First molecular subtyping and zoonotic significance of Blastocystis sp. in Dromedary (C. dromedarius) and Bactrian (C. bactrianus) camels in Iran: A molecular epidemiology and review of available literature.

BACKGROUND: Blastocystis sp. is a zoonotic protozoan parasite, and there is limited information about its molecular prevalence and subtypes (STs) distribution in camels globally, especially in Iran. OBJECTIVES: This study aimed to examine the prevalence, STs distribution, and zoonotic potential of Blastocystis sp. in one-humped and two-humped camels in Ardabil province, northwestern Iran. METHODS: A PCR-sequencing tool using the SSU rRNA gene was employed to examine the occurrence and genetic variation of Blastocystis sp. in 150 faecal samples from Bactrian (Camelus bactrianus, 50 samples) and Dromedary (Camelus dromedarius, 100 samples) camels in Ardabil province. RESULTS: The overall prevalence of Blastocystis sp. in camels was determined to be 12% (18/150) through microscopy and PCR analyses. Phylogenetically, this study identified three distinct zoonotic STs: ST7, ST10, and ST14. ST10 was the most prevalent, comprising 50% (9/18) of the isolated STs from camels. ST14 closely followed with 38.9% (7/18), while ST7 made up 11.1% (2/18) of the total STs. In brief, ST10, ST14, and ST7 represented 50% (7/14), 35.7% (5/14), and 14.3% (2/14) of the Blastocystis-positive cases in one-humped camels, respectively. Further, each of the ST10 and ST14 accounted for 50% (2/4) of the Blastocystis-positive samples in two-humped camels. An analysis of the available data reveals that out of the 37-44 identified Blastocystis STs, 15 (ST1-ST7, ST10, ST14, ST15, ST21, ST24, ST25, ST26, and ST30) have been reported in camels. The predominant STs observed are ST10 and ST14. Furthermore, among the 15 zoonotic STs (ST1-ST10, ST12-ST14, ST16, and ST23) of Blastocystis reported thus far, nine zoonotic STs (ST1-ST7, ST10, and ST14) have been found in camels. CONCLUSIONS: These findings indicate that camels serve as a proper reservoir for a diverse array of Blastocystis STs and thereby can play a significant role in the transmission of this protozoan infection to humans, animals, and water reservoirs.

Development of New PCR Protocols to Detect Genetic Diversity in the Metronidazole Metabolism Genes in Susceptible and Refractory Clinical Samples of Giardia duodenalis.

PURPOSE: Investigating the genetic variation in thioredoxin reductase (TrxR) and nitroreductase (NR) genes in both treatment-resistant and -sensitive Giardia duodenalis isolates can provide valuable information in identifying potential markers of resistance to metronidazole. The rapid increase in metronidazole treatment failures suggests the presence of genetic resistance mechanisms. By analyzing these genes, researchers can gain insights into the efficacy of metronidazole against G. duodenalis and potentially develop alternative treatment strategies. In this regard, four G. duodenalis isolates (two clinically sensitive and two clinically resistant to metronidazole) were collected from various hospitals of Shiraz, southwestern Iran. METHODS: Parasitological methods including sucrose flotation and microscopy were employed for the primary confirmation of G. duodenalis cysts in stool samples. Microscopy-positive samples were approved by SSU-PCR amplification of the parasite DNA. All four positive G. duodenalis specimens at SSU-PCR were afterward analyzed utilizing designed primers based on important metronidazole metabolism genes including TrxR, NR1, and NR2. RESULTS: Unlike TrxR gene, the results of NR1 and NR2 genes showed that there are non-synonymous variations between sequences of treatment-sensitive and -resistant samples compared to reference sequences. Furthermore, the outcomes of molecular docking revealed that there is an interaction between the protein sequence and spatial shape of treatment-resistant samples and metronidazole in the position of serine amino acid based on the NR1 gene. CONCLUSION: This issue can be one of the possible factors involved in the resistance of Giardia parasites to metronidazole. To reach more accurate results, a large sample size along with simulation and advanced molecular dynamics investigations are needed.

Comparative molecular epidemiology, subtype distribution, and zoonotic potential of Blastocystis sp. in Equus animals (horses, donkeys, and mules) in northwestern Iran.

A total of 500 fecal samples were collected from Equus animals in six different cities (Ardabil, Namin, Nir, Meshginshahr, Germi, and Khalkhal) of Ardabil Province, northwestern Iran, with 200 samples from horses, 200 from donkeys, and 100 from mules. Of the horse samples, 100 were from racing horses under special monitoring and care, while the remaining 100 were from non-racing horses, including those used for herding or in rural areas. All fecal samples were examined for the presence of Blastocystis sp. using PCR amplification of the SSU rRNA gene's barcode region after DNA extraction. The molecular prevalence of Blastocystis infection in Equus animals was 7.6% (38/500). Blastocystis was more common in horses [11.5% (23/200)] than in donkeys [5.5% (11/200)] and mules [4% (4/100)] (P > 0.05). Compared to racing horses [3% (3/100)], non-racing/rural horses [20% (20/100)] exhibited a substantially higher prevalence of Blastocystis (P < 0.05). The prevalence of Blastocystis in diarrheal samples and younger animals was remarkably higher than in formed samples and older animals, respectively (P < 0.05). No significant difference in Blastocystis infection prevalence was found between the genders of examined animals (P > 0.05). In Equus animals, 38 Blastocystis isolates included eight STs: ST10 [31.6% (12/38)], ST1 [21.1% (8/38)], ST2 [15.8% (6/38)], ST3 [10.5% (4/38)], ST4 [7.9% (3/38)], ST7 [5.2% (2/38)], ST14 [5.2% (2/38)], and ST6 [2.6% (1/38)]. These results suggest that Equus animals act as a proper reservoir for numerous Blastocystis STs, consequently playing a crucial part in the spread of this protozoan infection to humans, animals, and water reservoirs.

Current global status, subtype distribution and zoonotic significance of Blastocystis in dogs and cats: a systematic review and meta-analysis.

BACKGROUND: Blastocystis is a common intestinal protozoa found in animal and human fecal samples, with over 1 billion individuals infected worldwide. Since domestication, dogs and cats have had a close bond with humans. However, their close proximity poses a potential health risk since they may harbor several zoonotic agents. A global estimate of Blastocystis infection and subtype (ST) distribution in dogs and cats would therefore be of great health importance to humans. METHODS: We performed a comprehensive systematic search of four English-language databases (PubMed, Scopus, Google Scholar, Web of Science) for relevant articles up to 8 November 2021. The random-effects model was used to make pooled estimates with confidence intervals (CIs). RESULTS: In total, we identified 49 publications that met our inclusion criteria and subsequently analyzed the 65 datasets in these articles, of which 23 and 42 datasets were on cats and dogs, respectively. Among the 2934 cats included in the 23 datasets, which involved 16 countries, the prevalence rate of Blastocystis infection was 9.3% (95% CI 5.3-15.9%). The prevalence of Blastocystis infection was slightly lower [7%, 95% CI 4.7-10.4%) among the 7946 dogs included in the 42 datasets, involving 23 countries. The sensitivity analysis showed that no remarkable variation in the estimates upon the stepwise removal of each dataset. Higher ST diversity was found among the examined dogs (ST1-8, ST10, ST23, ST24) than among cats (ST1-4, ST10, ST14). Among dogs, ST3 was the most frequent ST (41.3%), followed by ST2 (39.3%), ST1 (30.9%), ST4 (13.4%), ST8 (12.7%), ST10 (11%) and ST5 (8.1%). Also among dogs, each of ST6, ST7, ST23 and ST24 was observed in only one study. Of the ST found in the cats examined, ST4 (29.5%), followed by ST10 (22.5%), ST1 (19.8%) and ST3 (17.6%) were the most common. A single study also reported the presence of both ST2 and ST14 in cats. With respect to zoonotic Blastocystis STs (ST1-ST9 and ST12), eight were reported from dogs (ST1-ST8) and four were isolated from cats (ST1-ST4), showing the implication of dog and cats in zoonotic transmission. CONCLUSIONS: Taken together, our results show that elucidation of the true epidemiology and ST distribution of Blastocystis in dogs and cats demands more comprehensive studies, particularly in the negelected regions of the world.