الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 113 |  |  |
| | | from | 113 | | |
Abstract
Blastocystis is a common enteric parasite, having a worldwide distribution. Its prevalence in developing countries reaches up to 60%. Genus Blastocystis is classified into 22 subtypes which explain the variations in symptoms and response to treatment.
Metronidazole is the drug of choice for treatment of Blastocystis. Most antimicrobial therapies against Blastocystis, including MTZ, have documented side effects that are not tolerated by many patients. Moreover, drug resistance has been reported. Thus, ongoing trials are being conducted for exploring anti-Blastocystis alternatives.
Proteases are attractive anti-protozoal drug targets, having documented roles in Blastocystis. Since drug repositioning is quite trendy and serine proteases are present in both hepatitis C virus and Blastocystis, the idea of trying serine protease inhibitor as a therapeutic alternative against Blastocystis has been encouraged. Simeprevir is a highly effective and safe anti-hepatitis serine protease inhibitor, with tolerable adverse effects. Hence, this study was designed to evaluate its in vitro efficacy against Blastocystis.
For fulfilling this aim, human collected stool samples, from Alexandria, Egypt, have been screened first by light microscopy. Positive samples were cultivated in Jones’ medium supplemented with 10% horse serum, 100 IU/mL penicillin and 100µg/ml streptomycin, where 1×104 Blastocystis /ml was inoculated to each subculture tube with five ml of the medium. Cultivated isolates were molecularly subtyped using subtype-specific diagnostic primers (ST1, ST2 and ST3) for assessing the efficacy of three SMV doses (100, 150 and 200μg/ml) for 72 hours, on the prevailing subtype, then the most efficient dose and duration was later tested on other subtypes. Subculture tubes for assessment of ST3 Blastocystisʹ response to SMV were divided into four groups and were performed in triplicates. group (I) was the non-treated infected control. group (II) was the DMSO-treated control. group (III), therapeutic control, was further subdivided into subgroups III (a, b & c); treated with MTZ at concentrations of 10, 100 and 250 μg/ml, successively. group (IV), experimental SMV-treated, was further subdivided into subgroups IV (a, b & c); which were treated with SMV at concentrations of 100, 150 and 200 μg/ml, successively. All subculture tubes were incubated for 72 hrs at 37 °C. The activity of SMV was evaluated after 24, 48 and 72 hrs through parasite growth, viability and its ability to re-culture. Moreover, an ultrastructural study was done to verify the effect of SMV on Blastocystis and was compared to the non-treated control group (I). This study included SEM and TEM of pooled subcultures of ST1, ST2 and ST3 Blastocystis treated with the most efficient dose and duration of SMV.