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Nemati S, Shalileh F, Mirjalali H, Omidfar K. Toward waterborne protozoa detection using sensing technologies. Front Microbiol 2023; 14:1118164. [PMID: 36910193 PMCID: PMC9999019 DOI: 10.3389/fmicb.2023.1118164] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 01/30/2023] [Indexed: 03/14/2023] Open
Abstract
Drought and limited sufficient water resources will be the main challenges for humankind during the coming years. The lack of water resources for washing, bathing, and drinking increases the use of contaminated water and the risk of waterborne diseases. A considerable number of waterborne outbreaks are due to protozoan parasites that may remain active/alive in harsh environmental conditions. Therefore, a regular monitoring program of water resources using sensitive techniques is needed to decrease the risk of waterborne outbreaks. Wellorganized point-of-care (POC) systems with enough sensitivity and specificity is the holy grail of research for monitoring platforms. In this review, we comprehensively gathered and discussed rapid, selective, and easy-to-use biosensor and nanobiosensor technologies, developed for the early detection of common waterborne protozoa.
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Affiliation(s)
- Sara Nemati
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farzaneh Shalileh
- Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Hamed Mirjalali
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Kobra Omidfar
- Biosensor Research Center, Endocrinology and Metabolism Molecular–Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran
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2
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Luka G, Samiei E, Tasnim N, Dalili A, Najjaran H, Hoorfar M. Comprehensive review of conventional and state-of-the-art detection methods of Cryptosporidium. JOURNAL OF HAZARDOUS MATERIALS 2022; 421:126714. [PMID: 34325293 DOI: 10.1016/j.jhazmat.2021.126714] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 07/06/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Cryptosporidium is a critical waterborne protozoan pathogen found in water resources that have been a major cause of death and serious illnesses worldwide, costing millions of dollars annually for its detection and treatment. Over the past several decades, substantial efforts have been made towards developing techniques for the detection of Cryptosporidium. Early diagnostic techniques were established based on the existing tools in laboratories, such as microscopes. Advancements in fluorescence microscopy, immunological, and molecular techniques have led to the development of several kits for the detection of Cryptosporidium spp. However, these methods have several limitations, such as long processing times, large sample volumes, the requirement for bulky and expensive laboratory tools, and the high cost of reagents. There is an urgent need to improve these existing techniques and develop low-cost, portable and rapid detection tools for applications in the water quality industry. In this review, we compare recent advances in nanotechnology, biosensing and microfluidics that have facilitated the development of sophisticated tools for the detection of Cryptosporidium spp.Finally, we highlight the advantages and disadvantages, of these state-of-the-art detection methods compared to current analytical methodologies and discuss the need for future developments to improve such methods for detecting Cryptosporidium in the water supply chain to enable real-time and on-site monitoring in water resources and remote areas.
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Affiliation(s)
- George Luka
- School of Engineering, University of British Columbia, 3333 University Way, Kelowna, BC V1V1V7, Canada.
| | - Ehsan Samiei
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8, Canada.
| | - Nishat Tasnim
- School of Engineering, University of British Columbia, 3333 University Way, Kelowna, BC V1V1V7, Canada.
| | - Arash Dalili
- School of Engineering, University of British Columbia, 3333 University Way, Kelowna, BC V1V1V7, Canada.
| | - Homayoun Najjaran
- School of Engineering, University of British Columbia, 3333 University Way, Kelowna, BC V1V1V7, Canada.
| | - Mina Hoorfar
- School of Engineering, University of British Columbia, 3333 University Way, Kelowna, BC V1V1V7, Canada.
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3
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Luka GS, Nowak E, Toyata QR, Tasnim N, Najjaran H, Hoorfar M. Portable on-chip colorimetric biosensing platform integrated with a smartphone for label/PCR-free detection of Cryptosporidium RNA. Sci Rep 2021; 11:23192. [PMID: 34853388 PMCID: PMC8636559 DOI: 10.1038/s41598-021-02580-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/16/2021] [Indexed: 11/13/2022] Open
Abstract
Cryptosporidium, a protozoan pathogen, is a leading threat to public health and the economy. Herein, we report the development of a portable, colorimetric biosensing platform for the sensitive, selective and label/PCR-free detection of Cryptosporidium RNA using oligonucleotides modified gold nanoparticles (AuNPs). A pair of specific thiolated oligonucleotides, complementary to adjacent sequences on Cryptosporidium RNA, were attached to AuNPs. The need for expensive laboratory-based equipment was eliminated by performing the colorimetric assay on a micro-fabricated chip in a 3D-printed holder assembly. A smartphone camera was used to capture an image of the color change for quantitative analysis. The detection was based on the aggregation of the gold nanoparticles due to the hybridization between the complementary Cryptosporidium RNA and the oligonucleotides immobilized on the AuNPs surface. In the complementary RNA's presence, a distinctive color change of the AuNPs (from red to blue) was observed by the naked eye. However, in the presence of non-complementary RNA, no color change was observed. The sensing platform showed wide linear responses between 5 and 100 µM with a low detection limit of 5 µM of Cryptosporidium RNA. Additionally, the sensor developed here can provide information about different Cryptosporidium species present in water resources. This cost-effective, easy-to-use, portable and smartphone integrated on-chip colorimetric biosensor has great potential to be used for real-time and portable POC pathogen monitoring and molecular diagnostics.
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Affiliation(s)
- George S Luka
- School of Engineering, Faculty of Applied Science, The University of British Columbia, Kelowna, BC, V1V 1V7, Canada
| | - Ephraim Nowak
- School of Engineering, Faculty of Applied Science, The University of British Columbia, Kelowna, BC, V1V 1V7, Canada
| | - Quin Robert Toyata
- School of Engineering, Faculty of Applied Science, The University of British Columbia, Kelowna, BC, V1V 1V7, Canada
| | - Nishat Tasnim
- School of Engineering, Faculty of Applied Science, The University of British Columbia, Kelowna, BC, V1V 1V7, Canada
| | - Homayoun Najjaran
- School of Engineering, Faculty of Applied Science, The University of British Columbia, Kelowna, BC, V1V 1V7, Canada
| | - Mina Hoorfar
- School of Engineering, Faculty of Applied Science, The University of British Columbia, Kelowna, BC, V1V 1V7, Canada.
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Gururajan A, Rajkumari N, Devi U, Borah P. Cryptosporidium and waterborne outbreaks - A mini review. Trop Parasitol 2021; 11:11-15. [PMID: 34195054 PMCID: PMC8213114 DOI: 10.4103/tp.tp_68_20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 12/24/2020] [Accepted: 03/03/2021] [Indexed: 01/13/2023] Open
Abstract
Cryptosporidium spp. is one of the prime agents of infectious diarrhea. Cryptosporidium spp. has been gaining awareness as a pathogen of public health importance in India and other developing countries. Owing to the nature of multiple transmission routes such as person-to-person, animal-to-person, waterborne and foodborne, the epidemiology of cryptosporidiosis in humans is not well known. A deeper understanding of the pathogenesis may lead to better diagnosis and better treatment of the condition. Asymptomatic human and animal transmission illustrates that the spread of infection through the environment is a more plausible explanation, waterborne transmission in particular. The disease burden is underestimated and its global impact is yet to be quantified due to the lack of country-specific estimates. Assessment of the disease itself has been crucial since the morphological indistinguishability, differences in distribution and transmission, and variations in the genotypes.
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Affiliation(s)
- Anusha Gururajan
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Nonika Rajkumari
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Utpala Devi
- Regional Medical Research Center (ICMR), NE-Region, Dibrugarh, Assam, India
| | - Parismita Borah
- Regional Medical Research Center (ICMR), NE-Region, Dibrugarh, Assam, India
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Hassan EM, Örmeci B, DeRosa MC, Dixon BR, Sattar SA, Iqbal A. A review of Cryptosporidium spp. and their detection in water. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2021; 83:1-25. [PMID: 33460403 DOI: 10.2166/wst.2020.515] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Cryptosporidium spp. are one of the most important waterborne pathogens worldwide and a leading cause of mortality from waterborne gastrointestinal diseases. Detection of Cryptosporidium spp. in water can be very challenging due to their low numbers and the complexity of the water matrix. This review describes the biology of Cryptosporidium spp. and current methods used in their detection with a focus on C. parvum and C. hominis. Among the methods discussed and compared are microscopy, immunology-based methods using monoclonal antibodies, molecular methods including PCR (polymerase chain reaction)-based assays, and emerging aptamer-based methods. These methods have different capabilities and limitations, but one common challenge is the need for better sensitivity and specificity, particularly in the presence of contaminants. The application of DNA aptamers in the detection of Cryptosporidium spp. oocysts shows promise in overcoming these challenges, and there will likely be significant developments in aptamer-based sensors in the near future.
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Affiliation(s)
- Eman M Hassan
- Department of Civil and Environmental Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, K1S 5B6, Canada E-mail:
| | - Banu Örmeci
- Department of Civil and Environmental Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, K1S 5B6, Canada E-mail:
| | - Maria C DeRosa
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Canada, K1S 5B6
| | - Brent R Dixon
- Bureau of Microbial Hazards, Food Directorate, Health Canada, Ottawa, Canada, K1A 0K9
| | - Syed A Sattar
- Department of Civil and Environmental Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, K1S 5B6, Canada E-mail: ; C.R.E.M. Co Labs, Units 1-2, 3403 American Drive, Mississauga, ON, Canada, L4V 1T4
| | - Asma Iqbal
- C.R.E.M. Co Labs, Units 1-2, 3403 American Drive, Mississauga, ON, Canada, L4V 1T4
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Prevalence and molecular characterization of Cryptosporidium spp. in yaks (Bos grunniens) in Naqu, China. Microb Pathog 2020; 144:104190. [PMID: 32272216 DOI: 10.1016/j.micpath.2020.104190] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 03/17/2020] [Accepted: 04/01/2020] [Indexed: 02/06/2023]
Abstract
The intestinal protozoan specie, Cryptosporidium causes serious diarrheal syndrome in humans and animals worldwide. However, limited knowledge is known about the infection caused by this specie in yaks in Naqu. About 950 serum and 150 fecal samples were collected and assayed by using commercial ELISA kits and nPCR detection methods to find the prevalence and molecular characterization of Cryptosporidium spp. in yaks. Results found that 103 out of 950 (10.8%) serums were uncovered against C. parvum antibodies. In different regions, the prevalence of C. parvum in yaks were in a range from 9.1% to 16.7%, with obvious difference among the three areas (P < 0.001). In male and female yaks, the prevalence of C. parvum was found to be 7.2% and 13.3% respectively (P < 0.001); and a significant difference (P < 0.001) with a range of 9.8%-18.2% was observed among different age groups. Out of 150 fecal samples, only 2 (1.3%) positive samples were detected via nPCR. The positive samples were sequenced and identified to be C. bovis. The two isolates were clustered to cattle and yak clade separately. Our results highlight the prevalence and epidemiological status of Cryptosporidium spp. in yaks which may contribute towards the prevention and control of this zoonotic disease in Naqu, China.
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Golan Shaposhnik E, Abozaid S, Grossman T, Marva E, On A, Azrad M, Peretz A. The Prevalence of Cryptosporidium among Children Hospitalized because of Gastrointestinal Symptoms and the Efficiency of Diagnostic Methods for Cryptosporidium. Am J Trop Med Hyg 2020; 101:160-163. [PMID: 31115293 DOI: 10.4269/ajtmh.19-0057] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cryptosporidium is a parasite that causes watery diarrhea among both children and adults. However, because many physicians do not routinely ask for Cryptosporidium diagnostic test, cryptosporidiosis prevalence is likely underestimated. The current study investigated the prevalence of cryptosporidiosis among children admitted to the hospital with gastrointestinal symptoms. Stool sample was collected from each child and subjected to routine microbiological culture. Cryptosporidium presence was tested by three different methods: real-time PCR (RT-PCR), quick antigen, and microscopic examination with acid-fast staining. Each positive specimen was further tested with BioFire FilmArray Multiplex PCR (bioMérieux SA, Marcy-l'Etoile, France) to determine that Cryptosporidium is the only pathogen in the sample. Demographic and epidemiological data were collected from the patients' medical records. Of 291 patient stool samples, nine were positive for Cryptosporidium hominis or Cryptosporidium parvum. The average age of the nine Cryptosporidium-positive cases was 2.3 years, lower than the average age of the study population (4.2 years). Of the positive cases, 66.7% were Arabs and 33.3% were Jews. The main complaint of children with Cryptosporidium was diarrhea. Regarding the laboratory methods for Cryptosporidium identification, of the positive samples, 100% (9/9) were identified by RT-PCR, 88% (8/9) were positive by antigen test, and only 67% (6/9) were positive by microscopic examination with acid-fast staining. Because of the low incidence of Cryptosporidium among patients in our facility, the prevalence of cryptosporidiosis still cannot be established. Nevertheless, among the other pathogens found in stool samples, Cryptosporidium is the second leading cause of hospitalization due to gastrointestinal disease in children in our area.
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Affiliation(s)
| | - Said Abozaid
- Department of Pediatrics, Baruch Padeh Medical Center, Poriya, Israel.,The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Tamar Grossman
- Reference Parasitology Laboratory, Central Laboratories, Ministry of Health, Jerusalem, Israel
| | - Esther Marva
- Reference Parasitology Laboratory, Central Laboratories, Ministry of Health, Jerusalem, Israel
| | - Avi On
- Pediatric Gastrointestinal Unit, Baruch Padeh Medical Center, Poriya, Israel.,The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Maya Azrad
- Clinical Microbiology Laboratory, Baruch Padeh Medical Center, Poriya, Israel
| | - Avi Peretz
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel.,Clinical Microbiology Laboratory, Baruch Padeh Medical Center, Poriya, Israel
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Adeyemo FE, Singh G, Reddy P, Stenström TA. Methods for the detection of Cryptosporidium and Giardia: From microscopy to nucleic acid based tools in clinical and environmental regimes. Acta Trop 2018; 184:15-28. [PMID: 29395034 DOI: 10.1016/j.actatropica.2018.01.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 12/21/2017] [Accepted: 01/22/2018] [Indexed: 01/18/2023]
Abstract
The detection and characterization of genotypes and sub genotypes of Cryptosporidium and Giardia is essential for their enumeration, surveillance, prevention, and control. Different diagnostic methods are available for the analysis of Cryptosporidium and Giardia including conventional phenotypic tools that face major limitations in the specific diagnosis of these protozoan parasites. The substantial advancement in the development of genetic signature based molecular tools for the quantification, diagnosis and genetic variation analysis has increased the understanding of the epidemiology and preventive measures of related infections. The conventional methods such as microscopy, antibody and enzyme based approaches, offer better detection results when combined with advanced molecular methods. Gene based approaches increase the precision of identification, for example, many signatures detected in environmental matrices represent species/genotype that are not infectious to humans. This review summarizes the available methods and the advantages and limitations of advance detection techniques like nucleic acid-based approaches for the detection of viable oocysts and cysts of Cryptosporidium and Giardia along with the conventional and widely accepted detection techniques like microscopy, antibody and enzyme based ones. This technical article also encourages the wide application of molecular methods in genetic characterization of distinct species of Cryptosporidium and Giardia, to adopt necessary preventive measures with reliable identification and mapping the source of contamination.
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Affiliation(s)
- Folasade Esther Adeyemo
- SARChI Chair, Institute for Water and Wastewater Technology (IWWT), Durban University of Technology, P.O. Box 1334, Durban, 4000, South Africa
| | - Gulshan Singh
- SARChI Chair, Institute for Water and Wastewater Technology (IWWT), Durban University of Technology, P.O. Box 1334, Durban, 4000, South Africa.
| | - Poovendhree Reddy
- Department of Community Health Studies, Faculty of Health Sciences, Durban University of Technology, P.O. Box 1334, Durban, 4000, South Africa
| | - Thor Axel Stenström
- SARChI Chair, Institute for Water and Wastewater Technology (IWWT), Durban University of Technology, P.O. Box 1334, Durban, 4000, South Africa
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Bahk YY, Cho PY, Ahn SK, Park S, Jheong WH, Park YK, Shin HJ, Lee SS, Rhee O, Kim TS. Monitoring of Noxious Protozoa for Management of Natural Water Resources. THE KOREAN JOURNAL OF PARASITOLOGY 2018; 56:205-210. [PMID: 29742877 PMCID: PMC5976025 DOI: 10.3347/kjp.2018.56.2.205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 03/12/2018] [Accepted: 03/19/2018] [Indexed: 11/23/2022]
Abstract
Waterborne parasitic protozoa, particularly Giardia lamblia and Cryptosporidium spp., are common causes of diarrhea and gastroenteritis worldwide. The most frequently identified source of infestation is water, and exposure involves either drinking water or recreation in swimming pools or natural bodies of water. In practice, studies on Cryptosporidium oocysts and Giardia cysts in surface water are challenging owing to the low concentrations of these microorganisms because of dilution. In this study, a 3-year monitoring of Cryptosporidium parvum, Giardia lamblia, and Naegleria fowleri was conducted from August 2014 to June 2016 at 5 surface water sites including 2 lakes, 1 river, and 2 water intake plants. A total of 50 water samples of 40 L were examined. Cryptosporidium oocysts were detected in 22% of samples and Giardia cysts in 32%. Water at the 5 sampling sites was all contaminated with Cryptosporidium oocysts (0-36/L), Giardia cysts (0-39/L), or both. The geometric mean concentrations of Cryptosporidium and Giardia were 1.14 oocysts/L and 4.62 cysts/L, respectively. Thus, effective monitoring plans must take into account the spatial and temporal parameters of contamination because they affect the prevalence and distribution of these protozoan cysts in local water resources.
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Affiliation(s)
- Young Yil Bahk
- Department of Biotechnology, College of Biomedical and Health Sciences, Konkuk University, Chungju 27478, Korea
| | - Pyo Yun Cho
- Protist Resources Research Division, Nakdonggang National Institute of Biological Resources Sciences, Sangju 37242, Korea
| | - Sung Kyu Ahn
- Department of Tropical Medicine and Parasitology, Inha University School of Medicine, Incheon 22212, Korea
| | - Sangjung Park
- Water Supply and Sewerage Research Division, National Institute of Environmental Research, Incheon 22689, Korea
| | - Won Hwa Jheong
- Environmental Health Research Division, National Institute of Environmental Research, Incheon 22689, Korea
| | - Yun-Kyu Park
- Department of Tropical Medicine and Parasitology, Inha University School of Medicine, Incheon 22212, Korea
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University School of Medicine, Suwon 16499, Korea
| | - Sang-Seob Lee
- Department of Life Science, Kyonggi University, Suwon 16227, Korea
| | - Okjae Rhee
- DK EcoV Environmental Microbiology Lab., Cheonan 31075, Korea
| | - Tong-Soo Kim
- Department of Tropical Medicine and Parasitology, Inha University School of Medicine, Incheon 22212, Korea
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Evaluation of enzyme linked immunosorbent assay for stool antigen detection for the diagnosis of cryptosporidiosis among HIV negative immunocompromised patients in a tertiary care hospital of northern India. J Infect Public Health 2017; 11:115-119. [PMID: 28668658 DOI: 10.1016/j.jiph.2017.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 05/08/2017] [Accepted: 06/09/2017] [Indexed: 11/21/2022] Open
Abstract
The diagnosis of cryptosporidiosis among HIV positive patients has been the focus of many studies worldwide. However, there is a paucity of data on HIV negative immunocompromised patients like post-renal transplant recipients and those with haematological malignancies. Stool microscopy, the conventional method of diagnosis, is fraught with difficulties like cumbersome sample processing and subjective interpretation. Enzyme linked immunosorbent assay (ELISA), on the other hand, is quicker and easier. The present study was conducted in a tertiary care and super speciality hospital of north India. Stool specimens from HIV negative immunocompromised patients were subjected to both modified acid fast staining for oocysts of Cryptosporidium and ELISA for detection of Cryptosporidium copro-antigen, over a period of six years. Of the 637 specimens evaluated, 97 (15.23%) samples were positive for Cryptosporidium by both techniques; 25 (3.92%) specimens were positive by ELISA and negative by microscopy, 14 (2.20%) specimens were positive by microscopy but negative by ELISA, while 501 (78.65%) specimens were negative for Cryptosporidium by both techniques. Significant correlation was observed as a measure of agreement (Kappa test value 0.795) between modified ZN stained microscopy and ELISA for the detection of Cryptosporidium oocysts. The sensitivity, specificity, positive and negative predictive value of ELISA, keeping stool microscopy as gold standard were 87.38%, 95.25%, 87.39% and 97.28% respectively. We conclude that ELISA may be used as a reliable substitute for microscopy in setups where the case load is higher or expertise in special staining techniques is not available. The cost of the kit can be justified if the sample load is sufficiently high or if immunocompromised patients form a significant patient population.
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Abstract
CONTEXT Cryptosporidium spp. is a zoonotic infection, now being recognized as a significant cause of diarrhea in both immunocompetent and immunocompromised hosts. However, there still exist significant knowledge gaps in its estimated global burden, epidemiology, diagnosis and management. EVIDENCE ACQUISITION A semi-systematic search was performed across PubMed to select studies on epidemiological burden of cryptosporidium diarrhea using the following keywords- ['crytosporidiosis' OR 'cryptosporidium'] AND ['diarrhea' OR 'diarrhoea']. Articles were included if participants were 'Humans', belonged to pediatric (0-18 y) age group, and were published after 1990. The results were compiled separately for acute and persistent diarrhea. RESULTS Cryptosporidium spp is commonly detected in stools of both cases (acute/ persistent diarrhea) and asymptomatic controls. The prevalence is higher in children with diarrhea than non-diarrheal controls (1.7-35% vs 0.3-15%); varying widely across different studies. The positivity rate is higher in younger children (<2 years) suffering from diarrhea. The main symptoms associated with cryptosporidiosis include fever, vomiting and abdominal pain with propensity for prolonged duration of diarrhea. It predisposes to malnutrition, which is also a risk factor for cryptosporidiosis. The prevalence is higher in HIV positive patients; certain socio-demographic factors play a more important role than mere geographical distribution for infection. CONCLUSION The high positivity rates during both acute and persistent diarrhea highlights the need to suspect this infection even in immunocompetent children.
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Nooshadokht M, Sharifi I, Mohammadi MA, Pirestani M, Afgar A, Mahootchi A, Salari S. Intestinal microsporidiosis in Iran: infection in immune-compromised and immunocompetent patients. Curr Med Mycol 2017. [PMID: 29302628 PMCID: PMC5747587 DOI: 10.29252/cmm.3.1.30] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Background and Purpose: Gastroenteritis and the clinical profile caused by Microsporidia, an opportunistic pathogen, may be severe in immunocompromised individuals, especially in AIDS patients. Conventionally, it is necessary to detect the small infective spores in stained smears. However, due to the limitations of the microscopy-based methods, several DNA-based methods such as polymerase chain reaction (PCR) have recently been developed to enhance diagnosis sensitivity. Therefore, we sought to evaluate the rate of infection in immunocompromised patients as compared with immunocompetent patients in Kerman, Iran. Materials and Methods: We collected stool samples of 199 human subjects (116 males and 83 females), aged 1 to 69 years old. They were divided into immunocompromised (i.e., AIDS [n=72] and cancer-positive patients [n=59]) and immunocompetent (n=68) groups. We comparatively examined the fecal materials using the microscopy and PCR methods. Results: The overall prevalence rate of Microsporidia infection was 10.05% (20/199). Entrocytozoon bieneusi was the only species within the Microsporidia genus that was identified in 14.5% (19/131) of the immunocompromised patients and 1.47% (1/68) of the immunocompetent individuals. Conclusion: Considering the higher prevalence rate of microsporidiosis in patients with immunodeficiency (10.03%), we suggest performing sensitive and specific techniques such as PCR for the detection of these parasites in immunocompromised patients.
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Affiliation(s)
- M Nooshadokht
- Department of Medical Parasitology and Mycology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran.,Department of Pathobiology, School of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
| | - I Sharifi
- Leishmaniasis Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - M A Mohammadi
- Research Center for Hydatid Disease in Iran, Kerman University of Medical Sciences, Kerman, Iran
| | - M Pirestani
- Department of Parasitology and Entomology, School of Medicine, Tarbiat Modares University, Tehran, Iran
| | - A Afgar
- Research Center for Hydatid Disease in Iran, Kerman University of Medical Sciences, Kerman, Iran
| | - A Mahootchi
- Department of Medical Parasitology and Mycology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - S Salari
- Regional Knowledge Hub and WHO Collaborating Centre for HIV Surveillance, Kerman University of Medical Sciences, Kerman, Iran
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13
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Nooshadokht M, Sharifi I, Mohammadi MA, Pirestani M, Afgar A, Mahootchi A, Salari S. Intestinal microsporidiosis in Iran: infection in immune-compromised and immunocompetent patients. Curr Med Mycol 2017; 3:30-36. [PMID: 29302628 PMCID: PMC5747587 DOI: 10.18869/acadpub.cmm.3.1.30] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 10/17/2017] [Accepted: 11/11/2017] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE Gastroenteritis and the clinical profile caused by Microsporidia, an opportunistic pathogen, may be severe in immunocompromised individuals, especially in AIDS patients. Conventionally, it is necessary to detect the small infective spores in stained smears. However, due to the limitations of the microscopy-based methods, several DNA-based methods such as polymerase chain reaction (PCR) have recently been developed to enhance diagnosis sensitivity. Therefore, we sought to evaluate the rate of infection in immunocompromised patients as compared with immunocompetent patients in Kerman, Iran. MATERIALS AND METHODS We collected stool samples of 199 human subjects (116 males and 83 females), aged 1 to 69 years old. They were divided into immunocompromised (i.e., AIDS [n=72] and cancer-positive patients [n=59]) and immunocompetent (n=68) groups. We comparatively examined the fecal materials using the microscopy and PCR methods. RESULTS The overall prevalence rate of Microsporidia infection was 10.05% (20/199). Entrocytozoon bieneusi was the only species within the Microsporidia genus that was identified in 14.5% (19/131) of the immunocompromised patients and 1.47% (1/68) of the immunocompetent individuals. CONCLUSION Considering the higher prevalence rate of microsporidiosis in patients with immunodeficiency (10.03%), we suggest performing sensitive and specific techniques such as PCR for the detection of these parasites in immunocompromised patients.
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Affiliation(s)
- M Nooshadokht
- Department of Medical Parasitology and Mycology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
- Department of Pathobiology, School of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
| | - I Sharifi
- Leishmaniasis Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - M A Mohammadi
- Research Center for Hydatid Disease in Iran, Kerman University of Medical Sciences, Kerman, Iran
| | - M Pirestani
- Department of Parasitology and Entomology, School of Medicine, Tarbiat Modares University, Tehran, Iran
| | - A Afgar
- Research Center for Hydatid Disease in Iran, Kerman University of Medical Sciences, Kerman, Iran
| | - A Mahootchi
- Department of Medical Parasitology and Mycology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - S Salari
- Regional Knowledge Hub and WHO Collaborating Centre for HIV Surveillance, Kerman University of Medical Sciences, Kerman, Iran
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Jafari R, Maghsood AH, Safari M, Latifi M, Fallah M. Comparison of fecal antigen detection using enzyme linked immunosorbent assay with the auramine phenol staining method for diagnosis of human cryptosporidiosis. Jundishapur J Microbiol 2015; 8:e16470. [PMID: 25825642 PMCID: PMC4376972 DOI: 10.5812/jjm.16470] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 03/19/2014] [Accepted: 04/14/2014] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Fecal antigen detection using the enzyme linked immunosorbent assay (ELISA) and oocyst detection using auramine phenol (AP) staining methods, are told to be more sensitive compared to other conventional methods, for diagnosis of cryptosporidiosis. OBJECTIVES The aim of the present study was to evaluate the antigen-detection capacity in the stool specimens using ELISA and oocyst detection by AP staining methods, for the diagnosis of human cryptosporidiosis. MATERIALS AND METHODS A total of 228 fecal samples were collected from residents of rural areas of Hamadan, West of Iran. Each fecal sample was divided into two parts, one kept frozen at -20˚C for Ag-capture ELISA and the other in 10% formalin for the AP staining method. Cryptosporidium Ag-detection ELISA procedure was performed according to the manual of the manufacturer. The preserved samples concentrated using the formalin-ether concentration technique were stained with AP and then investigated under florescent microscopy. RESULTS Eight (3.5%) and three (1.3%) out of 228 fecal samples were positive for Cryptosporidium infection by ELISA and AP staining methods, respectively. Cryptosporidium Ag-detection using ELISA showed an increased frequency of the infection, compared to the AP staining method (P = 0.062). CONCLUSIONS For epidemiological studies and diagnostic purposes of the Cryptosporidium infection, especially in asymptomatic individuals, Ag-detection ELISA is an easy to perform and accurate method, compared to other conventional microscopic methods.
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Affiliation(s)
- Rasool Jafari
- Department of Parasitology and Mycology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, IR Iran
| | - Amir Hossein Maghsood
- Department of Medical Parasitology and Mycology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran
| | - Marzieh Safari
- Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, IR Iran
| | - Milad Latifi
- Department of Medical Entomology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran
| | - Mohammad Fallah
- Department of Medical Parasitology and Mycology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran
- Corresponding author: Mohammad Fallah, Department of Medical Parasitology and Mycology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran. Tel: +98-9181113650, E-mail:
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Laboratory utility of coproscopy, copro immunoassays and copro nPCR assay targeting Hsp90 gene for detection of Cryptosporidium in children, Cairo, Egypt. J Parasit Dis 2014; 40:901-5. [PMID: 27605806 DOI: 10.1007/s12639-014-0601-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 10/13/2014] [Indexed: 10/24/2022] Open
Abstract
Cryptosporidium is a significant cause of diarrhea worldwide especially in children. Infection may end fatally in immunocompromised patients. Multi-attribute analysis was used to determine the lab utility of 4 diagnostics; coproscopy of AF stained fecal smear, fecal immunoassays by ICT and ELISA and copro-nPCR assay targeting Hsp90 gene, for detection of Cryptosporidium in stool of 250 Egyptian children (150 diarrheic and 100 non-diarrhaeic children). Also, to determine Cryptosporidium molecular prevalence. Cryptosporidium was an important enteric pathogen among both diarrheic and non-diarrheic study children with a clearly high prevalence of 16.4 % (n = 41). Conventional methods had perfect specificity (100 %) but couldn`t be used as a consistent single detection method due to their lowered sensitivities. Multi-attribute analysis ranked nPCR the highest test for lab use. Being the test with the best diagnostic yield, nPCR is a reliable diagnostic test and is going to replace conventional methods for reliable detection of Cryptosporidium.
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Ghaffari S, Kalantari N. Recognition of Cryptosporidium oocysts in fresh and old stool samples: comparison of four techniques. Asian Pac J Trop Biomed 2014. [DOI: 10.12980/apjtb.4.2014apjtb-2014-0067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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17
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Helmy YA, Krücken J, Nöckler K, von Samson-Himmelstjerna G, Zessin KH. Comparison between two commercially available serological tests and polymerase chain reaction in the diagnosis of Cryptosporidium in animals and diarrhoeic children. Parasitol Res 2013; 113:211-6. [PMID: 24221885 DOI: 10.1007/s00436-013-3645-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 10/09/2013] [Indexed: 12/13/2022]
Abstract
For the detection of Cryptosporidium species in 804 animals and 165 diarrhoeic children (<10 years) in Egypt, two copro-antigen tests, the RIDASCREEN® Cryptosporidium test [enzyme immunoassay (EIA)] and the RIDA®QUICK Cryptosporidium/Giardia Combi [immuno-chromatographic test (ICT)] as well as polymerase chain reaction (PCR) were used. Prevalence of Cryptosporidium was 15.0, 19.5 and 32.3% in animals and 2.4, 6.7 and 49.1% in children using EIA, ICT and PCR, respectively.Using PCR as reference method, animal samples sensitivity (Se) of the EIA was 46.5% when questionable samples were considered positive, whereas specificity (Sp) was 100%. Se of the ICT was 60.4% while Sp was 100%. Positive predictive values (PPVs) for both EIA and ICT test were 100%, and negative predictive values (NPVs) for EIA were 79.7 and 84.1% for ICT. For the children samples, the Se of EIA was 5%, Sp was 100%, PPV was 100% and NPV was 52.2%, while the Se of ICT was 13.6%, Sp was 100%, PPV was 100% and NPV was 54.6%.The Kappa score of agreement between PCR and ICT was 67.4%, 54.1% between PCR and EIA and 84.4% between ICT and EIA. Until the second serial dilution of the EIA and ICT test, 9 × 10(3) oocysts/μl of Cryptosporidia was detected, whereas in PCR, they were detected until the sixth serial dilution. Copro-antigen tests were easy to perform and less time-consuming but less sensitive compared to PCR. They obviously are best applicable for screening and epidemiological studies of large numbers of subjects, for batch specimen processing and in isolated or rural areas where reliable tests like PCR are unfeasible. When in children, a single stool sample is used for the diagnosis of clinical cases; better results can be obtained when non-standardized PCR due low specificity is coupled with copro-antigen tests.
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Affiliation(s)
- Yosra A Helmy
- Department Panel Veterinary Public Health, Freie Universität Berlin, 14163, Berlin, Germany,
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Ciccarelli S, Stolfi I, Caramia G. Management strategies in the treatment of neonatal and pediatric gastroenteritis. Infect Drug Resist 2013; 6:133-61. [PMID: 24194646 PMCID: PMC3815002 DOI: 10.2147/idr.s12718] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Acute gastroenteritis, characterized by the onset of diarrhea with or without vomiting, continues to be a major cause of morbidity and mortality in children in mostly resource-constrained nations. Although generally a mild and self-limiting disease, gastroenteritis is one of the most common causes of hospitalization and is associated with a substantial disease burden. Worldwide, up to 40% of children aged less than 5 years with diarrhea are hospitalized with rotavirus. Also, some microorganisms have been found predominantly in resource-constrained nations, including Shigella spp, Vibrio cholerae, and the protozoan infections. Prevention remains essential, and the rotavirus vaccines have demonstrated good safety and efficacy profiles in large clinical trials. Because dehydration is the major complication associated with gastroenteritis, appropriate fluid management (oral or intravenous) is an effective and safe strategy for rehydration. Continuation of breastfeeding is strongly recommended. New treatments such as antiemetics (ondansetron), some antidiarrheal agents (racecadotril), and chemotherapeutic agents are often proposed, but not yet universally recommended. Probiotics, also known as "food supplement," seem to improve intestinal microbial balance, reducing the duration and the severity of acute infectious diarrhea. The European Society for Paediatric Gastroenterology, Hepatology and Nutrition and the European Society of Paediatric Infectious Diseases guidelines make a stronger recommendation for the use of probiotics for the management of acute gastroenteritis, particularly those with documented efficacy such as Lactobacillus rhamnosus GG, Lactobacillus reuteri, and Saccharomyces boulardii. To date, the management of acute gastroenteritis has been based on the option of "doing the least": oral rehydration-solution administration, early refeeding, no testing, no unnecessary drugs.
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Affiliation(s)
- Simona Ciccarelli
- Neonatal Intensive Care Unit, Sapienza University of Rome, Rome, Italy
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Faye B, Dieng T, Tine RC, Diouf L, Sylla K, Ndiaye M, Sow D, Ndiaye JL, Ndiaye D, Ndiaye M, Badiane AS, Seck MC, Dieng Y, Faye O, Ndir O, Gaye O. [Cryptosporidiosis in Senegalese children: prevalence study and use of ELISA serologic diagnosis]. ACTA ACUST UNITED AC 2013; 106:258-63. [PMID: 24136663 DOI: 10.1007/s13149-013-0316-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 09/17/2013] [Indexed: 11/28/2022]
Abstract
This is a prospective, descriptive and analytic study conducted from July 2011 to September 2011 at the Children National Hospital Albert Royer of Dakar and at the Vélingara Health District. It was focused on children under 15 without reference to HIV status. For each child, a sample of stool was examined by the Ziehl-Neelsen modified staining and by ELISA using the "Cryptosporidium Antigen Detection Microwell ELISA kit" designed to detect Cryptosporidium spp antigens. The aim of our study was to determine the prevalence of cryptosporidiosis in rural and hospital areas and to measure the performance of the ELISA kit that we used. Out of the 375 stool examinations performed with the Ziehl-Neelsen modified staining, 17 had revealed the presence of Cryptosporidium spp (4.53%). The prevalence in rural areas was 2% while the hospital prevalence was 7.4%, of which 1.8% (1/57) were from urban areas and 9.8% (12/122) from suburban areas. No positive case was observed in children over 10 years. By ELISA, 23 positives cases were reported corresponding to a prevalence of 6.13% (1.8% in children living in urban areas, 13.1% in children from suburban areas and 3%living in rural areas).The correlation of this assay with the Ziehl-Neelsen modified staining, considered as the reference method, found that this assay had a sensitivity of 58.82% and a high specificity reaching 96.37%. The positive predictive value (PPV) was 43.4% while the negative predictive value was 98%. Cryptosporidiosis is a significant cause of parasitic infection among children in Senegal. Antigen detection of Cryptosporidium spp by ELISA in stool can be a complementary tool in the diagnosis of cryptosporidiosis.
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Affiliation(s)
- B Faye
- Service de parasitologie-mycologie, Faculté de médecine, pharmacie et odontologie, Université Cheikh Anta Diop de Dakar, Dakar, Sénégal,
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Pacheco FTF, Silva RKNR, Martins AS, Oliveira RR, Alcântara-Neves NM, Silva MP, Soares NM, Teixeira MCA. Differences in the detection of Cryptosporidium and Isospora (Cystoisospora) oocysts according to the fecal concentration or staining method used in a clinical laboratory. J Parasitol 2013; 99:1002-8. [PMID: 23829170 DOI: 10.1645/12-33.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Despite the availability of many parasitological methods for detection of Cryptosporidium and Isospora (Cystoisospora) belli in fecal samples, there are uncertainties about the accuracy of these techniques in laboratory practice. In this study, 27 formalin-fixed positive stool samples for Cryptosporidium and 15 for I. belli were analyzed by 2 concentration methods, sedimentation by centrifugation (SC) and formalin-ethyl acetate (FE), and by 3 tintorial techniques, modified Ziehl-Neelsen (ZN), safranin (SF), and auramine (AR). No significant differences were observed on Cryptosporidium identification between concentration methods, while a significantly higher number of I. belli oocysts (P < 0.0001) was detected in fecal smears concentrated by the SC than by the FE method. Fecal samples processed by FE produced a median oocyst loss to the fatty ring of 34.8% for Cryptosporidium and 45.4% for I. belli. However, FE concentration provided 63% of Cryptosporidium and 100% of I. belli slides classified as superior for microscopic examination. Regarding the efficiency of staining methods, a more significant detection of Cryptosporidium oocysts was observed in fecal smears stained by ZN (P < 0.01) or AR (P < 0.05) than by the SF method. Regular to high-quality slides for microscopic examination were mostly observed in fecal smears stained with AR or ZN for Cryptosporidium and with SF or ZN for I. belli. This study suggests a great variability in oocyst power detection by routine parasitological methods, and that the most frequent intestinal coccidians in humans have specific requirements for concentration and staining.
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Affiliation(s)
- Flávia T F Pacheco
- Faculdade de Farmácia, Universidade Federal da Bahia, Salvador, Bahia, Brazil, 40170-115
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Comparison of microscopy, rapid immunoassay, and molecular techniques for the detection of Giardia lamblia and Cryptosporidium parvum. Parasitol Res 2013; 112:1641-6. [DOI: 10.1007/s00436-013-3319-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 01/23/2013] [Indexed: 10/27/2022]
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El-Moamly AAR, El-Sweify MA. ImmunoCard STAT! cartridge antigen detection assay compared to microplate enzyme immunoassay and modified Kinyoun's acid-fast staining technique for detection of Cryptosporidium in fecal specimens. Parasitol Res 2011; 110:1037-41. [PMID: 21842383 DOI: 10.1007/s00436-011-2585-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 07/31/2011] [Indexed: 11/29/2022]
Abstract
Cryptosporidium species infect humans and a wide range of animals worldwide; outbreaks of cryptosporidiosis have been reported in several countries. Routine diagnostic methods may be insufficient to demonstrate the presence of these organisms. The study assessed the diagnostic accuracy of the antigen detection immuno-cartridge test, ImmunoCard STAT! (Meridian Bioscience Inc., Cincinnati, OH, USA), compared to the combined gold standard: modified Kinyoun's acid-fast technique confirmed with the microplate enzyme immunoassay (EIA) for the detection of Cryptosporidium in fecal specimens. Three hundred fifteen formalin-fixed stool specimens were submitted for testing. The Kinyoun's acid-fast-stained smear revealed 24 positive samples for Cryptosporidium (of which 23 specimens were confirmed by the EIA) and 291 negative samples (of which 289 were negative by EIA). Agreement between the three used tests was shown in 22 positive and 288 negative samples for Cryptosporidium. Kappa score of agreement between the immuno-cartridge test and EIA was 0.957, p = 0.000. The sensitivity of the immuno-cartridge test was 96% (95% confidence interval (CI), 87% to 104%) and the total accuracy of the test was 97% (95% CI, 93-103). The ImmunoCard STAT! Cryptosporidium cartridge assay is easy to use and does not require specialized training or equipment and is useful in routine diagnosis and screening for Cryptosporidium especially where rapid, point of care testing is needed or where other reliable tests are unfeasible with a performance comparable to the EIA and acid-fast technique.
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