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Fatemi M, Niyyati M, Rouhani S, Karamati SA, Mirjalali H, Karanis P. Contamination of fresh vegetables in municipal stores with pathogenic Acanthamoeba genotypes; a public health concern. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2023; 33:1010-1021. [PMID: 35443833 DOI: 10.1080/09603123.2022.2067328] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 04/12/2022] [Indexed: 05/23/2023]
Abstract
Acanthamoeba spp. cause keratitis and encephalitis, and are a proper carrier of foodborne pathogens. A total of 70 samples including garden cress, chives, mint, parsley, and basil were collected. Samples were cultured onto a 2% non-nutrient agar medium. The cultures were analyzed using morphological and molecular techniques. In total, 18 (25.7%) out of 70 samples were positive including garden cress 10/22 (45.45%), chives 3/12 (25%), mint 2/13 (15.38%), basil 2/13 (15.38%), and parsley 1/10 (10%). The diagnostic fragment 3 was successfully sequenced in 15 samples and represented 11 (73.3%) T4, three (20%) T5, and one T9 genotypes. In addition, three, two, and one strains, belonging to the genotypes T4, T5, and T9 were ranked highly pathogenic. This is the first study reporting contamination of the most commonly consumed fresh vegetables with pathogenic Acanthamoeba genotypes. Our findings signify the public health concerns due the contamination of vegetables in municipal public markets.
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Affiliation(s)
- Marziye Fatemi
- Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Medical Parasitology and Mycology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Niyyati
- Department of Medical Parasitology and Mycology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Soheila Rouhani
- Department of Medical Parasitology and Mycology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed Ahmad Karamati
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamed Mirjalali
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Panagiotis Karanis
- University of Cologne, Medical Faculty and University Hospital, Cologne 50931, Germany
- Department of Basic and Clinical Sciences, Nicosia University Medical School, Nicosia, Cyprus
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2
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Soler L, Moreno Y, Moreno-Mesonero L, Amorós I, Alonso JL, Ferrús MA. Microbiome of Free-Living Amoebae (FLA) Isolated from Fresh Organic Produce: Potential Risk to Consumers? Foods 2023; 12:3102. [PMID: 37628102 PMCID: PMC10453443 DOI: 10.3390/foods12163102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/11/2023] [Accepted: 08/13/2023] [Indexed: 08/27/2023] Open
Abstract
In response to growing global interest in organic agriculture, this study delves into the microbial landscape of organically grown raw produce with a focus on food safety. Vegetables that are consumed raw are potential vehicles for the transmission of any type of microorganism capable of causing human disease. Free-living amoebae (FLA) are ubiquitous protozoa found in many ecosystems and can serve as hosts to pathogenic bacteria. So far, data regarding the FLA bacterial microbiome in fresh produce remain scarce and are non-existent for those of organic origin. Thus, the aim of this preliminary work is to characterize the microbiome of FLA in commonly consumed raw vegetables to know their possible implications for consumers. A total of 40 organic cabbage, lettuce, spinach, and strawberry samples were analyzed. FLA were found in all samples, and their bacterial microbiome was obtained via amplicon sequencing using the Illumina MiSeq platform and pair-end protocol. Acanthamoeba spp. and Vermamoeba vermiformis were identified via qPCR in 65.0% and 25.0% of the samples, respectively. Regarding the bacterial microbiome of FLA, the most abundant genera were Pseudomonas (1.8-17.8%) and Flavobacterium (1.7-12.6%). Bacteria not previously related to FLA, such as Prosthecobacter or Cellvibrio, are described in this work. Importantly, several bacterial genera found within the FLA microbiome were identified as potential human pathogens, including Pseudomonas, Flavobacterium, Arcobacter, Klebsiella, Mycobacterium, Salmonella and Legionella. This is the first work in which FLA microbiome isolated from organic products has been characterized, underscoring the significance of understanding FLA's role as carriers of pathogenic bacteria in the context of organic food safety.
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Affiliation(s)
- Lara Soler
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain; (L.S.); (L.M.-M.); (I.A.); (J.L.A.)
| | - Yolanda Moreno
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain; (L.S.); (L.M.-M.); (I.A.); (J.L.A.)
| | - Laura Moreno-Mesonero
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain; (L.S.); (L.M.-M.); (I.A.); (J.L.A.)
- Biotechnology Department, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain;
| | - Inmaculada Amorós
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain; (L.S.); (L.M.-M.); (I.A.); (J.L.A.)
| | - José Luís Alonso
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain; (L.S.); (L.M.-M.); (I.A.); (J.L.A.)
| | - María Antonia Ferrús
- Biotechnology Department, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain;
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3
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Soler L, Moreno Y, Moreno-Mesonero L, Amorós I, Alonso JL, Ferrús MA. Microbiome of Free-Living Amoebae (FLA) Isolated from Fresh Organic Produce: Potential Risk to Consumers? Foods 2023; 12:3102. [DOI: https:/doi.org/10.3390/foods12163102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023] Open
Abstract
In response to growing global interest in organic agriculture, this study delves into the microbial landscape of organically grown raw produce with a focus on food safety. Vegetables that are consumed raw are potential vehicles for the transmission of any type of microorganism capable of causing human disease. Free-living amoebae (FLA) are ubiquitous protozoa found in many ecosystems and can serve as hosts to pathogenic bacteria. So far, data regarding the FLA bacterial microbiome in fresh produce remain scarce and are non-existent for those of organic origin. Thus, the aim of this preliminary work is to characterize the microbiome of FLA in commonly consumed raw vegetables to know their possible implications for consumers. A total of 40 organic cabbage, lettuce, spinach, and strawberry samples were analyzed. FLA were found in all samples, and their bacterial microbiome was obtained via amplicon sequencing using the Illumina MiSeq platform and pair-end protocol. Acanthamoeba spp. and Vermamoeba vermiformis were identified via qPCR in 65.0% and 25.0% of the samples, respectively. Regarding the bacterial microbiome of FLA, the most abundant genera were Pseudomonas (1.8–17.8%) and Flavobacterium (1.7–12.6%). Bacteria not previously related to FLA, such as Prosthecobacter or Cellvibrio, are described in this work. Importantly, several bacterial genera found within the FLA microbiome were identified as potential human pathogens, including Pseudomonas, Flavobacterium, Arcobacter, Klebsiella, Mycobacterium, Salmonella and Legionella. This is the first work in which FLA microbiome isolated from organic products has been characterized, underscoring the significance of understanding FLA’s role as carriers of pathogenic bacteria in the context of organic food safety.
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Affiliation(s)
- Lara Soler
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain
| | - Yolanda Moreno
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain
| | - Laura Moreno-Mesonero
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain
- Biotechnology Department, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain
| | - Inmaculada Amorós
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain
| | - José Luís Alonso
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain
| | - María Antonia Ferrús
- Biotechnology Department, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain
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4
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Mai Y, Zheng J, Zeng J, Wang Z, Liu F, Ma L, Zhou M, Zhao S, Wu B, Wang C, Yan Q, He Z, Shu L. Protozoa as Hotspots for Potential Pathogens in the Drinking Water of a Subtropical Megacity: Diversity, Treatment, and Health Risk. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:6108-6118. [PMID: 37026396 DOI: 10.1021/acs.est.2c09139] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Drinking water systems host a wide range of microorganisms essential for biosafety. However, one major group of waterborne pathogens, protozoa, is relatively neglected compared to bacteria and other microorganisms. Until now, little is known about the growth and fate of protozoa and their associated bacteria in drinking water systems. In this study, we aim to investigate how drinking water treatment affects the growth and fate of protozoa and their associated bacteria in a subtropical megacity. The results showed that viable protozoa were prevalent in the city's tap water, and amoebae were the major component of tap water protozoa. In addition, protozoan-associated bacteria contained many potential pathogens and were primarily enriched in amoeba hosts. Furthermore, this study showed that current drinking water disinfection methods have little effect on protozoa and their associated bacteria. Besides, ultrafiltration membranes unexpectedly served as an ideal growth surface for amoebae in drinking water systems, and they could significantly promote the growth of amoeba-associated bacteria. In conclusion, this study shows that viable protozoa and their associated bacteria are prevalent in tap water, which may present an emerging health risk in drinking water biosafety.
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Affiliation(s)
- Yingwen Mai
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Jianyi Zheng
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Jiaxiong Zeng
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Zihe Wang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Fei Liu
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Lu Ma
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Min Zhou
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Shanshan Zhao
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Bo Wu
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Cheng Wang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Qingyun Yan
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Zhili He
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
| | - Longfei Shu
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510006, China
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5
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Jackson KK, Mata C, Marcus RK. A rapid capillary-channeled polymer (C-CP) fiber spin-down tip approach for the isolation of plant-derived extracellular vesicles (PDEVs) from 20 common fruit and vegetable sources. Talanta 2023; 252:123779. [DOI: 10.1016/j.talanta.2022.123779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/18/2022] [Accepted: 07/24/2022] [Indexed: 10/15/2022]
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6
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Bashir I, War AF, Rafiq I, Reshi ZA, Rashid I, Shouche YS. Phyllosphere microbiome: Diversity and functions. Microbiol Res 2021; 254:126888. [PMID: 34700185 DOI: 10.1016/j.micres.2021.126888] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/15/2021] [Accepted: 09/30/2021] [Indexed: 12/28/2022]
Abstract
Phyllosphere or aerial surface of plants represents the globally largest and peculiar microbial habitat that inhabits diverse and rich communities of bacteria, fungi, viruses, cyanobacteria, actinobacteria, nematodes, and protozoans. These hyperdiverse microbial communities are related to the host's specific functional traits and influence the host's physiology and the ecosystem's functioning. In the last few years, significant advances have been made in unravelling several aspects of phyllosphere microbiology, including diversity and microbial community composition, dynamics, and functional interactions. This review highlights the current knowledge about the assembly, structure, and composition of phyllosphere microbial communities across spatio-temporal scales, besides functional significance of different microbial communities to the plant host and the surrounding environment. The knowledge will help develop strategies for modelling and manipulating these highly beneficial microbial consortia for furthering scientific inquiry into their interactions with the host plants and also for their useful and economic utilization.
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Affiliation(s)
- Iqra Bashir
- Department of Botany, University of Kashmir, Srinagar, 190006, Jammu and Kashmir, India.
| | - Aadil Farooq War
- Department of Botany, University of Kashmir, Srinagar, 190006, Jammu and Kashmir, India
| | - Iflah Rafiq
- Department of Botany, University of Kashmir, Srinagar, 190006, Jammu and Kashmir, India
| | - Zafar A Reshi
- Department of Botany, University of Kashmir, Srinagar, 190006, Jammu and Kashmir, India
| | - Irfan Rashid
- Department of Botany, University of Kashmir, Srinagar, 190006, Jammu and Kashmir, India
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7
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Cappable-Seq Reveals Specific Patterns of Metabolism and Virulence for Salmonella Typhimurium Intracellular Survival within Acanthamoeba castellanii. Int J Mol Sci 2021; 22:ijms22169077. [PMID: 34445780 PMCID: PMC8396566 DOI: 10.3390/ijms22169077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 01/21/2023] Open
Abstract
The bacterial pathogen Salmonella enterica, which causes enteritis, has a broad host range and extensive environmental longevity. In water and soil, Salmonella interacts with protozoa and multiplies inside their phagosomes. Although this relationship resembles that between Salmonella and mammalian phagocytes, the interaction mechanisms and bacterial genes involved are unclear. Here, we characterized global gene expression patterns of S. enterica serovar Typhimurium within Acanthamoeba castellanii at the early stage of infection by Cappable-Seq. Gene expression features of S. Typhimurium within A. castellanii were presented with downregulation of glycolysis-related, and upregulation of glyoxylate cycle-related genes. Expression of Salmonella Pathogenicity Island-1 (SPI-1), chemotaxis system, and flagellar apparatus genes was upregulated. Furthermore, expression of genes mediating oxidative stress response and iron uptake was upregulated within A. castellanii as well as within mammalian phagocytes. Hence, global S. Typhimurium gene expression patterns within A. castellanii help better understand the molecular mechanisms of Salmonella adaptation to an amoeba cell and intracellular persistence in protozoa inhabiting water and soil ecosystems.
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Liao J, Li J, Han Z, Lyu G, Ibekwe AM, Ma J. Persistence of Salmonella Typhimurium in apple-pear (Pyrus bretschneideri Rehd.) orchard soils influenced by bacterial communities and soil properties. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 768:144458. [PMID: 33444864 DOI: 10.1016/j.scitotenv.2020.144458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/30/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
2In this study, we investigated the persistence of Salmonella Typhimurium in 26 soil samples from apple-pear orchards in Yanji, Longjing and Helong in northeastern China. The time to reach detection limit (ttds) of Salmonella Typhimurium in soils varied from 20 to 120 days. Redundancy analysis and variation partition analysis elucidated that bacterial communities, clay content, pH, electrical conductivity (EC) salinity, and NO3--N could explain more than 85% of overall variation of the persistence behaviors. Results of structural equation models and Mantel tests revealed that clay content and EC displayed both direct and indirect effect on ttds, while NO3--N and pH exhibited direct and indirect effect on the survival patterns, respectively. Furthermore, Actinobacteria, Acidobacteria and Deltaproteobacteria at class level showed highly close correlations with ttds. Our results revealed that certain biotic and abiotic factors could greatly contribute to the overall persistence of Salmonella in apple-pear orchard soils.
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Affiliation(s)
- Jiafen Liao
- Key Laboratory of Ground Water Resource and Environment, Ministry of Education, Jilin University, Changchun 130021, China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun 130021, China
| | - Jiahang Li
- Key Laboratory of Ground Water Resource and Environment, Ministry of Education, Jilin University, Changchun 130021, China
| | - Ziming Han
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Guangze Lyu
- Key Laboratory of Ground Water Resource and Environment, Ministry of Education, Jilin University, Changchun 130021, China
| | - A Mark Ibekwe
- USDA-ARS, U.S. Salinity Laboratory, Riverside, CA 92507, USA
| | - Jincai Ma
- Key Laboratory of Ground Water Resource and Environment, Ministry of Education, Jilin University, Changchun 130021, China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun 130021, China.
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George AS, Rehfuss MYM, Parker CT, Brandl MT. The transcriptome of Escherichia coli O157: H7 reveals a role for oxidative stress resistance in its survival from predation by Tetrahymena. FEMS Microbiol Ecol 2020; 96:5721237. [PMID: 32009174 DOI: 10.1093/femsec/fiaa014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/28/2020] [Indexed: 11/14/2022] Open
Abstract
Pathogenic E. coli remains undigested upon phagocytosis by Tetrahymena and is egested from the ciliate as viable cells in its fecal pellets. Factors that are involved in the survival of Shiga toxin-producing E. coli serovar O157: H7 (EcO157) from digestion by Tetrahymena were identified by microarray analysis of its transcriptome in the protozoan phagosome. Numerous genes belonging to anaerobic metabolism and various stress responses were upregulated significantly ≥ 2-fold in EcO157 cells in the food vacuoles compared with in planktonic cells that remained uningested by the protist. Among these were the oxidative stress response genes, ahpF and katG. Fluorescence microscopy and staining with CellROX® Orange confirmed the presence of reactive oxygen species in food vacuoles containing EcO157 cells. Frequency distribution analysis of the percentage of EcO157 viable cells in Tetrahymena fecal pellets revealed that the ΔahpCF and ΔahpCFΔkatG mutants were less fit than the wild type strain and ΔkatG mutant after passage through the protist. Given the broad use of oxidants as sanitizers in the food industry, our observation of the oxidative stress response in EcO157 during its interaction with Tetrahymena emphasizes the importance of furthering our knowledge of the physiology of this human pathogen in environments relevant to its ecology and to food safety.
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Affiliation(s)
- Andree Sherlon George
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Marc Yi Ming Rehfuss
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Craig Thomas Parker
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Maria Theresa Brandl
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
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10
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Donoso A, Paredes N, Retamal P. Detection of Antimicrobial Resistant Salmonella enterica Strains in Larval and Adult Forms of Lesser Mealworm ( Alphitobius diaperinus) From Industrial Poultry Farms. Front Vet Sci 2020; 7:577848. [PMID: 33195584 PMCID: PMC7581672 DOI: 10.3389/fvets.2020.577848] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/01/2020] [Indexed: 11/13/2022] Open
Abstract
The lesser mealworms (Alphitobius diaperinus) constitute a common cosmopolitan pest in poultry flocks and may colonize the litter in adult and larval forms. Previous studies have documented their potential as carriers of enteric pathogens. In this context, S. enterica constitutes a prioritized zoonotic agent in the poultry industry due to the sanitary risks and economic losses associated with its presence. The aim of this study is to describe the presence of S. enterica strains in larval and adult forms of A. diaperinus collected from poultry litter belonging to industrial farms located in the central zone of Chile. A total of 403 specimens (203 adults and 200 larvae) were sampled from three farms and 25 flocks. For bacteriological isolation, beetles were processed to differentiate external and internal contamination. Then, isolates were serotyped according to the Kauffman-White scheme and antimicrobial resistance phenotypes were determined using the disk diffusion method. Gene sequences from the megaplasmid pESI were identified through a PCR based test. These procedures led to the detection of 15 S. enterica isolates, belonging to serotypes Infantis (14) and Livingstone (1), from both adults (6) and larval (9) specimens, with a similar external (7) and internal (8) distribution. Furthermore, all S. Infantis isolates showed antimicrobial resistance and evidence of megaplasmid pESI carriage, with all possessing multidrug-resistant phenotypes. Our results confirm that A. diaperinus constitutes a potential reservoir of zoonotic Salmonella strains of sanitary and economic concern for the industry and for public health.
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Affiliation(s)
- Alvaro Donoso
- Laboratorio de Enfermedades Infecciosas, Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
| | - Natalia Paredes
- Laboratorio de Enfermedades Infecciosas, Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
| | - Patricio Retamal
- Laboratorio de Enfermedades Infecciosas, Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
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Evidence that Bacteria Packaging by Tetrahymena Is a Widespread Phenomenon. Microorganisms 2020; 8:microorganisms8101548. [PMID: 33036410 PMCID: PMC7601845 DOI: 10.3390/microorganisms8101548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 10/03/2020] [Accepted: 10/04/2020] [Indexed: 11/17/2022] Open
Abstract
Protozoa are natural predators of bacteria, but some bacteria can evade digestion once phagocytosed. Some of these resistant bacteria can be packaged in the fecal pellets produced by protozoa, protecting them from physical stresses and biocides. Depending on the bacteria and protozoa involved in the packaging process, pellets can have different morphologies. In the present descriptive study, we evaluated the packaging process with 20 bacteria that have never been tested before for packaging by ciliates. These bacteria have various characteristics (shape, size, Gram staining). All of them appear to be included in pellets produced by the ciliates Tetrahymena pyriformis and/or T. thermophila in at least one condition tested. We then focused on the packaging morphology of four of these bacteria. Our results demonstrated that, as shown previously for Mycobacterium smegmatis, the packaging of Microbacterium oxydans, Micrococcus luteus, and Cupriavidus sp. was formed of a single layer of material. The packaging of Cellulosimicrobiumfunkei was made of indistinguishable material. A different pellet morphology was obtained for each of the four bacterial strains studied. The ingestion of small bacteria resulted in rounder, denser, and more regular pellets. These results support the idea that bacteria packaging is a relatively widespread phenomenon.
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12
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Meinersmann RJ, Berrang ME, Rigsby LL. Recoverability of
Listeria monocytogenes
after coculture with
Tetrahymena pyriformis
. J Food Saf 2020. [DOI: 10.1111/jfs.12778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Richard J. Meinersmann
- USDA Agricultural Research ServiceBacterial Epidemiology and Antimicrobial Resistance Research Unit Athens Georgia
| | - Mark E. Berrang
- USDA Agricultural Research ServiceBacterial Epidemiology and Antimicrobial Resistance Research Unit Athens Georgia
| | - Luanne L. Rigsby
- USDA Agricultural Research ServiceBacterial Epidemiology and Antimicrobial Resistance Research Unit Athens Georgia
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Moreno-Mesonero L, Hortelano I, Moreno Y, Ferrús MA. Evidence of viable Helicobacter pylori and other bacteria of public health interest associated with free-living amoebae in lettuce samples by next generation sequencing and other molecular techniques. Int J Food Microbiol 2020; 318:108477. [PMID: 31855786 DOI: 10.1016/j.ijfoodmicro.2019.108477] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/04/2019] [Accepted: 12/10/2019] [Indexed: 12/15/2022]
Abstract
Vegetables are one of the sources from which Helicobacter pylori can be acquired. This bacterium infects >50% of the global population and is a recognized type I human carcinogen. H. pylori enters into the viable but non-culturable state when it is in the environment, and therefore the use of molecular techniques is much convenient for its detection. Free-living amoebae (FLA) are protozoans found in vegetables. They are transmission vehicles for amoeba-resistant bacteria, among which H. pylori is included. The aim of this study is to study the occurrence and viability of H. pylori from lettuce samples, H. pylori internalized into FLA and the microbiome of FLA isolated from these samples. Special focus was pointed to human pathogenic bacteria. H. pylori was not directly detected in any lettuce sample by means of molecular techniques and neither by culture. However, intra-amoebic H. pylori DNA was detected by means of PMA-qPCR in 55% of the samples and viable intra-amoebic H. pylori cells in 25% of the samples by means of DVC-FISH technique. When FLA microbiome was studied, 21 bacterial genera were part of FLA microbiome in all samples. Helicobacter genus was detected as part of the FLA microbiome in two samples. Other bacteria of public health interest such as Aeromonas sp., Arcobacter sp., Legionella sp., Mycobacterium sp., Pseudomonas sp. and Salmonella sp. were detected as part of FLA microbiome along the analysed samples. This study demonstrates for the first time that H. pylori is internalized as well as alive inside FLA isolated from vegetables. Moreover, this study shows that FLA promote H. pylori detection in environmental samples. In addition, as far as we are aware, this is the first study which studies the microbiome of FLA isolated from vegetables. Among the FLA microbiome, bacteria of public health interest were detected, pointing out that FLA are carriers of these pathogens which can reach humans and cause a public health concern.
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Affiliation(s)
- Laura Moreno-Mesonero
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, 46022 Valencia, Spain.
| | - Irene Hortelano
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, 46022 Valencia, Spain.
| | - Yolanda Moreno
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, 46022 Valencia, Spain.
| | - Mª Antonia Ferrús
- Biotechnology Department, Universitat Politècnica de València, 46022 Valencia, Spain.
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Pushkareva VI, Podlipaeva JI, Goodkov AV, Ermolaeva SA. Experimental Listeria-Tetrahymena-Amoeba food chain functioning depends on bacterial virulence traits. BMC Ecol 2019; 19:47. [PMID: 31757213 PMCID: PMC6874821 DOI: 10.1186/s12898-019-0265-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 11/19/2019] [Indexed: 11/26/2022] Open
Abstract
Background Some pathogenic bacteria have been developing as a part of terrestrial and aquatic microbial ecosystems. Bacteria are consumed by bacteriovorous protists which are readily consumed by larger organisms. Being natural predators, protozoa are also an instrument for selection of virulence traits in bacteria. Moreover, protozoa serve as a “Trojan horse” that deliver pathogens to the human body. Here, we suggested that carnivorous amoebas feeding on smaller bacteriovorous protists might serve as “Troy” themselves when pathogens are delivered to them with their preys. A dual role might be suggested for protozoa in the development of traits required for bacterial passage along the food chain. Results A model food chain was developed. Pathogenic bacteria L. monocytogenes or related saprophytic bacteria L. innocua constituted the base of the food chain, bacteriovorous ciliate Tetrahymena pyriformis was an intermediate consumer, and carnivorous amoeba Amoeba proteus was a consumer of the highest order. The population of A. proteus demonstrated variations in behaviour depending on whether saprophytic or virulent Listeria was used to feed the intermediate consumer, T. pyriformis. Feeding of A. proteus with T. pyriformis that grazed on saprophytic bacteria caused prevalence of pseudopodia-possessing hungry amoebas. Statistically significant prevalence of amoebas with spherical morphology typical for fed amoebas was observed when pathogenic L. monocytogenes were included in the food chain. Moreover, consumption of tetrahymenas fed with saprophytic L. innocua improved growth of A. proteus population while L. monocytogenes-filled tetrahymenas provided negative effect. Both pathogenic and saprophytic bacteria were delivered to A. proteus alive but only L. monocytogenes multiplied within amoebas. Observed differences in A. proteus population behaviour suggested that virulent L. monocytogenes might slow down restoration of A. proteus ability to hunt again and thus restrict the size of A. proteus population. Comparison of isogenic bacterial pairs that did or did not produce the haemolysin listeriolysin O (LLO) suggested a role for LLO in passing L. monocytogenes along the food chain. Conclusions Our results support the idea of protozoa as a means of pathogen delivery to consumers of a higher order and demonstrated a dual role of protozoa as both a “Trojan horse” and “Troy.”
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Affiliation(s)
- Valentina I Pushkareva
- Gamaleya Research Centre of Epidemiology and Microbiology, Gamaleya st. 18, Moscow, 123098, Russia
| | - Julia I Podlipaeva
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Andrew V Goodkov
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Svetlana A Ermolaeva
- Gamaleya Research Centre of Epidemiology and Microbiology, Gamaleya st. 18, Moscow, 123098, Russia. .,National Research Centre on Virology and Microbiology, Pokrov, Russia.
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15
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Kavagutti VS, Andrei AŞ, Mehrshad M, Salcher MM, Ghai R. Phage-centric ecological interactions in aquatic ecosystems revealed through ultra-deep metagenomics. MICROBIOME 2019; 7:135. [PMID: 31630686 DOI: 10.1101/670067v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 09/24/2019] [Indexed: 05/22/2023]
Abstract
The persistent inertia in the ability to culture environmentally abundant microbes from aquatic ecosystems represents an obstacle in disentangling the complex web of ecological interactions spun by a diverse assortment of participants (pro- and eukaryotes and their viruses). In aquatic microbial communities, the numerically most abundant actors, the viruses, remain the most elusive, and especially in freshwaters their identities and ecology remain unknown. Here, using ultra-deep metagenomic sequencing from pelagic freshwater habitats, we recovered complete genomes of > 2000 phages, including small "miniphages" and large "megaphages" infecting iconic freshwater prokaryotic lineages. For instance, abundant freshwater Actinobacteria support infection by a very broad size range of phages (13-200 Kb). We describe many phages encoding genes that likely afford protection to their host from reactive oxygen species (ROS) in the aquatic environment and in the oxidative burst in protist phagolysosomes (phage-mediated ROS defense). Spatiotemporal abundance analyses of phage genomes revealed evanescence as the primary dynamic in upper water layers, where they displayed short-lived existences. In contrast, persistence was characteristic for the deeper layers where many identical phage genomes were recovered repeatedly. Phage and host abundances corresponded closely, with distinct populations displaying preferential distributions in different seasons and depths, closely mimicking overall stratification and mixis.
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Affiliation(s)
- Vinicius S Kavagutti
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, Na Sádkách 7, 370 05, České Budějovice, Czech Republic
| | - Adrian-Ştefan Andrei
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, Na Sádkách 7, 370 05, České Budějovice, Czech Republic
| | - Maliheh Mehrshad
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, Na Sádkách 7, 370 05, České Budějovice, Czech Republic
| | - Michaela M Salcher
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, Na Sádkách 7, 370 05, České Budějovice, Czech Republic
- Limnological Station, Institute of Plant and Microbial Biology, University of Zurich, Seestrasse 187, 8802, Kilchberg, Switzerland
| | - Rohit Ghai
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, Na Sádkách 7, 370 05, České Budějovice, Czech Republic.
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16
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Kavagutti VS, Andrei AŞ, Mehrshad M, Salcher MM, Ghai R. Phage-centric ecological interactions in aquatic ecosystems revealed through ultra-deep metagenomics. MICROBIOME 2019; 7:135. [PMID: 31630686 PMCID: PMC6802176 DOI: 10.1186/s40168-019-0752-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 09/24/2019] [Indexed: 05/20/2023]
Abstract
The persistent inertia in the ability to culture environmentally abundant microbes from aquatic ecosystems represents an obstacle in disentangling the complex web of ecological interactions spun by a diverse assortment of participants (pro- and eukaryotes and their viruses). In aquatic microbial communities, the numerically most abundant actors, the viruses, remain the most elusive, and especially in freshwaters their identities and ecology remain unknown. Here, using ultra-deep metagenomic sequencing from pelagic freshwater habitats, we recovered complete genomes of > 2000 phages, including small "miniphages" and large "megaphages" infecting iconic freshwater prokaryotic lineages. For instance, abundant freshwater Actinobacteria support infection by a very broad size range of phages (13-200 Kb). We describe many phages encoding genes that likely afford protection to their host from reactive oxygen species (ROS) in the aquatic environment and in the oxidative burst in protist phagolysosomes (phage-mediated ROS defense). Spatiotemporal abundance analyses of phage genomes revealed evanescence as the primary dynamic in upper water layers, where they displayed short-lived existences. In contrast, persistence was characteristic for the deeper layers where many identical phage genomes were recovered repeatedly. Phage and host abundances corresponded closely, with distinct populations displaying preferential distributions in different seasons and depths, closely mimicking overall stratification and mixis.
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Affiliation(s)
- Vinicius S Kavagutti
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, Na Sádkách 7, 370 05, České Budějovice, Czech Republic
| | - Adrian-Ştefan Andrei
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, Na Sádkách 7, 370 05, České Budějovice, Czech Republic
| | - Maliheh Mehrshad
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, Na Sádkách 7, 370 05, České Budějovice, Czech Republic
| | - Michaela M Salcher
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, Na Sádkách 7, 370 05, České Budějovice, Czech Republic
- Limnological Station, Institute of Plant and Microbial Biology, University of Zurich, Seestrasse 187, 8802, Kilchberg, Switzerland
| | - Rohit Ghai
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, Na Sádkách 7, 370 05, České Budějovice, Czech Republic.
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17
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Vibrio cholerae residing in food vacuoles expelled by protozoa are more infectious in vivo. Nat Microbiol 2019; 4:2466-2474. [PMID: 31570868 DOI: 10.1038/s41564-019-0563-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 07/19/2019] [Indexed: 11/09/2022]
Abstract
Vibrio cholerae interacts with many organisms in the environment, including heterotrophic protists (protozoa). Several species of protozoa have been reported to release undigested bacteria in expelled food vacuoles (EFVs) when feeding on some pathogens. While the production of EFVs has been reported, their biological role as a vector for the transmission of pathogens remains unknown. Here we report that ciliated protozoa release EFVs containing V. cholerae. The EFVs are stable, the cells inside them are protected from multiple stresses, and large numbers of cells escape when incubated at 37 °C or in the presence of nutrients. We show that OmpU, a major outer membrane protein positively regulated by ToxR, has a role in the production of EFVs. Notably, cells released from EFVs have growth and colonization advantages over planktonic cells both in vitro and in vivo. Our results suggest that EFVs facilitate V. cholerae survival in the environment, enhancing their infectious potential and may contribute to the dissemination of epidemic V. cholerae strains. These results improve our understanding of the mechanisms of persistence and the modes of transmission of V. cholerae and may further apply to other opportunistic pathogens that have been shown to be released by protists in EFVs.
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18
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Matsushita M, Okubo T, Hasegawa T, Matsuo J, Watanabe T, Iwasaki S, Fukumoto T, Hayasaka K, Akizawa K, Shimizu C, Yamaguchi H. Tetrahymena promotes interactive transfer of carbapenemase gene encoded in plasmid between fecal Escherichia coli and environmental Aeromonas caviae. Microbiol Immunol 2019; 62:720-728. [PMID: 30357893 DOI: 10.1111/1348-0421.12656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 10/01/2018] [Accepted: 10/22/2018] [Indexed: 01/06/2023]
Abstract
Tetrahymena can facilitate plasmid transfer among Escherichia coli or from E. coli to Salmonella Enteritidis via vesicle accumulation. In this study, whether ciliates promote the interactive transfer of plasmids encoding blaIMP-1 between fecal E. coli and environmental Aeromonas caviae was investigated. Both bacteria were mixed with or without ciliates and incubated overnight at 30°C. The frequency of plasmid-acquired bacteria was estimated by colony counts using an agar plate containing ceftazidim (CAZ) followed by determination of the minimum inhibitory concentration (MIC). Cultures containing ciliates interactively transferred the plasmid between E. coli and Aeromonas with a frequency of 10-4 to 10-5 . All plasmid-acquired bacteria showed a MIC against CAZ of >128 μg/mL and the plasmid transfer was confirmed by PCR amplification of the blaIMP-1 gene. Fluorescent observation showed that both bacteria accumulated in the same vesicle and that transwell sequestering significantly decreased the transfer frequency. Although ciliates preferentially ingested E. coli rather than A. caviae, both bacteria were co-localized into the same vesicles of ciliates, indicating that their meeting is associated with the gene transfer. Thus, ciliates interactively promote plasmid transfer between E. coli and A. caviae. The results of this study will facilitate control of the spread of multiple-antibiotic resistant bacteria.
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Affiliation(s)
- Mizue Matsushita
- Faculty of Health Sciences, Department of Medical Laboratory Science, Hokkaido University Graduate School of Health Sciences, Nishi-5 Kita-12 Jo, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Torahiko Okubo
- Faculty of Health Sciences, Department of Medical Laboratory Science, Hokkaido University Graduate School of Health Sciences, Nishi-5 Kita-12 Jo, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Takaki Hasegawa
- Faculty of Health Sciences, Department of Medical Laboratory Science, Hokkaido University Graduate School of Health Sciences, Nishi-5 Kita-12 Jo, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Junji Matsuo
- Faculty of Health Sciences, Department of Medical Laboratory Science, Hokkaido University Graduate School of Health Sciences, Nishi-5 Kita-12 Jo, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Takanori Watanabe
- Faculty of Health Sciences, Department of Medical Laboratory Science, Hokkaido University Graduate School of Health Sciences, Nishi-5 Kita-12 Jo, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Sumio Iwasaki
- Hokkaido University Hospital, Nishi-5 Kita-14 Jo, Kita-ku, Sapporo, Hokkaido 060-8648, Japan
| | - Tatsuya Fukumoto
- Hokkaido University Hospital, Nishi-5 Kita-14 Jo, Kita-ku, Sapporo, Hokkaido 060-8648, Japan
| | - Kasumi Hayasaka
- Hokkaido University Hospital, Nishi-5 Kita-14 Jo, Kita-ku, Sapporo, Hokkaido 060-8648, Japan
| | - Kozi Akizawa
- Hokkaido University Hospital, Nishi-5 Kita-14 Jo, Kita-ku, Sapporo, Hokkaido 060-8648, Japan
| | - Chikara Shimizu
- Hokkaido University Hospital, Nishi-5 Kita-14 Jo, Kita-ku, Sapporo, Hokkaido 060-8648, Japan
| | - Hiroyuki Yamaguchi
- Faculty of Health Sciences, Department of Medical Laboratory Science, Hokkaido University Graduate School of Health Sciences, Nishi-5 Kita-12 Jo, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
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19
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Long JJ, Jahn CE, Sánchez-Hidalgo A, Wheat W, Jackson M, Gonzalez-Juarrero M, Leach JE. Interactions of free-living amoebae with rice bacterial pathogens Xanthomonas oryzae pathovars oryzae and oryzicola. PLoS One 2018; 13:e0202941. [PMID: 30142182 PMCID: PMC6108499 DOI: 10.1371/journal.pone.0202941] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 06/23/2018] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Free-living amoebae (FLA) are voracious feeders, consuming bacteria and other microbes during colonization of the phytobiome. FLA are also known to secrete bacteriocidal or bacteriostatic compounds into their growth environment. METHODOLOGY AND PRINCIPAL FINDINGS Here, we explore the impacts of co-cultivation of five FLA species, including Acanthamoeba castellanii, A. lenticulata, A. polyphaga, Dictyostelium discoideum and Vermamoeba vermiformis, on survival of two devastating bacterial pathogens of rice, Xanthomonas oryzae pathovars (pv.) oryzae and oryzicola. In co-cultivation assays, the five FLA species were either bacteriostatic or bactericidal to X. oryzae pv. oryzae and X. oryzae pv. oryzicola. Despite these effects, bacteria were rarely detected inside amoebal cells. Furthermore, amoebae did not disrupt X. oryzae biofilms. The bactericidal effects persisted when bacteria were added to a cell-free supernatant from amoebal cultures, suggesting some amoebae produce an extracellular bactericidal compound. CONCLUSIONS/SIGNIFICANCE This work establishes novel, basal dynamics between important plant pathogenic bacteria and diverse amoebae, and lays the framework for future mechanistic studies.
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Affiliation(s)
- John J. Long
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado, United States of America
| | - Courtney E. Jahn
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado, United States of America
| | - Andrea Sánchez-Hidalgo
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - William Wheat
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mercedes Gonzalez-Juarrero
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Jan E. Leach
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado, United States of America
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20
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Dorati F, Barrett GA, Sanchez-Contreras M, Arseneault T, José MS, Studholme DJ, Murillo J, Caballero P, Waterfield NR, Arnold DL, Shaw LJ, Jackson RW. Coping with Environmental Eukaryotes; Identification of Pseudomonas syringae Genes during the Interaction with Alternative Hosts or Predators. Microorganisms 2018; 6:microorganisms6020032. [PMID: 29690522 PMCID: PMC6027264 DOI: 10.3390/microorganisms6020032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/09/2018] [Accepted: 04/20/2018] [Indexed: 12/13/2022] Open
Abstract
Understanding the molecular mechanisms underpinning the ecological success of plant pathogens is critical to develop strategies for controlling diseases and protecting crops. Recent observations have shown that plant pathogenic bacteria, particularly Pseudomonas, exist in a range of natural environments away from their natural plant host e.g., water courses, soil, non-host plants. This exposes them to a variety of eukaryotic predators such as nematodes, insects and amoebae present in the environment. Nematodes and amoeba in particular are bacterial predators while insect herbivores may act as indirect predators, ingesting bacteria on plant tissue. We therefore postulated that bacteria are probably under selective pressure to avoid or survive predation and have therefore developed appropriate coping mechanisms. We tested the hypothesis that plant pathogenic Pseudomonas syringae are able to cope with predation pressure and found that three pathovars show weak, but significant resistance or toxicity. To identify the gene systems that contribute to resistance or toxicity we applied a heterologous screening technique, called Rapid Virulence Annotation (RVA), for anti-predation and toxicity mechanisms. Three cosmid libraries for P. syringae pv. aesculi, pv. tomato and pv. phaseolicola, of approximately 2000 cosmids each, were screened in the susceptible/non-toxic bacterium Escherichia coli against nematode, amoebae and an insect. A number of potential conserved and unique genes were identified which included genes encoding haemolysins, biofilm formation, motility and adhesion. These data provide the first multi-pathovar comparative insight to how plant pathogens cope with different predation pressures and infection of an insect gut and provide a foundation for further study into the function of selected genes and their role in ecological success.
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Affiliation(s)
- Federico Dorati
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
| | - Glyn A Barrett
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
| | | | - Tanya Arseneault
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
- Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, Research and Development Centre, Quebec, J3B 3E6, Canada.
| | - Mateo San José
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
| | | | - Jesús Murillo
- Instituto de Agrobiotecnología, Universidad Pública de Navarra, 31192 Mutilva, Spain.
| | - Primitivo Caballero
- Instituto de Agrobiotecnología, Universidad Pública de Navarra, 31192 Mutilva, Spain.
| | - Nicholas R Waterfield
- Department of Biology and Biochemistry, University of Bath, Bath, BA1 9BJ, UK.
- Warwick Medical School, University of Warwick, Warwick, CV4 7AL, UK.
| | - Dawn L Arnold
- Centre for Research in Bioscience, Faculty of Health and Applied Sciences, University of the West of England, Bristol, BS16 1QY, UK.
| | - Liz J Shaw
- School of Archaeology, Geography and Environmental Science, University of Reading, Reading, RG6 6AX, UK.
| | - Robert W Jackson
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
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Flues S, Blokker M, Dumack K, Bonkowski M. Diversity of Cercomonad Species in the Phyllosphere and Rhizosphere of Different Plant Species with a Description of Neocercomonas epiphylla (Cercozoa, Rhizaria) a Leaf-Associated Protist. J Eukaryot Microbiol 2018; 65:587-599. [PMID: 29377417 DOI: 10.1111/jeu.12503] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 01/16/2018] [Accepted: 01/16/2018] [Indexed: 12/15/2022]
Abstract
Cercomonads are among the most abundant and diverse groups of heterotrophic flagellates in terrestrial systems and show an affinity to plants. However, we still lack basic knowledge of plant-associated protists. We isolated 75 Cercomonadida strains from the phyllosphere and rhizosphere of plants from three functional groups: grasses (Poa sp.), legumes (Trifolium sp.) and forbs (Plantago sp.), representing 28 OTUs from the genera Cercomonas, Neocercomonas and Paracercomonas. The community composition differed clearly between phyllosphere and rhizosphere, but was not influenced by plant species identity. From these isolates we describe three novel cercomonad species including Neocercomonas epiphylla that was consistently and exclusively isolated from the phyllosphere. For each new species we provide a detailed morphological description as well as an 18S rDNA gene sequence as a distinct marker of species identity. Our data contribute to a better resolution of the systematics of cercomonads and their association with plants, by describing three novel species and adding gene sequences of 10 new cercomonad genotypes and of nine previously described species. In view of the functional importance of cercozoan communities in the phyllosphere and rhizosphere of plants, a more detailed understanding of their composition, function and predator-prey interactions are clearly required.
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Affiliation(s)
- Sebastian Flues
- Department of Terrestrial Ecology, Institute for Zoology, University of Cologne, Cologne, 50674, Germany
| | - Malte Blokker
- Department of Terrestrial Ecology, Institute for Zoology, University of Cologne, Cologne, 50674, Germany
| | - Kenneth Dumack
- Department of Terrestrial Ecology, Institute for Zoology, University of Cologne, Cologne, 50674, Germany
| | - Michael Bonkowski
- Department of Terrestrial Ecology, Institute for Zoology, University of Cologne, Cologne, 50674, Germany.,Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, 50674, Germany
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22
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Deng W, Gibson KE. Interaction of microorganisms within leafy green phyllospheres: Where do human noroviruses fit in? Int J Food Microbiol 2017; 258:28-37. [DOI: 10.1016/j.ijfoodmicro.2017.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/21/2017] [Accepted: 07/18/2017] [Indexed: 02/06/2023]
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23
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Flues S, Bass D, Bonkowski M. Grazing of leaf‐associated Cercomonads (Protists: Rhizaria: Cercozoa) structures bacterial community composition and function. Environ Microbiol 2017; 19:3297-3309. [DOI: 10.1111/1462-2920.13824] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 06/06/2017] [Accepted: 06/07/2017] [Indexed: 01/06/2023]
Affiliation(s)
- Sebastian Flues
- Department of Terrestrial Ecology, Institute of ZoologyUniversity of CologneZülpicher Straße 47bKöln 50674 Germany
| | - David Bass
- Department of Life SciencesThe Natural History MuseumCromwell RoadLondonSW7 5BD UK
- CefasBarrack Road, The Nothe, Weymouth, Dorset DT4 8UB UK
| | - Michael Bonkowski
- Department of Terrestrial Ecology, Institute of ZoologyUniversity of CologneZülpicher Straße 47bKöln 50674 Germany
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Aijaz I, Koudelka GB. Tetrahymena phagocytic vesicles as ecological micro-niches of phage transfer. FEMS Microbiol Ecol 2017; 93:3061358. [PMID: 28334205 DOI: 10.1093/femsec/fix030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/01/2017] [Indexed: 11/14/2022] Open
Abstract
The microbial communities in natural environments such as soil, pond water, or animal rumens are composed of a diverse mixture of bacteria and protozoa including ciliates or flagellates. In such microbiomes, a major source of bacterial mortality is grazing by phagocytic protists. Many protists are omnivorous heterotrophs, feeding on a range of different bacterial species. Due to this indiscriminate feeding, different bacterial species can assemble together in the same phagocytic vesicles where they can potentially exchange genetic material. Here we show that Tetrahymena thermophila imports and accumulates phage donor and recipient bacterial strains in its phagocytic vesicles and that under laboratory conditions the ingested bacteria remain viable for ≥2 h. Prophages in the ingested bacteria induce immediately after ingestion, and the released phages are concentrated in the phagocytic vesicles of the ciliate. These phages retain their ability to infect phage-susceptible bacterial strains. As a consequence of being confined within the phagosome, the frequency of lysogen formation in these vesicles increases 6-fold as compared with the bulk solution. Collectively, these observations suggest that T. thermophila aids in dissemination of bacteriophages by accumulating susceptible bacteria and phages in their phagocytic vesicles.
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Ploch S, Rose LE, Bass D, Bonkowski M. High Diversity Revealed in Leaf-Associated Protists (Rhizaria: Cercozoa) of Brassicaceae. J Eukaryot Microbiol 2016; 63:635-41. [PMID: 27005328 PMCID: PMC5031217 DOI: 10.1111/jeu.12314] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/20/2016] [Accepted: 03/12/2016] [Indexed: 02/06/2023]
Abstract
The largest biological surface on earth is formed by plant leaves. These leaf surfaces are colonized by a specialized suite of leaf-inhabiting microorganisms, recently termed "phyllosphere microbiome". Microbial prey, however, attract microbial predators. Protists in particular have been shown to structure bacterial communities on plant surfaces, but virtually nothing is known about the community composition of protists on leaves. Using newly designed specific primers targeting the 18S rDNA gene of Cercozoa, we investigated the species richness of this common protist group on leaves of four Brassicaceae species from two different locations in a cloning-based approach. The generated sequences revealed a broad diversity of leaf-associated Cercozoa, mostly bacterial feeders, but also including known plant pathogens and a taxon of potential endophytes that were recently described as algal predators in freshwater systems. This initial study shows that protists must be regarded as an integral part of the microbial diversity in the phyllosphere of plants.
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Affiliation(s)
- Sebastian Ploch
- Institute of Population Genetics, Cluster of Excellence in Plant Sciences, University of Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
- Senckenberg Biodiversity and Climate Research Center, Georg-Voigt-Street 14-16, D-60325, Frankfurt, Germany
| | - Laura E Rose
- Institute of Population Genetics, Cluster of Excellence in Plant Sciences, University of Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
| | - David Bass
- Department of Life Sciences, The Natural History Museum, London, SW7 5BD, United Kingdom
- Centre for Environment, Fisheries, and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset, DT4 8UB, United Kingdom
| | - Michael Bonkowski
- Department of Terrestrial Ecology, Institute of Zoology, University of Cologne, Zülpicher Street 47b, D-50674, Köln, Germany
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Chavatte N, Lambrecht E, Van Damme I, Sabbe K, Houf K. Free-living protozoa in the gastrointestinal tract and feces of pigs: Exploration of an unknown world and towards a protocol for the recovery of free-living protozoa. Vet Parasitol 2016; 225:91-8. [DOI: 10.1016/j.vetpar.2016.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 01/26/2023]
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Trigui H, Paquet VE, Charette SJ, Faucher SP. Packaging of Campylobacter jejuni into Multilamellar Bodies by the Ciliate Tetrahymena pyriformis. Appl Environ Microbiol 2016; 82:2783-90. [PMID: 26921427 PMCID: PMC4836424 DOI: 10.1128/aem.03921-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/23/2016] [Indexed: 12/23/2022] Open
Abstract
Campylobacter jejuniis the leading cause of bacterial gastroenteritis worldwide. Transmission to humans occurs through consumption of contaminated food or water. The conditions affecting the persistence of C. jejuniin the environment are poorly understood. Some protozoa package and excrete bacteria into multilamellar bodies (MLBs). Packaged bacteria are protected from deleterious conditions, which increases their survival. We hypothesized that C. jejuni could be packaged under aerobic conditions by the amoeba Acanthamoeba castellanii or the ciliate Tetrahymena pyriformis, both of which are able to package other pathogenic bacteria.A. castellanii did not produce MLBs containing C. jejuni In contrast, when incubated with T. pyriformis,C. jejuni was ingested, packaged in MLBs, and then expelled into the milieu. The viability of the bacteria inside MLBs was confirmed by microscopic analyses. The kinetics of C. jejuni culturability showed that packaging increased the survival of C. jejuniup to 60 h, in contrast to the strong survival defect seen in ciliate-free culture. This study suggests that T. pyriformis may increase the risk of persistence of C. jejuniin the environment and its possible transmission between different reservoirs in food and potable water through packaging.
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Affiliation(s)
- Hana Trigui
- McGill University, Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Valérie E Paquet
- Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, Quebec City, QC, Canada Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Quebec City, QC, Canada Département de Biochimie, de Microbiologie, et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Quebec City, QC, Canada
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, Quebec City, QC, Canada Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Quebec City, QC, Canada Département de Biochimie, de Microbiologie, et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Quebec City, QC, Canada
| | - Sébastien P Faucher
- McGill University, Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
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Paquet VE, Charette SJ. Amoeba-resisting bacteria found in multilamellar bodies secreted by Dictyostelium discoideum: social amoebae can also package bacteria. FEMS Microbiol Ecol 2016; 92:fiw025. [PMID: 26862140 DOI: 10.1093/femsec/fiw025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2016] [Indexed: 11/14/2022] Open
Abstract
Many bacteria can resist phagocytic digestion by various protozoa. Some of these bacteria (all human pathogens) are known to be packaged in multilamellar bodies produced in the phagocytic pathway of the protozoa and that are secreted into the extracellular milieu. Packaged bacteria are protected from harsh conditions, and the packaging process is suspected to promote bacterial persistence in the environment. To date, only a limited number of protozoa, belonging to free-living amoebae and ciliates, have been shown to perform bacteria packaging. It is still unknown if social amoebae can do bacteria packaging. The link between the capacity of 136 bacterial isolates to resist the grazing of the social amoeba Dictyostelium discoideum and to be packaged by this amoeba was investigated in the present study. The 45 bacterial isolates displaying a resisting phenotype were tested for their capacity to be packaged. A total of seven isolates from Cupriavidus, Micrococcus, Microbacterium and Rathayibacter genera seemed to be packaged and secreted by D. discoideum based on immunofluorescence results. Electron microscopy confirmed that the Cupriavidus and Rathayibacter isolates were formally packaged. These results show that social amoebae can package some bacteria from the environment revealing a new aspect of microbial ecology.
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Affiliation(s)
- Valérie E Paquet
- Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, Quebec City, QC, G1V 0A6, Canada Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Hôpital Laval, Quebec City, QC, G1V 4G5, Canada
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, Quebec City, QC, G1V 0A6, Canada Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Hôpital Laval, Quebec City, QC, G1V 4G5, Canada Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, QC, G1V 0A6, Canada
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One Health and Food-Borne Disease: Salmonella Transmission between Humans, Animals, and Plants. Microbiol Spectr 2015; 2:OH-0020-2013. [PMID: 26082128 DOI: 10.1128/microbiolspec.oh-0020-2013] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
There are >2,600 recognized serovars of Salmonella enterica. Many of these Salmonella serovars have a broad host range and can infect a wide variety of animals, including mammals, birds, reptiles, amphibians, fish, and insects. In addition, Salmonella can grow in plants and can survive in protozoa, soil, and water. Hence, broad-host-range Salmonella can be transmitted via feces from wild animals, farm animals, and pets or by consumption of a wide variety of common foods: poultry, beef, pork, eggs, milk, fruit, vegetables, spices, and nuts. Broad-host-range Salmonella pathogens typically cause gastroenteritis in humans. Some Salmonella serovars have a more restricted host range that is associated with changes in the virulence plasmid pSV, accumulation of pseudogenes, and chromosome rearrangements. These changes in host-restricted Salmonella alter pathogen-host interactions such that host-restricted Salmonella organisms commonly cause systemic infections and are transmitted between host populations by asymptomatic carriers. The secondary consequences of efforts to eliminate host-restricted Salmonella serovars demonstrate that basic ecological principles govern the environmental niches occupied by these pathogens, making it impossible to thwart Salmonella infections without a clear understanding of the human, animal, and environmental reservoirs of these pathogens. Thus, transmission of S. enterica provides a compelling example of the One Health paradigm because reducing human infections will require the reduction of Salmonella in animals and limitation of transmission from the environment.
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Chavatte N, Lambrecht E, Van Damme I, Sabbe K, Houf K. Abundance, diversity and community composition of free-living protozoa on vegetable sprouts. Food Microbiol 2015; 55:55-63. [PMID: 26742616 DOI: 10.1016/j.fm.2015.11.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 11/09/2015] [Accepted: 11/20/2015] [Indexed: 01/20/2023]
Abstract
Interactions with free-living protozoa (FLP) have been implicated in the persistence of pathogenic bacteria on food products. In order to assess the potential involvement of FLP in this contamination, detailed knowledge on their occurrence, abundance and diversity on food products is required. In the present study, enrichment and cultivation methods were used to inventory and quantify FLP on eight types of commercial vegetable sprouts (alfalfa, beetroot, cress, green pea, leek, mung bean, red cabbage and rosabi). In parallel, total aerobic bacteria and Escherichia coli counts were performed. The vegetable sprouts harbored diverse communities of FLP, with Tetrahymena (ciliate), Bodo saltans and cercomonads (flagellates), and Acanthamoeba and Vannella (amoebae) as the dominant taxa. Protozoan community composition and abundance significantly differed between the sprout types. Beetroot harbored the most abundant and diverse FLP communities, with many unique species such as Korotnevella sp., Vannella sp., Chilodonella sp., Podophrya sp. and Sphaerophrya sp. In contrast, mung bean sprouts were species-poor and had low FLP numbers. Sampling month and company had no significant influence, suggesting that seasonal and local factors are of minor importance. Likewise, no significant relationship between protozoan community composition and bacterial load was observed.
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Affiliation(s)
- N Chavatte
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
| | - E Lambrecht
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
| | - I Van Damme
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
| | - K Sabbe
- Department of Biology, Faculty of Sciences, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium.
| | - K Houf
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
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Lambrecht E, Baré J, Chavatte N, Bert W, Sabbe K, Houf K. Protozoan Cysts Act as a Survival Niche and Protective Shelter for Foodborne Pathogenic Bacteria. Appl Environ Microbiol 2015; 81:5604-12. [PMID: 26070667 PMCID: PMC4510183 DOI: 10.1128/aem.01031-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 06/04/2015] [Indexed: 12/26/2022] Open
Abstract
The production of cysts, an integral part of the life cycle of many free-living protozoa, allows these organisms to survive adverse environmental conditions. Given the prevalence of free-living protozoa in food-related environments, it is hypothesized that these organisms play an important yet currently underinvestigated role in the epidemiology of foodborne pathogenic bacteria. Intracystic bacterial survival is highly relevant, as this would allow bacteria to survive the stringent cleaning and disinfection measures applied in food-related environments. The present study shows that strains of widespread and important foodborne bacteria (Salmonella enterica, Escherichia coli, Yersinia enterocolitica, and Listeria monocytogenes) survive inside cysts of the ubiquitous amoeba Acanthamoeba castellanii, even when exposed to either antibiotic treatment (100 μg/ml gentamicin) or highly acidic conditions (pH 0.2) and resume active growth in broth media following excystment. Strain- and species-specific differences in survival periods were observed, with Salmonella enterica surviving up to 3 weeks inside amoebal cysts. Up to 53% of the cysts were infected with pathogenic bacteria, which were located in the cyst cytosol. Our study suggests that the role of free-living protozoa and especially their cysts in the persistence and epidemiology of foodborne bacterial pathogens in food-related environments may be much more important than hitherto assumed.
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Affiliation(s)
- Ellen Lambrecht
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Julie Baré
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Natascha Chavatte
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Wim Bert
- Nematology Research Unit, Department of Biology, Ghent University, Ghent, Belgium
| | - Koen Sabbe
- Laboratory of Protistology and Aquatic Ecology, Department of Biology, Ghent University, Ghent, Belgium
| | - Kurt Houf
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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Hsueh TY, Gibson K. Transfer of Acanthamoeba
spp. to fresh produce from water and environmental surfaces. Lett Appl Microbiol 2015; 61:192-8. [DOI: 10.1111/lam.12445] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 05/07/2015] [Accepted: 05/14/2015] [Indexed: 11/30/2022]
Affiliation(s)
- T.-Y. Hsueh
- Department of Food Science; Center for Food Safety; Division of Agriculture; University of Arkansas; Fayetteville AR USA
| | - K.E. Gibson
- Department of Food Science; Center for Food Safety; Division of Agriculture; University of Arkansas; Fayetteville AR USA
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Santos-Montañez J, Benavides-Montaño JA, Hinz AK, Vadyvaloo V. Yersinia pseudotuberculosis IP32953 survives and replicates in trophozoites and persists in cysts of Acanthamoeba castellanii. FEMS Microbiol Lett 2015; 362:fnv091. [PMID: 26025069 DOI: 10.1093/femsle/fnv091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2015] [Indexed: 12/22/2022] Open
Abstract
Yersinia pseudotuberculosis is a foodborne enteric pathogen that causes a mild self-limiting diarrhea in humans. Yersinia pseudotuberculosis is able to persist in soil and water and in association with fresh produce, but the mechanism by which it persists is unknown. It has been shown that Y. pseudotuberculosis co-occurs with protozoans in these environments; therefore, this study investigates if bacterivorous free-living amoeba (FLA) are able to support persistence of Y. pseudotuberculosis. Coculture studies of Y. pseudotuberculosis and the prototype FLA, Acanthamoeba castellanii revealed that bacteria had an enhanced capacity to survive in association with amoeba and in the absence of any cytotoxic effects. Yersinia pseudotuberculosis is able to survive and replicate in trophozoites specifically localized within vacuoles, and persists within cysts over a period of at least a week. These data present the first evidence that Y. pseudotuberculosis is able to resist the bacterivorous nature of FLA and instead exhibits an enhanced ability to replicate and persist in coculture with amoeba. This study sheds light on the potential role of FLA in the ecology of Y. pseudotuberculosis which may have implications for food safety.
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Affiliation(s)
- Jennifer Santos-Montañez
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, WA 99164, USA
| | - Javier A Benavides-Montaño
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, WA 99164, USA Departamento Ciencia Animal, Universidad Nacional de Colombia, A. A. 237, Palmira Valle, Colombia
| | - Angela K Hinz
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, WA 99164, USA
| | - Viveka Vadyvaloo
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, WA 99164, USA
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Interactions between Human Norovirus Surrogates and Acanthamoeba spp. Appl Environ Microbiol 2015; 81:4005-13. [PMID: 25841006 DOI: 10.1128/aem.00649-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 03/28/2015] [Indexed: 11/20/2022] Open
Abstract
Human noroviruses (HuNoVs) are the most common cause of food-borne disease outbreaks, as well as virus-related waterborne disease outbreaks in the United States. Here, we hypothesize that common free-living amoebae (FLA)-ubiquitous in the environment, known to interact with pathogens, and frequently isolated from water and fresh produce-could potentially act as reservoirs of HuNoV and facilitate the environmental transmission of HuNoVs. To investigate FLA as reservoirs for HuNoV, the interactions between two Acanthamoeba species, A. castellanii and A. polyphaga, as well as two HuNoV surrogates, murine norovirus type 1 (MNV-1) and feline calicivirus (FCV), were evaluated. The results showed that after 1 h of amoeba-virus incubation at 25°C, 490 and 337 PFU of MNV-1/ml were recovered from A. castellanii and A. polyphaga, respectively, while only few or no FCVs were detected. In addition, prolonged interaction of MNV-1 with amoebae was investigated for a period of 8 days, and MNV-1 was demonstrated to remain stable at around 200 PFU/ml from day 2 to day 8 after virus inoculation in A. castellanii. Moreover, after a complete amoeba life cycle (i.e., encystment and excystment), infectious viruses could still be detected. To determine the location of virus associated with amoebae, immunofluorescence experiments were performed and showed MNV-1 transitioning from the amoeba surface to inside the amoeba over a 24-h period. These results are significant to the understanding of how HuNoVs may interact with other microorganisms in the environment in order to aid in its persistence and survival, as well as potential transmission in water and to vulnerable food products such as fresh produce.
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Abstract
A relatively short list of reference viral, bacterial and protozoan pathogens appears adequate to assess microbial risks and inform a system-based management of drinking waters. Nonetheless, there are data gaps, e.g. human enteric viruses resulting in endemic infection levels if poorly performing disinfection and/or distribution systems are used, and the risks from fungi. Where disinfection is the only treatment and/or filtration is poor, cryptosporidiosis is the most likely enteric disease to be identified during waterborne outbreaks, but generally non-human-infectious genotypes are present in the absence of human or calf fecal contamination. Enteric bacteria may dominate risks during major fecal contamination events that are ineffectively managed. Reliance on culture-based methods exaggerates treatment efficacy and reduces our ability to identify pathogens/indicators; however, next-generation sequencing and polymerase chain reaction approaches are on the cusp of changing that. Overall, water-based Legionella and non-tuberculous mycobacteria probably dominate health burden at exposure points following the various societal uses of drinking water.
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Affiliation(s)
- Nicholas J. Ashbolt
- School of Public Health, University of Alberta, Edmonton, Room 3-57D, South Academic Building, Alberta, T6G 2G7 Canada
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36
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Chavatte N, Baré J, Lambrecht E, Van Damme I, Vaerewijck M, Sabbe K, Houf K. Co-occurrence of free-living protozoa and foodborne pathogens on dishcloths: Implications for food safety. Int J Food Microbiol 2014; 191:89-96. [DOI: 10.1016/j.ijfoodmicro.2014.08.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 08/21/2014] [Accepted: 08/24/2014] [Indexed: 12/14/2022]
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Ravva SV, Sarreal CZ. Survival of Salmonella enterica in aerated and nonaerated wastewaters from dairy lagoons. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2014; 11:11249-60. [PMID: 25358096 PMCID: PMC4245611 DOI: 10.3390/ijerph111111249] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 10/20/2014] [Accepted: 10/21/2014] [Indexed: 01/05/2023]
Abstract
Salmonella is the most commonly identified foodborne pathogen in produce, meat and poultry. Cattle are known reservoirs of Salmonella and the pathogen excreted in feces ends up in manure flush lagoons. Salmonella enterica survival was monitored in wastewater from on-site holding lagoons equipped or not with circulating aerators at two dairies. All strains had poor survival rates and none proliferated in waters from aerated or settling lagoons. Populations of all three Salmonella serovars declined rapidly with decimal reduction times (D) of <2 days in aerated microcosms prepared from lagoon equipped with circulators. Populations of Salmonella decreased significantly in aerated microcosms (D = 4.2 d) compared to nonaerated waters (D = 7.4 d) and in summer (D = 3.4 d) compared to winter (D = 9.0 d). We propose holding the wastewater for sufficient decimal reduction cycles in lagoons to yield pathogen-free nutrient-rich water for crop irrigations and fertilization.
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Affiliation(s)
- Subbarao V Ravva
- Produce Safety and Microbiology Research Unit, United States Department of Agriculture, Agriculture Research Service, Western Regional Research Center, Albany, CA 94710, USA.
| | - Chester Z Sarreal
- Produce Safety and Microbiology Research Unit, United States Department of Agriculture, Agriculture Research Service, Western Regional Research Center, Albany, CA 94710, USA.
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Vaerewijck MJ, Baré J, Lambrecht E, Sabbe K, Houf K. Interactions of Foodborne Pathogens with Free-living Protozoa: Potential Consequences for Food Safety. Compr Rev Food Sci Food Saf 2014. [DOI: 10.1111/1541-4337.12100] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
| | - Julie Baré
- Dept. of Veterinary Public Health and Food Safety, Ghent Univ; Belgium
| | - Ellen Lambrecht
- Dept. of Veterinary Public Health and Food Safety, Ghent Univ; Belgium
| | - Koen Sabbe
- Laboratory of Protistology and Aquatic Ecology; Dept. of Biology, Ghent Univ; Belgium
| | - Kurt Houf
- Dept. of Veterinary Public Health and Food Safety, Ghent Univ; Belgium
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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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Vogeleer P, Tremblay YDN, Mafu AA, Jacques M, Harel J. Life on the outside: role of biofilms in environmental persistence of Shiga-toxin producing Escherichia coli. Front Microbiol 2014; 5:317. [PMID: 25071733 PMCID: PMC4076661 DOI: 10.3389/fmicb.2014.00317] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 06/10/2014] [Indexed: 11/13/2022] Open
Abstract
Escherichia coli is a heterogeneous species that can be part of the normal flora of humans but also include strains of medical importance. Among pathogenic members, Shiga-toxin producing E. coli (STEC) are some of the more prominent pathogenic E. coli within the public sphere. STEC disease outbreaks are typically associated with contaminated beef, contaminated drinking water, and contaminated fresh produce. These water- and food-borne pathogens usually colonize cattle asymptomatically; cows will shed STEC in their feces and the subsequent fecal contamination of the environment and processing plants is a major concern for food and public safety. This is especially important because STEC can survive for prolonged periods of time outside its host in environments such as water, produce, and farm soil. Biofilms are hypothesized to be important for survival in the environment especially on produce, in rivers, and in processing plants. Several factors involved in biofilm formation such as curli, cellulose, poly-N-acetyl glucosamine, and colanic acid are involved in plant colonization and adherence to different surfaces often found in meat processing plants. In food processing plants, contamination of beef carcasses occurs at different stages of processing and this is often caused by the formation of STEC biofilms on the surface of several pieces of equipment associated with slaughtering and processing. Biofilms protect bacteria against several challenges, including biocides used in industrial processes. STEC biofilms are less sensitive than planktonic cells to several chemical sanitizers such as quaternary ammonium compounds, peroxyacetic acid, and chlorine compounds. Increased resistance to sanitizers by STEC growing in a biofilm is likely to be a source of contamination in the processing plant. This review focuses on the role of biofilm formation by STEC as a means of persistence outside their animal host and factors associated with biofilm formation.
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Affiliation(s)
- Philippe Vogeleer
- Groupe de Recherche sur les Maladies Infectieuses du Porc, Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Centre de Recherche d'Infectiologie Porcine et Avicole, Université de Montréal St-Hyacinthe, QC, Canada
| | - Yannick D N Tremblay
- Groupe de Recherche sur les Maladies Infectieuses du Porc, Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Centre de Recherche d'Infectiologie Porcine et Avicole, Université de Montréal St-Hyacinthe, QC, Canada
| | - Akier A Mafu
- Food Research and Development Centre, Agriculture and Agri-Food Canada St-Hyacinthe, QC, Canada
| | - Mario Jacques
- Groupe de Recherche sur les Maladies Infectieuses du Porc, Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Centre de Recherche d'Infectiologie Porcine et Avicole, Université de Montréal St-Hyacinthe, QC, Canada
| | - Josée Harel
- Groupe de Recherche sur les Maladies Infectieuses du Porc, Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Centre de Recherche d'Infectiologie Porcine et Avicole, Université de Montréal St-Hyacinthe, QC, Canada
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Denoncourt AM, Paquet VE, Charette SJ. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria. Front Microbiol 2014; 5:240. [PMID: 24904553 PMCID: PMC4033053 DOI: 10.3389/fmicb.2014.00240] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 05/02/2014] [Indexed: 11/17/2022] Open
Abstract
Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse.
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Affiliation(s)
- Alix M Denoncourt
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada
| | - Valérie E Paquet
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada ; Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval Quebec City, QC, Canada
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42
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One Health and Food-Borne Disease: SalmonellaTransmission between Humans, Animals, and Plants. One Health 2014. [DOI: 10.1128/9781555818432.ch9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022] Open
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Fieseler L, Doyscher D, Loessner MJ, Schuppler M. Acanthamoeba release compounds which promote growth of Listeria monocytogenes and other bacteria. Appl Microbiol Biotechnol 2014; 98:3091-7. [DOI: 10.1007/s00253-014-5534-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 01/07/2014] [Accepted: 01/09/2014] [Indexed: 11/30/2022]
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Schuppler M. How the interaction of Listeria monocytogenes and Acanthamoeba spp. affects growth and distribution of the food borne pathogen. Appl Microbiol Biotechnol 2014; 98:2907-16. [PMID: 24557567 DOI: 10.1007/s00253-014-5546-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 01/10/2014] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
Abstract
Listeria monocytogenes is a foodborne opportunistic pathogen capable to switch from an environmental saprophyte to a potentially fatal human pathogen. The fact that the pathogen maintains the genes suitable for an elaborate infectious process indicates that these genes are required to survive in the environment. However, no environmental host reservoir for L. monocytogenes has been identified so far. The similarity of free-living, bacteria-scavenging amoebae to macrophages led to the hypothesis that protozoa may represent the missing link in the ecology and pathology of L. monocytogenes. Consequently, numerous studies have been published reporting on the potential of Acanthamoeba spp. to serve as host for a variety of pathogenic bacteria. However, the data on the interaction of L. monocytogenes with Acanthamoeba spp. are inconsistent and relatively little information on the impact of this interaction on growth and distribution of the foodborne pathogen is currently available. Hence, this review focuses on the interaction of L. monocytogenes and Acanthamoeba spp. affecting survival and growth of the foodborne pathogen in natural and man-made environments, in order to highlight the potential impact of this interplay on food safety and human health.
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Affiliation(s)
- Markus Schuppler
- Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, 8092, Zurich, Switzerland,
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Goñi P, Fernández MT, Rubio E. Identifying endosymbiont bacteria associated with free-living amoebae. Environ Microbiol 2014; 16:339-49. [PMID: 24422686 DOI: 10.1111/1462-2920.12363] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 12/17/2013] [Accepted: 12/17/2013] [Indexed: 11/30/2022]
Abstract
The association between free-living amoebae and pathogenic bacteria is an issue that has gained great importance due to the environmental and health consequences that it implies. In this paper, we analyse the techniques to follow an epidemiological study to identify associations between genera, species, genotypes and subgenotypes of amoebae with pathogenic bacteria, analysing their evolution and considering their usefulness. In this sense, we highlight the combination of microscopic and molecular techniques as the most appropriate way to obtain fully reliable results as well as the need to achieve the standardization of these techniques to allow the comparison of both environmental and clinical results.
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Affiliation(s)
- Pilar Goñi
- Area of Parasitology, University of Zaragoza, Zaragoza, Spain
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Vivant AL, Garmyn D, Piveteau P. Listeria monocytogenes, a down-to-earth pathogen. Front Cell Infect Microbiol 2013; 3:87. [PMID: 24350062 PMCID: PMC3842520 DOI: 10.3389/fcimb.2013.00087] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 11/08/2013] [Indexed: 11/23/2022] Open
Abstract
Listeria monocytogenes is the causative agent of the food-borne life threatening disease listeriosis. This pathogenic bacterium received much attention in the endeavor of deciphering the cellular mechanisms that underlie the onset of infection and its ability to adapt to the food processing environment. Although information is available on the presence of L. monocytogenes in many environmental niches including soil, water, plants, foodstuff and animals, understanding the ecology of L. monocytogenes in outdoor environments has received less attention. Soil is an environmental niche of pivotal importance in the transmission of this bacterium to plants and animals. Soil composition, microbial communities and macrofauna are extrinsic edaphic factors that direct the fate of L. monocytogenes in the soil environment. Moreover, farming practices may further affect its incidence. The genome of L. monocytogenes presents an extensive repertoire of genes encoding transport proteins and regulators, a characteristic of the genome of ubiquitous bacteria. Postgenomic analyses bring new insights in the process of soil adaptation. In the present paper focussing on soil, we review these extrinsic and intrinsic factors that drive environmental adaptation of L. monocytogenes.
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Affiliation(s)
- Anne-Laure Vivant
- UMR1347 Agroécologie, Université de BourgogneDijon, France
- UMR1347 Agroécologie, INRADijon, France
| | - Dominique Garmyn
- UMR1347 Agroécologie, Université de BourgogneDijon, France
- UMR1347 Agroécologie, INRADijon, France
| | - Pascal Piveteau
- UMR1347 Agroécologie, Université de BourgogneDijon, France
- UMR1347 Agroécologie, INRADijon, France
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Raghu Nadhanan R, Thomas CJ. Colpoda secrete viable Listeria monocytogenes within faecal pellets. Environ Microbiol 2013; 16:396-404. [PMID: 23981071 DOI: 10.1111/1462-2920.12230] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/21/2013] [Accepted: 07/28/2013] [Indexed: 01/30/2023]
Abstract
Transmission electron microscopy was used to demonstrate that co-cultures of the ciliate Colpoda RR (an environmental isolate) and Colpoda MLS-5 (a food processing environment isolate) with the pathogenic Listeria monocytogenes DRDC8 resulted in secretion of faecal pellets containing intact DRDC8 cells. A green fluorescent protein expressing variant of DRDC8 was used in co-cultures to confirm that the pellet-associated bacterial cells were L. monocytogenes. Viability was confirmed by plate counts, and assay of microbial respiratory activity-proved DRDC8 cells present within faecal pellets was metabolically active. Following treatment of faecal pellets secreted by Colpoda RR and MLS-5 with gentamycin and sodium hypochlorite (NaOCl), no loss of viability of the pellet-located DRDC8 cells was observed, indicating that faecal pellet encapsulated DRDC8 cells are resistant to biocidal agents. This work suggests that Colpoda-derived faecal pellets may provide a mechanism for transmission of L. monocytogenes and other pathogenic bacteria. Furthermore, bacteria encapsulated by faecal pellets may be resistant to disinfectants and cleaning agents used in food manufacturing and preparation facilities.
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Affiliation(s)
- Rethish Raghu Nadhanan
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA, 5005, Australia
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Moyne AL, Harris LJ, Marco ML. Assessments of total and viable Escherichia coli O157:H7 on field and laboratory grown lettuce. PLoS One 2013; 8:e70643. [PMID: 23936235 PMCID: PMC3728298 DOI: 10.1371/journal.pone.0070643] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 06/19/2013] [Indexed: 02/07/2023] Open
Abstract
Leafy green produce has been associated with numerous outbreaks of foodborne illness caused by strains of Escherichia coli O157:H7. While the amounts of culturable E. coli O157:H7 rapidly decline after introduction onto lettuce in the field, it remains to be determined whether the reduction in cell numbers is due to losses in cell viability, cell injury and a subsequent inability to be detected by standard laboratory culturing methods, or a lack of adherence and hence rapid removal of the organism from the plants during application. To assess which of these options is most relevant for E. coli O157:H7 on leafy green produce, we developed and applied a propidium monoazide (PMA) real-time PCR assay to quantify viable (with PMA) and total (without PMA) E. coli O157:H7 cells on growth chamber and field-grown lettuce. E. coli O157:H7, suspended in 0.1% peptone, was inoculated onto 4-week-old lettuce plants at a level of approximately 10(6) CFU/plant. In the growth chamber at low relative humidity (30%), culturable amounts of the nontoxigenic E. coli O157:H7 strain ATCC 700728 and the virulent strain EC4045 declined 100 to 1000-fold in 24 h. Fewer E. coli O157:H7 cells survived when applied onto plants in droplets with a pipette compared with a fine spray inoculation. Total cells for both strains were equivalent to inoculum levels for 7 days after application, and viable cell quantities determined by PMA real-time PCR were approximately 10(4) greater than found by colony enumeration. Within 2 h after application onto plants in the field, the number of culturable E. coli ATCC 700728 was reduced by up to 1000-fold, whereas PCR-based assessments showed that total cell amounts were equivalent to inoculum levels. These findings show that shortly after inoculation onto plants, the majority of E. coli O157:H7 cells either die or are no longer culturable.
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Affiliation(s)
- Anne-Laure Moyne
- Department of Food Science and Technology, University of California Davis, Davis, California, United States of America
- Western Center for Food Safety, University of California Davis, Davis, California, United States of America
| | - Linda J. Harris
- Department of Food Science and Technology, University of California Davis, Davis, California, United States of America
- Western Center for Food Safety, University of California Davis, Davis, California, United States of America
| | - Maria L. Marco
- Department of Food Science and Technology, University of California Davis, Davis, California, United States of America
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The microcosm mediates the persistence of shiga toxin-producing Escherichia coli in freshwater ecosystems. Appl Environ Microbiol 2013; 79:4821-8. [PMID: 23747699 DOI: 10.1128/aem.01281-13] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Water is a major route for infection of humans by exotoxin-producing bacteria, including Shiga toxin-producing Escherichia coli (STEC). While STEC has the potential to be present in nearly every type of water source, its distribution is sporadic, and an understanding of factors that govern its emergence and persistence within water is lacking. In this study, we examined the influence of microbe content on STEC persistence in freshwater. We found that depletion of microbes in the water leads to a considerable increase in the persistence of STEC, an effect that can be mitigated by adding grazing protists to the water. STEC strains appear to be more resistant to the impact of grazing protists than E. coli strains that lack the Shiga toxin (stx) gene. Our results demonstrate that the microcosm can dramatically influence the persistence of STEC in aquatic ecosystems and that the overall impact by microbes on STEC strains is fundamentally different from that of non-STEC strains of bacteria. Overall, these results provide insight into why STEC and possibly other exotoxin-producing bacterial pathogens display such variability in abundance, distribution, and persistence in aquatic ecosystems.
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Brandl MT, Cox CE, Teplitski M. Salmonella interactions with plants and their associated microbiota. PHYTOPATHOLOGY 2013; 103:316-325. [PMID: 23506360 DOI: 10.1094/phyto-11-12-0295-rvw] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The increase in the incidence of gastroenteritis outbreaks linked to the consumption of foods of plant origin has ignited public concern and scientific interest in understanding interactions of human enteric pathogens with plants. Enteric disease caused by nontyphoidal Salmonella is a major public health burden, with the number of cases of illness linked to fresh produce, spices, and nuts surpassing those linked to foods of animal origin. Mounting evidence supports the hypothesis that colonization of plants is an important part of the life cycle of this human pathogen. Although plant responses to human pathogens are distinct from the more specific responses to phytopathogens, plants appear to recognize Salmonella, likely by detecting conserved microbial patterns, which subsequently activates basal defenses. Numerous Salmonella genes have been identified as playing a role in its colonization of plant surfaces and tissues, and in its various interactions with other members of the phyto-microbial community. Importantly, Salmonella utilizes diverse and overlapping strategies to interact with plants and their microflora, and to successfully colonize its vertebrate hosts. This review provides insight into the complex behavior of Salmonella on plants and the apparent remarkable adaptation of this human pathogen to a potentially secondary host.
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