[Prevalence of Blastocystis hominis among food handlers from Caroni municipality, Bolivar State, Venezuela]

Blastocystis spp. and Giardia intestinalis co-infection profile in children suffering from acute diarrhea

Giardia intestinalis and Blastocystis spp. are two common zoonotic intestinal parasites responsible for the majority of diarrheic cases, especially in children. The study was planned to determine the impact role of both Giardia and Blastocystis co-infection in children up to 12 years old with acute diarrhea in Beni-Suef, Egypt. Also, to estimate the general prevalence rates and risk factors associated with intestinal parasitic infections. Stool samples collected from 125 children, within a period of 7 months, were examined using direct wet mount and trichrome stain in comparison to in vitro culture on Jones medium (for detecting Blastocystis spp.) and Immunochromatography techniques (for detecting Giardia). At least one type of intestinal parasites was harbored in 72% of the studied children, single infection constituted 37.6% while, 34.4% were polyparasitized children. The predominant parasites involved were Blastocystis spp.(53.6%), followed by Giardia intestinalis (27.2%). Co-infection between both parasites was recorded in 20% of cases. Two risk factors were significantly associated with higher risk of Giardia-Blastocystis co-infection including age category (5-7 years) and family size (≥ 6 members) by univariate analysis (P = 0.004, 0.009 respectively) and also by the multivariate model (OR = 0.526, 0.336). Abdominal pain was the only gastrointestinal manifestation associated with the co-infection using the univariate analysis (P = 0.0427). The present study detects a high prevalence of intestinal parasitic infection; in particular, Giardia-Blastocystis co-infection in diarrheic young children (up to 12 years) in Beni-Suef Governorate, Egypt and recommends further subtypes identification of both parasites.

Predominance and association risk of Blastocystis hominis subtype I in colorectal cancer: a case control study

Background

Blastocystis, a genetically diverse intestinal parasite with controversial pathogenic potential, has increasingly been incriminated for diarrheal illness in immunocompromised individuals including colorectal cancer (CRC) patients. The aim of the current study was to assess the possible association between Blastocystis infection and CRC condition in Makkah, Saudi Arabia (KSA).

Methods

Stool samples were collected from 80 non-cancer (NC) and 138 cancer subjects including 74 CRC patients and 64 patients with other cancers outside gastrointestinal tract (COGT). Molecularly confirmed Blastocystis isolates were genetically grouped and subtyped using multiplex polymerase chain reaction with restriction fragment length polymorphism (PCR-RFLP) and sequence-tagged site primers-based PCR (PCR-STS), respectively.

Results

Blastocystis hominis were confirmed in 29.7, 25 and 15% among CRC, COGT and NC patients, respectively. Obtained Blastocystis isolates were initially categorized into 2 groups (A and C), which were subsequently subtyped into 3 different subtypes; subtype-I (38%), subtype-II (44%) and subtype-V (22%). Interestingly, subtype-I was the most predominantly detected subtype (54.5%) among CRC patients with a significant association risk (COR 7.548; 95% CI: 1.629–34.987; P = 0.004).

Conclusion

To the best of our knowledge, the current study is the first to provide genetic insights on the prevalence of Blastocystis hominis among CRC patients in Makkah, KSA. Moreover, the study suggests for a possible association between subtype-I of Blastocystis hominis and CRC, which could indicate a potential influence of Blastocystis on CRC condition. Further studies are required to confirm this association risk and to investigate the possible underlying mechanism of postulated carcinogenic influence of Blastocystis hominis subtype-I.

Electronic supplementary material

The online version of this article (doi:10.1186/s13027-017-0131-z) contains supplementary material, which is available to authorized users.

Low prevalence of Vibrio cholerae O1 versus moderate prevalence of intestinal parasites in food-handlers working with health care personnel in Haiti

Food-handlers with poor personal hygiene working in food-service establishments could be potential sources of infection due to pathogenic organisms. In May 2011, a cross-sectional study was undertaken to determine the prevalence of bacteria and intestinal parasites among food-handlers working with Cuban health personnel in Haiti. Stool specimens were collected from 56 food-handlers and samples were examined using standard procedures. Of the food handlers, 26.8% had one bacterial or intestinal parasite. The most prevalent species of organism found were Blastocystis spp. (9%), followed by Vibrio cholerae O1 serotype Ogawa, Aeromonas spp. and Giardia intestinalis, each one with 4%. The prevalence of intestinal parasites was 19.7%. Five out of 56 food handlers had diarrhea at the time the study was conducted. It was found that there was a lower prevalence of V. cholerae O1 serotype Ogawa in comparison to intestinal parasites. The study highlights the importance of the precautions that must be taken in cholera-affected countries by medical teams and their organizations, with emphasis on the preparation, processing, and serving of meals. The recommendation is to intensify continuing education programs, periodical laboratory examinations to detect carriers and food-handlers reporting sick, and to observe strict adherence to hygienic food-handling practices. In addition, food handlers with diarrhea should refrain from preparation or delivery of food.

Blastocystis subtypes detected in humans and animals from Colombia

Blastocystis is a common enteric protist colonizing probably more than 1 billion people along with a large variety of non-human hosts. This protist has been linked to symptoms and diseases such as abdominal pain, constipation, diarrhea, flatulence and irritable bowel syndrome (IBS). Remarkable genetic diversity has been observed, leading to the subdivision of the genus into multiple subtypes (ST), some of which are exclusively found in non-human hosts. The aim of this study was to determine the distribution of Blastocystis STs in different Colombian hosts. We obtained fecal samples positive for Blastocystis by microscopy from 277 humans, 52 birds, and 117 mammals (25 cattle, 40 opossums, 40 dogs, 10 rats and 2 howler monkeys). The samples were submitted to DNA extraction, PCR and sequencing using primers targeting the small subunit rRNA gene, and ST identification was performed according to DNA barcoding. We observed the occurrence of ST1 (34%) and ST2 (23%) and lower proportions of STs 3 (11.4%), 4 (0.8%), 6 (19.8%) and 8 (10.5%). Domesticated mammals shared the same STs as those usually seen in humans (ST1, ST2, ST3), while birds and marsupials had STs, which are usually rare in humans (ST6, ST8). Further studies implementing high-resolution molecular markers are necessary to understand the phylodynamics of Blastocystis transmission and the role of this stramenopile in health and disease in Colombian populations, and to expand on the phylogeographic differences observed so far with a view to exploring and understanding host-parasite co-evolution.

Enteroparasitosis and their ethnographic relationship to food handlers in a tourist and economic center in Paraná, Southern Brazil

This study reports on the occurrence of enteroparasites based on data from an ethnographic study of food handlers in the city of Cascavel, Paraná, Brazil. Fecal material from 343 food handlers of both sexes, between 14 and 75 years of age, was analyzed using Lutz, modified Ritchie and Ziehl-Neelsen techniques. Ethnographic relationships were investigated by means of specific questionnaires. Positive fecal samples were found for 131 (38.2%) handlers. Endolimax nana (67.9%) was the predominant species, followed by Entamoeba coli (35.9%), Blastocystis hominis (28.2%), Entamoeba histolytica/dispar (10.1%) and Giardia duodenalis (8.4%). Protozoan infections were more common than helminth infections (p = 0.00). The positive results for some parasites were associated with the male sex, professional category, and the performance of other activities (p < 0.05). The high overall occurrence of enteroparasites found indicates improper hygiene and sanitation conditions. Effective educational measures should be implemented to prevent the transfer of pathogenic organisms to food via handling.

New insights on classification, identification, and clinical relevance of Blastocystis spp

SUMMARY

Blastocystis is an unusual enteric protozoan parasite of humans and many animals. It has a worldwide distribution and is often the most commonly isolated organism in parasitological surveys. The parasite has been described since the early 1900s, but only in the last decade or so have there been significant advances in our understanding of Blastocystis biology. However, the pleomorphic nature of the parasite and the lack of standardization in techniques have led to confusion and, in some cases, misinterpretation of data. This has hindered laboratory diagnosis and efforts to understand its mode of reproduction, life cycle, prevalence, and pathogenesis. Accumulating epidemiological, in vivo, and in vitro data strongly suggest that Blastocystis is a pathogen. Many genotypes exist in nature, and recent observations indicate that humans are, in reality, hosts to numerous zoonotic genotypes. Such genetic diversity has led to a suggestion that previously conflicting observations on the pathogenesis of Blastocystis are due to pathogenic and nonpathogenic genotypes. Recent epidemiological, animal infection, and in vitro host-Blastocystis interaction studies suggest that this may indeed be the case. This review focuses on such recent advances and also provides updates on laboratory and clinical aspects of Blastocystis spp.

Blastocystis hominis and other intestinal parasites in a community of Pitanga City, Paraná State, Brazil

The objective was to estimate the prevalence of Blastocystis hominis, to evaluate the effectiveness of different techniques for its diagnosis as well as to estimate the prevalence of other intestinal parasites in the community of Campo Verde, a district of Pitanga. The work was carried out from August to October 2004. Samples of feces from children and adults were collected and submitted to the techniques of direct wet mount, flotation in zinc sulphate solution, tube sedimentation, sedimentation in formalin-ether and staining by Kinyoun and iron hematoxylin methods. From 181 studied individuals, 128 (70.7%) showed protozoa and/or helminths in stool samples. The most prevalent species were Endolimax nana (33.7%); B. hominis (26.5%); Giardia lamblia (18.2%); Entamoeba coli (17.1%); Ascaris lumbricoides (16.6%); Iodamoeba bütschlii (9.4%); and ancylostomatidae (7.7%). B. hominis was only identified by the techniques of direct wet mount, sedimentation in formalin-ether and staining by iron hematoxylin, though the latter was less sensitive than the other methods. The high frequency of B. hominis demonstrated by this study indicates the need to include laboratory techniques that enable identification of the parasite on a routine basis.

[Relationship between intestinal parasites in food handlers and epidemiological factors in the city of Florianópolis, Santa Catarina, Brazil]

The presence of intestinal parasites and epidemiological aspects were evaluated in 238 workers from a fast food company and other individuals working in street markets and farmers' produce markets in the city of Florianópolis, Santa Catarina State, Brazil. Parasitological techniques used in this study were: Lutz, Baermann-Moraes, Graham, and Faust, and parasite infection rates were 42.85% and 47.06%, respectively. Socioeconomic factors such as income distribution, schooling, and occupational categories proved to be relevant in this context. Habitual daily intake of fruits and vegetables was the factor most heavily associated with infection. These data suggest that intestinal parasites are frequent among food handlers in this city and that there is a need for constant epidemiological surveillance through periodic parasitological tests and health education for this entire population segment.

Molecular phylogenies of Blastocystis isolates from different hosts: implications for genetic diversity, identification of species, and zoonosis

Small-subunit (SSU) rRNA gene sequences were obtained by PCR from 12 Blastocystis isolates from humans, rats, and reptiles for which elongation factor 1alpha (EF-1alpha) gene sequences are already available. These new sequences were analyzed by the Bayesian method in a broad phylogeny including, for the first time, all Blastocystis sequences available in the databases. Phylogenetic trees identified seven well-resolved groups plus several discrete lineages that could represent newly defined clades. Comparative analysis of SSU rRNA- and EF-1alpha-based trees obtained by maximum-likelihood methods from a restricted sampling (13 isolates) revealed overall agreement between the two phylogenies. In spite of their morphological similarity, sequence divergence among Blastocystis isolates reflected considerable genetic diversity that could be correlated with the existence of potentially >/=12 different species within the genus. Based on this analysis and previous PCR-based genotype classification data, six of these major groups might consist of Blastocystis isolates from both humans and other animal hosts, confirming the low host specificity of Blastocystis. Our results also strongly suggest the existence of numerous zoonotic isolates with frequent animal-to-human and human-to-animal transmissions and of a large potential reservoir in animals for infections in humans.