Comparison of the genetic variability of Blastocystis subtypes between human carriers from two contrasting climatic regions of México

Villegas-Gómez, Isaac; Martínez‐Hernández, Fernando; Urrea-Quezada, Alejandro; González-Díaz, Mariana; Durazo, María; Hernández, Jesús; Orozco-Mosqueda, Guadalupe Erendira; Villalobos, Guiehdani; Maravilla, Pablo; Valenzuela, Olivia

doi:10.1016/j.meegid.2016.07.036

Cited by 27 publications

(23 citation statements)

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“…We found that ST3 and ST1 were the most frequent subtypes, consistent with previous reports describing children infected with Blastocystis from other states in Mexico [ 41 , 43 ]. Similarly, the values obtained in this study for nucleotide diversity (π) and haplotype polymorphism (θ) for the 18S gene were in accordance with previous studies of genetic diversity in Blastocystis infections in children from other geographical regions of Mexico [ 41 , 43 ]. Interestingly, the π and θ values for ST1 or ST2 were almost 10-fold higher than those for ST3, indicating a high reduction of the variability within and among sequences in this subtype.…”

Section: Discussionsupporting

confidence: 92%

Can the pyruvate: ferredoxin oxidoreductase (PFOR) gene be used as an additional marker to discriminate among Blastocystis strains or subtypes?

et al. 2018

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BackgroundBlastocystis spp. are the most prevalent intestinal eukaryotes identified in humans, with at least 17 genetic subtypes (ST) based on genes coding for the small-subunit ribosomal RNA (18S). It has been argued that the 18S gene should not be the marker of choice to discriminate between STs of these strains because this marker exhibits high intra-genomic polymorphism. By contrast, pyruvate:ferredoxin oxidoreductase (PFOR) is a relevant enzyme involved in the core energy metabolism of many anaerobic microorganisms such as Blastocystis, which, in other protozoa, shows more polymorphisms than the 18S gene and thus may offer finer discrimination when trying to identify Blastocystis ST. Therefore, the objective of the present study was to assess the suitability of the PFOR gene as an additional marker to discriminate among Blastocystis strains or subtypes from symptomatic carrier children.MethodsFaecal samples from 192 children with gastrointestinal symptoms from the State of Mexico were submitted for coprological study. Twenty-one of these samples were positive only for Blastocystis spp.; these samples were analysed by PCR sequencing of regions of the 18S and PFOR genes. The amplicons were purified and sequenced; afterwards, both markers were assessed for genetic diversity.ResultsThe 18S analysis showed the following frequencies of Blastocystis subtypes: ST3 = 43%; ST1 = 38%; ST2 = 14%; and ST7 = 5%. Additionally, using subtype-specific primer sets, two samples showed mixed Blastocystis ST1 and ST2 infection. For PFOR, Bayesian inference revealed the presence of three clades (I-III); two of them grouped different ST samples, and one grouped six samples of ST3 (III). Nucleotide diversity (π) and haplotype polymorphism (θ) for the 18S analysis were similar for ST1 and ST2 (π = ~0.025 and θ = ~0.036); remarkably, ST3 showed almost 10-fold lower values. For PFOR, a similar trend was found: clade I and II had π = ~0.05 and θ = ~0.05, whereas for clade III, the values were almost 6-fold lower.ConclusionsAlthough the fragment of the PFOR gene analysed in the present study did not allow discrimination between Blastocystis STs, this marker grouped the samples in three clades with strengthened support, suggesting that PFOR may be under different selective pressures and evolutionary histories than the 18S gene. Interestingly, the ST3 sequences showed lower variability with probable purifying selection in both markers, meaning that evolutionary forces drive differential processes among Blastocystis STs.

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Section: Discussionsupporting

confidence: 92%

Can the pyruvate: ferredoxin oxidoreductase (PFOR) gene be used as an additional marker to discriminate among Blastocystis strains or subtypes?

et al. 2018

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“…Globally, ST3 predominance has been observed in different geographic areas and populations, including in South America (David et al, 2015;Melo et al, 2017;Ramirez et al, 2014Ramirez et al, , 2016Sánchez et al, 2017). Otherwise, our results showed the predominance of ST1 (56.1%) and this observation concurs to findings of some particular investigations in Africa (Forsell et al, 2016), Asia (Sanpool et al, 2017;Thathaisong et al, 2013;Yoshikawa et al, 2016b) and in some countries in Latin America as Brazil, Colombia and Mexico (Malheiros et al, 2011;Ramirez et al, 2014;Villegas-Gómez et al, 2016). Even though ST3 was not the most prevalent subtype in the sampled population, its prevalence (31.6%) was relevant.…”

Section: Discussionsupporting

confidence: 89%

“…About ST2, it was observed only in children (four samples). ST2 is one of the common subtypes in human infections, but interestingly in some studies it has been detected at lower ratios than ST1 and ST3 or it is absent in a given population (Pandey et al, 2015;Villegas-Gómez et al, 2016). Apart from this, it is worth noting that ST4 was absent in the present study which reinforces the fact that this subtype is rarely detected in South America's human populations, as previously shown (David et al, 2015;Malheiros et al, 2011;Melo et al, 2017).…”

Section: Discussionsupporting

confidence: 84%

“…Notwithstanding the progress made over the last two decades, current interest has focused on the distribution and relevance of Blastocystis subtypes in populations living in low-income areas. Those include Asia (Belleza et al, 2015;Nithyamathi et al, 2016;Pandey et al, 2015;Sanpool et al, 2017), Africa (El Safadi et al, 2014;Poulsen et al, 2016), the Middle East (AbuOdeh et al, 2016;Dogan et al, 2017) and also in Latin America (David et al, 2015;Macchioni et al, 2016;Malheiros et al, 2011;Melo et al, 2017;Ramirez et al, 2014Ramirez et al, , 2016Ramirez et al, , 2017Sánchez et al, 2017;Villegas-Gómez et al, 2016). Recently, the limited data from South America was highlighted (Ramirez et al, 2016(Ramirez et al, , 2017.…”

Section: Introductionmentioning

confidence: 99%

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Blastocystis genetic diversity among children of low-income daycare center in Southeastern Brazil

Oliveira-Arbex

David

Guimarães

2018

Infection, Genetics and Evolution

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Blastocystis, an unicellular anaerobic eukaryote, is known to be a very common intestinal parasite found in humans and animals fecal samples worldwide. Currently, there is an increasing interest to yield insights into its prevalence and diversity in human populations living in poor and deprived areas. In this study, we describe the prevalence and genetic variability of Blastocystis isolates obtained from daycare center attendees aged 0 to 6years and staff, as well as some children family members and their dogs in a low-income community in São Paulo State, Brazil. A total of 181 stool samples (123 from daycare children, 14 from workers, 44 from household members and 20 from dogs) were submitted to DNA extraction, tested by polymerase chain reaction (PCR) targeting the SSUrDNA gene and the amplicons retrieved were sequenced. The prevalence of Blastocystis was 40.7% (50/123) in children, 28.6% (4/14) in workers and 50% (22/44) in household members. No dog was found positive. Of the 76 PCR products generated, 57 were successfully sequenced. Four subtypes were identified and the most common were ST1 (54.4%) and ST3 (33.3%), followed by ST2 (7.0%) and ST7 (5.3%). The intra-subtype analysis revealed a total of 10 different alleles previously reported. No statistically significant correlation was observed between subtypes and sociodemographic variables analyzed. Here, the following findings must be highlighted: (1) predominance of subtypes 1 and 3, a pattern that has been observed in many populations worldwide; (2) absence of ST4, a common subtype in Europe but rarely detected in South America's human populations and, (3) human infection with ST7, a subtype primarily found in birds but occasionally seen in human infections, raising the possibility of zoonotic transmission.

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“…For Blastocystis, greater diversity was found in the Caribbean region in the departments of Bolívar and Córdoba. This was expected since Blastocystis usually has high inter-subtype variability , as reported in a study of SSU DNAr genes conducted in Mexico, where the results showed similar diversity indices within each subtype, despite their different geographical regions and different inter-subtype indices (Villegas-Gómez et al, 2016), and a greater diversity between the STs of a control group compared with one associated with irritable bowel syndrome (Vargas-Sanchez et al, 2015). Like G. intestinalis, the number of sequences for Córdoba was very small, avoiding any strong conclusions regarding this population.…”

Section: Discussionsupporting

confidence: 64%

Molecular detection and genotyping of intestinal protozoa from different biogeographical regions of Colombia

Higuera

Villamizar

Herrera

et al. 2020

PeerJ

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Background: Intestinal parasitic protozoa represent a serious problem of public health particularly in developing countries. Protozoa such as Blastocystis, Giardia intestinalis, Entamoeba histolytica and Cryptosporidium spp. are associated with diarrheal symptoms. In Colombia, there is little region-specific data on the frequency and circulating genotypes/species of these microorganisms. Therefore, the main objective of our study was to employ molecular detection and genotyping of G. intestinalis and Blastocystis, Cryptosporidium and Entamoeba spp. in samples from different biogeographical regions of Colombia. Methods: We collected 649 human fecal samples from five biogeographical regions of Colombia: the Amazon, Andean, Caribbean, Orinoco and Pacific regions. Blastocystis, G. intestinalis, Cryptosporidium spp. and Entamoeba complex were detected by microscopy and conventional PCR. Molecular genotyping was conducted to identify Blastocystis subtypes (STs) (18s), G. intestinalis assemblages (triose phosphate isomerase and glutamate dehydrogenase) and Cryptosporidium species (18s). Genetic diversity indices were determined using dnasp.5. Results: We detected G. intestinalis in 45.4% (n = 280) of samples, Blastocystis in 54.5% (n = 336) of samples, Cryptosporidium spp. in 7.3% (n = 45) of samples, Entamoeba dispar in 1.5% (n = 9) of samples, and Entamoeba moshkovskii in 0.32% (n = 2) of samples. Blastocystis STs 1-4, 8 and 9 and G. intestinalis assemblages AII, BIII, BIV, D and G were identified. The following Cryptosporidium species were identified: C. hominis, C. parvum, C. bovis, C. andersoni, C. muris, C. ubiquitum and C. felis. The Caribbean region had the highest frequency for each of the microorganisms evaluated (91.9% for G. duodenalis, 97.3% for Blastocystis, 10.8% for Cryptosporidium spp., 13.5% for E. dispar and 2.7% for E. moshkovskii). The Orinoco region had a high frequency of Blastocystis (97.2%) and the Andean region had a high frequency of G. intestinalis (69.4%). High and active transmission was apparent in several regions of the country, implying that mechanisms for prevention and control of intestinal parasitosis in different parts of the country must be improved. . 2014. Blastocystis sp. frequency and sources among children from 0 to 5 years of age attending public day care centers in Calarca. A novel, multi-parallel, real-time polymerase chain reaction approach for eight gastrointestinal parasites provides improved diagnostic capabilities to resource-limited at-risk populations.

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Comparison of the genetic variability of Blastocystis subtypes between human carriers from two contrasting climatic regions of México

Cited by 27 publications

References 33 publications

Can the pyruvate: ferredoxin oxidoreductase (PFOR) gene be used as an additional marker to discriminate among Blastocystis strains or subtypes?

Can the pyruvate: ferredoxin oxidoreductase (PFOR) gene be used as an additional marker to discriminate among Blastocystis strains or subtypes?

Blastocystis genetic diversity among children of low-income daycare center in Southeastern Brazil

Molecular detection and genotyping of intestinal protozoa from different biogeographical regions of Colombia

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