Publications by authors named "Marcia Benedita de Oliveira Silva"

11 Publications

  • Page 1 of 1

Evaluation of Different Oocyst DNA Extraction Methods for Cryptosporidium spp. Research in Environmental Samples.

Acta Parasitol 2020 Dec 12;65(4):995-998. Epub 2020 Jun 12.

Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Av. Getúlio Guaritá, 130, Abadia, Uberaba, MG, 38025-440, Brazil.

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 10 oocysts/mL and 10 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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http://dx.doi.org/10.1007/s11686-020-00235-wDOI Listing
December 2020

Chronic Cystoisospora belli infection in an HIV/AIDS patient treated at the specialized assistance service in Porto Velho County - Rondônia.

Rev Soc Bras Med Trop 2019 May 16;52:e20180204. Epub 2019 May 16.

Fundação Oswaldo Cruz, Porto Velho, RO, Brasil.

Cystoisospora belli infection manifests as diarrhea, and can potentially progress to malabsorption in HIV patients. Here, we report a case of C. belli infection in an HIV/AIDS patient with chronic diarrhea symptoms for at least 2 years. Coproscopic analyses based on direct technique and modified Ziehl-Neelsen technique without a commercial kit were performed. The current case report highlights the protocol to be adopted in coproscopic analyses applied to HIV patients. The importance of including the appropriate parasitological testing of patients with chronic intestinal isosporiasis in parasitological test routines must be considered.
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http://dx.doi.org/10.1590/0037-8682-0204-2018DOI Listing
May 2019

Occurrence of Blastocystis spp. in domestic animals in Triângulo Mineiro area of Brazil.

Rev Soc Bras Med Trop 2018 Mar-Apr;51(2):240-243

Instituto de Ciências da Saúde, Universidade Federal do Triângulo Mineiro, Uberaba, MG, Brasil.

Introduction: Currently, there are few studies regarding Blastocystis epidemiology. This study aimed to evaluate the occurrence of Blastocystis in animals in Uberaba, Brazil.

Methods: Fecal samples were examined by parasitological methods and screened for Blastocystis by polymerase chain reaction.

Results: Blastocystis spp. were observed in pigs, sheep, cattle, and dogs. Blastocystis polymerase chain reaction was positive in 14/22 samples positive by parasitological methods.

Conclusions: The occurrence of Blastocystis in animals is high, with a predominance of subtype 1 in the region. This is the first study conducted in Brazil showing the genetic profile of Blastocystis isolated from animals.
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http://dx.doi.org/10.1590/0037-8682-0484-2016DOI Listing
May 2018

OCCURRENCE OF Blastocystis spp. IN UBERABA, MINAS GERAIS, BRAZIL.

Rev Inst Med Trop Sao Paulo 2015 May-Jun;57(3):211-4

Instituto de Ciências Biológicas e Naturais, Universidade Federal do Triângulo Mineiro, Uberaba, MG, Brazil.

Intestinal parasites are a problem for public health all over the world. The infection with Blastocystis, a protozoan of controversial pathogenicity, is one of the most common among them all. In this study, the occurrence of intestinal parasites, with emphasis on Blastocystis, in patients at the Universidade Federal do Triângulo Mineiro was investigated in Uberaba (MG) through microscopy of direct smears and fecal concentrates using Ritchie's method. Feces of 1,323 patients were examined from April 2011 to May 2012. In 28.7% of them at least one intestinal parasite was identified, and the most frequent organisms were Blastocystis spp. (17.8%) and Giardia intestinalis (7.4%). The occurrence of parasitism was higher in children aged 6 -10 years old, and the infection with Blastocystis spp. was higher above the age of six (p < 0.001). The exclusive presence of G. intestinalis and of Blastocystis spp. was observed in 5.4% and 12.2% of the patients, respectively. Regarding patients with diarrheic feces, 8% revealed unique parasitism of Blastocystis spp. Other intestinal parasites observed in children were Ascaris lumbricoides (0.3%) and Entamoeba histolytica/dispar/moshkovskii (1.4%). The Ritchie's method was more sensitive (92.8%) when compared to direct microscopy (89.8%), with high agreement between them (97.7%, kappa = 0.92). In conclusion, the occurrence of Blastocystis spp. in Uberaba is high and the presence of diarrheic feces with exclusive presence of the parasite of Blastocystis spp. was observed.
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http://dx.doi.org/10.1590/S0036-46652015000300005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4544244PMC
January 2016

Production of anti-Cryptosporidium polyclonal antibodies and standardization of direct immunofluorescence for detecting oocysts in water.

Rev Soc Bras Med Trop 2011 Oct;44(5):587-90

Universidade Federal do Paraná, Curitiba, PR, Brazil.

Introduction: The production of anti-Cryptosporidium polyclonal antibodies and its use in direct immunofluorescence assays to determine the presence of Cryptosporidium in water are described in the present work.

Methods: Two rabbits were immunized with soluble and particulate antigens from purified Cryptosporidium oocysts. The sera produced were prepared for immunoglobulin G extraction, which were then purified and conjugated with fluorescein isothiocyanate (FITC). Slides containing known amounts of oocysts were prepared to determine the sensitivity of the technique. To test the specificity, slides containing Giardia duodenalis cysts were prepared.

Results: The conjugate was successfully used in water samples experimentally contaminated with Cryptosporidium oocysts, and it was possible to detect up to five oocysts/spot, corresponding to contamination of 250 oocysts/mL.

Conclusions: The three immunizations performed in the rabbits were enough to produce antibodies against Cryptosporidium, the standard direct immunofluorescence assay permitted the detection of five oocysts in 20% of the samples, and no cross-reaction with Giardia duodenalis cysts occurred.
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http://dx.doi.org/10.1590/s0037-86822011000500011DOI Listing
October 2011

Comparing the efficacy of chlorine, chlorine dioxide, and ozone in the inactivation of Cryptosporidium parvum in water from Parana State, Southern Brazil.

Appl Biochem Biotechnol 2008 Dec 23;151(2-3):464-73. Epub 2008 May 23.

Departamento de Patologia Básica, Setor de Ciências Biológicas, Centro Politécnico, Jardim das Américas, Universidade Federal do Paraná, Curitiba, PR, Brazil.

In the present work, assays were performed to compare the efficacy of hypochlorous acid, chlorine dioxide, and ozone in the inactivation of Cryptosporidium oocyst in public water supply from Brazilian South conditions. Experiments were carried out in samples containing 2 x 10(4) oocysts/ml of C. parvum purified from feces of experimentally contaminated calves. An in vitro excystation method was used to evaluate oocysts' viability and to determine the inactivation rates of hypochlorous acid at 2 ppm, chlorine dioxide at 1, 2, and 5 ppm, and ozone at the doses of 0.18, 0.24, 0.36, 0.48, and 1.44 mg/l. By using hypochlorous acid, the maximum inactivation rate obtained was 49.04% after 120 min. Chlorine dioxide at 5 ppm inactivated 90.56% of oocysts after 90 min of contact. Ozone was the most effective product, rendering an inactivation of 100% with the concentration of 24 mg/l. Resistance of Cryptosporidium to the usual disinfectants and the need for more effective water treatments to prevent waterborne diseases in Brazil are discussed in this manuscript.
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http://dx.doi.org/10.1007/s12010-008-8214-3DOI Listing
December 2008

Seasonal profile and level of CD4+ lymphocytes in the occurrence of cryptosporidiosis and cystoisosporidiosis in HIV/AIDS patients in the Triângulo Mineiro region, Brazil.

Rev Soc Bras Med Trop 2007 Sep-Oct;40(5):512-5

Disciplina de Parasitologia, Departamento de Ciências Biológicas, Universidade Federal do Triângulo Mineiro, Rua Frei Paulino 30, Uberaba, MG.

Patients with AIDS are particularly susceptible to infection with intestinal coccidia. In this study the prevalence of infections with Cryptosporidium sp and Cystoisospora belli were evaluated among HIV/AIDS patients in the Triângulo Mineiro region, Brazil. Between July 1993 and June 2003 faecal samples from 359 patients were collected and stained by a modified Ziehl-Neelsen method, resulting in 19.7% of positivity for coccidian (8.6% with Cryptosporidium sp, 10.3% with Cystoisospora belli and 0.8% with both coccidian). Patients with diarrhoea and T CD4+ lymphocyte levels < or =200 cells/mm3 presented higher frequency of these protozoans, demonstrating the opportunistic profile of these infections and its relationship with the immunological status of the individual. It was not possible to determine the influence of HAART, since only 8.5% of the patients positive for coccidian received this therapy regularly. Parasitism by Cryptosporidium sp was more frequent between December and February and thus was characterised by a seasonal pattern of infection, which was not observed with Cystoisospora belli.
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http://dx.doi.org/10.1590/s0037-86822007000500004DOI Listing
February 2008

[Pulmonary schistosoma nodule simulating neoplasia: case report].

Rev Soc Bras Med Trop 2003 Nov-Dec;36(6):735-7

Disciplina de Cirurgia Torácica da Faculdade de Medicina do Triângulo Mineiro, Uberaba, MG, Brasil.

Healthy patient in which during ordinary examination a pulmonary schistosomotic nodule with an adult parasite, was detected 25 years far from endemic region and after specific treatment with oxamniquine. Clinically the nodule simulated neoplasia.
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http://dx.doi.org/10.1590/s0037-86822003000600015DOI Listing
May 2004

Isospora belli infection: observation of unicellular cysts in mesenteric lymphoid tissues of a Brazilian patient with AIDS and animal inoculation.

J Eukaryot Microbiol 2003 ;50 Suppl:682-4

Department of Biology, Univ of New Mexico, Albuquerque, NM, USA.

We describe the finding of unizoic cysts of Isospora belli in lymphoid tissues of a Brazilian patient with AIDS, and discuss the possibilities of their drug resistance, they being the cause of relapses, and of being an indication for the existence of intermediary or paratenic animal hosts.
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http://dx.doi.org/10.1111/j.1550-7408.2003.tb00686.xDOI Listing
March 2004

[Extraintestinal finding of Isospora belli unizoic cysts in a patient with AIDS: case report].

Rev Soc Bras Med Trop 2003 May-Jun;36(3):409-12. Epub 2003 Jul 31.

University of New Mexico, Albuquerque, NM 87501, USA.

This report describes the presence of Isospora belli unizoic cysts in mesenteric lymph nodes and of gametocytes in the gallbladder epitelium of a 26 year-old Brazilian male patient with Acquired Immune Deficiency Syndrome. This patient had received treatment for several times with sulfamethoxazole-trimethoprim. It is discussed the significance of I. belli tissue cysts as possible foci of resistance of the parasite and their association with the infection relapse even post-treatment with anticoccidian medication.
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http://dx.doi.org/10.1590/s0037-86822003000300014DOI Listing
October 2003

[Granulomatous nodule with Enterobius vermicularis in epiploon simulating metastasis of ovarian cancer].

Rev Soc Bras Med Trop 2002 Mar-Apr;35(2):191-3

Faculdade de Medicina do Triângulo Mineiro, Brasil.

The authors describe a case of peritoneal enterobiasis presenting as necrotizing granuloma, in a adolescent with tumor of the ovarian endodermic sinus. The diagnosis was established through biopsy of peritoneal nodule, during laparotomy for staging system of ovarian cancer. Granulomatous nodules due to parasites could simulate metastasis, and cause confusion in the staging system for cancer.
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http://dx.doi.org/10.1590/s0037-86822002000200010DOI Listing
February 2003