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Detection of potential enteric pathogens in children with severe acute gastroenteritis using the filmarray: Results from a three - years hospital-based survey in Northern Italy. Diagn Microbiol Infect Dis 2021; 102:115611. [PMID: 34953368 DOI: 10.1016/j.diagmicrobio.2021.115611] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 11/24/2022]
Abstract
Acute gastroenteritis (AGE) are leading causes of morbidity and mortality in children. Therefore, rapid pathogens identification is needed. The AGE aetiology was investigated from 2018 to 2020 in 2,066 children in Parma (Italy) by FilmArray Gastrointestinal Panel and Enterovirus-targeting RT-PCR. Pathogens were detected in 1,162 (56.2%) stool samples from as many children; 798 (68.7%) were single and 364 (31.3%) mixed infections (68.7% vs 31.3%, P < 0.0001). Children aged 0-5 years showed the highest infection incidence (66.1%). The most frequent pathogens were Enteropathogenic Escherichia coli (EPEC; 19.14%), Clostridioides difficile (10.42%), Norovirus (10.36%), Enterovirus (9.44%), and Campylobacter (9.21%). EPEC, Campylobacter, enteroaggregative E. coli, Norovirus, and Rotavirus showed seasonality. The incidence of pathogens detected decreased between 2018 and 2020 (42.7% vs 20.8%, P < 0.0001), seemingly for the preventive measures imposed by the severe acute respiratory syndrome coronavirus-2 pandemic. A putative aetiology in half the children examined and an estimate of enteric pathogens epidemiology were assessed.
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Wahed MAA, Shehab YEA, Abou-Seri HM, Awad YMM. Clinical and Laboratory Diagnosis of Cryptosporidiosis among Children with Acute Gastroenteritis at a Tertiary Hospital, Cairo, Egypt. J Trop Pediatr 2021; 67:6344869. [PMID: 34363077 DOI: 10.1093/tropej/fmab064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Most studies on gastroenteritis have focused on viral and bacterial infections, while gastroenteritis where intestinal protozoan parasites may have played a role has not been well studied. This study was therefore, designed to assess the frequency and several potential risk factors for Cryptosporidium infection among children suffering from acute gastroenteritis and presented to a tertiary hospital in Cairo, Egypt. Effectiveness of modified Ziehl-Neelsen (MZN) and nested polymerase chain reaction (nPCR) for Cryptosporidium detection were evaluated as well. METHODS A cross-sectional study was performed during the period from July 2018 to December 2018, where 100 human diarrheic stool samples were collected from children aged 3 months up to 12 years old presented to Ain Shams University Pediatrics Hospital, Cairo, Egypt with acute gastroenteritis. Demographic and clinical data were obtained from the participants. Initial parasite screening was done using the MZN staining method, and microscopically examined for Cryptosporidium infection, while genotyping was based on molecular diagnostic assays using nPCR and sequencing for selected samples. RESULTS The overall frequency of Cryptosporidium infection was 5% using light microscopy, while 19% of samples were positive by nPCR. Cryptosporidium hominis was the only detected genotype. Clinical picture among cases were not significant in comparison to patients with other causes of gastroenteritis. CONCLUSION Cryptosporidium infection is more common below 5 years of age; however, clinical data are not enough for suspicion of infection. Nucleic acid-based methods are more sensitive and specific despite the high cost in developing countries. However, real estimation of Cryptosporidium disease burden is of an outmost importance to achieve prevention and detection of the Cryptosporidium species genetic diversity. Lay summaryCryptosporidium is a protozoan, which causes gastroenteritis in humans. It is most common below 5 years of age; however, diarrhea and vomiting characteristics are not different from other causes of gastroenteritis. General diagnostic methods are inadequate for detection of these infections. Nested polymerase chain reaction (nPCR) and sequencing are accurate methods for pathogen detection and species verification. Our study included 100 Egyptian children with acute gastroenteritis. The overall frequency of Cryptosporidium infection was 5% using light microscopy, while 19% of samples were positive by nPCR. The clinical picture of the children presenting with this disease was not significantly different from those presenting with gastroenteritis due to other causes. This emphasizes the importance of proper diagnosis to know the true burden of the disease.
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Angelici MC, Walochnik J, Calderaro A, Saxinger L, Dacks JB. Free-living amoebae and other neglected protistan pathogens: Health emergency signals? Eur J Protistol 2020; 77:125760. [PMID: 33340850 DOI: 10.1016/j.ejop.2020.125760] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 10/25/2020] [Accepted: 11/13/2020] [Indexed: 02/08/2023]
Abstract
Protistan parasites have an undisputed global health impact. However, outside of a few key exceptions, e.g. the agent of malaria, most of these infectious agents are neglected as important health threats. The Symposium entitled "Free-living amoebae and neglected pathogenic protozoa: health emergency signals?" held at the European Congress of Protistology in Rome, July 2019, brought together researchers addressing scientific and clinical questions about some of these fascinating organisms. Topics presented included the molecular basis of pathogenicity in Acanthamoeba; genomics of Naegleria fowleri; and epidemiology of poorly diagnosed enteric protistan species, including Giardia, Cryptosporidium, Blastocystis, Dientamoeba. The Symposium aim was to excite the audience about the opportunities and challenges of research in these underexplored organisms and to underline the public health implications of currently under-appreciated protistan infections. The major take home message is that any knowledge that we gain about these organisms will allow us to better address them, in terms of monitoring and treatment, as sources of future health emergencies.
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Affiliation(s)
| | - Julia Walochnik
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Adriana Calderaro
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Lynora Saxinger
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Alberta, Canada
| | - Joel B Dacks
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Alberta, Canada; Institute of Parasitology, Biology Centre, Czech Academy of Sciences České Budějovice, Czech Republic.
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Dahiya B, Mehta PK. Detection of potential biomarkers associated with outrageous diseases and environmental pollutants by nanoparticle-based immuno-PCR assays. Anal Biochem 2019; 587:113444. [PMID: 31545948 DOI: 10.1016/j.ab.2019.113444] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/18/2019] [Accepted: 09/18/2019] [Indexed: 12/20/2022]
Abstract
Immuno-polymerase chain reaction (I-PCR) assay with advantages of both enzyme-linked immunosorbent assay (ELISA) and PCR exhibits several-fold enhanced sensitivity in comparison to respective ELISA, which has wide applications for ultralow detection of several molecules, i.e. cytokines, protooncogenes and biomarkers associated with several diseases. Conjugation of reporter DNA to the detection antibodies is the most crucial step of I-PCR assay that usually employs streptavidin-protein A, streptavidin-biotin conjugate or succinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) system by a covalent binding. However, coupling of antibodies and oligonucleotides to nanoparticles (NPs) is relatively easier in the NP-based I-PCR (NP-I-PCR) that also displays better accuracy. This article is mainly focused on the detection of important biomarkers associated with several outrageous infectious and non-infectious diseases by NP-I-PCR assays, which would expedite an early initiation of therapy thus human health would be improved. Similarly, ultralow detection of environmental pollutants by these assays and their elimination would certainly improve human health.
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Affiliation(s)
- Bhawna Dahiya
- Centre for Biotechnology, Maharshi Dayanand University (MDU), Rohtak, 124001, Haryana, India
| | - Promod K Mehta
- Centre for Biotechnology, Maharshi Dayanand University (MDU), Rohtak, 124001, Haryana, India.
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Calderaro A, Martinelli M, Buttrini M, Montecchini S, Covan S, Rossi S, Ferraglia F, Montagna P, Pinardi F, Larini S, Arcangeletti MC, Medici MC, Chezzi C, De Conto F. Contribution of the FilmArray ® Gastrointestinal Panel in the laboratory diagnosis of gastroenteritis in a cohort of children: a two-year prospective study. Int J Med Microbiol 2018; 308:514-521. [PMID: 29748124 DOI: 10.1016/j.ijmm.2018.04.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/20/2018] [Accepted: 04/30/2018] [Indexed: 02/08/2023] Open
Abstract
This study represents a 2-year picture of the epidemiology of enteric pathogens in children suffering from gastroenteritis using the FilmArray® Gastrointestinal Panel (FA-GP), a multiplex molecular assay that allows to simultaneously detect a large panel of pathogens independently of the etiological suspicion and to evaluate its potential contribution to the diagnosis compared to the conventional methods. A total of 1716 stool samples, collected from children with clinical suspicion of bacterial and/or viral gastroenteritis attending the University Hospital of Parma, was submitted to the FA-GP and, when an adequate aliquot was available, to electron microscopy (n = 1163) for virus detection and to an enterovirus-targeting real-time PCR (n = 1703). Specimens with positive results for Salmonella, Yersinia enterocolitica, Vibrio, diarrheagenic Escherichia coli/Shigella, Campylobacter, Plesiomonas shigelloides and/or parasites by the FA-GP were also submitted to conventional diagnostic methods. The FA-GP gave positive results in 958 (55.8%) cases, 64.8% from inpatients: 647 (67.5%) contained a single agent and 311 (32.5%) multiple agents, for a total of 1374 pathogens. Enteropathogenic E. coli, rotavirus, norovirus, toxigenic Clostridioides difficile, and sapovirus were the most commonly detected pathogens. A total of 812 additional agents (344 of which as single pathogen) was detected by the FA-GP and not included in the clinical suspicion. The overall recovery rate of the conventional methods from stools that resulted positive by the FA-GP was 38.6% for bacteria, 50% and 84.2% for Giardia intestinalis and Cryptosporidium, respectively, and ranged from 3.7% to 64.6% for viruses, if excluding all electron microscopy-negative astroviruses. Enterovirus, an agent not targeted by the FA-GP, was revealed in 9.6% (164/1703) of the examined samples, and in 52 cases it was the only agent detected. The results of this study allowed to extend the range of detectable pathogens independently of the clinical suspicion, to detect co-infections in almost one third of children positive for at least one agent and to show that conventional methods would have missed more than half of the enteric agents detected by the FA-GP.
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Affiliation(s)
- Adriana Calderaro
- Department of Medicine and Surgery, University of Parma, Parma, Italy.
| | - Monica Martinelli
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Mirko Buttrini
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Sara Montecchini
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Silvia Covan
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Sabina Rossi
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | | | - Paolo Montagna
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Federica Pinardi
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Sandra Larini
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | | | | | - Carlo Chezzi
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Flora De Conto
- Department of Medicine and Surgery, University of Parma, Parma, Italy
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Calderaro A, Buttrini M, Montecchini S, Rossi S, Piccolo G, Arcangeletti MC, Medici MC, Chezzi C, De Conto F. MALDI-TOF MS as a new tool for the identification of Dientamoeba fragilis. Parasit Vectors 2018; 11:11. [PMID: 29301570 PMCID: PMC5755284 DOI: 10.1186/s13071-017-2597-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/17/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND In this study for the first time, a Dientamoeba fragilis protein profile by MALDI-TOF MS was created in order to identify specific markers for the application of this technology in the laboratory diagnosis of dientamoebiasis. In particular, one D. fragilis reference strain was used to create a reference spectrum and 14 clinical isolates to verify the reliability of the obtained results. RESULTS While 15 peaks were found to be discriminating between the reference strain and the culture medium used, six peaks, observed in all the 14 strains tested, were considered as markers able to identify D. fragilis. CONCLUSIONS In our hands, MALDI-TOF MS technology was demonstrated as a useful tool to be used in association with or in replacement of the real-time PCR assay for the identification of D. fragilis used in our laboratory on xenic cultures, due to its accuracy, rapidity and low cost.
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Affiliation(s)
- Adriana Calderaro
- Department of Medicine and Surgery, University of Parma, Parma, Italy.
| | - Mirko Buttrini
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Sara Montecchini
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Sabina Rossi
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Giovanna Piccolo
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | | | | | - Carlo Chezzi
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Flora De Conto
- Department of Medicine and Surgery, University of Parma, Parma, Italy
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Tang YW, Stratton CW. Interpretation and Relevance of Advanced Technique Results. ADVANCED TECHNIQUES IN DIAGNOSTIC MICROBIOLOGY 2018. [PMCID: PMC7120226 DOI: 10.1007/978-3-319-95111-9_31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Advanced techniques in the field of diagnostic microbiology have made amazing progress over the past 25 years due largely to a technological revolution in the molecular aspects of microbiology [1, 2]. In particular, rapid molecular methods for nucleic acid amplification and characterization combined with automation in the clinical microbiology laboratory as well as user-friendly software and robust laboratory informatics systems have significantly broadened the diagnostic capabilities of modern clinical microbiology laboratories. Molecular methods such as nucleic acid amplification tests (NAATs) rapidly are being developed and introduced in the clinical laboratory setting [3, 4]. Indeed, every section of the clinical microbiology laboratory, including bacteriology, mycology, mycobacteriology, parasitology, and virology, has benefited from these advanced techniques. Because of the rapid development and adaptation of these molecular techniques, the interpretation and relevance of the results produced by such molecular methods continues to lag behind. The purpose of this chapter is to review, update, and discuss the interpretation and relevance of results produced by these advanced molecular techniques.
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Affiliation(s)
- Yi-Wei Tang
- Departments of Laboratory Medicine and Internal Medicine, Memorial Sloan Kettering Cancer Center, New York, NY USA
| | - Charles W. Stratton
- Department of Pathology, Microbiology and Immunology and Medicine, Vanderbilt University Medical Center, Nashville, TN USA
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Beyhan YE, Taş Cengiz Z. Comparison of microscopy, ELISA, and real-time PCR for detection of Giardia intestinalis in human stool specimens. Turk J Med Sci 2017; 47:1295-1299. [PMID: 29156877 DOI: 10.3906/sag-1612-71] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Background/aim: This study included patients who had digestive system complaints between August 2015 and October 2015. The research was designed to compare conventional microscopy with an antigen detection ELISA kit and the TaqMan-based real-time PCR (RT-PCR) technique for detection of Giardia intestinalis in human stool specimens. Materials and methods: Samples were concentrated by formalin-ether sedimentation technique and microscopic examinations were carried out on wet mount slides. A commercially available ELISA kit (Giardia CELISA, Cellabs, Brookvale, Australia) was used for immunoassay. DNA was extracted from fecal samples of about 200 mg using the QIAamp Fast DNA Stool Mini Kit (QIAGEN, Hilden, Germany) and the LightCycler Nano system (Roche Diagnostics, Mannheim, Germany) was used for the TaqMan-based RT-PCR assay. Results: A total of 94 stool samples, 38 of them diagnosed positive (40.4%) and 56 of them diagnosed negative by microscopy, were selected for evaluation by antigen detection and molecular assays. The prevalence of G. intestinalis infection was found as 46.8% (n: 44) and 79.8% (n: 75) by ELISA and RT-PCR, respectively. RT-PCR revealed by far the highest positivity rate compared to the other two methods. The difference between these methods was found to be statistically significant (P < 0.05). In comparison to PCR, the sensitivity and specificity of microscopy and ELISA were 50.7% and 100% and 53.3% and 79%, respectively. Conclusion: RT-PCR seems to be much more sensitive and beneficial for rapid and accurate diagnosis of G. intestinalis in human stools.
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Nooshadokht M, Kalantari-Khandani B, Sharifi I, Kamyabi H, Liyanage NPM, Lagenaur LA, Kagnoff MF, Singer SM, Babaei Z, Solaymani-Mohammadi S. Stool antigen immunodetection for diagnosis of Giardia duodenalis infection in human subjects with HIV and cancer. J Microbiol Methods 2017; 141:35-41. [PMID: 28716658 DOI: 10.1016/j.mimet.2017.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 01/18/2023]
Abstract
Human infection with the protozoan parasite Giardia duodenalis is one the most common parasitic diseases worldwide. Higher incidence rates of giardiasis have been reported from human subjects with multiple debilitating chronic conditions, including hypogammaglobulinemia and common variable immunodeficiency (CVID). In the current study, stool specimens were collected from 199 individuals diagnosed with HIV or cancer and immunocompetent subjects. The sensitivity of microscopy-based detection on fresh stool preparations, trichrome staining and stool antigen immunodetection for the diagnosis of G. duodenalis were 36%, 45.5% and 100%, respectively when compared with a highly sensitive stool-based PCR method as the gold standard. Further multilocus molecular analyses using glutamate dehydrogenase (gdh) and triose phosphate isomerase (tpi) loci demonstrated that the AI genotype of G. duodenalis was the most prevalent, followed by the AII genotype and mixed (AI+B) infections. We concluded that stool antigen immunodetection-based immunoassays and stool-based PCR amplification had comparable sensitivity and specificity for the diagnosis of G. duodenalis infections in these populations. Stool antigen detection-based diagnostic modalities are rapid and accurate and may offer alternatives to conventional microscopy and PCR-based diagnostic methods for the diagnosis of G. duodenalis in human subjects living with HIV or cancer.
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Affiliation(s)
- Maryam Nooshadokht
- Department of Medical Parasitology and Mycology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | | | - Iraj Sharifi
- Leishmaniasis Research Center, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Hossein Kamyabi
- Department of Medical Parasitology and Mycology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Namal P M Liyanage
- Department of Microbial Infection and Immunity, College of Medicine, Ohio State University, Columbus, OH, USA
| | | | - Martin F Kagnoff
- Laboratory of Mucosal Immunology, School of Medicine, University of California, San Diego, California, USA
| | - Steven M Singer
- Department of Biology and Center for Infectious Disease, Georgetown University, Washington D.C., USA
| | - Zahra Babaei
- Leishmaniasis Research Center, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
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Rogawski ET, Bartelt LA, Platts-Mills JA, Seidman JC, Samie A, Havt A, Babji S, Trigoso DR, Qureshi S, Shakoor S, Haque R, Mduma E, Bajracharya S, Gaffar SMA, Lima AAM, Kang G, Kosek MN, Ahmed T, Svensen E, Mason C, Bhutta ZA, Lang DR, Gottlieb M, Guerrant RL, Houpt ER, Bessong PO. Determinants and Impact of Giardia Infection in the First 2 Years of Life in the MAL-ED Birth Cohort. J Pediatric Infect Dis Soc 2017; 6:153-160. [PMID: 28204556 PMCID: PMC5907871 DOI: 10.1093/jpids/piw082] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/28/2016] [Indexed: 11/13/2022]
Abstract
BACKGROUND. Giardia are among the most common enteropathogens detected in children in low-resource settings. We describe here the epidemiology of infection with Giardia in the first 2 years of life in the Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development Project (MAL-ED), a multisite birth-cohort study. METHODS. From 2089 children, 34916 stool samples collected during monthly surveillance and episodes of diarrhea were tested for Giardia using an enzyme immunoassay. We quantified the risk of Giardia detection, identified risk factors, and assessed the associations with micronutrients, markers of gut inflammation and permeability, diarrhea, and growth using multivariable linear regression. RESULTS. The incidence of at least 1 Giardia detection varied according to site (range, 37.7%-96.4%) and was higher in the second year of life. Exclusive breastfeeding (HR for first Giardia detection in a monthly surveillance stool sample, 0.46 [95% confidence interval (CI), 0.28-0.75]), higher socioeconomic status (HR, 0.74 [95% CI, 0.56-0.97]), and recent metronidazole treatment (risk ratio for any surveillance stool detection, 0.69 [95% CI, 0.56-0.84]) were protective. Persistence of Giardia (consecutive detections) in the first 6 months of life was associated with reduced subsequent diarrheal rates in Naushahro Feroze, Pakistan but not at any other site. Giardia detection was also associated with an increased lactulose/mannitol ratio. Persistence of Giardia before 6 months of age was associated with a -0.29 (95% CI, -0.53 to -0.05) deficit in weight-for-age z score and -0.29 (95% CI, -0.64 to 0.07) deficit in length-for-age z score at 2 years. CONCLUSIONS. Infection with Giardia occurred across epidemiological contexts, and repeated detections in 40% of the children suggest that persistent infections were common. Early persistent infection with Giardia, independent of diarrhea, might contribute to intestinal permeability and stunted growth.
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Affiliation(s)
- Elizabeth T. Rogawski
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville
| | - Luther A. Bartelt
- Division of Infectious Diseases, University of North Carolina-Chapel Hill
| | - James A. Platts-Mills
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville
| | - Jessica C. Seidman
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland
| | | | - Alexandre Havt
- Clinical Research Unit and Institute of Biomedicine, Federal University of Ceara, Fortaleza, Brazil
| | | | | | | | | | - Rashidul Haque
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | | | | | | | - Aldo A. M. Lima
- Clinical Research Unit and Institute of Biomedicine, Federal University of Ceara, Fortaleza, Brazil
| | | | - Margaret N. Kosek
- Asociación Benéfica PRISMA, Iquitos, Peru;,Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Tahmeed Ahmed
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | | | - Carl Mason
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand; and
| | | | - Dennis R. Lang
- Foundation for the National Institutes of Health, Bethesda, Maryland
| | - Michael Gottlieb
- Foundation for the National Institutes of Health, Bethesda, Maryland
| | - Richard L. Guerrant
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville
| | - Eric R. Houpt
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville
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Giardiasis: an update review on sensitivity and specificity of methods for laboratorial diagnosis. J Microbiol Methods 2016; 129:98-102. [DOI: 10.1016/j.mimet.2016.08.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/15/2016] [Accepted: 08/18/2016] [Indexed: 11/15/2022]
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Molecular testing for clinical diagnosis and epidemiological investigations of intestinal parasitic infections. Clin Microbiol Rev 2016; 27:371-418. [PMID: 24696439 DOI: 10.1128/cmr.00122-13] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Over the past few decades, nucleic acid-based methods have been developed for the diagnosis of intestinal parasitic infections. Advantages of nucleic acid-based methods are numerous; typically, these include increased sensitivity and specificity and simpler standardization of diagnostic procedures. DNA samples can also be stored and used for genetic characterization and molecular typing, providing a valuable tool for surveys and surveillance studies. A variety of technologies have been applied, and some specific and general pitfalls and limitations have been identified. This review provides an overview of the multitude of methods that have been reported for the detection of intestinal parasites and offers some guidance in applying these methods in the clinical laboratory and in epidemiological studies.
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Beckmann C, Heininger U, Marti H, Hirsch HH. Gastrointestinal pathogens detected by multiplex nucleic acid amplification testing in stools of pediatric patients and patients returning from the tropics. Infection 2015; 42:961-70. [PMID: 25015433 DOI: 10.1007/s15010-014-0656-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 06/23/2014] [Indexed: 12/29/2022]
Abstract
BACKGROUND Gastrointestinal infections are caused by a broad spectrum of pathogens. Conventional diagnostic procedures are resource and time consuming due to single pathogen testing, often in different laboratories. METHOD We analyzed 312 consecutive stool samples from pediatric patients (n = 127) with gastroenteritis or from adult travelers returning from the tropics with suspected parasite infestation (n = 185) using commercial multiplex nucleic acid amplification testing (NAT) (xTAG gastrointestinal pathogen panel, Luminex) covering 15 diarrhea-causing pathogens. The results of the positive samples and a representative number of negative samples were compared to standard methods, including NAT, direct antigen detection (DAD), bacterial culture and microscopy. RESULTS Of the 185 samples from adult travelers, 21 (11 %) were multiplexNAT-positive, with enterotoxigenic Escherichia coli (4 %) being the predominant pathogen. Microscopic examination revealed Blastocystis hominis in 23 % not covered by the panel. MultiplexNAT scored positive in 66 pediatric samples (52 %), with rotavirus (27 %) being the most prevalent. All adenovirus-, rotavirus-, Clostridium difficile- and Cryptosporidium-positive samples were confirmed in external laboratories, but only 40 % of norovirus- and 29 % of Giardia-positive samples. Analysis of frozen specimens by bacterial culture showed the highest discrepancies with the multiplexNAT. CONCLUSION Our study demonstrates broad detection of relevant gastroenteritis pathogens by multiplexNAT with a short turnaround time. This is important for diagnosis, infection control and empiric management of gastroenteritis patients, but may be selectively complemented by bacterial culture and resistance testing.
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Crannell ZA, Cabada MM, Castellanos-Gonzalez A, Irani A, White AC, Richards-Kortum R. Recombinase polymerase amplification-based assay to diagnose Giardia in stool samples. Am J Trop Med Hyg 2014; 92:583-7. [PMID: 25510713 DOI: 10.4269/ajtmh.14-0593] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Giardia duodenalis is one of the most commonly identified parasites in stool samples. Although relatively easy to treat, giardiasis can be difficult to detect as it presents similar to other diarrheal diseases. Here, we present a recombinase polymerase amplification-based Giardia (RPAG) assay to detect the presence of Giardia in stool samples. The RPAG assay was characterized on the bench top using stool samples spiked with Giardia cysts where it showed a limit-of-detection nearly as low as the gold standard polymerase chain reaction assay. The RPAG assay was then tested in the highlands of Peru on 104 stool samples collected from the surrounding communities where it showed 73% sensitivity and 95% specificity against a polymerase chain reaction and microscopy composite gold standard. Further improvements in clinical sensitivity will be needed for the RPAG assay to have clinical relevance.
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Affiliation(s)
- Zachary Austin Crannell
- Rice University, Bioengineering, Houston, Texas; Universidad Peruana Cayetano Heredia, Department of Internal Medicine, Cusco, Peru; University of Texas Medical Branch, Department of Internal Medicine, Galveston, Texas
| | - Miguel Mauricio Cabada
- Rice University, Bioengineering, Houston, Texas; Universidad Peruana Cayetano Heredia, Department of Internal Medicine, Cusco, Peru; University of Texas Medical Branch, Department of Internal Medicine, Galveston, Texas
| | - Alejandro Castellanos-Gonzalez
- Rice University, Bioengineering, Houston, Texas; Universidad Peruana Cayetano Heredia, Department of Internal Medicine, Cusco, Peru; University of Texas Medical Branch, Department of Internal Medicine, Galveston, Texas
| | - Ayesha Irani
- Rice University, Bioengineering, Houston, Texas; Universidad Peruana Cayetano Heredia, Department of Internal Medicine, Cusco, Peru; University of Texas Medical Branch, Department of Internal Medicine, Galveston, Texas
| | - Arthur Clinton White
- Rice University, Bioengineering, Houston, Texas; Universidad Peruana Cayetano Heredia, Department of Internal Medicine, Cusco, Peru; University of Texas Medical Branch, Department of Internal Medicine, Galveston, Texas
| | - Rebecca Richards-Kortum
- Rice University, Bioengineering, Houston, Texas; Universidad Peruana Cayetano Heredia, Department of Internal Medicine, Cusco, Peru; University of Texas Medical Branch, Department of Internal Medicine, Galveston, Texas
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Verkerke HP, Sobuz SU, Petri WA. Molecular diagnosis of infectious diarrhea: focus on enteric protozoa. Expert Rev Mol Diagn 2014; 14:935-46. [PMID: 25139776 DOI: 10.1586/14737159.2014.951035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Robust detection of enteric protozoa is a critical step toward determining the etiology of diarrhea. Widespread use of conventional microscopy, culturing and antigen detection in both industrial and developing countries is limited by relatively low sensitivity and specificity. Refinements of these conventional approaches that reduce turnaround time and instrumentation have yielded strong alternatives for clinical and research use. However, advances in molecular diagnostics for protozoal, bacterial, viral and helminth infections offer significant advantages in studies seeking to understand pathogenesis, transmission and long-term consequences of infectious diarrhea. Quantitation of enteropathogen burden and highly multiplexed platforms for molecular detection dramatically improve predictive power in emerging models of diarrheal etiology, while eliminating the expense of multiple tests.
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Affiliation(s)
- Hans P Verkerke
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, 22901, USA
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Boadi S, Polley SD, Kilburn S, Mills GA, Chiodini PL. A critical assessment of two real-time PCR assays targeting the (SSU) rRNA and gdh genes for the molecular identification of Giardia intestinalis in a clinical laboratory. J Clin Pathol 2014; 67:811-6. [DOI: 10.1136/jclinpath-2014-202224] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
IntroductionGiardiasis is an intestinal diarrhoeal illness caused by the flagellate protozoan parasite Giardia intestinalis. Molecular techniques for the identification of G. intestinalis have generally been shown to offer a better detection rate of the parasite than the traditional faecal concentration and microscopy techniques.AimThe aim of this study was to critically assess the performance of a commercial and a published real-time PCR assay for their potential use as frontline tests for the diagnosis of giardiasis.MethodsA composite reference standard of enzyme immunoassay and rapid membrane test was used in a diagnostic accuracy study to assess the performance of Primerdesign's, and Verweij et alG. intestinalis real-time PCR assays, comparing them with the traditional ova, cysts and parasite microscopy test (OCP-M).ResultsThe Verweij real-time PCR used primers for the (SSU) rRNA gene, and produced a diagnostic sensitivity of 93.4% (95% CI 88.30% to 98.50%) and an efficiency of 100%. Primerdesign's real-time PCR used primers for the glutamate dehydrogenase gene and produced a diagnostic sensitivity of 61.5% (95% CI 51.50% to 71.50%) and an efficiency of 203%. The OCP-M sensitivity was 83.5% (95% CI 75.87% to 91.13%).ConclusionsThe Verweij real-time PCR was robust and the most sensitive assay suited for use as a first-line diagnostic test for giardiasis.
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Application of PCR-based methods for diagnosis of intestinal parasitic infections in the clinical laboratory. Parasitology 2014; 141:1863-72. [DOI: 10.1017/s0031182014000419] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
SUMMARYFor many years PCR- and other DNA-based methods of pathogen detection have been available in most clinical microbiology laboratories; however, until recently these tools were not routinely exploited for the diagnosis of parasitic infections. Laboratories were initially reluctant to implement PCR as incorporation of such assays within the algorithm of tools available for the most accurate diagnosis of a large variety of parasites was unclear. With regard to diagnosis of intestinal parasitic infections, the diversity of parasites that one can expect in most settings is far less than the parasitological textbooks would have you believe, hence developing a simplified diagnostic triage is feasible. Therefore the classical algorithm based on population, patient groups, use of immuno-suppressive drugs, travel history etc. is also applicable to decide when to perform and which additional techniques are to be used, if a multiplex PCR panel is used as a first-line screening diagnostic.
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Ignatius R, Gahutu JB, Klotz C, Musemakweri A, Aebischer T, Mockenhaupt FP. Detection of Giardia duodenalis assemblage A and B isolates by immunochromatography in stool samples from Rwandan children. Clin Microbiol Infect 2014; 20:O783-5. [PMID: 24533695 DOI: 10.1111/1469-0691.12596] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 02/11/2014] [Accepted: 02/11/2014] [Indexed: 12/01/2022]
Abstract
We evaluated the performance of an immunochromatographic assay (ICA) in comparison with light microscopy and PCR for the detection of Giardia duodenalis in stool samples from 558 Rwandan children. The association of infection with clinical symptoms was similar for the three diagnostic tools. The ICA equally detected parasites of assemblages A and B and was more sensitive than light microscopy (50.4 versus 29.5% of PCR-positive samples considered true positive; p <0.0001). Hence, the ICA shows superior sensitivity compared with microscopy but still misses half of the G. duodenalis infections detected by PCR in this hyperendemic area.
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Affiliation(s)
- R Ignatius
- Institute of Tropical Medicine and International Health, Charité - Universitätsmedizin Berlin, Berlin, Germany
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Uda-Shimoda CF, Colli CM, Pavanelli MF, Falavigna-Guilherme AL, Gomes ML. Simplified protocol for DNA extraction and amplification of 2 molecular markers to detect and type Giardia duodenalis. Diagn Microbiol Infect Dis 2013; 78:53-8. [PMID: 24207076 DOI: 10.1016/j.diagmicrobio.2013.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 09/10/2013] [Accepted: 09/15/2013] [Indexed: 11/17/2022]
Abstract
We evaluated the ability of 3 kits: QIAmp® DNA stool mini kit (Qiagen, Hilden, Germany), PureLink PCR Purification®, and PureLink™ Genomic DNA® (Invitrogen, Carlsbad, CA, USA) for DNA extraction, and of 2 molecular markers (heat shock protein [HSP] and β-giardin genes) for detection and genotyping of Giardia duodenalis stool samples. The detection and typing limits of the markers were determined by the DNA concentration of trophozoites and cysts and were tested in 26 clinical samples. Of the 3 kits tested, the PureLink PCR Purification gave the best results when tested with clinical samples with low, intermediate, and high numbers of cysts. The DNA extracted from trophozoites and cysts was diluted successively in 1:2 ratios until it was no longer possible to observe the amplified product in polyacrylamide gel. Similarly, a suspension of cysts was diluted until no cysts were observed, and then the DNA was extracted. The amount of DNA of trophozoites and cysts for the typing of the parasite was smaller for the HSP marker than for β-giardin. Combined use of both markers allowed us to detect DNA of Giardia in parasitologically positive samples in a higher percentage (75%) than the results obtained for each marker and in 1 parasitologically negative sample, indicating that this combination increased the potential to accurately detect and genotype this parasite. We also concluded that the HSP marker has a higher limit of detection and typing than the β-giardin marker and that the DNA extraction method tested for G. duodenalis is simpler and more efficient than those that are currently in use and can be applied on a large scale.
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Affiliation(s)
- Carla Fernanda Uda-Shimoda
- Laboratory of Environmental Parasitology, Department of Basic Health Sciences, State University of Maringá, Maringá, Paraná 87020-900, Brazil
| | - Cristiane Maria Colli
- Laboratory of Environmental Parasitology, Department of Basic Health Sciences, State University of Maringá, Maringá, Paraná 87020-900, Brazil.
| | | | - Ana Lúcia Falavigna-Guilherme
- Laboratory of Environmental Parasitology, Department of Basic Health Sciences, State University of Maringá, Maringá, Paraná 87020-900, Brazil
| | - Mônica Lúcia Gomes
- Laboratory of Environmental Parasitology, Department of Basic Health Sciences, State University of Maringá, Maringá, Paraná 87020-900, Brazil
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Afra K, Laupland K, Leal J, Lloyd T, Gregson D. Incidence, risk factors, and outcomes of Fusobacterium species bacteremia. BMC Infect Dis 2013; 14:264. [PMID: 24886502 PMCID: PMC4029911 DOI: 10.1186/1471-2334-14-264] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 05/07/2014] [Indexed: 01/06/2023] Open
Abstract
Background The aim of this study was to assess the epidemiology of intestinal parasitoses during a 5-year period in patients attending a tertiary-care hospital in a non-endemic setting. Methods In the period 2006–2010, 15,752 samples from 8,886 patients with clinically suspected parasitosis were subjected to macroscopic and microscopic examination, to parasitic antigen detection assays, and to cultures for protozoa and nematodes. Real-time PCR assays for the differentiation of Entamoeba histolytica and E. dispar and for the detection of Dientamoeba fragilis were also used. A statistical analysis evaluating the demographic data of the patients with intestinal parasitic infections was performed. Results Intestinal parasitic infections were diagnosed in 1,477 patients (16.6% prevalence), mainly adults and immigrants from endemic areas for faecal-oral infections; protozoa were detected in 93.4% and helminths in 6.6% of the cases, the latter especially in immigrants. Blastocystis hominis was the most common intestinal protozoan, and G. intestinalis was the most frequently detected among pathogenic protozoa, prevalent in immigrants, males, and pediatric patients. Both single (77.9%) and mixed (22.1%) parasitic infections were observed, the latter prevalent in immigrants. Conclusions Despite the importance of the knowledge about the epidemiology of intestinal parasitoses in order to adopt appropriate control measures and adequate patient care all over the world, data regarding industrialized countries are rarely reported in the literature. The data presented in this study indicate that intestinal parasitic infections are frequently diagnosed in our laboratory and could make a contribution to stimulate the attention by physicians working in non-endemic areas on the importance of suspecting intestinal parasitoses.
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Papini R, Carreras G, Marangi M, Mancianti F, Giangaspero A. Use of a commercial enzyme-linked immunosorbent assay for rapid detection of Giardia duodenalis in dog stools in the environment. J Vet Diagn Invest 2013; 25:418-22. [DOI: 10.1177/1040638713485583] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Giardia duodenalis is considered a potentially zoonotic protozoan. Some animal species, including infected dogs, may play an important role in the spread of Giardia cysts through environmental contamination with their feces. In the present study, a commercial enzyme-linked immunosorbent assay (ELISA) was used to examine 143 samples of dog feces collected in urban areas as an indicator of the risk of field contamination. Using a Bayesian statistical approach, the ELISA showed a sensitivity of 88.9% and a specificity of 95.8% with positive and negative predictive values of 89.6% and 95.4%, respectively. The test affords the advantage of rapid processing of fecal samples without a complex technical structure and extensive costly labor. Moreover, the present results show that the assay provides public health veterinarians with a practical tool that can be used in screening programs, as a valid alternative or as an adjunct to other tests, in order to assess the biological risk of exposure to G. duodenalis cysts from dogs in human settlements. However, the test may not be completely accurate for human health risk evaluation, as it does not discriminate between zoonotic and non-zoonotic isolates.
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Affiliation(s)
- Roberto Papini
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy (Papini, Mancianti)
- Cancer Research and Prevention Institute, Florence, Italy (Carreras)
- Department of the Sciences of Agriculture, Food and Environment, University of Foggia, Foggia, Italy (Marangi, Giangaspero)
| | - Giulia Carreras
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy (Papini, Mancianti)
- Cancer Research and Prevention Institute, Florence, Italy (Carreras)
- Department of the Sciences of Agriculture, Food and Environment, University of Foggia, Foggia, Italy (Marangi, Giangaspero)
| | - Marianna Marangi
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy (Papini, Mancianti)
- Cancer Research and Prevention Institute, Florence, Italy (Carreras)
- Department of the Sciences of Agriculture, Food and Environment, University of Foggia, Foggia, Italy (Marangi, Giangaspero)
| | - Francesca Mancianti
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy (Papini, Mancianti)
- Cancer Research and Prevention Institute, Florence, Italy (Carreras)
- Department of the Sciences of Agriculture, Food and Environment, University of Foggia, Foggia, Italy (Marangi, Giangaspero)
| | - Annunziata Giangaspero
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy (Papini, Mancianti)
- Cancer Research and Prevention Institute, Florence, Italy (Carreras)
- Department of the Sciences of Agriculture, Food and Environment, University of Foggia, Foggia, Italy (Marangi, Giangaspero)
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Interpretation and Relevance of Advanced Technique Results. ADVANCED TECHNIQUES IN DIAGNOSTIC MICROBIOLOGY 2013. [PMCID: PMC7119927 DOI: 10.1007/978-1-4614-3970-7_47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Advanced techniques in the field of diagnostic microbiology have made amazing progress over the past two decades due largely to a technological revolution in the molecular aspects of microbiology [1, 2]. In particular, rapid molecular methods for nucleic acid amplification and characterization combined with automation and user-friendly software have significantly broadened the diagnostic capabilities of modern clinical microbiology laboratories. Molecular methods such as nucleic acid amplification tests (NAATs) rapidly are being developed and introduced in the clinical laboratory setting. Indeed, every section of the clinical microbiology laboratory, including bacteriology, mycology, mycobacteriology, parasitology, and virology, have benefited from these advanced techniques. Because of the rapid development and adaptation of these molecular techniques, the interpretation and relevance of the results produced by such molecular methods has lagged somewhat behind. The purpose of this chapter is to review and discuss the interpretation and relevance of results produced by these advanced molecular techniques. Moreover, this chapter will address the “myths” of NAATs, as these myths can markedly influence the interpretation and relevance of these results.
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Nazeer JT, El Sayed Khalifa K, von Thien H, El-Sibaei MM, Abdel-Hamid MY, Tawfik RAS, Tannich E. Use of multiplex real-time PCR for detection of common diarrhea causing protozoan parasites in Egypt. Parasitol Res 2012; 112:595-601. [PMID: 23114927 DOI: 10.1007/s00436-012-3171-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 10/08/2012] [Indexed: 02/05/2023]
Abstract
Diarrhea is an important cause of morbidity and mortality, worldwide. Giardia intestinalis, Cryptosporidium spp., and Entamoeba histolytica are the most common diarrhea-causing parasitic protozoa. Diagnosis of these parasites is usually performed by microscopy. However, microscopy lacks sensitivity and specificity. Replacing microscopy with more sensitive and specific nucleic acid based methods is hampered by the higher costs, in particular in developing countries. Multiplexing the detection of more than one parasite in a single test by real-time polymerase chain reaction (PCR) has been found to be very effective and would decrease the cost of the test. In the present study, stool samples collected from 396 Egyptian patients complaining of diarrhea along with 202 faecal samples from healthy controls were examined microscopically by direct smear method and after concentration using formol-ethyl acetate. Frozen portions of the same samples were tested by multiplex real-time for simultaneous detection of E. histolytica, G. intestinalis, and Cryptosporidium spp. The results indicate that among diarrheal patients in Egypt G. intestinalis is the most common protozoan parasite, with prevalence rates of 30.5 and 37.1 %, depending on the method used (microscopy vs. multiplex real-time PCR). Cryptosporidium spp. was detected in 1 % of the diarrheal patients by microscopy and in 3 % by real-time PCR. While E. histolytica/dispar was detected in 10.8 % by microscopy, less than one fifth of them (2 %) were found true positive for Entamoeba dispar by real-time PCR. E. histolytica DNA was not detected in any of the diarrheal patients. In comparison with multiplex real-time PCR, microscopy exhibited many false positive and negative cases with the three parasites giving sensitivities and specificities of 100 and 91 % for E. histolytica/dispar, 57.8 and 85.5 % for G. intestinalis, and 33.3 and 100 % for Cryptosporidium spp.
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Affiliation(s)
- John T Nazeer
- Department of Parasitology, Faculty of Medicine, Ain Shams University, Abbassia, 11566 Cairo, Egypt
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Abstract
The review provides current views on human protozoan parasites of the gut. The recognition of the importance of cryptosporidium, cyclospora and microsporidia over the last three decades emphasises the possibility that more pathogenic intestinal protozoa are presently unrecognized. Each of these is a zoonotic infection and the potential for a zoonotic element to the transmission of giardiasis has been recognized. A common theme in increased understanding of the biology and pathological mechanisms involved in causing disease is the application of molecular techniques to the various stages of the parasite life cycle. Molecular methods are increasingly contributing to laboratory diagnosis of these conditions with increased yields of positive results though in the tropics it is likely that fecal microscopy will remain the standard for some time to come. The nitroimidazole compounds are the mainstay of treatment for giardia and amebiasis with no major advance in therapeutics since their role was appreciated. Nitazoxanide was shown to be effective for cryptosporidiosis in the 1990s.
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Saliva and sera IgA and IgG in Egyptian Giardia-infected children. Parasitol Res 2012; 111:571-5. [PMID: 22402609 DOI: 10.1007/s00436-012-2869-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 02/16/2012] [Indexed: 10/28/2022]
Abstract
Giardiasis is a gastrointestinal infection of wide distribution that is more prevalent in childhood. Easy and rapid diagnosis of giardiasis is essential for reduction of this infection. This cross-sectional study included 62 children in which collection of saliva, stool and serum samples was performed. An enzyme-linked immunosorbent assay (ELISA) technique was evaluated to detect IgA and IgG responses in both saliva and serum samples. Twenty-two children were positive for Giardia duodenalis infection by direct examination of faecal specimens, 20 non-infected and 20 infected with other parasites. Salivary and serum IgA and IgG responses against G. duodenalis infection were significantly higher in Giardia parasitized than non-Giardia parasitized children (p < 0.001). This concludes that specific salivary IgA may serve as a diagnostic tool and specific salivary IgG as a screening tool in monitoring the exposure of various populations to Giardia duodenalis. The advantage of salivary assays over serum immunoglobulin assay is being easy and non-invasive in sampling technique which is important especially for young children.
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Intestinal parasitic infections in an industrialized country; a new focus on children with better DNA-based diagnostics. Parasitology 2011; 138:1492-8. [PMID: 21859503 DOI: 10.1017/s0031182011001211] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In recent years, the isolation of parasitic DNA from faecal samples and PCR techniques, have been improved and simplified. Moreover, the introduction of real-time PCR has made it possible to multiplex different targets into one reaction. These new technical possibilities make it feasible to introduce PCR with its unsurpassed sensitivity and specificity in a routine laboratory setting for the diagnosis of intestinal parasites. Detection rates of the parasitic infections included in the PCR are increased significantly compared with microscopy. Molecular diagnostics, especially in children, reveal a possible cause of the gastrointestinal complaints in many more cases compared with conventional methods. Usually in GP patients no other pathogenic parasites are detected using microscopy and in the returning travellers additional parasites are found with microscopy in a minority of cases only. Multiplex real-time PCR offers a highly sensitive and specific diagnostic alternative for labour intensive microscopy in clinical laboratory practice. Additional diagnostic methods for the detection of parasitic infections that are not included as PCR target can be limited to a selected group of patients.
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Calderaro A, Montecchini S, Gorrini C, Dettori G, Chezzi C. Similar diagnostic performances of antigen detection and nucleic acid detection of Cryptosporidium spp. in a low-prevalence setting. Diagn Microbiol Infect Dis 2011; 70:72-7. [PMID: 21513845 DOI: 10.1016/j.diagmicrobio.2010.11.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 11/16/2010] [Accepted: 11/25/2010] [Indexed: 11/25/2022]
Abstract
The diagnostic value of a real-time PCR assay for the detection of Cryptosporidium spp. in fecal samples was assessed as compared to the combination of the immunocromatographic assay (IC) and immunofluorescence assay (IF) currently performed in our laboratory for the diagnosis of cryptosporidiosis. On a total of 1040 samples collected from 2006 to 2010 and belonging to 533 patients suspected of having an intestinal parasitosis, Cryptosporidium spp. was detected in 31 samples (belonging to 12 patients) by IC and IF; the real-time PCR assay revealed Cryptosporidium spp. DNA in 5 additional samples for a total of 36 samples (13 patients). The real-time PCR assay exhibited higher sensitivity than IC and IF; however, its application to the diagnosis of cryptosporidiosis should be evaluated by every single laboratory, depending on the availability of trained personnel, financial resources, and the cost/effectiveness related to the prevalence of cryptosporidiosis.
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Affiliation(s)
- Adriana Calderaro
- Department of Pathology and Laboratory Medicine, Section of Microbiology, University Hospital of Parma, 43126 Parma, Italy.
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Evaluation of an immunochromatographic assay: Giardia-Strip® (Coris BioConcept) for detection of Giardia intestinalis in human fecal specimens. Eur J Clin Microbiol Infect Dis 2011; 31:623-5. [DOI: 10.1007/s10096-011-1332-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Accepted: 06/17/2011] [Indexed: 10/18/2022]
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Taniuchi M, Verweij JJ, Noor Z, Sobuz SU, Lieshout LV, Petri WA, Haque R, Houpt ER. High throughput multiplex PCR and probe-based detection with Luminex beads for seven intestinal parasites. Am J Trop Med Hyg 2011; 84:332-7. [PMID: 21292910 DOI: 10.4269/ajtmh.2011.10-0461] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Polymerase chain reaction (PCR) assays for intestinal parasites are increasingly being used on fecal DNA samples for enhanced specificity and sensitivity of detection. Comparison of these tests against microscopy and copro-antigen detection has been favorable, and substitution of PCR-based assays for the ova and parasite stool examination is a foreseeable goal for the near future. One challenge is the diverse list of protozoan and helminth parasites. Several existing real-time PCR assays for the major intestinal parasites-Cryptosporidium spp., Giardia intestinalis, Entamoeba histolytica, Ancylostoma duodenale, Ascaris lumbricoides, Necator americanus, and Strongyloides stercoralis-were adapted into a high throughput protocol. The assay involves two multiplex PCR reactions, one with specific primers for the protozoa and one with specific primers for the helminths, after which PCR products are hybridized to beads linked to internal oligonucleotide probes and detected on a Luminex platform. When compared with the parent multiplex real-time PCR assays, this multiplex PCR-bead assay afforded between 83% and 100% sensitivity and specificity on a total of 319 clinical specimens. In conclusion, this multiplex PCR-bead protocol provides a sensitive diagnostic screen for a large panel of intestinal parasites.
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Affiliation(s)
- Mami Taniuchi
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA22908, USA.
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Stensvold CR, Lebbad M, Verweij JJ. The impact of genetic diversity in protozoa on molecular diagnostics. Trends Parasitol 2010; 27:53-8. [PMID: 21168365 DOI: 10.1016/j.pt.2010.11.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 11/09/2010] [Accepted: 11/17/2010] [Indexed: 11/27/2022]
Abstract
Detection of intestinal parasitic protists, commonly referred to as 'intestinal protozoa,' by PCR is increasingly used not only for identification or confirmation but also as a first-line diagnostic tool. Apart from the ability to sample correctly and extract parasite DNA directly from faeces, primer and probe specificity and sensitivity affect predictive values and hence the utility of diagnostic assays. Molecular characterization of intestinal protists is necessary to design primers and probes because this is the basic material for current and future improved diagnostic PCRs for either detecting all genetic variants or specifically differentiating among such variants. As an example, this paper highlights the existence of interspecific and intraspecific genetic diversity among intestinal, unicellular parasites and its implications for nucleic acid-based diagnostic assays.
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Affiliation(s)
- C Rune Stensvold
- Department of Microbiology and Diagnostics, Statens Serum Institut, Artillerivej 3, DK-2300 Copenhagen S, Denmark.
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Abstract
PURPOSE OF REVIEW To update the reader on the latest developments in the laboratory diagnosis of intestinal protozoa. RECENT FINDINGS Correct identification of a diarrhoea causing pathogens is essential for the choice of treatment in an individual patient as well as to map the aetiology of diarrhoea in a variety of patient populations. Classical diagnosis of diarrhoea causing protozoa by microscopic examination of a stool sample lacks both sensitivity and specificity. Alternative diagnostic platforms are discussed. SUMMARY Recent literature on the diagnosis of intestinal protozoa has focused mainly on nucleic acid-based assays, in particular the specific detection of parasite DNA in stool samples using real-time PCR. In addition, the trend has been moving from single pathogen detection to a multiplex approach, allowing simultaneous identification of multiple parasites. Different combinations of targets can be used within a routine diagnostic setting, depending on the patient population, such as children, immunocompromised individuals and those who have been travelling to tropical regions. Large-scale monitoring and evaluation of control strategies become feasible due to automation and high-throughput facilities. Improved technology also has become available for differentiating protozoa subspecies, which facilitates outbreak investigations and extensive research in molecular epidemiology.
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Calderaro A, Gorrini C, Montecchini S, Peruzzi S, Piccolo G, Rossi S, Gargiulo F, Manca N, Dettori G, Chezzi C. Evaluation of a real-time polymerase chain reaction assay for the detection of Dientamoeba fragilis. Diagn Microbiol Infect Dis 2010; 67:239-45. [PMID: 20462728 DOI: 10.1016/j.diagmicrobio.2010.02.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 02/02/2010] [Accepted: 02/14/2010] [Indexed: 11/28/2022]
Abstract
The diagnostic value of a real-time polymerase chain reaction (PCR) assay targeting the 5.8S rDNA of Dientamoeba fragilis was investigated as compared with conventional parasitologic methods including cultivation testing 959 fecal samples from 491 patients attending a tertiary-care hospital and suspected of having an intestinal parasitosis. The real-time PCR assay revealed 117 additional D. fragilis-positive samples as compared with conventional methods, showing 100% sensitivity and specificity in our experience. On the whole, D. fragilis infection was detected in 186 samples from 105 patients (21.4%, third in frequency among the diagnosed intestinal parasitoses). The evaluated real-time PCR assay represents an effective tool to obtain both an accurate diagnosis and a reliable epidemiologic picture of dientamoebiasis.
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Affiliation(s)
- Adriana Calderaro
- Department of Pathology and Laboratory Medicine, Section of Microbiology, University Hospital of Parma, Parma, Italy.
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