Antiprotozoal potential of Salvadora persica against three virulent subtypes of Blastocystis sp

Blastocystis sp. is a group of anaerobic protozoa parasitizing the gastrointestinal tract of humans and a broad variety of animals. Evidences of Blastocystis parasites resistance development to antiprotozoal drugs urge the exploration of new therapeutics. Antiprotozoal potential of Salvadora persica, a medicinal plant traditionally used for oral hygiene, was evaluated in vitro against Blastocystis sp. human isolates. Until now, no study has described the effect of S. persica extracts on this parasitic protozoa. Blastocystis sp. positive stool samples collected from patients with gastrointestinal complaints and asymptomatic individuals diagnosed by microscopy were furthermore cultured in vitro and characterized by PCR and multiplex-PCR using sequence-tagged-site primers to determine their subtypes. Out of 21 Blastocystis sp. isolates, five were determined as ST1, 14 as ST3, and two as ST5 subtypes. Antiprotozoal activity of untreated and heat-treated S. persica roots aqueous extracts was evaluated in vitro by serial dilutions on three Blastocystis sp. subtypes; ST1, ST3, and ST5 isolated from symptomatic patients. A significant killing activity was observed with both, untreated and heat-treated aqueous extracts of S. persica at minimal concentration of 2.5 μl/ml compared to parasites' growth controls (P < 0.05). Maximal antiprotozoal effect was reached at a concentration of 20 µl/ml of S. persica aqueous extract. Means of growth inhibition effect obtained with untreated and heat-treated extracts at 40 µl/ml against the three subtypes of Blastocystis sp. were 80% (SD 2.3) and 82% (SD 1.1), respectively. No significant difference was observed in the inhibitory effect of S. persica extracts between the three Blastocystis sp. subtypes. Aqueous extract of S. persica roots contains therefore heat-stable components with significant antiprotozoal activity against Blastocystis sp. subtypes ST1, ST3, and ST5 in vitro. Further investigations are required to determine and characterize the active antiprotozoal components of S. persica roots and their evaluation in vivo.

Prevalence of Cryptosporidium species isolated from diarrheic children in Makkah, Saudi Arabia

Cryptosporidiosis has been identified as a significant underlying cause of morbidity and mortality worldwide. Studies in high and low income countries have recognized the importance of Cryptosporidium as a cause of diarrhea. The objectives of the current study were to determine the prevalence rate and genotypes of Cryptosporidiumin in diarrheic children in Makkah Region. A total of 1,380 fecal samples were collected from children aged up to 14 years attending 3 major hospitals of Makkah between March 2015 and March 2016. Stool collected were subjected to direct microscopic examination and crypto antigen detection using ImmunoCard STAT, Cryptosporidium/Giardia rapid test. Part of each positive stool sample was kept frozen at -20ºC for molecular characterization. Initial screening by immunochromatographic detection kit revealed 23 positive cases. PCR was performed for positive cases by amplification of a piece of the gene encoding the small (18S) subunit of rRNA producing a 435-438 bp product. Cryptosporidium genotyping was performed by RFLP analysis of PCR products. Genotyping revealed 18 cases C. hominis genotype, 4 cases C. parvaum genotype and one sample failed to be amplified. The data revealed a higher incidence of the common human species C. hominis (81.8%). The detection of both C. hominis and C. parvaum genotypes point to the possibility of both anthroponotic and zoonotic transmission routes occurring in Makkah region. Further studies are needed to verify the subgenotypes of Cryptosporidium to elucidate the real transmission modes and hence plan for effective control strategies.

Subtyping of Blastocystis sp. isolated from symptomatic and asymptomatic individuals in Makkah, Saudi Arabia

BACKGROUND

Blastocystis is a group of cosmopolitan gastrointestinal parasite of humans and a wide variety of animals. These anaerobic protozoans include more than 17 specific small-subunit ribosomal RNA subtypes, of which nine are found in humans with a variable geographical distribution. Until now, no study has described the Blastocystis subtypes present in Saudi Arabia.

METHODS

In total, 1,262 faecal samples were collected from patients with gastrointestinal complaints and asymptomatic individuals visiting two major hospitals. All samples were analysed by F1/R1 diagnostic PCR, microscopy and culture methods. The subtypes of Blastocystis sp. isolates were determined by the sequenced-tagged site (STS)-based method.

RESULTS

One-hundred-thirty-three positive cases were detected by F1/R1 diagnostic PCR, of which 122 were also positive by the culture method and 83 by direct microscopy. The sensitivities of direct microscopy and the culture method were 62% and 92%, respectively. Subtype (ST3) was the most prevalent (80.5%), followed by ST1 (14.5%) and ST2 (5%). ST4, ST5, ST6 and ST7 were not detected in this study. ST3 infections were significantly predominant (P < 0.05) among symptomatic patients.

CONCLUSIONS

To our knowledge, this study provides the first run-through information on Blastocystis sp. epidemiology in Makkah city, revealing a rather moderate prevalence of 10.5% and the presence of three subtypes, ST1, ST2, and ST3. ST3 was the most predominant, particularly among symptomatic patients.