Background: Acanthamoebae are a causative agent of Acanthamoeba keratitis (AK) in immunocompetent individuals. Since access to propamidine isethionate (Brolene®, ) as a first-line treatment has been limited in recent years, in the current study, we examined the effects of pentamidine isethionate against TROPHOZOITE and cyst forms of Acanthamoeba. Methods: This experimental study was conducted in the Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran, during 2019-2020. Pentamidine isethionate at concentrations of 50, 100, 200, 400, 600, 800, and 1000 µ, M were tested against TROPHOZOITEs and cyst stages of T4 genotype, at 24- and 48-hour incubation period, and the viability was determined by trypan blue staining. In addition, the cytotoxic effect of the drug was examined in Vero cells using the 3-(4, 5dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Results: The 50% inhibitory concentration (IC50) of pentamidine isethionate on TROPHOZOITE after 24 and 48h were 97. 4 µ, M and 60. 99 µ, M. These results on cyst after 24 and 48h were 470 µ, M and 175. 5 µ, M, respectively. In MTT assay, the drug showed an inhibitory effect on Vero cell growth with IC50 values of 115. 4 µ, M and 87. 42 µ, M after 24h and 48h, respectively. Conclusion: Pentamidine isethionate exhibited an inhibitory effect on TROPHOZOITE and cyst. Given that the trophozoicidal activity of the drug is in the safe dose, it could be suggested as an alternative in patients with AK,however, further investigation is needed in an animal model to confirm the data.

Background and purpose: Antimicrobial peptides (AMP) are one of the most diverse antimicrobial compounds that have received much attention due to the development of drug resistance of pathogens to conventional antibiotics. But, few studies have evaluated anti-parasitic properties of AMP. The present study was conducted to compare the effect of a cecropin– melittin chimeric peptide (CM11) and metronidazole on Giardia lamblia TROPHOZOITE. Materials and methods: In this study, using MTT assay, the cytotoxicity of CM-11 peptide (0. 5-32 μ g/ml) and metronidazole (0. 25-25 μ g/ml) was investigated on Caco-2 cells and IC50 was calculated. Flow cytometry was used to determine the rate of induction of apoptosis by CM11 and metronidazole. The toxicity of peptide on G. lamblia trophozitis was evaluated in vitro under different conditions. Results: MTT results showed that the highest percentage of cytotoxicity in caco2 cells was seen at 32 μ g/ml of CM11 peptide after 24 (84. 3± 1. 2%), 48 (88. 7± 0. 9%) and 72 (87± 1. 5%) hours. In metronidazole group, the highest cytotoxicity was observed in 20 μ g/ml after 24 (35± 2. 3), 48 (39. 3± 1. 2) and 72 (48. 3± 1. 8%) hours. The highest concentrations of peptide (32 μ g/ml) and metronidazole (20 μ g/ml) showed 99. 8± 0. 2% and 99± 0. 6% cytotoxicity effect, respectively. The cytotoxicity effect of peptide and metronidazole on G. lamblia attached to caco2 cells at highest concentrations were 99. 7± 0. 1% and 99. 5± 0. 3%, respectively. Conclusion: This study showed that cecropin-melittin chimeric peptide could be an appropriate candidate for the treatment of giardiasis.

Giardiais a flagellate protozoan with worldwide distribution that causes significant gastrointestinal diseases. The life cycle of the organism alternates between the active, proliferating TROPHOZOITE and the dormant cyst.5-Nitroimidazoles have been used extensively in the treatment of amoebiasis, giardia sis, and trichomoniasis. We have previously synthesized some new analogues of metronidazole containing a phenyl or cyclohexanol ring in the side chain of the imidazole ring, and evaluated their antigiardia sis activity on giardia cyst. In the present study, we evaluated their activity against TROPHOZOITEs of the parasite. For this purpose TYI-S-33 media was used and their MIC were compared with metronidazole and DMSO as positive and negative controls, respectively. The results showed that the new compounds had desirable antigiardia sis activities.Analogues which contain phenyl group in their structure are more active than those which contain cyclohexanol moiety. Although all the new compounds had higher MIC than metronidazole but their antigiardia sis activity were comparable to metronidazole and they may prove good alternatives for metronidazole.

Background: Acanthamoeba is a globally dispersed protozoan that can cause different clinical manifestations in infected individuals. Various drugs have been proposed against its drug-resistant forms. Objective: The present study examined silver nanoparticles (NPs) with a good anti-parasitic background. More precisely, the study focused on evaluating the anti-parasitic effect of silver nano-scale particles on protozoan TROPHOZOITE and cysts by microscopic counting and flow cytometry after exposure to different concentrations. Methods: To this end, MTT assay and IC50 were used to assess the macrophage toxicity and cysts/TROPHOZOITEs, respectively. Results: Based on the results, 100 ppm silver NPs had better anti-parasitic effects than 80 ppm concentration and even the standard treatment of Acanthamoeba on both TROPHOZOITE and cystic phases. Macrophages toxicity at 100 ppm concentration was similar to the control group. Conclusion: In general, further studies should be conducted to confirm the present results given the significant effects of silver NPs against TROPHOZOITE and parasite cysts.

Objectives: Trichomonas vaginalis which is flagellated unicellular organism is the causative agent of vaginitis. Medications used to treat trichomoniasis often have unpleasant side effects or are not effective. Given the prevalence of this disease, the production of safe, effective and affordable medicines is necessary. Various species of ferula are antibacterial and anti-fungal and anti- protozoan. So far, no study has been done on the effect of Ferula szowitsiana on TROPHOZOITE of Trichomonas vaginalis.Materials and Methods: Coma (Ferula), native to Eastern Azerbaijan province, was collected and methanol extracts were prepared. TROPHOZOITE of Trichomonas vaginalis was cultured in vitro in CPLM medium and the effect of the mentioned extracts on the growth and survival of Trichomonas vaginalis TROPHOZOITE was measured by Mack-master slide.Results: Concentrations of 2 and 3 mg/ml in Methanol extracts of F. szowitsiana and could inhibit the growth of Trichomonas vaginalis TROPHOZOITE completely after 72-hour incubation. Trichomonas vaginalis TROPHOZOITE survived at concentrations of 0.5 and 0.375 and 0.25 mg/ml and methanol extract of F. szowitsiana were 42, 52 and 68%, respectively. The reduction of the number of parasites was visible 48 hours after incubation which was statistically significant (P<0.05).Conclusion: Ferula extract in different concentrations inhibited the growth of the dose-dependent TROPHOZOITE of Trichomonas vaginalis. The results of this study showed that native species of F. szowitsiana is suitable for the study of anti-trichomonas nature of it in vitro. Therefore, further study and identification of effective components in the methanol extract in the studied species are required.

Background and purpose: Acanthamoeba species are ubiquitous amphizoic organisms whichcan cause lethal diseases, such as keratitis and encephalitis in domestic animals and humans. The firststage in studies related to Acanthamoeba is achieving abundant amount of amoebae in culture medium. The aim of this study was to evaluate TYM medium as a rich medium for the diagnosis of Acanthamoebakeratitis in corneal scrapes. Materials and Methods: In this experimental study, we used one species of Acanthamoeba thatwas previously genotyped. Acanthamoeba was cultured in five plates of non-nutrient agar (NNA)medium with E. coli without TYM and in five plates of non-nutrient agar containing E. coli and TYM. Amoebae growth was observed for 24 to 48 hours by invert microscope. Results: According to current results using TYM medium increased the growth of TROPHOZOITEs8. 8 folds and amoebas can be isolated form medium after 24 to 48 hours. Conclusion: Due to the significant growth of Acanthamoeba in NNA improved medium, it isrecommended for agglutination and early detection of Acanthamoeba in clinical and environmentalsamples.

Background: Acanthamoeba is an opportunistic protozoan pathogen that is known to infect the cornea to produce eye keratitis and the central nervous system to produce lethal granulomatous encephalitis. The overall aim of the present study was to determine the anti-amoebic potential of natural compound Peganum harmala against the TROPHOZOITEs and cysts of Acanthamoeba in vitro.Materials and Methods: In this experimental study, a clinical isolate of Acanthamoeba was cultured and genotyped. The ethanolic extract of Peganum harmala was prepared. The TROPHOZOITEs and cysts were collected by washing in page's saline. Various concentrations (1.25, 2.5, 5, and 10 mg/ml) of the ethanolic extract and polyhexanide 0.02% drop as positive control were tested at three different times (24, 48 and 72 h) on TROPHOZOITEs and cysts of Acanthamoebain vitro. The viability of TROPHOZOITEs or cysts was tested by eozin method, MTT, and flowcytometry analysis.Results: The results revealed that alcoholic extract had remarkable inhibitory effect on the proliferation of Acanthamoeba cysts as compared to non-treated control, and the inhibition was time and dose dependent. In the presence of 10 mg/ml ethanolic extract in medium culture after 72 h, no viable TROPHOZOITEs were determined and 21.10% cysts of Acanthamoeba were viable. Percentage of TROPHOZOITEs and cysts viability after adding polyhexanide 0.02% drop in medium culture after 72 hours was 0% and 23.71%, respectively.Conclusion: Ethanolic extracts of Peganum harmala could be considered a new natural compound against the Acanthamoeba TROPHOZOITEs and cysts. Further works are required to evaluate the exact effect of this extract on Acanthamoeba agents in animal models.

Objective: Free-living amoebae, including Acanthamoeba constitute a large group of amoebae that live in fresh water, salty and bitter, moist soil, carious plants, and some on the stool. They are medically important agents. It is a medically important agent. The aim of the present study is to determine the effects of aqueous and alcoholic extracts of Artemisia annuaon TROPHOZOITEs and cysts of Acanthamoeba in vitro.Methods: In this experimental research, after genotyping the clinical isolate, we prepared the aqueous and alcoholic extracts of Artemisia annua. Various concentrations (1.25, 2.5, 5, and 10 mg/ml) of the aqueous and alcoholic extracts of this plant as well as artemisinin were tested at three different times (24, 48 and 72 h) on TROPHOZOITEs and cysts of Acanthamoebain vitro. We evaluated viability of the parasite by trypan blue, MTT, and flow cytometry analyses.Results: We observed the anti-acanthamoeba activity of different concentrations of the Artemisia extract. In the presence of 10 mg/ml alcoholic extract in medium culture after 72 h, we observed that 30.51% TROPHOZOITEs and 91.40% cysts of Acanthamoeba were viable. However, in the presence of 10 mg/ml aqueous extract of Artemisia annua, only 58.25% TROPHOZOITEs and 81.53% cysts were alive in the in medium culture after 72 h.Conclusion: Aqueous and alcoholic extracts of Artemisia annua had dose- and time dependent anti-acanthamoeba activity.