Identification of α-L-fucosidase (ALFuc) of Blastocystis sp. subtypes ST1, ST2 and ST3

ABSTRACT Blastocystis sp. is a common intestinal microorganism. The α-L-fucosidase (ALFuc) is an enzyme long associated with the colonization of the gut microbiota. However, this enzyme has not been experimentally identified in Blastocystis cultures. The objective of the present study was to identify ALFuc in supernatants of axenic cultures of Blastocystis subtype (ST)1 ATCC-50177 and ATCC-50610 and to compare predicted ALFuc proteins of alfuc genes in sequenced STs1-3 isolates in human Blastocystis carriers. Excretion/secretion (Es/p) and cell lysate proteins were obtained by processing Blastocystis ATCC cultures and submitting them to SDS-PAGE and immunoblotting. In addition, 18 fecal samples from symptomatic Blastocystis human carriers were analyzed by sequencing of amplification products for subtyping. A complete identification of the alfuc gene and phylogenetic analysis were performed. Immunoblotting showed that the amplified band corresponding to ALFuc (~51 kDa) was recognized only in the ES/p. Furthermore, prediction analysis of ALFuc 3D structures revealed that the domain α-L-fucosidase and the GH29 family's catalytic sites were conserved; interestingly, the galactose-binding domain was recognized only in ST1 and ST2. The phylogenetic inferences of ALFuc showed that STs1-3 were clearly identifiable and grouped into specific clusters. Our results show, for the first time through experimental data that ALFuc is a secretion product of Blastocystis sp., which could have a relevant role during intestinal colonization; however, further studies are required to clarify this condition. Furthermore, the alfuc gene is a promising candidate for a phylogenetic marker, as it shows a conserved classification with the SSU-rDNA gene.

Current status of research regarding Blastocystis sp, an enigmatic protist, in Brazil

The present study aimed to evaluate the occurrence of Blastocystis sp. in Brazilian studies over a period of years (2000-2020), as well as point out relevant aspects of this enigmatic organism. We performed a literature search using six sources of international databases. The data were divided into diagnostic by parasitological and molecular techniques, and relevant aspects. After applying the inclusion and exclusion criteria, 52 studies were included in the final analysis. The occurrence of Blastocystis sp. in Brazil ranged from 0.5% to 86.6%, as determined using parasitological techniques. The highest occurrence was in the North (27.3%) and the lowest, in the Midwest region (13.4%). In Brazil, most studies have employed molecular techniques and are concentrated in the Southeast region. The Blastocystis sp. subtype ST3 had the highest average positivity, followed by ST1 and ST2. These findings represent a panorama that reflects the reality of Brazil; thus, we believe that the effectiveness of parasitological diagnosis should be considered with regard to making an appropriate choice of technique for detecting Blastocystis sp. Additionally, we emphasize the importance of further studies in the context of molecular epidemiology with regard to this genus. Blastocystis sp. is not well understood yet, and very little information regarding this genus is available; hence, further research regarding this genus is urgently needed.

Prevalence and risk factors of Blastocystis infections among primary school students in Jiangjin District, Chongqing City / 中国血吸虫病防治杂志

Objective To investigate the prevalence and risk factors of Blastocystis infections among primary school students in Jiangjin District, Chongqing City. Methods A cross-sectional questionnaire survey was conducted among students sampled from a primary school in Jiangjin District, Chongqing City on April, 2018, and their stool samples were collected for microscopic examinations, in vitro culture and PCR assays to analyze the prevalence of Blastocystis infections and subtype of the parasite. In addition, the risk factors of Blastocystis infections among primary school students were identified using univariate analysis and multivariate logistic regression analysis. Results A total of 466 primary students were surveyed, and the subjects had a mean age of (9.81±1.66) years and included 236 males (50.64%) and 230 females (49.36%). The prevalence of Blastocystis infections was 15.24% (71/466) among the study students, and there was no significance difference in the prevalence between male and fe- male students (16.52% vs. 13.91%; χ2 = 0.616, P = 0.433). In addition, there was a significant difference in the prevalence of Blastocystis infections among grade 1 (6.35%, 4/63), grade 2 (5.17%, 3/58), grade 3 (21.74%, 15/69), grade 4 (25.30%, 21/83), grade 5 (10.19%, 11/108) and grade 6 students (20.00%, 17/85) (χ2 = 15.410, P = 0.009). There were four Blastocystis subtypes characterized (ST1, ST3, ST6 and ST7), in which ST6 was the most common subtype (45.07%, 32/71), followed by ST3 (25.35%, 18/71). Multivariate logistic regression analysis revealed that minority ethnicity [odds ratio (OR) = 4.259, 95% confidential inter- val (CI) : (1.161, 15.621)] and low maternal education level (primary school and below) [OR = 9.038, 95% CI: (1.125, 72.642)] were identified as risk factors of Blastocystis infection among primary school students in Jiangjin District, Chongqing City. Conclusions There is a high prevalence of Blastocystis infections detected among primary school students in Jiangjin District, Chongqing City, and ST6 and ST3 are predominant subtypes. Minority ethnicity and low maternal education level (primary school and below) are risk factors for Blastocystis infections in primary school students.

Blastocystis sp. puesta al día sobre su papel parasitario

Blatocystis sp. un parásito unicelular, anaerobio y de gran variabilidad genética del intestino de animal y del ser humano de distribución mundial y el de mayor prevalencia entre las zoonosis intestinales que ha estado inmerso en controversias y revisiones por su taxonomía, características morfológicas, ciclo de vida y papel patógeno. Por tanto, el objetivo del presente escrito es la consolidación de información sobre estos y otros aspectos de Blatocystis sp. producto de la revisión de la literatura científica. Se trata de un estudio documental. Los datos encontrados fueron agrupados en 8 capítulos a saber: tipificación, comportamiento epidemiológico, ciclo de vida y morfología parasitaria, patogenia, manifestaciones clínicas, diagnóstico, tratamiento y reflexiones finales. En esta revisión se actualizan aspectos relativos a Blatocystis sp. con el objeto de mostrar las tendencias del conocimiento sobre esta parasitosis como base esencial de las estrategias de promoción y prevención que adoptan los países contra Blatocystis sp.

Blastocystis sp. a single-celled, anaerobic parasite of great genetic variability in the intestine of animals and humans of worldwide distribution and the one with the highest prevalence among intestinal zoonoses that has been immersed in controversies and reviews due to its taxonomy, morphological characteristics, life cycle and role pathogen. Therefore, the objective of this paper is the consolidation of information on these and other aspects of Blastocystis sp. product of the review of the scientific literature. It is a documentary study. The data found were grouped into 8 chapters: typification, epidemiological behavior, life cycle and parasitic morphology, pathogenesis, clinical manifestations, diagnosis, treatment and final reflections. In this review, aspects related to Blastocystis sp. in order to show the current trends of knowledge about this parasitism as an essential basis of the promotion and prevention strategies that countries adopt against Blastocystis sp.

Intestinal parasites in children with neurological disorders treated at a rehabilitation institution in Niterói, Rio de Janeiro, Brazil

Enteroparasitosis presents high prevalence in developing countries, and is frequent among children, and those with disabilities present even higher susceptibility. The present study evaluated 156 children with neurological disorders to whose parents or guardians an epidemiological questionnaire was applied with a view to identifying risk factors. Stool samples were processed using Ritchie modified by Young, Faust et al., Lutz and Baermann-Moraes techniques. Thirteen samples (8.3%) were positive, being Blastocystis sp. the most frequent parasite (46.2%). Higher positivity was observed for protozoa, especially non-pathogenic. A statistically significant association was only found between the educational level of the mother and positivity for enteroparasites. Among positive children, the habit of placing their hands and objects in their mouths and the consumption of raw vegetables was more frequent. The results show the existence of care and sanitation minimizing the acquisition of intestinal parasite diseases. It is important to alert parents and caregivers about personal hygiene, water and food quality, as well as the environment, considering that transmission of these parasites occurs via the fecal-oral route, in association with multiple factors.

Blastocystis sp. en humanos: actualización y experiencia clínico-terapéutica

Blastocystis sp. es uno de los parásitos del humano más frecuentemente identificados en el laboratorio clínico durante el estudio parasitológico de las muestras de heces. En esta revisión se actualizan los aspectos relativos a la diversidad genética y especificidad del huésped, la taxonomía, caracterización molecular, formas clínicas y experiencia terapéutica en pacientes inmuno-competentes y comprometidos, sintomáticos y asintomáticos, de la consulta de la Sección de Geohelmintiasis del Instituto de Medicina Tropical de la Facultad de Medicina de la Universidad Central de Venezuela, proponiendo el secnidazol como droga de primera elección. Se analiza la presencia de Blastocystis como patógeno humano o como comensal, formando parte de la microbiota intestinal. Se considera la tendencia actual entre los diferentes grupos de investigación a mirar la blastocistosis como un problema de salud pública en lugar de una entidad clínica frecuente y se incluyen elementos que pudieran reforzar esta visión. Se incluyen las medidas que pudieran contribuir a prevenir la parasitosis. Dado que la investigación sobre este parásito progresa rápidamente, se recomienda realizar revisiones frecuentes para mantener actualizados los conceptos relacionados con su epidemiología, diagnóstico, tratamiento y prevención en el paciente inmunocompetente así como en el inmunosuprimido.

Blastocystis sp. is one of the human parasites most frequently identified in the clinical laboratory during the parasitological study of stool samples. This review updates the aspects related to genetic diversity and host specificity, taxonomy, molecular characterization, clinical forms and therapeutic experience in symptom free and symptomatic immune-competent and compromised patients who attended to the Soil Transmitted Helminth Section of the Institute of Tropical Medicine of the Faculty of Medicine of the Central University of Venezuela, proposing secnidazole as the drug of first choice. The presence of Blastocystis as human pathogen or as part of the gut microbiota, are analyzed. The current trend among the different research groups is to look at Blastocystosis as a public health problem rather than a common clinical entity and include elements that could reinforce this view. Measures that could help prevent parasitic disease are also included. Since research on this parasite is progressing rapidly, frequent reviews are recommended to keep the concepts related to its epidemiology, diagnosis, treatment and prevention updated in the immunocompetent as well as the immunosuppressed patient.

Blastocystis sp: EVIDENCIAS DE SU ROL PATÓGENO / Blastocystis sp: EVIDENCE OF ITS PATHOGENIC ROLE

Blastocystis sp. es un parásito de distribución mundial, que se transmite por vía fecal-oral, colonizando el tracto gastrointestinal, tanto de animales como de humanos. Existen múltiples factores que favorecen su transmisión tales como el pobre saneamiento, el consumo de alimentos contaminados y la propagación de vectores. Este parásito ha despertado gran interés científico y clínico en los últimos años, por su potencial asociación con enfermedad; sin embargo, no ha sido posible establecer con exactitud su rol patógeno. También ha sido considerado agente oportunista, por su alta prevalencia en pacientes inmunosuprimidos, específicamente en aquellos con VIH/SIDA y cáncer. Actualmente, en el GenBank se han descrito secuencias de 33 subtipos (STs) diferentes, si bien en la literatura solo se encuentran reportados 17 subtipos hasta el momento, de los cuales 9 han sido aislados en el ser humano. Aunque buena parte de los estudios reportan a ST3 como el de mayor prevalencia, unos cuantos autores sugieren predominio de ST1 y ST4 en ciertas zonas, indicando que algunos subtipos varían dependiendo de la distribución geográfica. Varios de estos STs se han relacionado directamente con sintomatología gastrointestinal aguda y crónica e incluso con manifestaciones clínicas extraintestinales, encontrándose con mayor frecuencia el ST3 en pacientes sintomáticos, generalmente seguido de ST1 y en algunos casos de ST2. Además, se han reportado infecciones mixtas, de las cuales la más común se ha presentado entre los ST1 - ST3. En Latinoamérica, y particularmente en Colombia, se han desarrollado pocas investigaciones orientadas a identificar y definir la prevalencia, coinfección y potencial patógeno de las diferentes formas y subtipos conocidos de Blastocystis sp., por lo cual el conocimiento que se tiene hasta el momento es escaso e inespecífico, requiriéndose más estudios que permitan obtener mayor información al respecto.

Blastocystis sp. is a globally distributed parasite which is transmitted by the fecal-oral route by colonizing the gastrointestinal tract of both animals and humans. There are many factors which allow its transmiBion such as poor sanitation, the consumption of contaminated food and vectors propagation. This parasite has awakened scientific and clinical interest in recent years because of its aBociation with disease. However, its pathogen role has not been accurately established. Also, it has been considered as an opportunistic agent due to its high prevalence in immunosuppreBed patients, specifically in those with HIV / AIDS and cancer. Currently, in GenBank database the sequences of 33 different subtypes (STs) have been described even though only 17 subtypes are reported in the literature so far, from which nine have been isolated in humans. Although many studies indicate the subtype 3 (ST3) as the most prevalent, some authors suggest the predominance of ST1 and ST4 in particular areas, suggesting that some subtypes vary depending on the geographical distribution. Several of these STs have been directly related to acute and chronic gastrointestinal symptoms and even with clinical extraintestinal manifestations, being ST3 found with more frequency in symptomatic patients followed by ST1 and ST2 in some cases. Furthermore, mixed infections have been reported of which the most common has been present between ST1 - ST3. In Latin America, and particularly in Colombia, little research has been developed that aims to identify and define the prevalence, coinfection, and pathogenic potential of different forms and known subtypes of Blastocystis sp., therefore the knowledge at hand so far is scarce and unspecific, requiring more studies which allow obtaining more information about it.

Prevalencia de parásitos intestinales en una muestra de manipuladores de alimentos de una empresa estatal / Prevalence of Intestinal Parasites in a Sample of Food Handlers at a State Enterprise

Esta investigación tuvo como objetivo determinar la prevalencia de parásitos intestinales en manipuladores de alimentos de varios comedores de PDVSA; que acudieron en solicitud del certificado de salud en clínicas de PDVSA, ubicadas en la Costa Oriental del Lago. Se analizaron 166 muestras de heces, por métodos coproparasitológicos: evaluación microscópica en solución salina fisiológica al 0,85%, lugol y técnica de Ritchie. La prevalencia de enteroparásitos fue de 25,90% (43/166). Del porcentaje de parasitados 17,47% correspondió al grupo de 20 a 40 años y 8,43% al grupo mayores de 40 años. No se observó diferencia estadísticamente significativa entre edad y frecuencia de parasitosis intestinal (Chi²= 0,539; P >0,05). De acuerdo al sexo, del porcentaje casos parasitados; 15,66% correspondieron al sexo masculino y 10,24% al sexo femenino (Chi²= 0,016; P >0,05). Solo se identificaron protozoarios, destacándose Blastocystis sp. con 83,72%. El presente estudio demostró que los manipuladores de alimentos estuvieron infectados por protozoarios entéricos, la prevalencia detectada es similar a otros estudios en poblaciones parecidas.

The objective of this research was to determine the prevalence of intestinal parasites in food handlers at several PDVSA dining rooms, who requested a health certificate at PDVSA clinics on the East Lake Coast. One-hundred sixty-six stool samples were analyzed using parasitological methods: microscopic evaluation in physiological saline solution at 0.85%, Lugol’s solution and the Ritchie method. The prevalence of intestinal parasites was 25.90% (43/166). Of those who had parasites, 17.47% corresponded to the group of 20 to 40 years old and 8.43% to the group of 40 years or older. No statistically significant difference was observed between age and frequency of intestinal parasitosis (Chi² = 0.539, P> 0.05). According to sex, 15.66% of the parasitized cases were male and 10.24% female (Chi² = 0.016, P> 0.05). Only protozoa were identified, highlighting Blastocystis sp. with 83.72%. This study showed that food handlers were infected with enteric protozoa. The detected prevalence is similar to other studies in similar populations.

Prevalencia y epidemiología de Blastocystis sp. en dos comunidades del municipio Maracaibo-Estado Zulia / Prevalence and Epidemiology of Blastocystis Sp. In Two Communties of The Maracaibo Municipality, State of Zulia

Para determinar la prevalencia de Blastocystis sp. y su asociación con características epidemiológicas se realizó una investigación descriptiva en dos comunidades del Municipio Maracaibo del Estado Zulia. Para la recolección de datos se empleó una ficha epidemiológica; participaron 406 individuos seleccionados aleatoriamente realizándoseles a cada uno, un examen coproparasitológico directo con SSF-Lugol. Entre los estudiados predominaron los mayores de 18 años (72,1%) y el género femenino (51,4%). La prevalencia de Blastocystis sp. fue 38,9%, con mayor frecuencia de poliparasitismo (54,4%), identificándose Endolimax nana (36,1%) como especie comensal principalmente asociada, seguida de Giardia intestinalis (22,1%) entre los patógenos. Hubo asociación significativa (p<0.05) entre la prevalencia de la infección con el status de ocupación activa, hacinamiento, consumo de agua no tratada y ausencia de adecuadas condiciones para disponer y eliminar basura. Dichas variables mostraron valores OR 95% IC que evidencian su influencia como factores de riesgo, presentándose para el status de ocupación activa el mayor riesgo de infección (OR = 3,18). No se observó asociación significativa entre presencia de Blastocystis sp. con otras características epidemiológicas (p>0.05). Las limitaciones en los estándares de higiene comunal y personal son determinantes de la prevalencia de Blastocystis sp. en estas comunidades.

To determine the prevalence of Blastocystis sp. and its association with epidemiological characteristics, a cross-sectional study was conducted in two communities of the Maracaibo Municipality, State of Zulia. To collect data, an epidemiological record was used; 406 randomly selected individuals participated; for each one, a direct parasitological examination with SSF- Lugol was performed. Individuals over 18 years (72.1%) and females (51.4%) predominated. The overall prevalence of Blastocystis sp. infection was 38.9%; poly-parasitism predominated (54.4 %), identifying Endolimax nana (36.1%) as the most frequently associated commensal species, followed by Giardia intestinalis (22.1%), among the pathogens. There was significant association (p<0.05) between the prevalence of infection with active occupation status, overcrowding, untreated water consumption and lack of adequate conditions to dispose of and eliminate waste. These variables showed OR 95% CI values, which demonstrates their influence as risk factors, reporting the greatest risk of infection (OR=3.18) for the active occupation status. No significant association was noted between the presence of Blastocystis sp. and other epidemiological characteristics (p >0.05). Limitations in community and personal hygiene standards are determinants for the prevalence of Blastocystis sp. in these communities.

Morfología y respuesta de anticuerpos IgM e IgG anti-Blastocystis sp. en pacientes con síntomas gastrointestinales / Morphology and response of IgM and IgG anti-Blastocystis sp. in patients with gastrointestinal symptoms

Es importante definir criterios diagnósticos que permitan dilucidar el papel patógeno de Blastocystis sp. Se evaluó morfología y se estimó el diámetro de las formas, número de parásitos por campo y por gramo de heces y los anticuerpos IgM e IgG anti- Blastocystis sp. mediante ELISA, en sujetos con sintomatología general y portadores sanos. Se encontró 77% de muestras positivas para Blasctocystis sp, 52% provenientes de pacientes con síntomas como flatulencia 6 (24%), dolor abdominal 5 (20%), náuseas 2 (8%), diarrea 6 (24%) y estreñimiento 6 (24%). Los rangos de parásitos por campo más frecuente en sintomáticos fueron 0-3 (74%) y 10-12 (26%), mientras que 100% de los pacientes asintomáticos presentaron Blastocystis sp. en el rango 0-3. Los pacientes asintomáticos presentaron menor número de parásitos por gramo de heces, en el rango de 0-3 y el rango 7-10 con altas cargas parasitarias solo fue observado en sintomáticos. Se encontró menor cantidad de formas granulares en ambos grupos, en el rango 0-3 en sintomáticos: 85% vacuolares y 15% granulares; 76% vacuolares y 24% granulares, en asintomáticos. En el rango 10-12, 98% vacuolares y 2% de granulares, en sintomáticos. El diámetro promedio de las formas vacuolares fue 11,9±2 μm en los pacientes sintomáticos y 7,9±3,7 μm en asintomáticos. En los granulares fue 9,3±2,3 μm en sintomáticos y 8,2±0,1 μm en asintomáticos. Observándose diferencias significativas entre las formas vacuolares de ambos grupos (P=0,000026), pero no en los granulares (P=0,346). El 3,5% de los pacientes sintomáticos presentaron anticuerpos IgG anti-Blastocystis sp. El estudio morfológico empleado contribuyó en la optimización del diagnóstico, mientras que las técnicas inmunoenzimáticas resultaron de baja sensibilidad.

It is important to define diagnostic criteria to elucidate the pathogenic role of Blastocystis sp. Morphology was assessed and diameter of the shapes, number of parasites per field and per gram of faeces and Blastocystis sp. IgM and IgG antibodies was estimated by ELISA in subjects with constitutional symptoms and healthy carriers. Seventy percent Blasctocystis sp positive samples were found, 52% from patients with symptoms such as flatulence 6 (24%), abdominal pain 5 (20 %), nausea 2 (8%), diarrhea 6 (24%) and constipation 6 (24%). Ranges of parasites per field found more frequently in symptomatic patients were 0-3 (74%) and 10-12 (26%), while 100% of asymptomatic patients had Blastocystis sp. in the range 0-3. Asymptomatic patients showed lower number of parasites per gram feces in the range of 0-3 and the 7-10 range with high parasitic load was only observed in symptomatic. Less granular forms in both groups was found, in the range 0-3 in symptomatic patients: 85% vacuolar and 15% granular; 76% vacuolar and 24% granular in asymptomatics. In the range 10-12, 98% vacuolar and 2% granular in symptomatic patients. The average diameter of the vacuolar forms was 11.9 ± 2 μm in symptomatic patients and 7.9 ± 3.7 μm in asymptomatics . In the granular form was 9.3 ± 2.3 μm in symptomatic and 8.2 ± 0.1 μm in asymptomatics. Significant difference was found among vacuolar forms of both groups (P= 0.000026), but not in the granular form (P= 0.346). Only 3.5 % of symptomatic patients had IgG antibodies to Blastocystis sp. The morphological study employed contributed to the diagnosis optimization while immunoenzymatic techniques were of low sensitivity.

Mantenimiento y transporte del Blastocystis sp. en condiciones de vitalidad / Maintenance and transport Blastocystis sp in conditions of vitality

El Blastocystis sp es un protozoario con alta prevalencia en Venezuela. Es controversial por su papel patógeno y su gran variabilidad genética, relacionada con la dificultad de mantenerlo en condiciones de viabilidad fuera del hospedador. Se evaluó la utilidad de los medios de cultivo in vitro RPMI1640, TB1, MBD y MBDM para mantener la viabilidad del Blastocystis sp. Se seleccionaron 97 muestras de heces, 43 (44%) de las cuales resultaron positivas solo para Blastocystis sp y de 15 de ellas se purificaron los Blastocystis sp mediante gradiente (ficol-diatrizaoato de sodio). En cada medio de cultivo y en solución salina 0,85% (SSI) se inoculó1x103 parásitos por paciente y se evaluó la viabilidad mediante coloración con azul de tripano a las 24, 48 y 72 horas. Los resultados mostraron porcentajes de viabilidad a las 24 h: en SSI de 2%, en RPMI1640 5%, en TB1 5%, MBD 24% y MBDM 40%. A las 48 h: en SSI de 3%, en RPMI1640 4%, en TB1 4%, MBD 17% y MBDM 21%. A las 72 h: en SSI 2%, en RPMI1640 2%, en TB1 2%, MBD 15% y MBDM 16%. Se observaron diferencias estadísticamente significativas después de las 24 h, entre los medios TB1, MBD y MBDM comparado con SSI. Se concluye que el medio MBDM es el que ofrece las mejores condiciones para mantener viable a Blastocystis sp por 72 h.

The protozoan Blastocystis sp is a high prevalence in Venezuela. Its role is controversial pathogen and its wide genetic variability related to the difficulty of keeping it in a position outside the host viability. We evaluated the utility of in vitro culture media RPMI1640, TB1, and MBDM MBD to maintain the vitality of Blastocystis sp. They selected 97 stool samples, 43 (44%) of which were positive for Blastocystis sp and only 15 of them were purified by gradient Blastocystis sp (ficoll-sodium diatrizaoato). In each culture medium and 0.85% saline (SSI) is inoculó1x103 parasites per patient and viability was assessed by trypan blue staining after 24, 48 and 72 hours. The results showed viability percentage at 24 hours: in SSI of 2%, 5% RPMI1640 at TB1 5%, 24% and MBDM MBD 40%. After 48 h: SSI 3% in RPMI1640 4%, 4% TB1, MBD MBDM 17% and 21%. After 72 h: SSI 2% in RPMI1640 2%, 2% TB1, MBD 15% and 16% MBDM. Statistically significant differences were observed after 24 h, between TB1 media, compared MBDM MBD and SSI. We conclude that the medium is MBDM which offers the best conditions for maintaining viable Blastocystis sp for 72 h.

Prevalencia de Blastocystis sp. en preescolares y escolares del municipio Maracaibo, Venezuela / Prevalence of Blastocystis sp. in pre-school and school children of the Maracaibo Municipality, Venezuela

Se analizaron 74 muestras fecales pertenecientes a niños de ambos sexos de una institución educativa del municipio Maracaibo, estado Zulia con edades entre 3 y 11 años para determinar la prevalencia de Blastocystis sp. Cada muestra fue sometida a un examen coproparasitológico directo con solución salina 0,85%, tinción temporal de lugol y método de concentración formol-éter. La prevalencia de enteroparásitos en la población estudiada fue de 41,9%; de éstos 80,6% correspondió a Blastocystis sp. En relación a esta especie y su asociación al grupo etario, se reportó un mayor porcentaje de niños parasitados a los 10 años de edad (9,4%), mientras que el parasitismo por otras especies en toda la población estudiada presentó una prevalencia de 19,4%. La forma evolutiva vacuolar predominó, presentándose el mayor número de casos en heces pastosas. Se encontró relación significativa entre las variables parasitismo y edad, más no fue significativa al evaluar las variables parasitismo y sexo. La alta prevalencia de este protozoario en escolares plantea la necesidad de evaluar el comportamiento en la higiene alimentaria y el abastecimiento de agua.

Seventy four fecal samples obtained from children of both sexes at an educational institution of the Maracaibo Municipality, Zulia State, with ages between 3 and 11 years, were analyzed in order to determine the prevalence of Blastocystis sp. Each sample was submitted to a direct coproparasitologic examination with an 0.85% saline solution, temporal lugol staining, and formalin-ether concentration method. Enteroparasite prevalence in the population studied was 41.9%, and of these, 80.6% corresponded to Blastocystis sp. Regarding this species and its association with an age group, a higher percentage of parasitized children was reported in the 10 years age group (9.4%), while parasitism by other species in all the population studied showed a 19.4% prevalence. There was predominance of the vacuolar evolutionary form, and the highest number of cases was seen in tarry stools. There was a significant relationship between parasitism variables and age, but not in the parasitism and sex variables. The high prevalence of this protozoan in school children indicates the need of evaluating the status of food and water supply hygiene.

Uso del cultivo en el diagnóstico de Blastocystis sp. / Use of cultures for the diagnosis of Blastocystis sp.

Se realizó un estudio para comparar el rendimiento del cultivo con el examen directo y la sedimentación espontánea en el diagnóstico de Blastocystis sp. Para el cultivo de Blastocystis sp. se utilizó una modificación del medio de Boeck y Drbohlav. Se emplearon 100 muestras fecales procedentes de habitantes de la comunidad indígena Itopoicon, municipio Heres, estado Bolívar. De las 100 muestras cultivadas y sometidas a examen directo y sedimentación espontánea, en 90 se diagnosticó Blastocystis sp. De ellas, 83 resultaron positivas en el cultivo; mientras que 60 fueron positivas en el examen directo y 57 en la sedimentación espontánea. En conclusión, el cultivo presentó un mayor rendimiento (83%) que el examen directo (60%) y la sedimentación espontánea (57%) en el diagnóstico de Blastocystis sp.

A study for comparing the yield of cultures by direct examination and by spontaneous sedimentation for the diagnosis of Blastocystis sp. was carried out. Blastocystis sp. was cultured in a modification of the Boeck and Drbohlav medium. The material used corresponded to 100 fecal samples from inhabitants of the Itopoicon indigenous community, Heres municipality, Bolivar State. Of the 100 samples cultured and submitted to direct examination and spontaneous sedimentation, 90 gave a diagnosis of Blastocystis sp. Of these 90, 83 were positive in culture, while 60 were positive at direct examination, and 57 in spontaneous sedimentation. In conclusion, culture showed a higher yield (83%), than direct examination (60%) and spontaneous sedimentation (57%), for the diagnosis of Blastocystis sp.

Prevalencia de Blastocystis sp. y otros protozoarios comensales en individuos de Santa Rosa de Agua, Maracaibo, estado Zulia / Prevalence of Blastocystis sp. and other commensal protozoa in individuals from Santa Rosa del Agua, Zulia State

Con la finalidad de determinar la prevalencia de Blastocystis sp. y especies de protozoarios comensales intestinales del hombre según diferentes aspectos como la edad y el sexo, se evaluaron muestras de heces de 111 individuos varones y mujeres de todas las edades, pobladores de Santa Rosa de Agua, Maracaibo, estado Zulia. Cada muestra fecal se analizó a través de un examen al fresco, tinción de lugol y técnica de concentración de Ritchie. Se utilizó la tinción de hematoxilina férrica para identificar trofozoitos de Dientamoeba fragilis. Las especies del complejo Entamoeba histolytica/Entamoeba dispar se diferenciaron mediante técnicas de PCR. Blastocystis sp. fue la especie predominante (45,6%), seguida por Entamoeba coli (17,9%), Endolimax nana (14,8%), Chilomastix mesnili (6,2%), Entamoeba dispar (5,6%), Dientamoeba fragilis, Pentatrichomonas hominis, Iodamoeba butschlii (3,1%) respectivamente y Entamoeba hartmanni (0,6%). Hubo afinidad parasitaria entre las especies Entamoeba coli y Endolimax nana. No se demostró asociación entre presencia de infección y sexo. Los grupos etarios preescolares y escolares demostraron asociación significativa con la infección parasitaria. Se determinó una elevada prevalencia de Blastocystis sp. y especies comensales intestinales, todas indicadoras de contaminación fecal, donde probablemente factores ambientales y socioculturales promovieron su transmisión.

With the purpose of determining Blastocytis sp. and other commensal intestinal protozoa species prevalence according to different aspects such as age and sex, we evaluated 111 feces samples from male and female individuals of all ages, living at Santa Rosa del Agua, Maracaibo, Zulia State, Venezuela. Each fecal sample was analyzed fresh, stained with lugol, and by Ritchie’s concentration test. We used ferric hematoxilin stain to identify Dientamoeba fragilis trophozoites. Species belonging to the Entamoeba histolytica/Entamoeba dispar complex were differentiated through PCR techniques. Blastocytis sp. was the predominant species (45.6%), followed by Entamoeba coli (17.9%), Endolimax nana (14.8%), Chilomastix mesnili (6.2%), Entamoeba dispar (5.6%), Dientamoeba fragilis, Pentatrichomonas hominis, Iodamoeba butschlii (3.1%, respectively), and Entamoeba hartmanni (0.6%). There was parasitic affinity between the Entamoeba coli and Endolimax nana species. There was no association between presence of infection and sex. Pre-school and school age groups showed a significant association with parasite infection. A high prevalence of Blastocystis sp. and intestinal commensal species was determined, all indicative of fecal contamination, where environmental and sociocultural factors probably promote transmission.

Comparison of direct fecal smear microscopy, culture, and polymerase chain reaction for the detection of Blastocystis sp. in human stool samples

OBJECTIVE@#To compare the sensitivity and specificity of direct fecal smear microscopy, culture, and polymerase chain reaction in the detection of Blastocystis sp. in human stool.@*METHODS@#Human stool samples were collected from a community in San Isidro, Rodriguez, Rizal, Philippines. These samples were subjected to direct fecal smear microscopy, culture and polymerase chain reaction to detect the presence of Blastocystis sp.@*RESULTS@#Of the 110 stool samples collected, 28 (25%) were detected positive for the presence of Blastocystis sp. by two or more tests. Culture method detected the highest number of Blastocystis-positive stool samples (n=36), followed by PCR of DNA extracted from culture (n=26), PCR of DNA extracted from stool (n=10), and direct fecal smear (n=9). Compared to culture, the sensitivity of the other detection methods were 66.7% for PCR from culture and 19.4% for both PCR from stool and direct fecal smear. Specificity of the methods was high, with PCR from culture and direct fecal smear having 97.3%, while PCR from stool at 95.9%.@*CONCLUSIONS@#In this study, in vitro culture is the best method for detecting Blastocystis sp. in human stool samples.

Tipos morfológicos, número de parásitos por campo y carga parasitaria de Blastocystis sp proveniente de pacientes sintomáticos y asintomáticos

El papel patógeno de Blastocystis sp es controversial, por lo que es importante definir criterios diagnósticos que permitan dilucidar tal rol. Se evaluó la morfología de Blastocystis sp, número de parásitos por campo y por gramo de heces, en sujetos con sintomatología general y portadores sanos. El estudio fue descriptivo y el diseño no-experimental. La observación y contaje al microscopio se hizo en diez campos consecutivos de 40X y en relación al peso de las heces en gramos, en parásitos teñidos con lugol. Se encontró 77% de muestras positivas para Blastocystis sp, 52% provenientes de pacientes con síntomas como flatulencia 6 (24%), dolor abdominal 5 (20%), náuseas 2 (8 %), diarrea 6 (24%) y estreñimiento 6 (24%). Los rangos de parásitos por campo más frecuente en sintomáticos fueron 0-3 (74%) y 10-12 (26%), mientras que 100% de los pacientes asintomáticos presentaron Blastocystis sp en el rango 0-3. Los pacientes asintomáticos presentaron menor número de parásitos por gramo de heces, en el rango de 0-3 y el rango 7-10 con altas cargas parasitarias sólo fue observado en sintomáticos. Se encontró menor cantidad de formas granulares en ambos grupos, en el rango 0-3 en sintomáticos: 85% vacuolares y 15% granulares; 76% vacuolares y 24% granulares, en asintomáticos. En el rango 10-12, 98% vacuolares y 2% de granulares, en sintomáticos. En conclusión, el estudio de las morfologías, el reporte de la cuantificación diferencial de formas por campo y la cuantificación del número de parásitos por campo pueden contribuir a optimizar el diagnóstico y el manejo quimioterapeútico del paciente.

Morphological types, number of parasites per field and parasite load of Blastocystis sp from symptomatic and asymptomatic patients The pathogenicity of Blastocystis sp is controversial, therefore, it is important to define diagnostic criteria for its determination. We evaluated the morphology of Blastocystis sp, number of parasites per field and per gram of faeces in patients with general symptoms and in healthy carriers. The study was a descriptive and nonexperimental design. The microscopic observation and counting was done in ten consecutive fields in relation to 40X and stool weight in grams. We found 77% of samples positive for Blastocystis sp, 52% from patients with symptoms such as flatulence 6 (24%), abdominal pain 5 (20%), nausea 2 (8 %), diarrhea 6 (24%) and constipation 6 (24%) . The ranges of parasites per field more frequent in symptomatic patients were 0-3 (74%) and 7-10 (26%); and in the asymptomatic group 100% of the patients were in the 0-3 range. In the 0-3 range asymptomatic patients had a lower number of parasites per gram of feces, while in the 7-10 range high parasite loads were observed only in symptomatic patients. Less granular forms in relation to vacuolar ones were found in both groups, in the 0-3 range of the symptomatic group, 85% vacuolar and 15% granular, and 76% vacuolar, and 24% granular in the asymptomatic. In conclusion, the study of the morphologies, the quantification of differential forms by field and the quantification of the number of parasites per field contributes to the technical optimization of routine coproparasitology.

Protozoarios y helmintos intestinales en adultos asintomáticos del estado Zulia, Venezuela / Intestinal protozoa and helminths in asymptomatic adults in the Zulia state, Venezuela

Los estudios de prevalencia de enteroparásitos generalmente se efectúan en población infantil, por ser la más susceptible a estas infecciones; sin embargo, para evaluar la situación en adultos se realizó la presente investigación. Se efectuó el examen coproparasitológico a 95 personas asintomáticas mayores de 18 años, provenientes de 3 diferentes localidades del estado Zulia, Venezuela. Las muestras fecales se sometieron al examen microscópico con SSF-Lugol y método de concentración con formol-éter. 64 individuos (67,36%) presentaron una o varias especies de parásitos intestinales y de éstos, el 81,25% presentaba al menos un parásito patógeno para los humanos. 31 individuos presentaron más de una especie parasitaria (poliparasitismo), con un máximo de 3 especies por hospedador. Se identificaron 7 especies de protozoarios intestinales incluyendo patógenos y comensales, así como 2 especies de helmintos. Predominaron los casos de protozoosis (93) sobre las helmintiasis (10). La mayor frecuencia correspondió a Blastocystis sp. entre los protozoarios y Ascaris lumbricoides entre los helmintos, así mismo, existió un predominio de A. lumbricoides y Trichuris trichiura en la comunidad Los Pescadores, al comparar las tres comunidades estudiadas. La asociación parasitaria más frecuente fue Blastocystis sp. con varias amibas. Este estudio detectó una elevada prevalencia de protozoarios intestinales y particularmente de Blastocystis sp.

Prevalence studies for intestinal parasites are usually performed on children, since they are the most susceptible to these infections; however, this research was conducted to assess the situation in adults. Stool examination was performed on 95 asymptomatic persons over 18 years old, from three different locations in the state of Zulia, Venezuela. Fecal samples were submitted to microscopic examination with SSF-Lugol and the concentration method with formalin ether. Sixty-four individuals (67.36%) had one or more species of intestinal parasites and of these, 81.25% had at least one parasite pathogenic for humans. Thirty-one individuals had more than one parasite species (polyparasitism), with a maximum of three species per host. Seven intestinal protozoa species were identified, including pathogens and commensals, as well as 2 species of helminths. Protozoosis cases predominated (93) over helminths (10). The greatest frequencies corresponded to Blastocystis sp. among protozoa and Ascaris lumbricoides among helminths; also, there was a predominance of A. lumbricoides and Trichuris trichiura in the community Los Pescadores, when comparing the three communities studied. The most frequent parasitic association was Blastocystis sp. with several amoebas. This study found a high prevalence of intestinal protozoa and particularly Blastocystis sp.

Investigación de blastocystis sp. en agua de consumo humano en una población escolar de la zona rural del estado Mérida, Venezuela / Blastocystis sp. in drinking water at a rural school in Mérida, Venezuela

Para detectar la presencia de Blastocystis sp. en el agua de consumo de una escuela rural del estado Mérida, se recolectaron 36 muestras provenientes de la fuente natural que surte el tanque de distribución, del tanque y de los grifos, durante los meses de Septiembre 2008, Febrero y Diciembre del 2009 y Mayo 2010. El procesamiento de las muestras se realizó siguiendo la técnica propuesta por Suresh y col. (2005). Los resultados sugieren que el agua de consumo estaba exenta de Blastocystis o que la cantidad de quistes viables presentes en las muestras fue muy baja, lo que no permitió lograr la recuperación del parásito en el cultivo. Por ello se requiere el uso de técnicas más sensibles que permitan detectar cantidades bajas del microorganismo en aguas de consumo humano. El estudio de los hábitos de consumo de agua de la población estudiantil de la escuela rural, mostró que más de la mitad de la población consume agua hervida, esto probablemente se deba a que están conscientes que el agua a la cual tienen acceso proviene de una fuente natural no tratada

In order to determine the presence of Blastocystis sp. in drinking water at a rural school in Merida, 36 water samples were collected from natural sources that feed the distribution tank and faucets during the months of September, 2008, February and December, 2009, and May, 2010. Samples were processed using the technique proposed by Suresh et al. (2005). All samples were negative. These results suggest that the water was exempt from Blastocystis or that the quantity of viable cysts present in the samples was very low, not permitting reproduction in the culture. This report suggests the importance of using more sensitive techniques to detect low amounts of the organismin drinking water. The study of student water consumption habits at the rural school showed that more than half the population consume boiled water; probably, they are aware that the water source has not been treated for drinking

Algunas consideraciones acerca de Blastocystissp, un parásito controversial / Some considerations about Blastocystis sp, a controversial parasite / Algumas considerações sobre Blastocystis sp, Um parasita controverso

Blastocystis es un organismo unicelular, anaerobio y uno de los parásitos intestinales de mayor prevalencia a nivel mundial. Durante mucho tiempo su ubicación taxonómica fue difícil de definir. Actualmente es considerado el único parásito humano del Reino Chromista. Se le reconocen numerosas formas evolutivas (vacuolares, granulares, ameboidales, avacuolares, multivacuolares y quísticas) que conforman un ciclo vital aún en estudio. Los quistes son las formas de resistencia y transmisión. Se lo considera un parásito zoonótico con 9 subtipos que pueden tener diferentes especificidades entre hospedadores humanos y animales. Su carácter patógeno ha sido motivo también de controversia dado que puede presentar infecciones asintomáticas o sintomáticas con manifestaciones digestivas, y dérmicas, entre otras. El diagnóstico de laboratorio puede ser microscópico o mediante cultivos, serología y técnicas moleculares.

Blastocystis is an anaerobic, unicellular organism and it is one of the most prevalent among intestinal parasites. It has a worldwide distribution. Nowadays, it is considered the only human parasite that belongs to the kingdom Chromista. Many morphological forms of the parasite are known: vacuolar, granular, amoeboid, avacuolar, multivacuolar and cyst. Its life cycle is not completely understood. Cysts are the forms of resistance and transmission. It is considered a zoonotic parasite with 9 subtypes, with different specificities for human and animal hosts. Its pathogenesis is controversial because it can cause asymptomatic and symptomatic infections, with gastrointestinal and cutaneous manifestations. Laboratory diagnosis may be performed by microscopic, cultural, serological and molecular techniques.

Blastocystis sp. and other intestinal parasites in hemodialysis patients

Chronic renal insufficiency disease (CRI) leads to uremia in hemodialysis patients and induces a state of immunodepression that results in higher frequencies of infections and diarrhea. Hemodialysis patients resident in the city of Campo Mourão, Paraná, Brazil were analyzed from April 2006 through September 2007 for Blastocystis sp. and other intestinal parasites and for associated diarrhea. Fecal samples from 86 hemodialysis patients and 146 healthy (reference) persons were examined by standard methods for detecting ova, larvae and cysts, which included preservation in 10 percent formalin and the Kinyoun method. Thirty-three hemodialysis patients (45.1 percent) and 36 reference individuals (25.7 percent) were found to be parasitized. The differences in the percentages of parasitism and polyparasitism between the reference group and the chronic renal patients was significant (p= 0.0318 and 0.0019, respectively). Blastocystis sp. (18 percent-20.1 percent), Endolimax nana (14 percent-16.3 percent), Cryptosporidium sp. (4 percent-4.7 percent) and Entamoeba coli (4 percent-4.7 percent) were the most frequent protozoa found in the hemodialysis patients. Parasitism was not significantly associated with diarrhea (p=0.9947) or with decreased white blood cell counts (p=0.7046) in these individuals. Because parasitic infections may be an important comorbidity factor in hemodialysis patients, we suggest that parasitological stool examinations, especially for Blastocystis sp. and Cryptosporidium sp., be included in routine medical follow-up examinations of these patients.