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Dąbrowska J, Sroka J, Cencek T. Investigating Cryptosporidium spp. Using Genomic, Proteomic and Transcriptomic Techniques: Current Progress and Future Directions. Int J Mol Sci 2023; 24:12867. [PMID: 37629046 PMCID: PMC10454211 DOI: 10.3390/ijms241612867] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/04/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023] Open
Abstract
Cryptosporidiosis is a widespread disease caused by the parasitic protozoan Cryptosporidium spp., which infects various vertebrate species, including humans. Once unknown as a gastroenteritis-causing agent, Cryptosporidium spp. is now recognized as a pathogen causing life-threatening disease, especially in immunocompromised individuals such as AIDS patients. Advances in diagnostic methods and increased awareness have led to a significant shift in the perception of Cryptosporidium spp. as a pathogen. Currently, genomic and proteomic studies play a main role in understanding the molecular biology of this complex-life-cycle parasite. Genomics has enabled the identification of numerous genes involved in the parasite's development and interaction with hosts. Proteomics has allowed for the identification of protein interactions, their function, structure, and cellular activity. The combination of these two approaches has significantly contributed to the development of new diagnostic tools, vaccines, and drugs for cryptosporidiosis. This review presents an overview of the significant achievements in Cryptosporidium research by utilizing genomics, proteomics, and transcriptomics approaches.
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Affiliation(s)
- Joanna Dąbrowska
- Department of Parasitology and Invasive Disease, National Veterinary Research Institute, Partyzantów 57 Avenue, 24-100 Puławy, Poland (T.C.)
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Dhal AK, Panda C, Yun SIL, Mahapatra RK. An update on Cryptosporidium biology and therapeutic avenues. J Parasit Dis 2022; 46:923-939. [PMID: 35755159 PMCID: PMC9215156 DOI: 10.1007/s12639-022-01510-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 06/07/2022] [Indexed: 12/02/2022] Open
Abstract
Cryptosporidium species has been identified as an important pediatric diarrheal pathogen in resource-limited countries, particularly in very young children (0–24 months). However, the only available drug (nitazoxanide) has limited efficacy and can only be prescribed in a medical setting to children older than one year. Many drug development projects have started to investigate new therapeutic avenues. Cryptosporidium’s unique biology is challenging for the traditional drug discovery pipeline and requires novel drug screening approaches. Notably, in recent years, new methods of oocyst generation, in vitro processing, and continuous three-dimensional cultivation capacities have been developed. This has enabled more physiologically pertinent research assays for inhibitor discovery. In a short time, many great strides have been made in the development of anti-Cryptosporidium drugs. These are expected to eventually turn into clinical candidates for cryptosporidiosis treatment in the future. This review describes the latest development in Cryptosporidium biology, genomics, transcriptomics of the parasite, assay development, and new drug discovery.
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Affiliation(s)
- Ajit Kumar Dhal
- School of Biotechnology, KIIT Deemed to Be University, Bhubaneswar, Odisha 751024 India
| | - Chinmaya Panda
- School of Biotechnology, KIIT Deemed to Be University, Bhubaneswar, Odisha 751024 India
| | - Soon-IL Yun
- Department of Food Science and Technology, Jeonbuk National University, Jeonju, 54896 Republic of Korea
- Department of Agricultural Convergence Technology, Jeonbuk National University, Jeonju, 54896 Republic of Korea
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Mthethwa NP, Amoah ID, Reddy P, Bux F, Kumari S. A review on application of next-generation sequencing methods for profiling of protozoan parasites in water: Current methodologies, challenges, and perspectives. J Microbiol Methods 2021; 187:106269. [PMID: 34129906 DOI: 10.1016/j.mimet.2021.106269] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/08/2021] [Accepted: 06/08/2021] [Indexed: 01/23/2023]
Abstract
The advancement in metagenomic techniques has provided novel tools for profiling human parasites in environmental matrices, such as water and wastewater. However, application of metagenomic techniques for the profiling of protozoan parasites in environmental matrices is not commonly reported in the literature. The key factors leading to the less common use of metagenomics are the complexity and large eukaryotic genome, the prevalence of small parasite populations in environmental samples compared to bacteria, difficulties in extracting DNA from (oo)cysts, and limited reference databases for parasites. This calls for further research to develop optimized methods specifically looking at protozoan parasites in the environment. This study reviews the current workflow, methods and provide recommendations for the standardization of techniques. The article identifies and summarizes the key methods, advantages, and limitations associated with metagenomic analysis, like sample pre-processing, DNA extraction, sequencing approaches, and analysis methods. The study enhances the understanding and application of standardized protocols for profiling of protozoan parasite community from highly complexe samples and further creates a resourceful comparison among datasets without any biases.
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Affiliation(s)
- N P Mthethwa
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban 4000, South Africa; Department of Community Health Studies, Faculty of Health Sciences, Durban University of Technology, Durban 4000, South Africa
| | - I D Amoah
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban 4000, South Africa
| | - P Reddy
- Department of Community Health Studies, Faculty of Health Sciences, Durban University of Technology, Durban 4000, South Africa
| | - F Bux
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban 4000, South Africa
| | - S Kumari
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban 4000, South Africa.
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Widmer G, Carmena D, Kváč M, Chalmers RM, Kissinger JC, Xiao L, Sateriale A, Striepen B, Laurent F, Lacroix-Lamandé S, Gargala G, Favennec L. Update on Cryptosporidium spp.: highlights from the Seventh International Giardia and Cryptosporidium Conference. ACTA ACUST UNITED AC 2020; 27:14. [PMID: 32167464 PMCID: PMC7069357 DOI: 10.1051/parasite/2020011] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 03/02/2020] [Indexed: 01/23/2023]
Abstract
While cryptosporidiosis is recognized as being among the most common causes of human parasitic diarrhea in the world, there is currently limited knowledge on Cryptosporidium infection mechanisms, incomplete codification of diagnostic methods, and a need for additional therapeutic options. In response, the Seventh International Giardia and Cryptosporidium Conference (IGCC 2019) was hosted from 23 to 26 June 2019, at the Rouen Normandy University, France. This trusted event brought together an international delegation of researchers to synthesize recent advances and identify key research questions and knowledge gaps. The program of the interdisciplinary conference included all aspects of host-parasite relationships from basic research to applications to human and veterinary medicine, and environmental issues associated with waterborne parasites and their epidemiological consequences. In relation to Cryptosporidium and cryptosporidiosis, the primary research areas for which novel findings and the most impressive communications were presented and discussed included: Cryptosporidium in environmental waters, seafood, and fresh produce; Animal epidemiology; Human cryptosporidiosis and epidemiology; Genomes and genomic evolution encompassing: Comparative genomics of Cryptosporidium spp., Genomic insights into biology, Acquiring and utilizing genome sequences, Genetic manipulation; Host-parasite interaction (immunology, microbiome); and Diagnosis and treatment. High quality presentations discussed at the conference reflected decisive progress and identified new opportunities that will engage investigators and funding agencies to spur future research in a “one health” approach to improve basic knowledge and the clinical and public health management of zoonotic cryptosporidiosis.
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Affiliation(s)
- Giovanni Widmer
- Department of Infectious Disease & Global Health, Cummings School of Veterinary Medicine at Tufts University, North Grafton, 01536 MA, USA
| | - David Carmena
- Spanish National Centre for Microbiology, 28220 Majadahonda, Spain
| | - Martin Kváč
- Institute of Parasitology, Biology Centre CAS, 370 05 České Budějovice, Czech Republic - Faculty of Agriculture, University of South Bohemia in České Budějovice, 370 05 České Budějovice, Czech Republic
| | - Rachel M Chalmers
- Cryptosporidium Reference Unit, Public Health Wales, SA2 8QA Swansea, UK - Swansea Medical School, Swansea University, SA2 8PP Swansea, UK
| | - Jessica C Kissinger
- Center for Tropical and Emerging Global Diseases, Institute of Bioinformatics and Department of Genetics, University of Georgia, Athens, 30602 GA, USA
| | - Lihua Xiao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642 Guangdong, PR China
| | - Adam Sateriale
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, 19104 PA, USA
| | - Boris Striepen
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 380 South University Avenue, Philadelphia, 19104 PA, USA
| | - Fabrice Laurent
- INRAE, Université François Rabelais de Tours, Centre Val de Loire, ISP, Laboratoire Apicomplexes et Immunité Mucosale, 37380 Nouzilly, France
| | - Sonia Lacroix-Lamandé
- INRAE, Université François Rabelais de Tours, Centre Val de Loire, ISP, Laboratoire Apicomplexes et Immunité Mucosale, 37380 Nouzilly, France
| | - Gilles Gargala
- French National Cryptosporidiosis Reference Center, Rouen University Hospital, 1 Rue de Germont, 76031 Rouen Cedex, France - EA 7510, UFR Santé, University of Rouen Normandy, Normandy University, 22 Bd. Gambetta, 76183 Rouen Cedex, France
| | - Loïc Favennec
- French National Cryptosporidiosis Reference Center, Rouen University Hospital, 1 Rue de Germont, 76031 Rouen Cedex, France - EA 7510, UFR Santé, University of Rouen Normandy, Normandy University, 22 Bd. Gambetta, 76183 Rouen Cedex, France
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Fan Y, Feng Y, Xiao L. Comparative genomics: how has it advanced our knowledge of cryptosporidiosis epidemiology? Parasitol Res 2019; 118:3195-3204. [DOI: 10.1007/s00436-019-06537-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 10/30/2019] [Indexed: 11/30/2022]
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Abstract
Cryptosporidium spp. (Apicomplexa) causing cryptosporidiosis are of medical and veterinary significance. The genus Cryptosporidium has benefited from the application of what is considered a DNA-barcoding approach, even before the term 'DNA barcoding' was formally coined. Here, the objective to define the DNA barcode diversity of Cryptosporidium infecting mammals is reviewed and considered to be accomplished. Within the Cryptosporidium literature, the distinction between DNA barcoding and DNA taxonomy is indistinct. DNA barcoding and DNA taxonomy are examined using the latest additions to the growing spectrum of named Cryptosporidium species and within-species and between-species identity is revisited. Ease and availability of whole-genome DNA sequencing of the relatively small Cryptosporidium genome offer an initial perspective on the intra-host diversity. The opportunity emerges to apply a metagenomic approach to purified field/clinical Cryptosporidum isolates. The outstanding question remains a reliable definition of Cryptosporidium phenotype. The complementary experimental infections and metagenome approach will need to be applied simultaneously to address Cryptosporidium phenotype with carefully chosen clinical evaluations enabling identification of virulence factors.
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Beser J, Hallström BM, Advani A, Andersson S, Östlund G, Winiecka-Krusnell J, Lebbad M, Alm E, Troell K, Arrighi RBG. Improving the genotyping resolution of Cryptosporidium hominis subtype IbA10G2 using one step PCR-based amplicon sequencing. INFECTION GENETICS AND EVOLUTION 2017; 55:297-304. [PMID: 28919550 DOI: 10.1016/j.meegid.2017.08.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/16/2017] [Accepted: 08/22/2017] [Indexed: 10/18/2022]
Abstract
Cryptosporidium hominis gp60 subtype IbA10G2 is a common cause of cryptosporidiosis. This subtype is responsible for many waterborne outbreaks as well as sporadic cases and is considered virulent and highly important in the epidemiology of cryptosporidiosis. Due to low heterogeneity within the genome of C. hominis it has been difficult to identify epidemiological markers with higher resolution than gp60. However, new markers are required in order to improve outbreak investigations and studies of the transmission dynamics of this clinically important subtype. Based on the whole genome sequences of 17 C. hominis isolates, we have identified several differential loci and developed a new sequence based typing panel with higher resolution than gp60. An amplicon sequencing method was also developed which is based on a one-step PCR which can be sequenced using a Next Generation Sequencing (NGS) platform. Such a system provides a rapid and high-throughput workflow. A panel of nine loci with 10 single nucleotide variants (SNV) was selected and evaluated using clinical IbA10G2 isolates from sporadic, cluster and outbreak associated cases. The specimens were separated into 10 different genetic profiles named sequence types (STs). All isolates within an outbreak or cluster belonged to the same ST, including several samples from the two large waterborne outbreaks which occurred in Sweden between 2010 and 2011 indicating that these outbreaks might be linked. The results demonstrate the methods suitability for improved genotyping of C. hominis IbA10G2.
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Affiliation(s)
| | | | | | | | | | | | | | - Erik Alm
- Public Health Agency of Sweden, Solna, Sweden
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Xiao L, Feng Y. Molecular epidemiologic tools for waterborne pathogens Cryptosporidium spp. and Giardia duodenalis. Food Waterborne Parasitol 2017; 8-9:14-32. [PMID: 32095639 PMCID: PMC7034008 DOI: 10.1016/j.fawpar.2017.09.002] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/19/2017] [Accepted: 09/19/2017] [Indexed: 01/26/2023] Open
Abstract
Molecular diagnostic tools have played an important role in improving our understanding of the transmission of Cryptosporidium spp. and Giardia duodenalis, which are two of the most important waterborne parasites in industrialized nations. Genotyping tools are frequently used in the identification of host-adapted Cryptosporidium species and G. duodenalis assemblages, allowing the assessment of infection sources in humans and public health potential of parasites found in animals and the environment. In contrast, subtyping tools are more often used in case linkages, advanced tracking of infections sources, and assessment of disease burdens attributable to anthroponotic and zoonotic transmission. More recently, multilocus typing tools have been developed for population genetic characterizations of transmission dynamics and delineation of mechanisms for the emergence of virulent subtypes. With the recent development in next generation sequencing techniques, whole genome sequencing and comparative genomic analysis are increasingly used in characterizing Cryptosporidium spp. and G. duodenalis. The use of these tools in epidemiologic studies has identified significant differences in the transmission of Cryptosporidium spp. in humans between developing countries and industrialized nations, especially the role of zoonotic transmission in human infection. Geographic differences are also present in the distribution of G. duodenalis assemblages A and B in humans. In contrast, there is little evidence for widespread zoonotic transmission of giardiasis in both developing and industrialized countries. Differences in virulence have been identified among Cryptosporidium species and subtypes, and possibly between G. duodenalis assemblages A and B, and genetic recombination has been identified as one mechanism for the emergence of virulent C. hominis subtypes. These recent advances are providing insight into the epidemiology of waterborne protozoan parasites in both developing and developed countries.
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Affiliation(s)
- Lihua Xiao
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
| | - Yaoyu Feng
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China
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Genomic Variation in IbA10G2 and Other Patient-Derived Cryptosporidium hominis Subtypes. J Clin Microbiol 2016; 55:844-858. [PMID: 28003424 DOI: 10.1128/jcm.01798-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/15/2016] [Indexed: 12/26/2022] Open
Abstract
In order to improve genotyping and epidemiological analysis of Cryptosporidium spp., genomic data need to be generated directly from a broad range of clinical specimens. Utilizing a robust method that we developed for the purification and generation of amplified target DNA, we present its application for the successful isolation and whole-genome sequencing of 14 different Cryptosporidium hominis patient specimens. Six isolates of subtype IbA10G2 were analyzed together with a single representative each of 8 other subtypes: IaA20R3, IaA23R3, IbA9G3, IbA13G3, IdA14, IeA11G3T3, IfA12G1, and IkA18G1. Parasite burden was measured over a range of more than 2 orders of magnitude for all samples, while the genomes were sequenced to mean depths of between 17× and 490× coverage. Sequence homology-based functional annotation identified several genes of interest, including the gene encoding Cryptosporidium oocyst wall protein 9 (COWP9), which presented a predicted loss-of-function mutation in all the sequence subtypes, except for that seen with IbA10G2, which has a sequence identical to the Cryptosporidium parvum reference Iowa II sequence. Furthermore, phylogenetic analysis showed that all the IbA10G2 genomes form a monophyletic clade in the C. hominis tree as expected and yet display some heterogeneity within the IbA10G2 subtype. The current report validates the aforementioned method for isolating and sequencing Cryptosporidium directly from clinical stool samples. In addition, the analysis demonstrates the potential in mining data generated from sequencing multiple whole genomes of Cryptosporidium from human fecal samples, while alluding to the potential for a higher degree of genotyping within Cryptosporidium epidemiology.
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Pérez-Cordón G, Robinson G, Nader J, Chalmers RM. Discovery of new variable number tandem repeat loci in multiple Cryptosporidium parvum genomes for the surveillance and investigation of outbreaks of cryptosporidiosis. Exp Parasitol 2016; 169:119-28. [PMID: 27523797 DOI: 10.1016/j.exppara.2016.08.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 08/09/2016] [Accepted: 08/10/2016] [Indexed: 01/28/2023]
Abstract
Cryptosporidium parvum is a protozoan parasite causing gastro-intestinal disease (cryptosporidiosis) in humans and animals. The ability to investigate sources of contamination and routes of transmission by characterization and comparison of isolates in a cost- and time-efficient manner will help surveillance and epidemiological investigations, but as yet there is no standardised multi-locus typing scheme. To systematically identify variable number tandem repeat (VNTR) loci, which have been shown to provide differentiation in moderately conserved species, we interrogated the reference C. parvum Iowa II genome and seven other C. parvum genomes using a tandem repeat finder software. We identified 28 loci that met criteria defined previously for robust typing schemes for inter-laboratory surveillance, that had potential for generating PCR amplicons analysable on most fragment sizing platforms: repeats ≥6 bp, occurring in tandem in a single repeat region, and providing a total amplicon size of <300 bp including 50 bp for the location of the forward and reverse primers. The qualifying loci will be further investigated in vitro for consideration as preferred loci in the development of a robust VNTR scheme.
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Affiliation(s)
- Gregorio Pérez-Cordón
- Cryptosporidium Reference Unit, Public Health Wales Microbiology, Singleton Hospital, Swansea, SA2 8QA, UK
| | - Guy Robinson
- Cryptosporidium Reference Unit, Public Health Wales Microbiology, Singleton Hospital, Swansea, SA2 8QA, UK; Swansea University Medical School, Grove Building, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Johanna Nader
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Rachel M Chalmers
- Cryptosporidium Reference Unit, Public Health Wales Microbiology, Singleton Hospital, Swansea, SA2 8QA, UK; Swansea University Medical School, Grove Building, Swansea University, Singleton Park, Swansea, SA2 8PP, UK.
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Troell K, Hallström B, Divne AM, Alsmark C, Arrighi R, Huss M, Beser J, Bertilsson S. Cryptosporidium as a testbed for single cell genome characterization of unicellular eukaryotes. BMC Genomics 2016; 17:471. [PMID: 27338614 PMCID: PMC4917956 DOI: 10.1186/s12864-016-2815-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 06/07/2016] [Indexed: 12/11/2022] Open
Abstract
Background Infectious disease involving multiple genetically distinct populations of pathogens is frequently concurrent, but difficult to detect or describe with current routine methodology. Cryptosporidium sp. is a widespread gastrointestinal protozoan of global significance in both animals and humans. It cannot be easily maintained in culture and infections of multiple strains have been reported. To explore the potential use of single cell genomics methodology for revealing genome-level variation in clinical samples from Cryptosporidium-infected hosts, we sorted individual oocysts for subsequent genome amplification and full-genome sequencing. Results Cells were identified with fluorescent antibodies with an 80 % success rate for the entire single cell genomics workflow, demonstrating that the methodology can be applied directly to purified fecal samples. Ten amplified genomes from sorted single cells were selected for genome sequencing and compared both to the original population and a reference genome in order to evaluate the accuracy and performance of the method. Single cell genome coverage was on average 81 % even with a moderate sequencing effort and by combining the 10 single cell genomes, the full genome was accounted for. By a comparison to the original sample, biological variation could be distinguished and separated from noise introduced in the amplification. Conclusions As a proof of principle, we have demonstrated the power of applying single cell genomics to dissect infectious disease caused by closely related parasite species or subtypes. The workflow can easily be expanded and adapted to target other protozoans, and potential applications include mapping genome-encoded traits, virulence, pathogenicity, host specificity and resistance at the level of cells as truly meaningful biological units. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2815-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Karin Troell
- Department of Microbiology, National Veterinary Institute, Uppsala, Sweden.
| | - Björn Hallström
- Department of Microbiology, Public Health Agency of Sweden, Solna, Sweden
| | - Anna-Maria Divne
- Microbial Single Cell Genomics Facility, Department of Cell and Molecular Biology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Cecilia Alsmark
- Department of Microbiology, National Veterinary Institute, Uppsala, Sweden.,Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Romanico Arrighi
- Department of Microbiology, Public Health Agency of Sweden, Solna, Sweden
| | - Mikael Huss
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Jessica Beser
- Department of Microbiology, Public Health Agency of Sweden, Solna, Sweden
| | - Stefan Bertilsson
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
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Suitability of loci for multiple-locus variable-number of tandem-repeats analysis of Cryptosporidium parvum for inter-laboratory surveillance and outbreak investigations. Parasitology 2016; 144:37-47. [PMID: 26831252 DOI: 10.1017/s0031182015001766] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cryptosporidium parvum is the major cause of livestock and zoonotically-acquired human cryptosporidiosis. The ability to track sources of contamination and routes of transmission by further differentiation of isolates would assist risk assessment and outbreak investigations. Multiple-locus variable-number of tandem-repeats (VNTR) analysis provides a means for rapid characterization by fragment sizing and estimation of copy numbers, but structured, harmonized development has been lacking for Cryptosporidium spp. To investigate potential for application in C. parvum surveillance and outbreak investigations, we studied nine commonly used VNTR loci (MSA, MSD, MSF, MM5, MM18, MM19, MS9-Mallon, GP60 and TP14) for chromosome distribution, repeat unit length and heterogeneity, and flanking region proximity and conservation. To investigate performance in vitro, we compared these loci in 14 C. parvum samples by capillary electrophoresis in three laboratories. We found that many loci did not contain simple repeat units but were more complex, hindering calculations of repeat unit copy number for standardized reporting nomenclature. However, sequenced reference DNA enabled reproducible fragment sizing and inter-laboratory allele assignation based on size normalized to that of the sequenced fragments by both single round and nested polymerase chain reactions. Additional Cryptosporidium loci need to be identified and validated for robust inter-laboratory surveillance and outbreak investigations.
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