Subtypes and phylogenetic analysis of Blastocystis sp. isolates from West Ismailia, Egypt

Abstract

In Egypt, Blastocystis sp. is not yet on the diagnostic list of parasitology reports, and information about its subtypes (STs) is scarce. This study investigated its prevalence and its STs/alleles, performed phylogenetic analysis, and considered the distribution of risk factors associated with Blastocystis sp. infections in West Ismailia, Ismailia governorate. Sociodemographic data, exposure factors, and previous parasitic infection status were recorded for symptomatic and asymptomatic individuals. Microscopy, polymerase chain reaction, sequencing, and phylogenetic analysis for Blastocystis sp. isolated from fecal samples were performed. Eighty Blastocystis sp.-infected individuals (15.3%) were examined. The age of the individuals ranged between 0.60 and 85.0 (mean 17.10 ± 15.70), the male/female ratio was 33/47, and the asymptomatic/symptomatic ratio was 55/25. The findings demonstrate clear evidence of direct contact with animals, poor water quality, and previous parasitic infections. Eleven samples yielded three Blastocystis STs (ST1: allele 4, ST2: alleles 9 and 12, and ST3: allele 34), with ST3 (45.5%) representing the most common subtype. Phylogenetic analysis with a robust bootstrap revealed three distinct clades for isolates of each subtype. This study updates the epidemiological knowledge of the distribution of Blastocystis sp. STs in Egypt and expands the current understanding of the prevalence, risk factor frequencies, and genetic diversity of this protist in the studied area.

Molecular characterization of Blastocystis subtypes in symptomatic patients from the southern region of Syria

“…No association was detected with any particular ST. Our data comes in line with the study of Khaled et al conducted on Syrian refugees living in North Lebanon [49], and with research from Qatar by Abu-Madi et al where no difference was found between the prevalence of Blastocystis and between age groups [32]. However, our finding did not support previous reports indicating an association between age and infection being more common in young or adult patients [29,36].…”

“…Previous studies have shown that ST1 and ST3 are the most prevalent subtypes distributed among human individuals and several kinds of animals worldwide [31,40,41]. Earlier reports from the Middle East revealed that the most dominant Blastocystis subtype was ST3 followed by ST1 [26,36,42,43]. However, in our study, ST1 was the most predominant (66.7%).…”

“…ranged from 44.4% up to 86.6% [1,[32][33][34][35]. Whereas other studies from Iran [29], Tunisia [15], Egypt [36] and Lebanon [37] showed low infection rates (8.1%, 13%, 15.3% and 19% respectively). This difference can be explained according to the prevailing epidemiological situation and different climatic conditions [38].…”

Predicting Phylogenetic Bootstrap Values via Machine Learning

“…In analogy to the lower bound prediction for the EBG regressor, EBG also provides a prediction uncertainty measure for its classifier. As the EBG classifier solves a binary classification problem, with one class defined as SBS > t and the other as SBS ≤ t , we can leverage the Shannon entropy [27] of the two class probabilities to obtain a prediction uncertainty measure u ∈ [0, 1]. Here, u = 0 represents absolute certainty, and u = 1 corresponds to absolute uncertainty.…”

“…Despite the availability of these tools, SBS remains an important approach for measuring branch support [6, 1, 20]. Guindon et al [10] propose to combine the SBS with the SH-like aLRT to obtain a holistic estimate of branch robustness.…”