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Development and Preliminary Evaluation of a Nanoparticle-Assisted PCR Assay for the Detection of Cryptosporidium parvum in Calves. Animals (Basel) 2022; 12:ani12151953. [PMID: 35953942 PMCID: PMC9367258 DOI: 10.3390/ani12151953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 07/26/2022] [Accepted: 07/28/2022] [Indexed: 11/16/2022] Open
Abstract
C. parvum is an important diarrheal pathogen in humans and animals, especially in young hosts. To accurately and rapidly detect C. parvum infection in calves, we established a nano-PCR assay targeting the cgd3_330 gene for the specific detection of C. parvum. This nano-PCR assay was ten times more sensitive than that of the normal PCR assay by applying the same primers and did not cross-react with C. andersoni, C. bovis, C. ryanae, Balantidium coli, Enterocytozoon bieneusi, Giardia lamblia, and Blastocystis sp. To further test the nano-PCR in clinical settings, a total of 20 faecal samples from calves were examined by using the nano-PCR, the normal PCR, and the nested PCR assays. The positive rates were 30% (6/20), 30% (6/20), and 25% (5/20) for the nano-PCR, the normal PCR, and the nested PCR assays, respectively, indicating that the nano-PCR and the normal PCR assays had the same positive rate (30%). Taken together, the present study could provide a candidate method for the specific detection of C. parvum infection in calves in clinical settings.
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Yin YL, Wang Y, Lai P, Yao Q, Li Y, Zhang LX, Yang X, Song JK, Zhao GH. Establishment and preliminary application of nanoparticle-assisted PCR assay for detection of Cryptosporidium spp. Parasitol Res 2021; 120:1837-1844. [PMID: 33649965 DOI: 10.1007/s00436-021-07101-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 02/22/2021] [Indexed: 11/30/2022]
Abstract
Cryptosporidium is an important intestinal protozoan parasite that causes diarrhoea in humans and animals. To rapidly and specifically detect Cryptosporidium spp., we designed a pair of primers based on the small subunit ribosomal RNA (SSU rRNA) gene of Cryptosporidium spp. to be used in a new nanoparticle-assisted PCR (nano-PCR) assay. The minimum detectable concentration (1.02 pg) of this nano-PCR was 10 times more sensitive than conventional PCR using the same primer pair. The DNA samples of C. parvum, C. baileyi, C. xiaoi, C. ryanae, and C. andersoni were successfully detected by the nano-PCR. No amplifications were evident with DNA samples of some common intestinal pathogens, including Eimeria tenella, Blastocystis sp., Giardia lamblia, Enterocytozoon bieneusi, and Balantidium coli. To validate the clinical usefulness of the novel nano-PCR, a total of 40 faecal samples from goats, camels, calves, and chickens were examined. The positive rate of Cryptosporidium spp. was 27.5% (11/40), which was consistent with that of an established nested PCR. These results indicate that the novel nano-PCR assay enables the rapid, specific, and accurate detection of Cryptosporidium infection in animals. The findings provide a technical basis for the clinical diagnosis, prevention, and control of cryptosporidiosis.
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Affiliation(s)
- Yan-Ling Yin
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi Province, People's Republic of China
| | - Yi Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi Province, People's Republic of China
| | - Peng Lai
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi Province, People's Republic of China
| | - Qian Yao
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi Province, People's Republic of China
| | - Yuan Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi Province, People's Republic of China
| | - Long-Xian Zhang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan Province, People's Republic of China
| | - Xin Yang
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi Province, People's Republic of China
| | - Jun-Ke Song
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi Province, People's Republic of China.
| | - Guang-Hui Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi Province, People's Republic of China.
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Moreira NC, Cabrine-Santos M, de Oliveira-Silva MB. Evaluation of Different Oocyst DNA Extraction Methods for Cryptosporidium spp. Research in Environmental Samples. Acta Parasitol 2020; 65:995-998. [PMID: 32533417 DOI: 10.1007/s11686-020-00235-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 05/22/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE The major problem of the PCR method for the search of protozoan cysts/oocysts in environmental samples is the presence of inhibitors. DNA extraction methods capable of removing inhibitory substances of environmental origin and recovering the DNA are decisive for the efficiency of PCR. This study aimed to compare the efficiency of different DNA extraction methods for the search by Cryptosporidium oocysts in water samples by molecular methods. METHODS DNA extraction from water samples was performed using four different methods. Two methods use a chaotropic buffer to extract DNA and promote the selective binding of DNA to a silica membrane (GuSCN-silica and GFX Kit). The other method is based on the lysis and digestion of the samples in buffer and proteinase K, adsorption of impurities by an "InhibitEX" insertion matrix and purification of the DNA by a silica column (QIAamp Kit). The fourth method uses ionic and non-ionic detergents and proteinase K, to solubilize and separate the DNA from proteins, and a paramagnetic resin for DNA purification in the presence of high concentrations of guanidine ions (MAGNEX DNA Kit). Nested-PCR was performed, and the Cryptosporidium SSU rDNA gene amplified. RESULTS The results demonstrated that MAGNEX and GFX commercial kits showed higher sensitivity, with detection of up to 100 oocysts/mL and 104 oocysts/mL respectively. CONCLUSION In conclusion, this study confirmed that for low-DNA environmental samples, extraction methods should include an efficient oocyst wall breaking step, and showed that the best Cryptosporidium DNA extraction methods are those that use paramagnetic resins.
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Affiliation(s)
- Neliane Cristina Moreira
- Tropical Medicine and Infectology Postgraduate, UFTM, Cefores-Professional Education Center, Federal University of Triângulo Mineiro, Uberaba, MG, Brazil
| | - Marlene Cabrine-Santos
- Institute of Health Sciences, Federal University of Triângulo Mineiro, Uberaba, MG, Brazil
| | - Márcia Benedita de Oliveira-Silva
- Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Av. Getúlio Guaritá, 130, Abadia, Uberaba, MG, 38025-440, Brazil.
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Periurban outbreaks of bovine calf scours in Northern India caused by Cryptosporidium in association with other enteropathogens. Epidemiol Infect 2017; 145:2717-2726. [PMID: 28784188 PMCID: PMC7113022 DOI: 10.1017/s0950268817001224] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bovine calf scours reported to be caused by multiple aetiologies resulting in heavy mortality in unweaned calves and huge economic loss to the dairy farmers. Among these, cryptosporidiosis is an emerging waterborne zoonoses and one of the important causes of neonatal calf diarrhoea. Poor immune response coupled with primary cryptosporidial infections predispose neonatal calves to multiple secondary infections resulting in their deaths. In the present study, faecal samples from 100 diarrhoeic calves randomly picked up out of 17 outbreaks of bovine calf diarrhoea in periurban Ludhiana, Punjab in Northern India were subjected to conventional (microscopy, modified Zeihl-Neelsen (mZN) staining) and immunological and molecular techniques (faecal antigen capture ELISA and PCR) for detection of primary Cryptosporidium parvum infection as well as other frequently reported concurrent pathogens, viz. rotavirus and coronavirus, Salmonella spp., Escherichia coli, Clostridium perfringens and Eimeria spp. The faecal antigen capture ELISA and PCR revealed 35% prevalence of C. parvum in contrast to 25% by mZN staining with a relatively higher prevalence (66·7%) in younger (8-14-day-old) calves. The detection rate of the other enteropathogens associated with C. parvum was 45·71% for C. perfringens followed by Salmonella spp (40·0%), rotavirus (36·0%), coronavirus (16·0%), E. coli (12·0%) and Eimeria spp (4·0%) The sensitivity for detection of C. parvum by ELISA and mZN staining in comparison to PCR was 97·14% and 72·72%, respectively. An important finding of the study was that C. parvum alone was found in only 10% of the diarrhoeic faecal samples, whereas, majority of the samples (90%) showed mixed infections ranging from a combination of two to five agents. This is the first documentary proof of C. parvum and associated pathogens responsible for severe periurban outbreaks of bovine calf diarrhoea culminating in heavy mortality from Northern India.
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Protozoan Parasites. Food Microbiol 2014. [DOI: 10.1128/9781555818463.ch28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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A comparison of nested PCR assay with conventional techniques for diagnosis of intestinal cryptosporidiosis in AIDS cases from northern India. J Parasitol Res 2014; 2014:706105. [PMID: 24523958 PMCID: PMC3913498 DOI: 10.1155/2014/706105] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 10/29/2013] [Indexed: 12/02/2022] Open
Abstract
Cryptosporidiosis is a very important opportunistic infection and is responsible for significant morbidity and mortality in HIV/AIDS patients. Although current laboratory methods are generally considered adequate to detect high concentrations of oocysts, they fail to detect cases of cryptosporidiosis in many immunocompromised patients. The present study was done to determine the diagnostic efficacy of modified Ziehl-Neelsen (ZN), antigen detection ELISA, and a nested PCR assay for detection of Cryptosporidium in 58 adult AIDS cases with diarrhea from the ART clinic of Lok Nayak Hospital, New Delhi. Cryptosporidium was detected in 17 (29.4%), 39 (67.3%), and 45 (77.5%) cases by modified ZN staining, antigen ELISA, and nested PCR assay, respectively. Taking nested PCR as the gold standard, specificity of both modified ZN staining and Cryptosporidium antigen detection ELISA was 100% while the sensitivity of the tests was 37.8% and 86.6%, respectively. PCR was more sensitive than the other two diagnostic modalities but required a more hands-on time per sample and was more expensive than microscopy. PCR, however, was very adaptable to batch analysis, reducing the costs considerably. This assay can therefore have considerable advantages in the treatment of immunosuppressed individuals like AIDS patients, allowing their early diagnosis and decreasing the morbidity and the mortality.
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Cho YI, Yoon KJ. An overview of calf diarrhea - infectious etiology, diagnosis, and intervention. J Vet Sci 2013; 15:1-17. [PMID: 24378583 PMCID: PMC3973752 DOI: 10.4142/jvs.2014.15.1.1] [Citation(s) in RCA: 313] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 11/20/2013] [Accepted: 11/21/2013] [Indexed: 01/28/2023] Open
Abstract
Calf diarrhea is a commonly reported disease in young animals, and still a major cause of productivity and economic loss to cattle producers worldwide. In the report of the 2007 National Animal Health Monitoring System for U.S. dairy, half of the deaths among unweaned calves was attributed to diarrhea. Multiple pathogens are known or postulated to cause or contribute to calf diarrhea development. Other factors including both the environment and management practices influence disease severity or outcomes. The multifactorial nature of calf diarrhea makes this disease hard to control effectively in modern cow-calf operations. The purpose of this review is to provide a better understanding of a) the ecology and pathogenesis of well-known and potential bovine enteric pathogens implicated in calf diarrhea, b) describe diagnostic tests used to detect various enteric pathogens along with their pros and cons, and c) propose improved intervention strategies for treating calf diarrhea.
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Affiliation(s)
- Yong-Il Cho
- National Institute of Animal Science, Rural Development Administration, Cheonan, Korea
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Elwin K, Robinson G, Hadfield SJ, Fairclough HV, Iturriza-Gómara M, Chalmers RM. A comparison of two approaches to extracting Cryptosporidium DNA from human stools as measured by a real-time PCR assay. J Microbiol Methods 2012; 89:38-40. [PMID: 22366300 DOI: 10.1016/j.mimet.2012.02.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 02/07/2012] [Accepted: 02/10/2012] [Indexed: 10/28/2022]
Abstract
Direct extraction of Cryptosporidium DNA from 46 stools by bead-beating, guanidine thiocyanate and silica purification provided slightly lower PCR positivity (93.5% vs. 100%) and higher threshold cycle values (mean 34.93 vs. 28.03; P=0.00) than spin-column extraction from boiled, semi-purified oocyst suspensions. However, direct extraction is cheaper, and amenable to automation.
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Affiliation(s)
- K Elwin
- UK Cryptosporidium Reference Unit, Public Health Wales Microbiology, Singleton Hospital, Swansea, SA2 8QA, United Kingdom
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Abstract
In this article, Una Morgan and Andrew Thompson briefly review the latest information on polymerase chain reaction (PCR)detection of Cryptosporidium parvum in both clinical and environmental samples. Current detection methods for Cryptosporidium are cumbersome, time-consuming and lack sensitivity. A variety of PCR tests have been described recently in the literature and this article discusses the advantages and disadvantages of each new technique and their potential for future diagnosis of Cryptosporidium.
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Affiliation(s)
- U M Morgan
- World Health Organization Collaborating Centre for the Molecular Epidemiology of Parasitic Infections and State Agricultural Biotechnology Centre, School of Veterinary Studies, Murdoch University, Murdoch WA 6150, Australia
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Evaluation of multiplex tandem real-time PCR for detection of Cryptosporidium spp., Dientamoeba fragilis, Entamoeba histolytica, and Giardia intestinalis in clinical stool samples. J Clin Microbiol 2010; 49:257-62. [PMID: 21048004 DOI: 10.1128/jcm.01796-10] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to describe the first development and evaluation of a multiplex tandem PCR (MT-PCR) assay for the detection and identification of 4 common pathogenic protozoan parasites, Cryptosporidium spp., Dientamoeba fragilis, Entamoeba histolytica, and Giardia intestinalis, from human clinical samples. A total of 472 fecal samples submitted to the Department of Microbiology at St. Vincent's Hospital were included in the study. The MT-PCR assay was compared to four real-time PCR (RT-PCR) assays and microscopy by a traditional modified iron hematoxylin stain. The MT-PCR detected 28 G. intestinalis, 26 D. fragilis, 11 E. histolytica, and 9 Cryptosporidium sp. isolates. Detection and identification of the fecal protozoa by MT-PCR demonstrated 100% correlation with the RT-PCR results, and compared to RT-PCR, MT-PCR exhibited 100% sensitivity and specificity, while traditional microscopy of stained fixed fecal smears exhibited sensitivities and specificities of 56% and 100% for Cryptosporidium spp., 38% and 99% for D. fragilis, 47% and 97% for E. histolytica, and 50% and 100% for G. intestinalis. No cross-reactivity was detected in 100 stool samples containing various other bacterial, viral, and protozoan species. The MT-PCR assay was able to provide rapid, sensitive, and specific simultaneous detection and identification of the four most important diarrhea-causing protozoan parasites that infect humans. This study also highlights the lack of sensitivity demonstrated by microscopy, and thus, molecular methods such as MT-PCR must be considered the diagnostic methods of choice for enteric protozoan parasites.
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Cho YI, Kim WI, Liu S, Kinyon JM, Yoon KJ. Development of a panel of multiplex real-time polymerase chain reaction assays for simultaneous detection of major agents causing calf diarrhea in feces. J Vet Diagn Invest 2010; 22:509-17. [PMID: 20622219 DOI: 10.1177/104063871002200403] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Calf diarrhea is a major economic burden to the bovine industry. Since multiple infectious agents can be involved in calf diarrhea, and the detection of each of the causative agents by traditional methods is laborious and expensive, a panel of 2 multiplex real-time polymerase chain reaction (PCR) assays was developed for rapid and simultaneous detection of the 5 major bovine enteric pathogens (i.e., Bovine coronavirus [BCoV; formally known as Betacoronavirus 1], group A Bovine rotavirus [BRV], Salmonella spp., Escherichia coli K99(+), and Cryptosporidium parvum). The estimated detection limit (i.e., analytic sensitivity) of the panel was 0.1 TCID(50) (50% tissue culture infective dose) for BCoV and group A BRV; 5 and 0.5 colony-forming units for E. coli K99(+) and Salmonella, respectively; and 50 oocysts for Cryptosporidium per reaction. In testing 243 fecal samples obtained from submissions to the Iowa State University Veterinary Diagnostic Laboratory or from experimental animals with known infection status, the newly developed multiplex real-time PCR panel simultaneously detected all 5 pathogens directly from fecal samples and was more rapid and sensitive than the traditional diagnostic tests. The PCR panel showed 89%-97% agreement with those conventional diagnostic tests, demonstrating diagnostic sensitivity equal to or better than that of the conventional tests. In conclusion, the multiplex real-time PCR panel can be a tool for a timely and accurate diagnosis of calf diarrhea associated with BCoV, group A BRV, E. coli K99(+), Salmonella, and/or Cryptosporidium.
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Affiliation(s)
- Yong-Il Cho
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
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Recognition and prevention of hospital-associated enteric infections in the intensive care unit. Crit Care Med 2010; 38:S324-34. [PMID: 20647790 DOI: 10.1097/ccm.0b013e3181e69f05] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The objectives of this article were to review the causes and extent of hospital-associated infectious diarrhea and associated risks in the general hospital ward and intensive care unit (ICU), to compare microorganisms with similar symptoms to aid in recognition that will lead to timely and appropriate treatment and control measures, and to propose infection prevention protocols that could decrease human process errors in the ICU. This literature review describes epidemiology, comparison of microbial characteristics for potential hospital-associated enteric pathogens, diagnosis, and prevention, especially if important in the ICU, and particularly in regard to Clostridium difficile. Enteric organisms that most commonly cause hospital-associated infectious diarrhea in acute care settings and the ICU are C. difficile, rotavirus, and norovirus, although others may also be important, particularly in developing countries. To recognize and control infectious diarrhea successfully in the ICU, intensivists should be aware that epidemiology, risks, and prevention measures may differ between these microorganisms. In addition, intensivists should be ready to implement systems changes related to notification, isolation precautions and prevention, and environmental cleaning in the ICU.
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Mor SM, Tumwine JK, Ndeezi G, Srinivasan MG, Kaddu-Mulindwa DH, Tzipori S, Griffiths JK. Respiratory cryptosporidiosis in HIV-seronegative children in Uganda: potential for respiratory transmission. Clin Infect Dis 2010; 50:1366-72. [PMID: 20377408 DOI: 10.1086/652140] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Respiratory cryptosporidiosis is recognized as a late-stage complication in persons with human immunodeficiency virus (HIV) infection and AIDS. However, respiratory signs and symptoms are common in otherwise healthy children with intestinal cryptosporidiosis, which suggests that respiratory infection may occur in immunocompetent hosts. METHODS We recruited children 9-36 months of age who presented with diarrhea to Mulago Hospital in Kampala, Uganda, from November 2007 through January 2009. Children with stool samples positive or negative for Cryptosporidium species were selected for further evaluation, including sputum induction in those with cough or unexplained respiratory signs and collection of saliva and blood specimens. Sputum samples were subjected to comprehensive bacteriologic testing, and both sputum and saliva specimens were tested for Cryptosporidium species by nested polymerase chain reaction. RESULTS Of 926 fecal samples screened, 116 (12.5%) were positive for Cryptosporidium. Seventeen (35.4%) of 48 sputum samples tested from children with positive stool samples were positive for Cryptosporidium. Sixteen (94.1%) of the 17 children with confirmed respiratory cryptosporidiosis were HIV seronegative, and 10 (58.8%) of 17 children were not malnourished. None of the 12 sputum specimens from children with negative stool samples tested positive for Cryptosporidium (P = .013, compared with children who tested positive for Cryptosporidium in the stool). Parasite DNA was detected in only 2 (1.9%) of 103 saliva samples (P < .001, compared with sputum samples). CONCLUSIONS Respiratory cryptosporidiosis was documented in one-third of HIV-seronegative children who were tested. These novel findings suggest the potential for respiratory transmission of cryptosporidiosis. Trial registration. ClinicalTrials.gov identifier: NCT00507871.
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Affiliation(s)
- Siobhan M Mor
- Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, USA
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Stark D, Barratt JLN, van Hal S, Marriott D, Harkness J, Ellis JT. Clinical significance of enteric protozoa in the immunosuppressed human population. Clin Microbiol Rev 2009; 22:634-50. [PMID: 19822892 PMCID: PMC2772358 DOI: 10.1128/cmr.00017-09] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Globally, the number of immunosuppressed people increases each year, with the human immunodeficiency virus (HIV) pandemic continuing to spread unabated in many parts of the world. Immunosuppression may also occur in malnourished persons, patients undergoing chemotherapy for malignancy, and those receiving immunosuppressive therapy. Components of the immune system can be functionally or genetically abnormal as a result of acquired (e.g., caused by HIV infection, lymphoma, or high-dose steroids or other immunosuppressive medications) or congenital illnesses, with more than 120 congenital immunodeficiencies described to date that either affect humoral immunity or compromise T-cell function. All individuals affected by immunosuppression are at risk of infection by opportunistic parasites (such as the microsporidia) as well as those more commonly associated with gastrointestinal disease (such as Giardia). The outcome of infection by enteric protozoan parasites is dependent on absolute CD4(+) cell counts, with lower counts being associated with more severe disease, more atypical disease, and a greater risk of disseminated disease. This review summarizes our current state of knowledge on the significance of enteric parasitic protozoa as a cause of disease in immunosuppressed persons and also provides guidance on recent advances in diagnosis and therapy for the control of these important parasites.
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Affiliation(s)
- D Stark
- Department of Microbiology, St. Vincent's Hospital, Darlinghurst 2010, NSW, Australia.
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Paul S, Chandra D, Tewari A, Banerjee P, Ray D, Boral R, Rao J. Comparative evaluation and economic assessment of coprological diagnostic methods and PCR for detection of Cryptosporidium spp. in bovines. Vet Parasitol 2009; 164:291-5. [DOI: 10.1016/j.vetpar.2009.06.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2009] [Revised: 05/30/2009] [Accepted: 06/11/2009] [Indexed: 10/20/2022]
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Yu JR, Lee SU, Park WY. Comparative sensitivity of PCR primer sets for detection of Cryptosporidium parvum. THE KOREAN JOURNAL OF PARASITOLOGY 2009; 47:293-7. [PMID: 19724705 DOI: 10.3347/kjp.2009.47.3.293] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 04/22/2009] [Accepted: 05/16/2009] [Indexed: 11/23/2022]
Abstract
Improved methods for detection of Cryptosporidium oocysts in environmental and clinical samples are urgently needed to improve detection of cryptosporidiosis. We compared the sensitivity of 7 PCR primer sets for detection of Cryptosporidium parvum. Each target gene was amplified by PCR or nested PCR with serially diluted DNA extracted from purified C. parvum oocysts. The target genes included Cryptosporidium oocyst wall protein (COWP), small subunit ribosomal RNA (SSU rRNA), and random amplified polymorphic DNA. The detection limit of the PCR method ranged from 10(3) to 10(4) oocysts, and the nested PCR method was able to detect 10(0) to 10(2) oocysts. A second-round amplification of target genes showed that the nested primer set specific for the COWP gene proved to be the most sensitive one compared to the other primer sets tested in this study and would therefore be useful for the detection of C. parvum.
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Affiliation(s)
- Jae-Ran Yu
- Department of Environmental and Tropical Medicine, Konkuk University, School of Medicine, Seoul, Korea.
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Nair P, Mohamed JA, DuPont HL, Figueroa JF, Carlin LG, Jiang ZD, Belkind-Gerson J, Martinez-Sandoval FG, Okhuysen PC. Epidemiology of cryptosporidiosis in North American travelers to Mexico. Am J Trop Med Hyg 2008; 79:210-214. [PMID: 18689626 PMCID: PMC2560987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
We studied 1,179 North American travelers who visited Mexico from 2005 to 2007. Travelers' diarrhea (TD) was reported by 521 (44%) participants. Among subjects with TD, 218 cases were examined for cryptosporidiosis by polymerase chain reaction (PCR) and enzyme-linked immunoassays (ELISA). There were 14 (6%) cases of cryptosporidiosis and 141 cases (64%) of bacterial diarrhea. Compared with bacterial diarrhea, a longer stay in Mexico was a risk factor for cryptosporidiosis. Additionally, Cryptosporidium cases passed greater number of watery stools (P < 0.05), suffered more episodes of diarrhea (P < or = 0.05), and were more likely to experience tenesmus (P < or = 0.05) compared with bacterial causes of TD. ELISA detected seven (3%) cases of Cryptosporidium, whereas PCR identified an additional seven cases (6%). Speciation by 18SrRNA sequencing showed that 13 cases were caused by C. parvum and only 1 case was caused by C. hominis. ELISA showed a sensitivity of 50% and specificity of 100% compared with PCR.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Pablo C. Okhuysen
- Address correspondence to Pablo C. Okhuysen, Division of Infectious Diseases, The University of Texas Medical School, 6431 Fannin Street, MSB 2.112, Houston, TX 77030. E-mail:
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Nichols RAB, Moore JE, Smith HV. A rapid method for extracting oocyst DNA from Cryptosporidium-positive human faeces for outbreak investigations. J Microbiol Methods 2006; 65:512-24. [PMID: 16290112 DOI: 10.1016/j.mimet.2005.09.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Revised: 09/13/2005] [Accepted: 09/14/2005] [Indexed: 11/24/2022]
Abstract
We describe a rapid method for extracting and concentrating Cryptosporidium oocysts from human faecal samples with subsequent DNA preparation for mainstream PCR applications. This method consists of extracting faecal lipids using a modified water-ether treatment and releasing DNA from semi-purified oocysts by freeze thawing in lysis buffer. Following immunomagnetisable separation (IMS), recovery rates of 29.5%, 43.2% and 49.8% were obtained from oocyst-negative solid, semi-solid and liquid faeces, respectively, seeded with 100 +/- 2 C. parvum oocysts, which were enumerated by flow cytometry. A retrospective analysis was conducted on 92 positive human faecal samples including 78 oocyst-positive cases from 2 UK cryptosporidiosis outbreaks (outbreak A = 34 samples, outbreak B = 44 samples) and 14 oocyst-positive, sporadic cases. We used primers targeting the Cryptosporidium oocyst wall protein gene (COWP; STN-COWP), the 18S rRNA (direct PCR) and the dihydrofolate reductase gene (dhfr, MAS-PCR) fragments to evaluate extracted DNA by PCR. PCR inhibitors were present in 20 samples when template was co-amplified with the 18S rRNA gene primers and an internal control. Template dilution (1/5) in polyvinylpyrrolidone (10 mg ml(-1), pH 8.0) transformed four PCR-negative samples to PCR-positive and increased amplicon intensity in previously positive samples. Eighteen of 20 PCR-negative samples produced visible amplicons when Taq polymerase concentration in the STN-COWP PCR was increased from 2.5 to 5 U. The STN-COWP PCR assay amplified 90 of 92 samples (97.8%) and the MAS-PCR assay amplified 70 of 92 samples (76.1%) tested. In the absence of inhibitors, DNA equivalent to 3 C. parvum oocysts was amplified.
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Jiang J, Alderisio KA, Singh A, Xiao L. Development of procedures for direct extraction of Cryptosporidium DNA from water concentrates and for relief of PCR inhibitors. Appl Environ Microbiol 2005; 71:1135-41. [PMID: 15746310 PMCID: PMC1065175 DOI: 10.1128/aem.71.3.1135-1141.2005] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Extraction of high-quality DNA is a key step in PCR detection of Cryptosporidium and other pathogens in environmental samples. Currently, Cryptosporidium oocysts in water samples have to be purified from water concentrates before DNA is extracted. This study compared the effectiveness of six DNA extraction methods (DNA extraction with the QIAamp DNA minikit after oocyst purification with immunomagnetic separation and direct DNA extraction methods using the FastDNA SPIN kit for soil, QIAamp DNA stool minikit, UltraClean soil kit, or QIAamp DNA minikit and the traditional phenol-chloroform technique) for the detection of Cryptosporidium with oocyst-seeded samples, DNA-spiked samples, and field water samples. The study also evaluated the effects of different PCR facilitators (nonacetylated bovine serum albumin, the T4 gene 32 protein, and polyvinylpyrrolidone) and treatments (the use of GeneReleaser or ultrafiltration) for the relief from or removal of inhibitors of PCR amplification. The results of seeding and spiking studies showed that PCR inhibitors were presented in all DNA solutions extracted by the six methods. However, the effect of PCR inhibitors could be relieved significantly by the addition of 400 ng of bovine serum albumin/mul or 25 ng of T4 gene 32 protein/mul to the PCR mixture. With the inclusion of bovine serum albumin in the PCR mixture, DNA extracted with the FastDNA SPIN kit for soil without oocyst isolation resulted in PCR performance similar to that produced by the QIAamp DNA minikit after oocysts were purified by immunomagnetic separation.
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Affiliation(s)
- Jianlin Jiang
- Division of Parasitic Disease, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Mail Stop F-12, 4770 Buford Hwy., Atlanta, GA 30341-3717, USA
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21
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Muccio JL, Grooms DL, Mansfield LS, Wise AG, Maes RK. Evaluation of two rapid assays for detecting Cryptosporidium parvum in calf feces. J Am Vet Med Assoc 2005; 225:1090-2. [PMID: 15515989 DOI: 10.2460/javma.2004.225.1090] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate 2 rapid, patient-side assays for detection of Cryptosporidium parvum in feces from neonatal calves with diarrhea. DESIGN Diagnostic test evaluation Sample Population-Fecal samples from 96 neonatal (1 to 30 days old) calves with diarrhea. PROCEDURE Results of the rapid assays were compared with results of microscopic examination of fecal smears that had been stained with diamant fuchsin stain. RESULTS One of the rapid assays correctly identified 56 of 62 (90%) fecal samples positive for C. parvum oocysts and 33 of 34 (97%) fecal samples negative for oocysts. The other assay correctly identified 53 of 62 (85%) fecal samples positive for oocysts and 33 of 34 (97%) fecal samples negative for oocysts. CONCLUSIONS AND CLINICAL RELEVANCE Results suggest that these 2 rapid assays are accurate when used to detect C. parvum in fecal samples from neonatal calves with diarrhea.
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Affiliation(s)
- Janna L Muccio
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
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22
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Drogemuller M, Beelitz P, Pfister K, Schnieder T, von Samson-Himmelstjerna G. Amplification of ribosomal DNA of Anoplocephalidae: Anoplocephala perfoliata diagnosis by PCR as a possible alternative to coprological methods. Vet Parasitol 2004; 124:205-15. [PMID: 15381301 DOI: 10.1016/j.vetpar.2004.07.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Revised: 06/13/2004] [Accepted: 07/22/2004] [Indexed: 12/01/2022]
Abstract
The diagnosis of tapeworm infections in horses relies on copro-diagnostic methods, which are time-consuming and of limited sensitivity for determination of the exact prevalence. The development of serological tests has slightly improved the detection of tapeworm infections, but more sensitive methods are still required. A polymerase chain reaction (PCR)-based approach may constitute a valuable tool to improve tapeworm diagnosis. Nuclear ribosomal DNA (rDNA) is a useful target for species and/or strain markers. Partial 18S, the internal transcribed spacer 1 (ITS-1), the 5.8S, the internal transcribed spacer 2 (ITS-2), and partial 28S rDNA of the equine tapeworms Anoplocephala perfoliata and Anoplocephaloides mamillana were amplified and sequenced. The lengths and GC contents of the regions sequenced were 2087-2091bp and 49.35-49.69% for A. perfoliata, and 2110-2119bp and 49.15-49.32% for A. mamillana, respectively. Sequence alignment and comparison of both taxa showed 79.3-80.2% identity. The lowest identities were found in the ITS regions with 39.9-43.5% for the ITS-1 and 59.5-61.2% for the ITS-2. No matches of the ITS-2 of A. perfoliata and A. mamillana were found with other species by BLAST search. For this reason, ITS-2 sequences seemed appropriate as accurate species markers and A. perfoliata ITS-2 primers were developed. The ITS-2 PCR enabled the detection of genomic DNA as low as 0.5 pgs. First efforts on the practical application of the PCR-based approach were made. A 6-mg fragment of a tapeworm proglottid was detected in 0.5 and 1g of faeces.
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Affiliation(s)
- Michaela Drogemuller
- Institute of Parasitology, School of Veterinary Medicine Hannover, Buenteweg 17, D-30559 Hannover, Germany
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23
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Amar CFL, Dear PH, McLauchlin J. Detection and identification by real time PCR/RFLP analyses of Cryptosporidium species from human faeces. Lett Appl Microbiol 2004; 38:217-22. [PMID: 14962043 DOI: 10.1111/j.1472-765x.2004.01473.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To detect a wide range of Cryptosporidium species from human faeces by analysis of the Cryptosporidium oocyst wall protein gene by PCR. METHODS AND RESULTS The nested-assay comprised an initial amplification using a conventional thermocycler followed by real time PCR using a LightCycler with SYBR Green I for the characterization of the amplicons. The technique uses four sets of primers composed of five to six oligonucleotides with one to six base differences corresponding to the inter-species sequence differences of the gene fragment. Restriction fragment length polymorphism analysis identified Cryptosporidium hominis and C. parvum. The assay was evaluated using DNA extracted from purified material and faecal specimens containing a range of potential pathogens (including Cryptosporidium). The assay was specific, sensitive, reproducible and rapid. CONCLUSIONS This unique technique enables the rapid detection of a range of polymorphic COWP gene sequences directly from faeces using real time PCR. SIGNIFICANCE AND IMPACT OF THE STUDY This study demonstrates a novel approach to identification of Cryptosporidium species and the identification of C. hominis and C. parvum. The technique may be especially useful for the analysis of environmental samples which are likely to contain heterogeneous mixtures of Cryptosporidium species.
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Affiliation(s)
- C F L Amar
- Food Safety Microbiology Laboratory, Health Protection Agency, London, UK
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24
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Carey CM, Lee H, Trevors JT. Biology, persistence and detection of Cryptosporidium parvum and Cryptosporidium hominis oocyst. WATER RESEARCH 2004; 38:818-862. [PMID: 14769405 DOI: 10.1016/j.watres.2003.10.012] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2003] [Revised: 10/06/2003] [Accepted: 10/22/2003] [Indexed: 05/24/2023]
Abstract
Cryptosporidium parvum and Cryptosporidium hominis are obligate enteric protozoan parasites which infect the gastrointestinal tract of animals and humans. The mechanism(s) by which these parasites cause gastrointestinal distress in their hosts is not well understood. The risk of waterborne transmission of Cryptosporidium is a serious global issue in drinking water safety. Oocysts from these organisms are extremely robust, prevalent in source water supplies and capable of surviving in the environment for extended periods of time. Resistance to conventional water treatment by chlorination, lack of correlation with biological indicator microorganisms and the absence of adequate methods to detect the presence of infectious oocysts necessitates the development of consistent and effective means of parasite removal from the water supply. Additional research into improving water treatment and sewage treatment practices is needed, particularly in testing the efficiency of ozone in oocyst inactivation. Timely and efficient detection of infectious C. parvum and C. hominis oocysts in environmental samples requires the development of rapid and sensitive techniques for the concentration, purification and detection of these parasites. A major factor confounding proper detection remains the inability to adequately and efficiently concentrate oocysts from environmental samples, while limiting the presence of extraneous materials. Molecular-based techniques are the most promising methods for the sensitive and accurate detection of C. parvum and C. hominis. With the availability of numerous target sequences, RT-PCR will likely emerge as an important method to assess oocyst viability. In addition, a multiplex PCR for the simultaneous detection of C. parvum, C. hominis and other waterborne pathogens such as Giardia lamblia would greatly benefit the water industry and protect human health.
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Affiliation(s)
- C M Carey
- Department of Environmental Biology, University of Guelph, Guelph, Ont, Canada N1G 2W1
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25
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Hallier-Soulier S, Guillot E. An immunomagnetic separation-reverse transcription polymerase chain reaction (IMS-RT-PCR) test for sensitive and rapid detection of viable waterborne Cryptosporidium parvum. Environ Microbiol 2003; 5:592-8. [PMID: 12823191 DOI: 10.1046/j.1462-2920.2003.00442.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The public health problem posed by the waterborne parasite Cryptosporidium parvum incited the water supply industry to develop very accurate analytical tools able to assess the presence of viable oocysts in drinking water. In this study, we report the development of a viability assay for C. parvum oocysts based on immunomagnetic separation and reverse transcription polymerase chain reaction (IMS-RT-PCR). The detection limit of the IMS-RT-PCR assay, which targets the hsp70 heat shock-induced mRNA, was in the range of ten viable oocysts per 100-l tap water samples. Purified Cryptosporidium parvum oocysts were exposed to heating, freezing and three chemical disinfection treatments namely, chlorination, chlorine dioxide treatment and ozonation under conventional doses used in water treatment plants, then detected by IMS-PCR and IMS-RT-PCR. The results obtained by IMS-PCR showed that none of the treatments had an effect on oocyst detection. The inactivation of oocysts by boiling resulted in no RT-PCR signal. Chlorine as well as chlorine dioxide did not influence oocyst viability as determined by IMS-RT-PCR. Ozone more effectively inactivated oocysts. The IMS-RT-PCR assay in conjunction with IMS-PCR marks the development of a combined detection and viability test which can be used for drinking water quality control as well as for reliable evaluation of treatment efficiency.
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Affiliation(s)
- Sylvie Hallier-Soulier
- ONDEO Services, CIRSEE, Technology and Research Centre, 38 Avenue du Président Wilson, 78230 Le Pecq, France
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Sestak K, Aye PP, Buckholt M, Mansfield KG, Lackner AA, Tzipori S. Quantitative evaluation of Enterocytozoon bieneusi infection in simian immunodeficiency virus-infected rhesus monkeys. J Med Primatol 2003; 32:74-81. [PMID: 12823629 DOI: 10.1034/j.1600-0684.2003.00006.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The association of the microsporidia Enterocytozoon bieneusi with chronic diarrhea and wasting in individuals with acquired immunodeficiency syndrome (AIDS) has been demonstrated. The disease caused by E. bieneusi has been linked to decreased levels of circulating CD4+ T lymphocytes. In this study, we investigated the relationship between the extent of excretion of E. bieneusi in feces of simian immunodeficiency virus (SIV)-infected juvenile macaques and the CD4+ T lymphocyte counts in the peripheral blood. Twelve juvenile rhesus monkeys (Macaca mulatta) were intravenously inoculated with the pathogenic molecular clone SIVmac239. Numbers of CD4+ T lymphocytes were assessed by three-color flow cytometry. The presence of E. bieneusi DNA in feces was assessed by nested PCR. In addition, selected samples of feces were examined by competitive quantitative PCR to assess the level of E. bieneusi infection. Low (n = 5) to undetectable (n = 7) quantities of E. bieneusi were present in feces of the twelve animals in prior to inoculation with SIV. After SIV inoculation the number of animals shedding E. bieneusi increased (n = 10) as did the quantity of E. bieneusi shedding in the feces. Of the twelve juvenile animals, five animals died within 8 months post-SIV inoculation with symptoms of AIDS. Four of the five deceased animals showed shedding of E. bieneusi DNA in feces (> or =100 spores/g) for at least three consecutive months. Increased number of E. bieneusi in feces was accompanied by decreased counts of circulating CD4+ T lymphocytes and increased SIV plasma viral load.
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Affiliation(s)
- K Sestak
- Tufts University School of Veterinary Medicine, North Grafton, MA, USA.
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Rimhanen-Finne R, Hörman A, Ronkainen P, Hänninen ML. An IC-PCR method for detection of Cryptosporidium and Giardia in natural surface waters in Finland. J Microbiol Methods 2002; 50:299-303. [PMID: 12031580 DOI: 10.1016/s0167-7012(02)00047-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
We developed an immunocapture-based polymerase chain reaction (PCR) assay for simultaneous detection of Cryptosporidium parvum oocysts and Giardia intestinalis cysts in surface water. Using primer pairs Cry9/Cry15 and LaxA/LaxB for Cryptosporidium and Gdh1/Gdh4 for Giardia, the sensitivity of the entire detection procedure (dealing with concentration, separation, DNA purification and PCR amplification) was at the level of 50-100 oocysts and cysts. Of 54 surface water samples, 4 were positive for Cryptosporidium and 1 for Giardia. Cryptosporidium and Giardia were detected for the first time in surface water in Finland.
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Affiliation(s)
- Ruska Rimhanen-Finne
- Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, P.O. Box 57, 00014 University of Helsinki, Finland.
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28
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Guyot K, Follet-Dumoulin A, Recourt C, Lelièvre E, Cailliez JC, Dei-Cas E. PCR-restriction fragment length polymorphism analysis of a diagnostic 452-base-pair DNA fragment discriminates between Cryptosporidium parvum and C. meleagridis and between C. parvum isolates of human and animal origin. Appl Environ Microbiol 2002; 68:2071-6. [PMID: 11916736 PMCID: PMC123841 DOI: 10.1128/aem.68.4.2071-2076.2002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genomic DNAs from human Cryptosporidium isolates previously typed by analysis of the 18S ribosomal DNA locus (Cryptosporidium parvum bovine genotype, C. parvum human genotype, Cryptosporidium meleagridis, and Cryptosporidium felis) were used to amplify the diagnostic fragment described by Laxer et al. (M. A. Laxer, B. K. Timblin, and R. J. Patel, Am. J. Trop. Med. Hyg., 45:688-694, 1991). The obtained 452-bp amplified fragments were sequenced and aligned with the homologous Cryptosporidium wrairi sequence. Polymorphism was exploited to develop a restriction fragment length polymorphism method able to discriminate Cryptosporidium species and C. parvum genotypes.
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Affiliation(s)
- K Guyot
- Ecologie du Parasitisme, IFR 17, Institut Pasteur de Lille, 59019 Lille, France.
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29
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Kitahara M, Sakamoto M, Benno Y. PCR detection method of Clostridium scindens and C. hiranonis in human fecal samples. Microbiol Immunol 2001; 45:263-6. [PMID: 11345537 DOI: 10.1111/j.1348-0421.2001.tb02616.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Clostridium scindens and C. hiranonis have high bile acid 7alpha-dehydroxylating activity. Direct PCR and nested PCR with the specific primers for C. scindens and C. hiranonis were developed and tested for the detection of them in human fecal samples. Nested PCR detected C. scindens in all samples, but direct PCR detected it in 27 of 34 samples. Regarding C. hiranonis, nested PCR detected it in only 18 of 34 samples although nested PCR has a high level of sensitivity. Nested PCR was a specific and sensitive method for the detection of C. scindens and C. hiranonis in fecal samples.
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Affiliation(s)
- M Kitahara
- Japan Collection of Microorganisms, RIKEN, Wako, Saitama.
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30
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Abstract
The polymerase chain reaction (PCR) offers one of the most sensitive methods for detecting Cryptosporidium parvum but its sensitivity in fecal material can be greatly reduced by a variety of poorly defined 'inhibitors'. Methods that separate the parasitic oocyst from fecal material prior to DNA extraction circumvent inhibitor interference but are problematic for frozen specimens since 'intact' oocysts are required for separation. We report here a relatively low-cost, rapid method for extracting C. parvum DNA from frozen fecal materials that can be used in a PCR assay for detection of single parasitic oocysts.
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Affiliation(s)
- L A Ward
- The Ohio State University, Ohio Agricultural Research and Development Center, Department of Veterinary Preventive Medicine and Food Animal Health Research Program, Wooster, Ohio 44691, USA.
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31
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Ruttkowski B, Joachim A, Daugschies A. PCR-based differentiation of three porcine Eimeria species and Isospora suis. Vet Parasitol 2001; 95:17-23. [PMID: 11163694 DOI: 10.1016/s0304-4017(00)00408-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Isospora suis and Eimeria are frequent coccidian parasites of pigs. The unsporulated oocysts of Eimeria species and of I. suis are difficult to differentiate. Therefore, a species-specific PCR was developed. PCR products were amplified from Eimeria polita, Eimeria porci, and Eimeria scabra using primers from the conserved 18S rRNA regions and were subsequently sequenced. Based on variable sequence regions, primers were constructed for the differentiation of the three Eimeria species and I. suis. Using a combination of PCRs detecting one or two species, all four coccidian species were detected (theoretical lower detection level: DNA content of 250 oocysts of each Eimeria species or 25 oocysts of Isospora in 1microl) and differentiated. The PCR-based differentiation of the above mentioned species provides a useful alternative to microscopy.
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Affiliation(s)
- B Ruttkowski
- Institut für Parasitologie, Tierärztliche Hochschule Hannover, Bünteweg 17, D-30559, Hannover, Germany
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32
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Eradication of cryptosporidia and microsporidia following successful antiretroviral therapy. J Acquir Immune Defic Syndr 2000. [PMID: 11103042 DOI: 10.1097/00126334-200010010-00006] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Incidence of opportunistic protozoal infections causing diarrheal illnesses in patients with HIV has decreased since the introduction of highly active antiretroviral therapy (HAART). The objective of this study was to determine whether the parasites, cryptosporidia, and microsporidia were effectively eradicated or only suppressed following treatment. DESIGN Six HIV-positive patients with diarrheal symptoms caused by cryptosporidia or microsporidia were prospectively followed up with stool samples and duodenal biopsies. Samples were taken before HAART, between 1 to 3 months, and 6 months post-HAART. METHODS Duodenal samples were analyzed using routine histology and transmission electron microscopy. Stool samples were analyzed by both light microscopy and polymerase chain reaction (PCR) techniques. RESULTS Patients who responded successfully to HAART eradicated both cryptosporidial and microsporidial organisms. Symptoms improved within 1 month of therapy but complete eradication of the organisms was only observed after 6 months of treatment. CONCLUSIONS AIDs-related cryptosporidiosis and microsporidiosis can be cured following successful antiretroviral therapy.
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33
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Miao YM, Awad-El-Kariem FM, Franzen C, Ellis DS, Müller A, Counihan HM, Hayes PJ, Gazzard BG. Eradication of cryptosporidia and microsporidia following successful antiretroviral therapy. J Acquir Immune Defic Syndr 2000; 25:124-9. [PMID: 11103042 DOI: 10.1097/00042560-200010010-00006] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Incidence of opportunistic protozoal infections causing diarrheal illnesses in patients with HIV has decreased since the introduction of highly active antiretroviral therapy (HAART). The objective of this study was to determine whether the parasites, cryptosporidia, and microsporidia were effectively eradicated or only suppressed following treatment. DESIGN Six HIV-positive patients with diarrheal symptoms caused by cryptosporidia or microsporidia were prospectively followed up with stool samples and duodenal biopsies. Samples were taken before HAART, between 1 to 3 months, and 6 months post-HAART. METHODS Duodenal samples were analyzed using routine histology and transmission electron microscopy. Stool samples were analyzed by both light microscopy and polymerase chain reaction (PCR) techniques. RESULTS Patients who responded successfully to HAART eradicated both cryptosporidial and microsporidial organisms. Symptoms improved within 1 month of therapy but complete eradication of the organisms was only observed after 6 months of treatment. CONCLUSIONS AIDs-related cryptosporidiosis and microsporidiosis can be cured following successful antiretroviral therapy.
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Affiliation(s)
- Y M Miao
- Department of HIV Medicine, St. Stephen's Centre, Chelsea and Westminster Hospital, London, UK
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34
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Abstract
Since the first reported case of HIV infection in 1981, many HIV-seropositive patients have died as a result of diarrhoea induced by opportunistic protozoal infections: pathogens that would normally cause only a transient illness in immunocompetent individuals. The introduction of highly active antiretroviral therapy (HAART) in 1996 has been associated with a significant decline in incidence and mortality arising from infections such as cryptosporidia and microsporidia. Previously, there were no chemotherapeutic agents known to be effective in eradicating these parasites, but since the availability of HAART, the memory of the emaciated terminally ill patient with advanced AIDS suffering from refractory diarrhoea will hopefully be a thing of the past. Significant advances in the knowledge of the pathogenesis of HIV disease, earlier detection and thus treatment of the virus, and availability of improved diagnostic techniques and HAART have transformed the way HIV-associated diarrhoea is managed. In this review, we look specifically at the management of protozoa-induced diarrhoea.
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Affiliation(s)
- Y M Miao
- Department of HIV/GUM, Chelsea and Westminster Hospital, London, UK
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35
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Kozwich D, Johansen KA, Landau K, Roehl CA, Woronoff S, Roehl PA. Development of a novel, rapid integrated Cryptosporidium parvum detection assay. Appl Environ Microbiol 2000; 66:2711-7. [PMID: 10877759 PMCID: PMC92064 DOI: 10.1128/aem.66.7.2711-2717.2000] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/1999] [Accepted: 04/04/2000] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to develop a reverse transcription-PCR assay and lateral flow detection protocol for specific identification of Cryptosporidium parvum. The method which we developed is sensitive and specific and has a low limit of detection. In our protocol a solid phase material, the Xtra Bind Capture System, was used for extraction and purification of double-stranded RNA (dsRNA) specific for C. parvum. The Xtra Bind Capture System interfaced with pellets concentrated from water samples collected with previously developed filtration devices. The pellets were resuspended in reagent water (final volume, 0.5 ml), and an equal amount of rupture buffer and the Xtra Bind Capture System was added to the resuspended pellet mixture. The dsRNA target sequences in a 0. 5-ml portion were captured by the solid phase material via hybridization. The debris and potential inhibitors were removed by washing the Xtra Bind material several times with buffer. The Xtra Bind material with its bound dsRNA was added directly to an amplification reaction mixture, and the target was amplified without elution from the Xtra Bind material. A PCR was performed in the presence of the Xtra Bind Capture System, which resulted in robust amplification of the target. The detection system which we used was adapted from lateral flow chromatography methods typically used for antigen-antibody reactions. The result was a colored line that was visible if the organism was present. When this method was used, we were able to reproducibly and correctly identify 10 oocysts added to 0.5 ml of reagent water. When the protocol was evaluated with a small set of environmental samples, the level of detection was as low as 1 oocyst/liter. The total time from resuspension of the pellet to detection was about 3 h, which is considerably less than the 5 h required for immunomagnetic separation followed by an indirect immunofluorescence assay and microscopy.
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Affiliation(s)
- D Kozwich
- Xtrana Inc., Denver, Colorado 80230, USA
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36
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Hallier-Soulier S, Guillot E. Detection of cryptosporidia and Cryptosporidium parvum oocysts in environmental water samples by immunomagnetic separation-polymerase chain reaction. J Appl Microbiol 2000; 89:5-10. [PMID: 10945772 DOI: 10.1046/j.1365-2672.2000.01029.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cryptosporidium parvum has emerged as one of the most important new contaminants found in drinking water. Current protocols for the detection of cryptosporidia are time-consuming and rather inefficient. We recently described an immunomagnetic separation-polymerase chain reaction (IMS-PCR) assay permitting highly sensitive detection of C. parvum oocysts in drinking water samples. In this study, a second IMS-PCR assay to detect all cryptosporidial oocysts was developed, and both IMS-PCR assays were optimized on river water samples. A comparative study of the two IMS-PCR assays and the classical detection method based on an immunofluorescence assay (IFA) was carried out on 50 environmental samples. Whatever the type of water sample, the discrepancy in C. parvum detection between the IFA and IMS-PCR took the form of IFA-negative/IMS-PCR-positive results, and was caused mainly by the greater sensitivity of IMS-PCR as compared with IFA. Of the 50 water samples, only five tested positive for C. parvum using IMS-PCR, and could constitute a threat to human health. These results show that both IMS-PCR assays provide a rapid (1 d) and sensitive means of screening environmental water samples for the presence of cryptosporidia and C. parvum oocysts.
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Abstract
Cryptosporidium parvum is an important cause of diarrhea worldwide. Cryptosporidium causes a potentially life-threatening disease in people with AIDS and contributes significantly to morbidity among children in developing countries. In immunocompetent adults, Cryptosporidium is often associated with waterborne outbreaks of acute diarrheal illness. Recent studies with human volunteers have indicated that Cryptosporidium is highly infectious. Diagnosis of infection with this parasite has relied on identification of acid-fast oocysts in stool; however, new immunoassays or PCR-based assays may increase the sensitivity of detection. Although the mechanism by which Cryptosporidium causes diarrhea is still poorly understood, the parasite and the immune response to it probably combine to impair absorption and enhance secretion within the intestinal tract. Important genetic studies suggest that humans can be infected by at least two genetically distinct types of Cryptosporidium, which may vary in virulence. This may, in part, explain the clinical variability seen in patients with cryptosporidiosis.
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Affiliation(s)
- D P Clark
- Department of Pathology and Laboratory Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland 21287, USA.
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38
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Hallier-Soulier S, Guillot E. An immunomagnetic separation polymerase chain reaction assay for rapid and ultra-sensitive detection of Cryptosporidium parvum in drinking water. FEMS Microbiol Lett 1999; 176:285-9. [PMID: 10427711 DOI: 10.1111/j.1574-6968.1999.tb13674.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
A sensitive and rapid method was developed to detect Cryptosporidium parvum oocysts in drinking water. This molecular assay combined immunomagnetic separation with polymerase chain reaction amplification to detect very low levels of C. parvum oocysts. Magnetic beads coated with anti-cryptosporidium were used to capture oocysts directly from drinking water membrane filter concentrates, at the same time removing polymerase chain reaction inhibitory substances. The DNA was then extracted by the freeze-boil Chelex-100 treatment, followed by polymerase chain reaction. The immunomagnetic separation-polymerase chain reaction product was identified by non-radioactive hybridization using an internal oligonucleotide probe labelled with digoxigenin. This immunomagnetic separation-polymerase chain reaction assay can detect the presence of a single seeded oocyst in 5-100-1 samples of drinking water, thereby assuring the absence of C. parvum contamination in the sample under analysis.
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39
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Miao YM, Awad-El-Kariem FM, Gibbons CL, Gazzard BG. Cryptosporidiosis: eradication or suppression with combination antiretroviral therapy? AIDS 1999; 13:734-5. [PMID: 10397573 DOI: 10.1097/00002030-199904160-00019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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40
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Kostrzynska M, Sankey M, Haack E, Power C, Aldom JE, Chagla AH, Unger S, Palmateer G, Lee H, Trevors JT, De Grandis SA. Three sample preparation protocols for polymerase chain reaction based detection of Cryptosporidium parvum in environmental samples. J Microbiol Methods 1999; 35:65-71. [PMID: 10076632 DOI: 10.1016/s0167-7012(98)00106-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Cryptosporidium parvum is a protozoan parasite responsible for an increasing number of outbreaks of gastrointestinal illness worldwide. In this report, we describe development of sample preparation protocols for polymerase chain reaction (PCR)-based detection of C. parvum in fecal material and environmental water samples. Two of these methods were found adequate for isolation of Cryptosporidium DNA from filtered water pellet suspensions. The first involved several filtration steps, immunomagnetic separation and freeze-thaw cycles. The second method involved filtration, addition of EnviroAmp lysis reagent, freeze-thaw cycles and precipitation of the DNA with isopropanol. Using nested PCR, we detected 100 oocysts/ml of filtered water pellet suspension, with either of the above sample preparation procedures. Nested PCR increased sensitivity of the assay by two to three orders of magnitude as compared to the primary PCR. The detection limit for seeded fecal samples was 10-fold higher than for filtered environmental water pellet suspension. Nested PCR results showed 62.4 and 91.1% correlation with immunofluorescence assay (IFA) for fecal samples and filtered environmental water pellet suspensions, respectively. This correlation decreased to 47.2% and 44.4%, respectively, when only IFA positive samples were analyzed. However, in fecal samples contaminated with a high number (> 10(5)/g) of C. parvum oocysts, this correlation was 100%.
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Affiliation(s)
- M Kostrzynska
- Laboratory Services Division, University of Guelph, Ontario, Canada
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41
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Shetab R, Cohen SH, Prindiville T, Tang YJ, Cantrell M, Rahmani D, Silva J. Detection of Bacteroides fragilis enterotoxin gene by PCR. J Clin Microbiol 1998; 36:1729-32. [PMID: 9620408 PMCID: PMC104908 DOI: 10.1128/jcm.36.6.1729-1732.1998] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Bacteroides fragilis constitutes about 1% of the bacterial flora in intestines of normal humans. Enterotoxigenic strains of B. fragilis have been associated with diarrheal diseases in humans and animals. The enterotoxin produced by these isolates induces fluid changes in ligated intestinal loops and an in vitro cytotoxic response in HT-29 cells. We developed a nested PCR to detect the enterotoxin gene of B. fragilis in stool specimens. After DNA extraction, a 367-bp fragment was amplified with two outer primers. The amplicon from this reaction was subjected to a second round of amplification with a set of internal primers. With these inner primers, a 290-bp DNA fragment was obtained which was confirmed as part of the B. fragilis enterotoxin gene by Southern blotting with a nonradioactive internal probe and a chemiluminescence system. By this approach, B. fragilis enterotoxin gene sequences were detected in eight known enterotoxigenic human isolates and nine enterotoxigenic horse isolates. No amplification products were obtained from DNA extracted from 28 nonenterotoxigenic B. fragilis isolates or B. distasonis, B. thetaiotaomicron, B. uniformis, B. ovatus, Escherichia coli, or Clostridium difficile. The sensitivity of this assay allowed us to detect as little as 1 pg of enterotoxin DNA sequences or 100 to 1,000 cells of enterotoxigenic B. fragilis/g of stool. Enterotoxin production of all isolates was confirmed in vitro in HT-29 cells. A 100% correlation was obtained between enterotoxin detection by cytotoxin assay and the nested PCR assay. This rapid and sensitive assay can be used to identify enterotoxigenic B. fragilis and may be used clinically to determine the role of B. fragilis in diarrheal diseases.
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Affiliation(s)
- R Shetab
- Division of Infectious and Immunologic Diseases, University of California, Davis Medical Center, Sacramento 95817, USA
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42
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Detection of Cryptosporidium parvum and C. muris Oocysts in Spiked Backwash Water using Three PCR-Based Protocols. Protist 1998. [DOI: 10.1016/s1434-4610(98)70017-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Pereira M das G, Atwill ER, Crawford MR, Lefebvre RB. DNA sequence similarity between California isolates of Cryptosporidium parvum. Appl Environ Microbiol 1998; 64:1584-6. [PMID: 9546195 PMCID: PMC106196 DOI: 10.1128/aem.64.4.1584-1586.1998] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We evaluated whether nucleic acid amplification with primers specific for Cryptosporidium parvum followed by automated DNA sequence analysis of the PCR amplicons could differentiate between California isolates of C. parvum obtained from livestock, humans, and feral pigs. Almost complete sequence identity existed among the livestock isolates and between the livestock and human isolates. DNA sequences from feral pig isolates differed from those from livestock and humans by 1.0 to 1.2%. The reference sequence obtained by Laxer et al. (M. A. Laxer, B. K. Timblin, and R. J. Patel, Am. J. Trop. Med. Hyg. 45:688-694, 1991.) differed from California isolates of C. parvum by 1.8 to 3.2%. These data suggest that DNA sequence analysis of the amplicon of Laxer et al. does not allow for differentiation between various strains of C. parvum or that our collection of isolates obtained from various hosts from across California was limited to one strain of C. parvum.
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Affiliation(s)
- G Pereira M das
- Veterinary Medicine Teaching and Research Center, School of Veterinary Medicine, University of California, Davis, Tulare 93274, USA
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44
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Ignatius R, Eisenblätter M, Regnath T, Mansmann U, Futh U, Hahn H, Wagner J. Efficacy of different methods for detection of low Cryptosporidium parvum oocyst numbers or antigen concentrations in stool specimens. Eur J Clin Microbiol Infect Dis 1997; 16:732-6. [PMID: 9405942 DOI: 10.1007/bf01709253] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The detection of Cryptosporidium parvum oocysts in stool specimens by acid-fast (AF) stains or immunofluorescence assays (IFA) requires the presence of large numbers of oocysts. To determine whether new commercially available enzyme immunoassays (EIAs) are more sensitive alternatives, three EIAs, a direct IFA, and the modified cold Kinyoun AF stain were compared, particularly with respect to detection of low oocyst numbers or antigen concentrations. Thirty-one negative and 31 calf stool-enriched human stool specimens were tested. One EIA method detected only nine positive specimens, demonstrating a sensitivity significantly less (p < 0.0001) than that of the IFA, the AF stain, and the other two EIAs. No differences could be found with respect to specificity. In addition, serial dilutions of 28 patients' stool samples containing cryptosporidian oocysts were prepared and examined using two EIAs, IFA, and the AF stain. One EIA yielded significantly inferior results (p < 0.0001), whereas the other one and the two microscopic methods did not differ significantly in either part of the study. The results indicate that the new EIAs do not exhibit higher sensitivities for detection of Cryptosporidium parvum than the two routinely used microscopic methods. Thus, for most laboratories, the IFA or AF stain may still represent the preferred method for the diagnosis of cryptosporidiosis.
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Affiliation(s)
- R Ignatius
- Institut für Medizinische Mikrobiologie und Infektionsimmunologie, Klinikum Benjamin Franklin, Freien Universität Berlin, Germany
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45
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Atwill ER, Sweitzer RA, Pereira MG, Gardner IA, Van Vuren D, Boyce WM. Prevalence of and associated risk factors for shedding Cryptosporidium parvum oocysts and Giardia cysts within feral pig populations in California. Appl Environ Microbiol 1997; 63:3946-9. [PMID: 9327560 PMCID: PMC168707 DOI: 10.1128/aem.63.10.3946-3949.1997] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Populations of feral pigs (Sus scrofa) may serve as an environmental reservoir of Cryptosporidium parvum oocysts and Giardia sp. cysts for source water. We conducted a cross-sectional study to determine the prevalence of and associated demographic and environmental risk factors for the shedding of C. parvum oocysts and Giardia sp. cysts. Feral pigs were either live-trapped or dispatched from 10 populations located along the coastal mountains of western California, and fecal samples were obtained for immunofluorescence detection of C. parvum oocysts and Giardia sp. cysts. We found that 12 (5.4%) and 17 (7.6%) of 221 feral pigs were shedding C. parvum oocysts and Giardia sp. cysts, respectively. The pig's sex and body condition and the presence of cattle were not associated with the probability of the shedding of C. parvum oocysts. However, younger pigs (< or = 8 months) and pigs from high-density populations (> 2.0 feral pigs/km2) were significantly more likely to shed oocysts compared to older pigs (> 8 months) and pigs from low-density populations (< or = 1.9 feral pigs/km2). In contrast, none of these demographic and environmental variables were associated with the probability of the shedding of Giardia sp. cysts among feral pigs. These results suggest that given the propensity for feral pigs to focus their activity in riparian areas, feral pigs may serve as a source of protozoal contamination for surface water.
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Affiliation(s)
- E R Atwill
- Veterinary Medicine Teaching and Research Center, School of Veterinary Medicine, University of California, Davis 93274, USA.
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46
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Deng MQ, Cliver DO, Mariam TW. Immunomagnetic capture PCR to detect viable Cryptosporidium parvum oocysts from environmental samples. Appl Environ Microbiol 1997; 63:3134-8. [PMID: 9251200 PMCID: PMC168611 DOI: 10.1128/aem.63.8.3134-3138.1997] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A method to detect viable Cryptosporidium parvum oocysts was developed. Polyclonal immunoglobulin G against C. parvum oocyst and sporozoite surface antigens was purified from rabbit immune serum, biotinylated, and bound to streptoavidin-coated magnetic particles. C. parvum oocysts were captured by a specific antigen-antibody reaction and magnetic separation. The oocysts were then induced to excyst, and DNA was extracted by heating at 95 degrees C for 10 min. A 452-bp fragment of C. parvum DNA was amplified by using a pair of C. parvum-specific primers in PCR. The method detected as few as 10 oocysts in purified preparations and from 30 to 100 oocysts inoculated in fecal samples. The immunomagnetic capture PCR (IC-PCR) product was identified and characterized by a nested PCR that amplified a 210-bp fragment, followed by restriction endonuclease digestion of the IC-PCR and nested-PCR products at the StyI site and a nonradioactive hybridization using an internal oligonucleotide probe labeled with biotin. PCR specificity was also tested, by using DNAs from other organisms as templates. In the control experiments, inactivated oocysts were undetectable, indicating the ability of this method to differentiate between viable and nonviable oocysts. Thus, this system can be used to specifically detect viable C. parvum oocysts in environmental samples with great sensitivity, providing an efficient way to monitor the environment for C. parvum contamination.
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Affiliation(s)
- M Q Deng
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California at Davis 95616-8743, USA
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47
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Rochelle PA, Ferguson DM, Handojo TJ, De Leon R, Stewart MH, Wolfe RL. An assay combining cell culture with reverse transcriptase PCR to detect and determine the infectivity of waterborne Cryptosporidium parvum. Appl Environ Microbiol 1997; 63:2029-37. [PMID: 9143132 PMCID: PMC168492 DOI: 10.1128/aem.63.5.2029-2037.1997] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The presence of Cryptosporidium in drinking water supplies is a significant problem faced by the water industry. Although a variety of methods exist for the detection of waterborne oocysts, water utilities currently have no way of assessing the infectivity of detected oocysts and consequently are unable to accurately determine the risks posed to public health by waterborne Cryptosporidium. In this paper, the development of an infectivity assay for waterborne Cryptosporidium parvum is described. Oocysts were inoculated onto monolayers of Caco-2 cells and grown on microscope slides, and infections were detected by C. parvum specific reverse transcriptase PCR of extracted mRNA, targeting the heat shock protein 70 (hsp70) gene. A single infectious oocyst was detected by this experimental procedure. The use of concentrated samples obtained from 250 liters of finished water had no observable effect on the integrity of cell monolayers or on the infectivity of oocysts seeded into the concentrate. Intracellular developmental stages of the parasite were also detected by using fluorescently labeled antibodies. One pair of PCR primers targeting the hsp70 gene was specific for C. parvum, while a second pair recognized all species of Cryptosporidium tested. The C. parvum-specific primers amplified DNA from 1 to 10 oocysts used to seed 65 to 100 liters of concentrated environmental water samples and were compatible with multiplex PCR for the simultaneous detection of C. parvum and Giardia lambia. This paper confirms the utility of PCR for the detection of waterborne C. parvum and, most importantly, demonstrates the potential of an in vitro infectivity assay.
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Affiliation(s)
- P A Rochelle
- Water Quality Laboratory, Metropolitan Water District of Southern California, La Verme 91750-3399, USA.
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48
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Gobet P, Buisson JC, Vagner O, Naciri M, Grappin M, Comparot S, Harly G, Aubert D, Varga I, Camerlynck P, Bonnin A. Detection of Cryptosporidium parvum DNA in formed human feces by a sensitive PCR-based assay including uracil-N-glycosylase inactivation. J Clin Microbiol 1997; 35:254-6. [PMID: 8968918 PMCID: PMC229549 DOI: 10.1128/jcm.35.1.254-256.1997] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We developed a PCR-based method that can be used to identify Cryptosporidium parvum in human feces. Fecal oocysts were concentrated by centrifugation on a sodium chloride gradient and filtration on a nitrocellulose filter prior to DNA extraction and PCR amplification of a 452-bp C. parvum-specific DNA sequence with a protocol including dUTP and uracil-N-glycosylase. All samples obtained from naturally infected humans (n = 10), calves (n = 4), and goats (n = 2) were positive. A 100% detection rate was achieved with both formed and solid stools (n = 10) seeded with 1,000 C. parvum oocysts per g. Procedures based on stool concentration by a modified Ritchie method and subsequent oocyst identification by immunofluorescent labeling or acid-fast staining require concentrations of 50,000 to 500,000 oocysts per g to achieve a 100% detection rate with formed stools. The described PCR-based assay thus has a 50- to 500-fold increase in sensitivity compared to those of the methods commonly used to analyze formed feces.
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Affiliation(s)
- P Gobet
- Laboratoire de Parasitologie et Mycologie, Hôpital du Bocage, Dijon, France
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