by 12 to 16 days. Encystment of the amoebic cultures after 4 weeks resulted in a 2-log reduction in the level of M. avium subsp. paratuberculosis, which returned to the original level by 24 weeks. Extracts of resection samples of human gut from 39 patients undergoing abdominal surgery were fed to cultures of A. polyphaga. M. avium subsp. paratuberculosis detected by nested IS900 PCR with amplicon sequencing and visualized by IS900 in situ hybridization and auramine-rhodamine staining was found in cultures derived from 13 of the patients and was still present in the cultures after almost 4 years of incubation. Control cultures were negative. M. avium subsp. paratuberculosis has the potential for long-term persistence in environmental protists.
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Affiliation(s)
- Manuela Mura
- Department of Cardiac and Vascular Sciences (Surgery), St. George's University of London, London SW17 0RE, United Kingdom
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Shadrach WS, Rydzewski K, Laube U, Holland G, Ozel M, Kiderlen AF, Flieger A. Balamuthia mandrillaris, free-living ameba and opportunistic agent of encephalitis, is a potential host for Legionella pneumophila bacteria. Appl Environ Microbiol 2005; 71:2244-9. [PMID: 15870307 PMCID: PMC1087515 DOI: 10.1128/aem.71.5.2244-2249.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Balamuthia mandrillaris is a free-living ameba and an opportunistic agent of granulomatous encephalitis in humans and other mammalian species. Other free-living amebas, such as Acanthamoeba and Hartmannella, can provide a niche for intracellular survival of bacteria, including the causative agent of Legionnaires' disease, Legionella pneumophila. Infection of amebas by L. pneumophila enhances the bacterial infectivity for mammalian cells and lung tissues. Likewise, the pathogenicity of amebas may be enhanced when they host bacteria. So far, the colonization of B. mandrillaris by bacteria has not been convincingly shown. In this study, we investigated whether this ameba could host L. pneumophila bacteria. Our experiments showed that L. pneumophila could initiate uptake by B. mandrillaris and could replicate within the ameba about 4 to 5 log cycles from 24 to 72 h after infection. On the other hand, a dotA mutant, known to be unable to propagate in Acanthamoeba castellanii, also did not replicate within B. mandrillaris. Approaching completion of the intracellular cycle, L. pneumophila wild-type bacteria were able to destroy their ameboid hosts. Observations by light microscopy paralleled our quantitative data and revealed the rounding, collapse, clumping, and complete destruction of the infected amebas. Electron microscopic studies unveiled the replication of the bacteria in a compartment surrounded by a structure resembling rough endoplasmic reticulum. The course of intracellular infection, the degree of bacterial multiplication, and the ultrastructural features of a L. pneumophila-infected B. mandrillaris ameba resembled those described for other amebas hosting Legionella bacteria. We hence speculate that B. mandrillaris might serve as a host for bacteria in its natural environment.
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Affiliation(s)
- Winlet Sheba Shadrach
- Robert Koch-Institut, Research Group Pathogenesis of Legionella Infections, D-13353 Berlin, Germany
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Schuster FL, Visvesvara GS. Amebae and ciliated protozoa as causal agents of waterborne zoonotic disease. Vet Parasitol 2005; 126:91-120. [PMID: 15567581 DOI: 10.1016/j.vetpar.2004.09.019] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The roles free-living amebae and the parasitic protozoa Entamoeba histolytica and Balantidium coli play as agents of waterborne zoonotic diseases are examined. The free-living soil and water amebae Naegleria fowleri, Acanthamoeba spp., and Balamuthia mandrillaris are recognized etiologic agents of mostly fatal amebic encephalitides in humans and other animals, with immunocompromised and immunocompetent hosts among the victims. Acanthamoeba spp. are also agents of amebic keratitis. Infection is through the respiratory tract, breaks in the skin, or by uptake of water into the nostrils, with spread to the central nervous system. E. histolytica and B. coli are parasitic protozoa that cause amebic dysentery and balantidiasis, respectively. Both intestinal infections are spread via a fecal-oral route, with cysts as the infective stage. Although the amebic encephalitides can be acquired by contact with water, they are not, strictly speaking, waterborne diseases and are not transmitted to humans from animals. Non-human primates and swine are reservoirs for E. histolytica and B. coli, and the diseases they cause are acquired from cysts, usually in sewage-contaminated water. Amebic dysentery and balantidiasis are examples of zoonotic waterborne infections, though human-to-human transmission can occur. The epidemiology of the diseases is examined, as are diagnostic procedures, anti-microbial interventions, and the influence of globalization, climate change, and technological advances on their spread.
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Affiliation(s)
- Frederick L Schuster
- California Department of Health Services, Viral and Rickettsial Disease Laboratory, 850 Marina Bay Parkway, Richmond, CA 94804, USA.
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Vaerewijck MJM, Huys G, Palomino JC, Swings J, Portaels F. Mycobacteria in drinking water distribution systems: ecology and significance for human health. FEMS Microbiol Rev 2005; 29:911-34. [PMID: 16219512 DOI: 10.1016/j.femsre.2005.02.001] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2004] [Revised: 11/29/2004] [Accepted: 02/05/2005] [Indexed: 01/04/2023] Open
Abstract
In contrast to the notorious pathogens Mycobacterium tuberculosis and M. leprae, the majority of the mycobacterial species described to date are generally not considered as obligate human pathogens. The natural reservoirs of these non-primary pathogenic mycobacteria include aquatic and terrestrial environments. Under certain circumstances, e.g., skin lesions, pulmonary or immune dysfunctions and chronic diseases, these environmental mycobacteria (EM) may cause disease. EM such as M. avium, M. kansasii, and M. xenopi have frequently been isolated from drinking water and hospital water distribution systems. Biofilm formation, amoeba-associated lifestyle, and resistance to chlorine have been recognized as important factors that contribute to the survival, colonization and persistence of EM in water distribution systems. Although the presence of EM in tap water has been linked to nosocomial infections and pseudo-infections, it remains unclear if these EM provide a health risk for immunocompromised people, in particular AIDS patients. In this regard, control strategies based on maintenance of an effective disinfectant residual and low concentration of nutrients have been proposed to keep EM numbers to a minimum in water distribution systems.
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Affiliation(s)
- Mario J M Vaerewijck
- Laboratory of Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
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Park M, Yun ST, Kim MS, Chun J, Ahn TI. Phylogenetic characterization of Legionella-like endosymbiotic X-bacteria in Amoeba proteus: a proposal for 'Candidatus Legionella jeonii' sp. nov. Environ Microbiol 2005; 6:1252-63. [PMID: 15560823 DOI: 10.1111/j.1462-2920.2004.00659.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The X-bacteria which initiated organismic association with the D strain of Amoeba proteus in 1966 as parasites have changed to obligate endosymbionts on which the host depends for survival. Owing to the difficulty in cultivating the bacteria in vitro, the identity of X-bacteria has not been determined. As the life cycle of X-bacteria is similar to that of Legionella spp. in soil amoebae, we applied the polymerase chain reaction method with specific primers aimed at Legionella spp. for the detection and cloning of 16S rRNA gene. The identity and intracellular localization of the endosymbiont were confirmed by the application of a specific fluorescently labelled 16S rRNA-targeted probe. In addition we cloned RNA polymerase beta-subunit gene (rpoB) of X-bacteria by genomic library tagging. A phylogenetic analysis of the 16S rRNA gene placed the bacterium within a unique monophyletic group containing all other members of the genus Legionella. Phylogeny from rpoB and mip genes further confirmed the taxonomic context of X-bacteria to be a Legionella sp. In all three phylogenic analyses, X-bacterium was placed apart from Legionella-like amoebal pathogens present in soil amoebae. Thus, we propose the name 'Candidatus Legionella jeonii' sp. nov. for the endosymbiotic X-bacteria in Amoeba proteus.
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MESH Headings
- Amino Acid Sequence
- Amoeba/microbiology
- Animals
- Bacterial Proteins/genetics
- DNA, Bacterial/chemistry
- DNA, Bacterial/isolation & purification
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- DNA, Ribosomal/isolation & purification
- DNA-Directed RNA Polymerases/genetics
- Genes, rRNA
- Immunophilins/genetics
- In Situ Hybridization, Fluorescence
- Legionella/classification
- Legionella/genetics
- Legionella/isolation & purification
- Membrane Proteins/genetics
- Molecular Sequence Data
- Peptidylprolyl Isomerase/genetics
- Phylogeny
- RNA, Bacterial/genetics
- RNA, Ribosomal, 16S/genetics
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Symbiosis
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Affiliation(s)
- Miey Park
- School of Biological Sciences, Seoul National University, Seoul 151-742, Korea
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Schuster FL, Visvesvara GS. Free-living amoebae as opportunistic and non-opportunistic pathogens of humans and animals. Int J Parasitol 2004; 34:1001-27. [PMID: 15313128 DOI: 10.1016/j.ijpara.2004.06.004] [Citation(s) in RCA: 490] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2004] [Revised: 05/31/2004] [Accepted: 06/01/2004] [Indexed: 10/26/2022]
Abstract
Knowledge that free-living amoebae are capable of causing human disease dates back some 50 years, prior to which time they were regarded as harmless soil organisms or, at most, commensals of mammals. First Naegleria fowleri, then Acanthamoeba spp. and Balamuthia mandrillaris, and finally Sappinia diploidea have been recognised as etiologic agents of encephalitis; Acanthamoeba spp. are also responsible for amoebic keratitis. Some of the infections are opportunistic, occurring mainly in immunocompromised hosts (Acanthamoeba and Balamuthia encephalitides), while others are non-opportunistic (Acanthamoeba keratitis, Naegleria meningoencephalitis, and cases of Balamuthia encephalitis occurring in immunocompetent humans). The amoebae have a cosmopolitan distribution in soil and water, providing multiple opportunities for contacts with humans and animals, as evidenced by antibody titers in surveyed human populations. Although, the numbers of infections caused by these amoebae are low in comparison to other protozoal parasitoses (trypanosomiasis, toxoplasmosis, malaria, etc.), the difficulty in diagnosing them, the challenge of finding optimal antimicrobial treatments and the morbidity and relatively high mortality associated with, in particular, the encephalitides have been a cause for concern for clinical and laboratory personnel and parasitologists. This review presents information about the individual amoebae: their morphologies and life-cycles, laboratory cultivation, ecology, epidemiology, nature of the infections and appropriate antimicrobial therapies, the immune response, and molecular diagnostic procedures that have been developed for identification of the amoebae in the environment and in clinical specimens.
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Affiliation(s)
- Frederick L Schuster
- Viral and Rickettsial Disease Laboratory, California Department Health Services, 850 Marina Bay Parkway, Richmond, CA 94804, USA.
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Yli-Pirilä T, Kusnetsov J, Haatainen S, Hänninen M, Jalava P, Reiman M, Seuri M, Hirvonen MR, Nevalainen A. Amoebae and other protozoa in material samples from moisture-damaged buildings. ENVIRONMENTAL RESEARCH 2004; 96:250-256. [PMID: 15364591 DOI: 10.1016/j.envres.2003.12.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2003] [Accepted: 12/09/2003] [Indexed: 05/24/2023]
Abstract
Mold growth in buildings has been shown to be associated with adverse health effects. The fungal and bacterial growth on moistened building materials has been studied, but little attention has been paid to the other organisms spawning in the damaged materials. We examined moist building materials for protozoa, concentrating on amoebae. Material samples (n = 124) from moisture-damaged buildings were analyzed for amoebae, fungi, and bacteria. Amoebae were detected in 22% of the samples, and they were found to favor cooccurrence with bacteria and the fungi Acremonium spp., Aspergillus versicolor, Chaetomium spp., and Trichoderma spp. In addition, 11 seriously damaged samples were screened for other protozoa. Ciliates and flagellates were found in almost every sample analyzed. Amoebae are known to host pathogenic bacteria, such as chlamydiae, legionellae, and mycobacteria and they may have a role in the complex of exposure that contributes to the health effects associated with moisture damage in buildings.
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Affiliation(s)
- Terhi Yli-Pirilä
- Department of Environmental Health, National Public Health Institute, PO Box 95, FIN-70701 Kuopio, Finland.
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Affiliation(s)
- Jacqueline Dawn Parry
- Department of Biological Sciences, The Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom
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Abstract
Acanthamoeba spp. are free-living amebae that inhabit a variety of air, soil, and water environments. However, these amebae can also act as opportunistic as well as nonopportunistic pathogens. They are the causative agents of granulomatous amebic encephalitis and amebic keratitis and have been associated with cutaneous lesions and sinusitis. Immuno compromised individuals, including AIDS patients, are particularly susceptible to infections with Acanthamoeba. The immune defense mechanisms that operate against Acanthamoeba have not been well characterized, but it has been proposed that both innate and acquired immunity play a role. The ameba's life cycle includes an active feeding trophozoite stage and a dormant cyst stage. Trophozoites feed on bacteria, yeast, and algae. However, both trophozoites and cysts can retain viable bacteria and may serve as reservoirs for bacteria with human pathogenic potential. Diagnosis of infection includes direct microscopy of wet mounts of cerebrospinal fluid or stained smears of cerebrospinal fluid sediment, light or electron microscopy of tissues, in vitro cultivation of Acanthamoeba, and histological assessment of frozen or paraffin-embedded sections of brain or cutaneous lesion biopsy material. Immunocytochemistry, chemifluorescent dye staining, PCR, and analysis of DNA sequence variation also have been employed for laboratory diagnosis. Treatment of Acanthamoeba infections has met with mixed results. However, chlorhexidine gluconate, alone or in combination with propamidene isethionate, is effective in some patients. Furthermore, effective treatment is complicated since patients may present with underlying disease and Acanthamoeba infection may not be recognized. Since an increase in the number of cases of Acanthamoeba infections has occurred worldwide, these protozoa have become increasingly important as agents of human disease.
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Affiliation(s)
- Francine Marciano-Cabral
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia 23298-0678, USA.
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Abstract
The molecular aetiology of familial susceptibility to disseminated mycobacterial disease, usually involving weakly pathogenic strains of mycobacteria, has now been elucidated in more than 30 families. Mutations have been identified in five genes in the interleukin-12-dependent interferon-gamma pathway, highlighting the importance of this pathway in human mycobacterial immunity. Knowledge derived from the study of these rare patients contributes to our understanding of the immune response to common mycobacterial pathogens such as Mycobacterium tuberculosis and Mycobacterium leprae, which remain major public health problems globally. This knowledge can be applied to the rational development of novel therapies and vaccines for these important mycobacterial diseases.
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Affiliation(s)
- Melanie Newport
- Cambridge Institute for Medical Research, Addenbrookes Hospital, Hills Road, Cambridge, CB2 2XY, UK.
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Muder RR, Yu VL. Infection due to Legionella species other than L. pneumophila. Clin Infect Dis 2002; 35:990-8. [PMID: 12355387 DOI: 10.1086/342884] [Citation(s) in RCA: 204] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2002] [Revised: 06/03/2002] [Indexed: 11/03/2022] Open
Abstract
In addition to Legionella pneumophila, 19 Legionella species have been documented as human pathogens on the basis of their isolation from clinical material. Like L. pneumophila, other Legionella species are inhabitants of natural and man-made aqueous environments. The major clinical manifestation of infection due to Legionella species is pneumonia, although nonpneumonic legionellosis (Pontiac fever) and extrapulmonary infection may occur. The majority of confirmed infections involving non-pneumophila Legionella species have occurred in immunosuppressed patients. Definitive diagnosis requires culture on selective media. Fluoroquinolones and newer macrolides are effective therapy. A number of nosocomial cases have occurred in association with colonization of hospital water systems; elimination of Legionella species from such systems prevents their transmission to susceptible patients. It is likely that many cases of both community-acquired and nosocomial Legionella infection remain undiagnosed. Application of appropriate culture methodology to the etiologic diagnosis of pneumonia is needed to further define the role of these organisms in disease in humans.
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Affiliation(s)
- Robert R Muder
- Infectious Diseases Section, VA Pittsburgh Healthcare System and University of Pittsburgh School of Medicine, Pittsburgh, PA 15240 , USA.
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Newsome AL, Farone MB, Berk SG, Gunderson JH. Free living amoebae as opportunistic hosts for intracellular bacterial parasites. J Eukaryot Microbiol 2002; Suppl:13S-14S. [PMID: 11906030 DOI: 10.1111/j.1550-7408.2001.tb00436.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A L Newsome
- Middle Tennessee State University, Murfreesboro, USA.
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Vernhes MC, Benichou A, Pernin P, Cabanes PA, Teissié J. Elimination of free-living amoebae in fresh water with pulsed electric fields. WATER RESEARCH 2002; 36:3429-3438. [PMID: 12230188 DOI: 10.1016/s0043-1354(02)00065-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This study investigates the effects of pulsed electric fields on the inactivation of trophozoite form of Naegleria lovaniensis Ar9M-1 in batch and flow processes, systematically examining the lethal effect of field strength, pulse duration, number of pulses, and pulse frequency. Our results show that amoebae eradication is modulated by pulse parameters, composition of the pulsing medium, and physiological state of the cells. Cell survival is not related to the energy delivered to the cell suspension during the electrical treatment. For a given energy a strong field applied for a short cumulative pulse duration affects viability more than a weak field with a long cumulative pulsation. We also determine the optimal electrical conditions to obtain an inactivation rate higher than 95% while using the least energy. Flow processes allow to treat large-scale volumes. Our results show that the most efficient flow process for amoeba eradication requires a field parallel to the flow. Pulsed electric fields are a new and attractive method for inactivating amoebae in large volumes of fresh water.
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Affiliation(s)
- M C Vernhes
- Institut de Pharmacologic et de Biologie Structurale, CNRS UMR 5089, Toulouse, France
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40
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Abstract
Free-living amebas are widely distributed in soil and water, particularly members of the genera Acanthamoeba and NAEGLERIA: Since the early 1960s, they have been recognized as opportunistic human pathogens, capable of causing infections of the central nervous system (CNS) in both immunocompetent and immunocompromised hosts. Naegleria is the causal agent of a fulminant CNS condition, primary amebic meningoencephalitis; Acanthamoeba is responsible for a more chronic and insidious infection of the CNS termed granulomatous amebic encephalitis, as well as amebic keratitis. Balamuthia sp. has been recognized in the past decade as another ameba implicated in CNS infections. Cultivation of these organisms in vitro provides the basis for a better understanding of the biology of these amebas, as well as an important means of isolating and identifying them from clinical samples. Naegleria and Acanthamoeba can be cultured axenically in cell-free media or on tissue culture cells as feeder layers and in cultures with bacteria as a food source. Balamuthia, which has yet to be isolated from the environment, will not grow on bacteria. Instead, it requires tissue culture cells as feeder layers or an enriched cell-free medium. The recent identification of another ameba, Sappinia diploidea, suggests that other free-living forms may also be involved as causal agents of human infections.
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Affiliation(s)
- Frederick L Schuster
- Viral and Rickettsial Disease Laboratory, State of California Department of Health Services, Richmond, California 94804, USA.
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Aksozek A, McClellan K, Howard K, Niederkorn JY, Alizadeh H. Resistance of Acanthamoeba castellanii cysts to physical, chemical, and radiological conditions. J Parasitol 2002; 88:621-3. [PMID: 12099437 DOI: 10.1645/0022-3395(2002)088[0621:roacct]2.0.co;2] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Resistance of Acanthamoeba castellanii cysts to disinfection agents, antimicrobial agents, heat, freeze-thawing, ultraviolet radiation (UV), gamma irradiation, and cellulase were evaluated in vitro. Following exposure to different agents, the cysts were removed and cultured for A. castellanii trophozoites for 3-14 days. Solutions containing 20% isopropyl alcohol or 10% formalin effectively killed A. castellanii cysts. Hydrogen peroxide (3%, AOSept Disinfectant) effectively killed A. castellanii cysts after 4 hr of exposure. Polyhexamethylene biguanide (0.02%), clotrimazole (0.1%), or propamidine isethionate (Brolene) were effective in killing A. castellanii cysts in vitro. Acanthamoeba castellanii cysts were resistant to both 250 K rads of gamma irradiation and 800 mJ/cm2 of UV irradiation. Excystment of trophozoites was accelerated after exposure to 10, 100, and, 1,000 units of cellulase. These results suggest that A. castellanii cysts benefit by enhanced survival because of their resistance to very harsh environmental conditions.
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Affiliation(s)
- A Aksozek
- Department of Microbiology and Clinical Microbiology, Istanbul Faculty of Medicine, University of Istanbul, Capa, Turkey
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Murga R, Forster TS, Brown E, Pruckler JM, Fields BS, Donlan RM. Role of biofilms in the survival of Legionella pneumophila in a model potable-water system. MICROBIOLOGY (READING, ENGLAND) 2001; 147:3121-6. [PMID: 11700362 DOI: 10.1099/00221287-147-11-3121] [Citation(s) in RCA: 219] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Legionellae can infect and multiply intracellularly in both human phagocytic cells and protozoa. Growth of legionellae in the absence of protozoa has been documented only on complex laboratory media. The hypothesis upon which this study was based was that biofilm matrices, known to provide a habitat and a gradient of nutrients, might allow the survival and multiplication of legionellae outside a host cell. This study determined whether Legionella pneumophila can colonize and grow in biofilms with and without an association with Hartmannella vermiformis. The laboratory model used a rotating disc reactor at a retention time of 6.7 h to grow biofilms on stainless steel coupons. The biofilm was composed of Pseudomonas aeruginosa, Klebsiella pneumoniae and a Flavobacterium sp. The levels of L. pneumophila cells present in the biofilm were monitored for 15 d, with and without the presence of H. vermiformis, and it was found that, although unable to replicate in the absence of H. vermiformis, L. pneumophila was able to persist.
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Affiliation(s)
- R Murga
- Epidemiology and Laboratory Branch, Division of Healthcare Quality Promotion, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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Abstract
Freshwater amoebae are ubiquitous. Some species can cause infections in humans while others can ingest and protect opportunistic bacteria. Although the presence of free-living amoebae in various water sources has been reported, few studies have looked at their concentration, which may be clinically relevant, especially if they are present in healthcare devices. A simple technique was used to detect, observe, and evaluate the concentration of free-living amoebae in dental unit and tap water samples. Fifty-three water samples were collected from 35 dental units (air/water syringes) and 18 water taps. The technique was based on the ability of waterborne bacteria to create a biofilm and serve as substratum for the development of amoebae naturally present in the water samples. Laboratory-grown freshwater biofilms support the proliferation of a wide variety of free-living amoebae. All the dental unit water samples tested contained amoebae at concentrations up to 330/mL, or more than 300 times the concentration in tap water from the same source. Hartmanella, Vanella, and Vahlkampfia spp. were the most frequently encountered. Naegleria and Acanthamoeba spp. were also present in 40% of the samples. Four of the samples collected from dental units, but none from water taps, contained amoebae able to proliferate at 44 degrees C. Biofilms that form inside some dental instruments can considerably increase the concentration of free-living amoebae, some of which are potential human pathogens.
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Affiliation(s)
- J Barbeau
- Department de stomatologie, Faculté de médecine dentaire, Université de Montreal, Quebec, Canada.
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Chappell CL, Wright JA, Coletta M, Newsome AL. Standardized method of measuring acanthamoeba antibodies in sera from healthy human subjects. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2001; 8:724-30. [PMID: 11427418 PMCID: PMC96134 DOI: 10.1128/cdli.8.4.724-730.2001] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acanthamoeba species can cause serious, debilitating, and sometimes life-threatening infections. Three groups have been identified using morphological and immunological comparisons. Previous serological studies have utilized a variety of antigen preparations and assay methods and reported disparate (3 to 100%) results. This study was designed to (i) optimize an enzyme-linked immunosorbent assay for detecting serum antibodies to each of the Acanthamoeba serogroups and (ii) test 55 healthy individuals for specific immunoglobulin G reactivity. The highest signal-to-background ratio was found when 3,000 fixed, intact trophozoites per well were used with a 1:10 serum dilution. Sera yielding optical densities of <0.25 against all three Acanthamoeba serogroups were used to define the cutoff for positive results. The highest background reactivity with these sera was seen with Acanthamoeba polyphaga (serogroup 2), followed by Acanthamoeba culbertsoni (serogroup 3) and Acanthamoeba astronyxis (serogroup 1). Of 55 subjects tested, the highest number of positive results was seen with A. polyphaga (81.8%), followed by A. astronyxis (52.8%) and A. culbertsoni (40%). Seven serum samples (12.7%) were negative for all three Acanthamoeba serogroups, 16 (29.1%) were positive for one serogroup only, 16 were positive for two serogroups, and 16 reacted to all three serogroups. Further analysis showed no significant associations between serogroup reactivity and age or gender. However, some ethnic differences were noted, especially with A. polyphaga antigens. In that case, serum samples from Hispanic subjects were 14.5 times less likely to be positive (P = 0.0025) and had lower mean absorbance values (P = 0.047) than those from Caucasian subjects. Overall, these data suggest that Acanthamoeba colonization or infection is more common than previously thought. Mild or asymptomatic infections may contribute to the observed serum reactivities.
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Affiliation(s)
- C L Chappell
- Center for Infectious Diseases, School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas, USA.
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Fritsche TR, Horn M, Wagner M, Herwig RP, Schleifer KH, Gautom RK. Phylogenetic diversity among geographically dispersed Chlamydiales endosymbionts recovered from clinical and environmental isolates of Acanthamoeba spp. Appl Environ Microbiol 2000; 66:2613-9. [PMID: 10831445 PMCID: PMC110588 DOI: 10.1128/aem.66.6.2613-2619.2000] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The recently proposed reorganization of the order Chlamydiales and description of new taxa are broadening our perception of this once narrowly defined taxon. We have recovered four strains of gram-negative cocci endosymbiotic in Acanthamoeba spp., representing 5% of the Acanthamoeba sp. isolates examined, which displayed developmental life cycles typical of members of the Chlamydiales. One of these endosymbiont strains was found stably infecting an amoebic isolate recovered from a case of amoebic keratitis in North America, with three others found in acanthamoebae recovered from environmental sources in North America (two isolates) and Europe (one isolate). Analyses of nearly full-length 16S rRNA gene sequences of these isolates by neighbor joining, parsimony, and distance matrix methods revealed their clustering with other members of the Chlamydiales but in a lineage separate from those of the genera Chlamydia, Chlamydophila, Simkania, and Waddlia (sequence similarities, <88%) and including the recently described species Parachlamydia acanthamoebae (sequence similarities, 91.2 to 93.1%). With sequence similarities to each other of 91.4 to 99.4%, these four isolates of intra-amoebal endosymbionts may represent three distinct species and, perhaps, new genera within the recently proposed family Parachlamydiaceae. Fluorescently labeled oligonucleotide probes targeted to 16S rRNA signature regions were able to readily differentiate two groups of intra-amoebal endosymbionts which corresponded to two phylogenetic lineages. These results reveal significant phylogenetic diversity occurring among the Chlamydiales in nontraditional host species and supports the existence of a large environmental reservoir of related species. Considering that all described species of Chlamydiales are known to be pathogenic, further investigation of intra-amoebal parachlamydiae as disease-producing agents is warranted.
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Affiliation(s)
- T R Fritsche
- Department of Laboratory Medicine, University of Washington, Seattle, Washington 98195, USA.
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48
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Desai R, Welsh C, Summy M, Farone M, Newsome AL. The potential of in situ hybridization and an immunogold assay to identify Legionella associations with other microorganisms. J Microbiol Methods 1999; 37:155-64. [PMID: 10445314 DOI: 10.1016/s0167-7012(99)00057-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Based on in vitro studies, bacteria in the genus Legionella are believed to multiply within protozoa such as amoebae in aquatic environments. Current methods used for detection of Legionella species, however, are not designed to show this relationship. Thus the natural intimate association of Legionella with other microorganisms remains to be clearly documented and the extent to which protozoa might be infected with Legionella species remains undefined. In this report we describe methods based on the use of Legionella specific reagents that would prove useful in describing its associations with other microorganisms. An immunogold and in situ hybridization technique have the potential to demonstrate the natural occurrence of Legionella species in free-living amoebae. In preliminary observations, however, bacteria reactive with Legionella specific reagents were often not intimately associated with amoebae. Bacteria occurred as free single cells, as cell aggregates, in proximity to other cells and debris, and only occasionally in close proximity to amoebae. Although some Legionella species replicate within amoebae, these preliminary observations suggest the bacteria may be encountered most frequently as extracellular microorganisms, either free-floating or in association with other structures or microorganisms. The future use of these techniques will aid in the elucidation of any naturally occurring relationships between Legionella species and other microorganisms.
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Affiliation(s)
- R Desai
- Department of Biology, Middle Tennessee State University, Murfreesboro 37132, USA
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49
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Abstract
Studies on Legionella show a continuum from environment to human disease. Legionellosis is caused by Legionella species acquired from environmental sources, principally water sources such as cooling towers, where Legionella grows intracellularly in protozoa within biofilms. Aquatic biofilms, which are widespread not only in nature, but also in medical and dental devices, are ecological niches in which Legionella survives and proliferates and the ultimate sources to which outbreaks of legionellosis can be traced. Invasion and intracellular replication of L. pneumophila within protozoa in the environment play a major role in the transmission of Legionnaires' disease. Protozoa provide the habitats for the environmental survival and reproduction of Legionella species. L. pneumophila proliferates intracellularly in various species of protozoa within vacuoles studded with ribosomes, as it also does within macrophages. Growth within protozoa enhances the environmental survival capability and the pathogenicity (virulence) of Legionella. The growth requirements of Legionella, the ability of Legionella to enter a viable non-culturable state, the association of Legionella with protozoa and the occurrence of Legionella within biofilms complicates the detection of Legionella and epidemiological investigations of legionellosis. Polymerase chain reaction (PCR) methods have been developed for the molecular detection of Legionella and used in environmental and epidemiological studies. Various physical and chemical disinfection methods have been developed to eliminate Legionella from environmental sources, but gaining control of Legionella in environmental waters, where they are protected from disinfection by growing within protozoa and biofilms, remains a challenge, and one that must be overcome in order to eliminate sporadic outbreaks of legionellosis.
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Affiliation(s)
- R M Atlas
- Department of Biology, University of Louisville, KY 40292, USA.
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Ford TE. Microbiological safety of drinking water: United States and global perspectives. ENVIRONMENTAL HEALTH PERSPECTIVES 1999; 107 Suppl 1:191-206. [PMID: 10229718 DOI: 10.2307/3434483] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Waterborne disease statistics only begin to estimate the global burden of infectious diseases from contaminated drinking water. Diarrheal disease is dramatically underreported and etiologies seldom diagnosed. This review examines available data on waterborne disease incidence both in the United States and globally together with its limitations. The waterborne route of transmission is examined for bacterial, protozoal, and viral pathogens that either are frequently associated with drinking water (e.g., Shigella spp.), or for which there is strong evidence implicating the waterborne route of transmission (e.g., Leptospira spp.). In addition, crucial areas of research are discussed, including risks from selection of treatment-resistant pathogens, importance of environmental reservoirs, and new methodologies for pathogen-specific monitoring. To accurately assess risks from waterborne disease, it is necessary to understand pathogen distribution and survival strategies within water distribution systems and to apply methodologies that can detect not only the presence, but also the viability and infectivity of the pathogen.
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Affiliation(s)
- T E Ford
- Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA.
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