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Naegleria fowleri, known as the brain-eating amoeba, is the pathogen that causes the primary amoebic meningoencephalitis (PAM), a severe neurodegenerative disease with a fatality rate exceeding 95%. Moreover, PAM cases commonly involved previous activities in warm freshwater bodies that allow amoebae-containing water through the nasal passages. Hence, awareness among healthcare professionals and the general public are the key to contribute to a higher and faster number of diagnoses worldwide. Current treatment options for PAM, such as amphotericin B and miltefosine, are limited by potential cytotoxic effects. In this context, the repurposing of existing compounds has emerged as a promising strategy. In this study, the evaluation of the COVID Box which contains 160 compounds demonstrated significant in vitro amoebicidal activity against two type strains of N. fowleri. From these compounds, terconazole, clemastine, ABT-239 and PD-144418 showed a higher selectivity against the parasite compared to the remaining products. In addition, programmed cell death assays were conducted with these four compounds, unveiling compatible metabolic events in treated amoebae. These compounds exhibited chromatin condensation and alterations in cell membrane permeability, indicating their potential to induce programmed cell death. Assessment of mitochondrial membrane potential disruption and a significant reduction in ATP production emphasized the impact of these compounds on the mitochondria, with the identification of increased ROS production underscoring their potential as effective treatment options. This study emphasizes the potential of the mentioned COVID Box compounds against N. fowleri, providing a path for enhanced PAM therapies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Acanthamoeba is an opportunistic pathogen that can cause human infections such as granulomatous amebic encephalitis and acanthamoeba keratitis. However, no specific drug to treat the diseases has been developed. Therefore, the discovery or development of novel drugs for treating Acanthamoeba infections is urgently needed. The anti-protozoan activity of (‒)-epicatechin (EC) has been reported, suggesting it is an attractive anti-protozoal drug candidate. In this study, the amoebicidal activity of EC against A. castellanii was assessed and its mechanism of action was unveiled., Methods: The amoebicidal activity of EC against A. castellanii trophozoites and the cytotoxicity of EC in HCE-2 and C6 cells were determined with cell viability assay. The underlying amoebicidal mechanism of EC against A. castellanii was analyzed by the apoptosis/necrosis assay, TUNEL assay, mitochondrial dysfunction assay, caspase-3 assay, and quantitative reverse transcription polymerase chain reaction. The cysticidal activity of EC was also investigated., Results: EC revealed amoebicidal activity against A. castellanii trophozoites with an IC 50 of 37.01 ± 3.96 µM, but was not cytotoxic to HCE-2 or C6 cells. EC induced apoptotic events such as increases in DNA fragmentation and intracellular reactive oxygen species production in A. castellanii. EC also caused mitochondrial dysfunction in the amoebae, as evidenced by the loss of mitochondrial membrane potential and reductions in ATP production. Caspase-3 activity, autophagosome formation, and the expression levels of autophagy-related genes were also increased in EC-treated amoebae. EC led to the partial death of cysts and the inhibition of excystation., Conclusion: EC revealed promising amoebicidal activity against A. castellanii trophozoites via programmed cell death events. EC could be a candidate drug or supplemental compound for treating Acanthamoeba infections., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Rationale: Amebic colitis has been less prevalent in recent times in China, and the similarity of its symptoms to those of inflammatory bowel disease (IBD) results in the difficulty of early identification and diagnosis., Patient Concerns: A 31-year-old male who exhibited intermittent diarrhea and hematochezia was highly suspected as IBD initially. Despite the partial relief of symptoms following the administration of mesalamine, the endoscopic ulcers remained largely unchanged., Diagnoses: Two years after the onset of mesalamine therapy, amebic cysts were detected in stool microscopy and trophozoites were found on the surface of cecal ulcers. The patient was then diagnosed with amebic colitis., Interventions: After 2 rounds of standardized metronidazole treatment, amebic colitis remained refractory until diloxanide was administered., Outcomes: The patient remained asymptomatic, and the mucosa of colon was normal during the annual follow-up., Lessons: Individuals newly diagnosed with IBD should undergo essential screening for amebiasis. And the use of steroids should be taken with caution, especially in cases where the effect of mesalamine is limited. For symptomatic intestinal amebiasis, even after the administration of tissue amebicides, the continued use of luminal amebicides is necessary to prevent recurrence., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Treatment of visceral leishmaniasis (VL) is compromised by drug toxicity, high cost and/or the emergence of resistant strains. Though canine vaccines are available, there are no licensed prophylactic human vaccines. One strategy to improve clinical outcome for infected patients is immunotherapy, which associates a chemotherapy that acts directly to reduce parasitism and the administration of an immunogen-adjuvant that activates the host protective Th1-type immune response. In this study, we evaluated an immunotherapy protocol in a murine model by combining recombinant (r)LiHyp1 (a hypothetical amastigote-specific Leishmania protein protective against Leishmania infantum infection), with monophosphoryl-lipid A (MPLA) as adjuvant and amphotericin B (AmpB) as reference antileishmanial drug. We used this protocol to treat L. infantum infected-BALB/c mice, and parasitological, immunological and toxicological evaluations were performed at 1 and 30 days after treatment. Results showed that mice treated with rLiHyp1/MPLA/AmpB presented the lowest parasite burden in all organs evaluated, when both a limiting dilution technique and qPCR were used. In addition, these animals produced higher levels of IFN-γ and IL-12 cytokines and IgG2a isotype antibody, which were associated with lower production of IL-4 and IL-10 and IgG1 isotype. Furthermore, low levels of renal and hepatic damage markers were found in animals treated with rLiHyp1/MPLA/AmpB possibly reflecting the lower parasite load, as compared to the other groups. We conclude that the rLiHyp1/MPLA/AmpB combination could be considered in future studies as an immunotherapy protocol to treat against VL., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

As the number of contact lens users increases, contact lens induced corneal infection is becoming more common. Acanthamoeba keratitis (AK) is a type of those which is caused by Acanthamoeba species, and may cause severe ocular inflammation and visual loss. We evaluated whether Torreya nucifera (T. nucifera) extract has an anti-amoebic effect and studied its mechanism of action on Acanthamoeba lugdunensis (A. lugdunensis). Cell viability was tested using the alamarBlue™ method, and the cell death mechanism was confirmed using the Tali® Apoptosis Kit. The SYTOX® Green assay was performed to check the plasma membrane permeability. The JC-1 dye was used to measure the mitochondrial membrane potential. A CellTiter-Glo® Luminescent Assay was used to measure the adenosine-triphosphate (ATP) level. Morphological changes in the mitochondria were examined by transmission electron microscopy (TEM). Cystic changes and a decrease in cell viability after treatment with T. nucifera were observed. Both apoptotic and necrotic cells were found in the Tali® Apoptosis assay. There was no significant difference in plasma membrane permeability between the control and T. nucifera treated groups. The collapse of the mitochondrial membrane potential and reduced ATP level in A. lugdunensis was confirmed in the groups treated with T. nucifera. Structural damage to the mitochondria was observed on TEM in the groups treated with T. nucifera. T. nucifera showed an anti-amoebic effect on A. lugdunensis, by inducing the loss of mitochondrial membrane potential. Thus, it could be a future therapeutic agent for AK., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Kang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Statins are effective sterol lowering agents with high amoebicidal activity. Nevertheless, due to their poor aqueous solubility, they remain underused especially in eye drop formulation. The aim of the present study is to develop Pitavastatin loaded nanoparticles suitable for ophthalmic administration and designed for the management of Acanthamoeba Keratitis. These nanocarriers are aimed to solve both the ophthalmic route-associated problems and the limited aqueous drug solubility issues of Pitavastatin. Nanoparticles were obtained by a nanoprecipitation-solvent displacement method and their amoebicidal activity was evaluated against four strains of Acanthamoeba: A. castellanii Neff, A. polyphaga, A. griffini and A. quina. In Acanthamoeba polyphaga, the effect of the present nanoparticles was investigated with respect to the microtubule distribution and several programmed cell death features. Nanoparticles were able to eliminate all the tested strains and Acanthamoeba polyphaga was determined to be the most resistance strain. Nanoparticles induced chromatin condensation, autophagic vacuoles and mitochondria dysfunction., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Acanthamoeba castellanii is a protist pathogen that can cause sight-threatening keratitis and a fatal infection of the central nervous system, known as granulomatous amoebic encephalitis. In this study, effects of five malonic acid and salicylic acid-based deep eutectic solvents (DES) on A. castellanii were investigated. These are salicylic acid-trioctylphosphine (DES 1), salicylic acid- trihexylamine (DES 2), salicylic acid-trioctylamine (DES 3), malonic acid-trioctylphosphine (DES 4) and malonic acid-trihexylamine (DES 5). The experiments were done by performing amoebicidal, encystment, excystment, cytopathogenicity, and cytotoxicity assays. At micromolar dosage, the solvents DES 2 and DES 3 displayed significant amoebicidal effects (P < 0.05), inhibited encystment and excystment, undermined the cell-mediated cytopathogenicity of A. castellanii, and also displayed minimal cytotoxicity to human cells. Conversely, the chemical components of these solvents: salicylic acid, trihexylamine, and trioctylamine showed minimal effects when tested individually. These results are very promising and to the best of our knowledge, are reported for the first time on the effects of deep eutectic solvents on amoebae. These results can be applied in the development of new formulations of novel contact lens disinfectants against Acanthamoeba castellanii., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Acanthamoeba is opportunistic pathogens that cause vision-threatening Acanthamoeba keratitis (AK). Previous studies proposed the use of chloroquine (CQ) and 5-fluorouracil (5FU) as anti-Acanthamoeba agents. The objective of this study was to determine the benefit of using 5FU and CQ nanoparticles (NP) formulations against A. castellanii that belonging to the T4 genotype and evaluate their anti-Acanthamoebic characteristic. Triplicate batches of 5FU nanoparticles (5FU-NP) were synthesized by using a modified nanoprecipitation method, while CQ nanoparticles (CQ-NP) synthesized using a modified double emulsion method. The synthesized nanoparticles were subjected to biological assays to investigate their amoebicidal, amoebistatic, anti-encystation, and anti-excystation effects against A. castellanii, as well as cell cytotoxicity. Cytotoxicity assays were performed using human keratinocyte cells (HaCaT) to determine the effect of CQ and 5FU nanoformulations on host cells. 5FU-NP with a concentration of 60 µM showed significant inhibition to amoeba binding into human cell lines and remarkable prevention mainly during the encystation stage. Moreover, 5FU-NP resulted in less cytotoxicity and pathogenicity when compared with the free 5FU. On the other hand, CQ and CQ-NP, at the same concentration, showed poor inhibition to amoeba binding into human cells and insignificant prevention to encystation stage. Moderate human cells damage was resulted following their treatment with CQ and CQ-NP. In conclusion, 5FU may have the potential as an antiamoebic agent against Acanthamoeba spp. preferably as a nanoformulation to enhance its activity and reduce its cytoxicity., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Traditional cysticidal assays for Acanthamoeba species revolve around treating cysts with compounds and manually observing the culture for evidence of excystation. This method is time-consuming, labor-intensive, and low throughput. We adapted and trained a YOLOv3 machine learning, object detection neural network to recognize Acanthamoeba castellanii trophozoites and cysts in microscopy images to develop an automated cysticidal assay. This trained neural network was used to count trophozoites in wells treated with compounds of interest to determine if a compound treatment was cysticidal. We validated this new assay with known cysticidal and noncysticidal compounds. In addition, we undertook a large-scale bioluminescence-based screen of 9,286 structurally unique marine microbial metabolite fractions against the trophozoites of A. castellanii and identified 29 trophocidal hits. These hits were then subjected to this machine learning-based automated cysticidal assay. One marine microbial metabolite fraction was identified as both trophocidal and cysticidal. IMPORTANCE The free-living Acanthamoeba can exist as a trophozoite or cyst and both stages can cause painful blinding keratitis. Infection recurrence occurs in approximately 10% of cases due to the lack of efficient drugs that can kill both trophozoites and cysts. Therefore, the discovery of therapeutics that are effective against both stages is a critical unmet need to avert blindness. Current efforts to identify new anti- Acanthamoeba compounds rely primarily upon assays that target the trophozoite stage of the parasite. We adapted and trained a machine learning, object detection neural network to recognize Acanthamoeba trophozoites and cysts in microscopy images. Our machine learning-based cysticidal assay improved throughput, demonstrated high specificity, and had an exquisite ability to identify noncysticidal compounds. We combined this cysticidal assay with our bioluminescence-based trophocidal assay to screen about 9,000 structurally unique marine microbial metabolites against A. castellanii. Our screen identified a marine metabolite that was both trophocidal and cysticidal.

Introduction : Acanthamoeba encompasses several species of free-living ameba encountered commonly throughout the environment. Unfortunately, these species of ameba can cause opportunistic infections that result in Acanthamoeba keratitis, granulomatous amebic encephalitis, and occasionally systemic infection. Areas covered : This review discusses relevant literature found through PubMed and Google scholar published as of January 2021. The review summarizes current common Acanthamoeba keratitis treatments, drug discovery methodologies available for screening potential anti- Acanthamoeba compounds, and the anti- Acanthamoeba activity of various azole antifungal agents. Expert opinion : While several biguanide and diamidine antimicrobial agents are available to clinicians to effectively treat Acanthamoeba keratitis, no singular treatment can effectively treat every Acanthamoeba keratitis case.Efforts to identify new anti-Acanthamoeba agents include trophozoite cell viability assays, which are amenable to high-throughput screening. Cysticidal assays remain largely manual and would benefit from further automation development. Additionally, the existing literature on the effectiveness of various azole antifungal agents for treating Acanthamoeba keratitis is incomplete or contradictory, suggesting the need for a systematic review of all azoles against different pathogenic Acanthamoeba strains.

The main corneal infections reported worldwide are caused by bacteria and viruses but, recently, the number of Acanthamoeba keratitis (AK) cases has increased. Acanthamoeba genus is an opportunistic free living protozoa widely distributed in environmental and clinical sources, with two life-cycle stages: the trophozoite and the cyst. AK presents as primary symptoms eye redness, epithelial defects, photophobia and intense pain. An early diagnosis and an effective treatment are crucial to avoid blindness or eye removal but, so far, there is no established treatment to this corneal infection. Diverse research studies have reported the efficacy of commercialized eye drops and ophthalmic solutions against the two life cycle stages of Acanthamoeba strains, that usually present preservatives such as Propylene Glycol of Benzalkonium chloride (BAK). These compounds present toxic effects in corneal cells, favouring the inflammatory response in the so sensitive eye tissue. In the present work we have evaluated the efficacy of nine proprietary ophthalmic solutions with and without preservatives (ASDA Dry Eyes Eyedrops, Miren®, ODM5®, Ectodol®, Systane® Complete, Ocudox®, Matrix Ocular®, Alins® and Coqun®) against the two life cycle stages of three Acanthamoeba strains. Our work has demonstrated the high anti-Acanthamoeba activity of Matrix Ocular®, which induces the programmed cell death mechanisms in Acanthamoeba spp. trophozoites. The high efficacy and the absence of ocular toxic effects of Matrix Ocular®, evidences the use of the Arabinogalactan derivatives as a new source of anti-AK compounds., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Free-living amoebae (FLAs) are protozoa developing autonomously in diverse natural or artificial environments. The FLAs Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri represent a risk for human health as they can become pathogenic and cause severe cerebral infections, named granulomatous amoebic encephalitis (GAE), Balamuthia amoebic encephalitis (BAE), and primary amoebic meningoencephalitis (PAM), respectively. Additionally, Acanthamoeba sp. can also rarely disseminate to diverse organs, such as the skin, sinuses, or bones, and cause extracerebral disseminated acanthamebiasis (EDA). No consensus treatment has been established for cerebral FLA infections or EDA. The therapy of cerebral and disseminated FLA infections often empirically associates a large diversity of drugs, all exhibiting a high toxicity. Nevertheless, these pathologies lead to a high mortality, above 90% of the cases, even in the presence of a treatment. In the present work, a total of 474 clinical cases of FLA infections gathered from the literature allowed to determine the frequency of usage, as well as the efficacy of the main drugs and drug combinations used in the treatment of these pathologies. The efficacy of drug usage was determined based on the survival rate after drug administration. The most efficient drugs, drug combinations, and their mechanism of action were discussed in regard to the present recommendations for the treatment of GAE, EDA, BAE, and PAM. At the end, this review aims to provide a useful tool for physicians in their choice to optimize the treatment of FLA infections., (© 2021 The Authors. Clinical and Translational Science published by Wiley Periodicals LLC on behalf of the American Society for Clinical Pharmacology and Therapeutics.)

The validation of anti-Acanthamoeba activity of commercial eye drops has gained a great interest recently and a growing number of commercials eye drop were evaluated for their aptitude to inhibit Acanthamoeba as a second pharmacological effect. In the present study, three different eye drops, commercializing in Spain, including TobraDex, Cusimolol and Colircusi antiedema have been tested in vitro against trophozoites and cysts stage of the facultative pathogen Acanthamoeba. The alamarBlue™ method was used to evaluate both trophocidal and cysticidal properties. The most active eye drops were tested for their impact on some programmed cell death features. We found out that the cells inhibition was strain and eye drop dependent, and 5% eye drop was able to eliminate both trophozoite and cyst stage of Acanthamoeba spp. A treatment of 24 h with 5% of TobraDex or Cusimolol was able to show DNA condensation, collapse in the mitochondrial membrane potential and reduction of the ATP level production in Acanthamoeba. We could assume that the present eye drops could induce programed cell death like process in Acanthamoeba via mitochondrial pathway., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Acanthamoeba sp. is a free living amoeba that causes severe, painful and fatal infections, viz. Acanthamoeba keratitis and granulomatous amoebic encephalitis among humans. Antimicrobial chemotherapy used against Acanthamoeba is toxic to human cells and show side effects as well. Infections due to Acanthamoeba also pose challenges towards currently used antimicrobial treatment including resistance and transformation of trophozoites to resistant cyst forms that can lead to recurrence of infection. Therapeutic agents targeting central nervous system infections caused by Acanthamoeba should be able to cross blood-brain barrier. Nanoparticles based drug delivery put forth an effective therapeutic method to overcome the limitations of currently used antimicrobial chemotherapy. In recent years, various researchers investigated the effectiveness of nanoparticles conjugated drug and/or naturally occurring plant compounds against both trophozoites and cyst form of Acanthamoeba. In the current review, a reasonable effort has been made to provide a comprehensive overview of various nanoparticles tested for their efficacy against Acanthamoeba. This review summarizes the noteworthy details of research performed to elucidate the effect of nanoparticles conjugated drugs against Acanthamoeba., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Amoebiasis is a human parasitic disease caused by Entamoeba histolytica. The parasite can invade the large intestine and other organs such as liver; resistance to the host tissue oxygen is a condition for parasite invasion and survival. Thioredoxin reductase of E. histolytica (EhTrxR) is a critical enzyme mainly involved in maintaining reduced the redox system and detoxifying the intracellular oxygen; therefore, it is necessary for E. histolytica survival under both aerobic in vitro and in vivo conditions. In the present work, it is reported that rabeprazole (Rb), a drug widely used to treat heartburn, was able to inhibit the EhTrxR recombinant enzyme. Moreover, Rb affected amoebic proliferation and several functions required for parasite virulence such as cytotoxicity, oxygen reduction to hydrogen peroxide, erythrophagocytosis, proteolysis, and oxygen and complement resistances. In addition, amoebic pre-incubation with sublethal Rb concentration (600 μM) promoted amoebic death during early liver infection in hamsters. Despite the high Rb concentration used to inhibit amoebic virulence, the wide E. histolytica pathogenic-related functions affected by Rb strongly suggest that its molecular structure can be used as scaffold to design new antiamoebic compounds with lower IC 50 values.

Rationale: Lupus miliaris disseminatus faciei (LMDF) is an inflammatory granulomatous skin disease without a clear etiology that frequently involves the middle area of the face and the upper eyelids. Pathological features of the disease include caseation necrosis and epithelioid granuloma. Consensus treatment for LMDF is currently unavailable., Patient Concerns: A 47-year-old Chinese female patient who presented with facial pruritic, erythematous papules 8 months before this study. She was diagnosed with skin tuberculosis at another hospital and given antituberculosis medication. However, the treatment was not efficacious., Diagnoses: In this study, the diagnosis of Demodex-induced LMDF was made by a dermatologist according to physical examination, skin biopsy pathology, and microscopic examination., Interventions: The patient was given ornidazole tablets (500 mg twice a day) and recombinant bovine basic fibroblast growth factor gel (0.2 g/cm twice a day) for an 8-week period., Outcomes: Eight weeks after the treatment, the facial erythematous papules were improved, and no new skin lesions were observed. The patient showed no signs of recurrence during the 6-month follow-up., Lessons Subsections: This case showed that ornidazole combined with recombinant bovine basic fibroblast growth factor gel might be useful in treatment of Demodex-induced LMDF. In addition, the results suggested that pathological caseation necrosis was caused by a series of inflammatory and immune responses to Demodex infection.

Current treatments for Acanthamoeba keratitis rely on a combination of chlorhexidine gluconate, propamidine isethionate, and polyhexamethylene biguanide. These disinfectants are nonspecific and inherently toxic, which limits their effectiveness. Furthermore, in 10% of cases, recurrent infection ensues due to the difficulty in killing both trophozoites and double-walled cysts. Therefore, development of efficient, safe, and target-specific drugs which are capable of preventing recurrent Acanthamoeba infection is a critical unmet need for averting blindness. Since both trophozoites and cysts contain specific sets of membrane sterols, we hypothesized that antifungal drugs targeting sterol 14-demethylase (CYP51), known as conazoles, would have deleterious effects on A. castellanii trophozoites and cysts. To test this hypothesis, we first performed a systematic screen of the FDA-approved conazoles against A. castellanii trophozoites using a bioluminescence-based viability assay adapted and optimized for Acanthamoeba The most potent drugs were then evaluated against cysts. Isavuconazole and posaconazole demonstrated low nanomolar potency against trophozoites of three clinical strains of A. castellanii Furthermore, isavuconazole killed trophozoites within 24 h and suppressed excystment of preformed Acanthamoeba cysts into trophozoites. The rapid action of isavuconazole was also evident from the morphological changes at nanomolar drug concentrations causing rounding of trophozoites within 24 h of exposure. Given that isavuconazole has an excellent safety profile, is well tolerated in humans, and blocks A. castellanii excystation, this opens an opportunity for the cost-effective repurposing of isavuconazole for the treatment of primary and recurring Acanthamoeba keratitis., (Copyright © 2020 American Society for Microbiology.)

Recently, the search for novel therapeutic agents against Acanthamoeba species has been focused on the evaluation of natural resources. Among them, marine microorganisms have risen as a source of bioactive compounds with the advantage of the ability to obtain unlimited and constant amounts of the compounds in contrast to other natural sources such as plants. Furthermore, marine actinomycetes have recently been reported as highly rich in bioactive agents including salinosporamides, xiamycines, indolocarbazoles, naphtyridines, phenols, dilactones such as antimycines and macrolides among others. In this study, staurosporine (STS) was isolated from a strain of Streptomyces sanyensis and tested against Acanthamoeba to characterize the therapeutic potential of STS against this protozoan parasite. We have established that STS is active against both stages of the Acanthamoeba life cycle, by the activation of Programmed Cell Death via the mitochondrial pathway of the trophozoite. We have also established that STS has relatively low toxicity towards a macrophage cell line. However, previous studies have highlighted higher toxicity levels induced on other vertebrate cell lines and future research to lower these toxicity issues should be developed.

Primary amoebic meningoencephalitis (PAM) caused by Naegleria fowleri is a rare and deadly disease that requires prompt treatment with multiple therapies. Although N. fowleri previously was only found in warmer areas, climate change appears to be contributing to its geographic spread. Clinicians should consider PAM when faced with a patient with meningitis, especially if the patient participates in outdoor water activities or practices nasal rinsing.

Entamoeba histolytica is the etiological agent of amebiasis, which is an endemic parasitic disease in developing countries and is the cause of approximately 70,000 deaths annually. E. histolytica trophozoites usually reside in the colon as a non-pathogenic commensal in most infected individuals (90% of infected individuals are asymptomatic). For unknown reasons, these trophozoites can become virulent and invasive, cause amebic dysentery, and migrate to the liver where they cause hepatocellular damage. Amebiasis is usually treated either by amebicides which are classified as (a) luminal and are active against the luminal forms of the parasite, (b) tissue and are effective against those parasites that have invaded tissues, and (c) mixed and are effective against the luminal forms of the parasite and those forms which invaded the host's tissues. Of the amebicides, the luminal amebicide, metronidazole (MTZ), is the most widely used drug to treat amebiasis. Although well tolerated, concerns about its adverse effects and the possible emergence of MTZ-resistant strains of E. histolytica have led to the development of new therapeutic strategies against amebiasis. These strategies include improving the potency of existing amebicides, discovering new uses for approved drugs (repurposing of existing drugs), drug rediscovery, vaccination, drug targeting of essential E. histolytica components, and the use of probiotics and bioactive natural products. This review examines each of these strategies in the light of the current knowledge on the gut microbiota of patients with amebiasis., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Splenic abscess is a rare condition, which is often asymptomatic in the absence of comorbidity and is associated with high mortality rates. Given the importance of the differential diagnosis of patients who present to the emergency department with fever or septic shock, we report the case of a patient with amoebic splenic abscess who presented to our clinic with widespread skin rash and signs of septic shock following amoebic dysentery caused by Entamoeba histolytica, which is rarely reported in the literature. KEY WORDS: Amoebic Spleen Abscess, Amoebic Abscess, Entamoeba Histolytica, Splenic Abscess.

Background: Infection with the protozoan Entamoeba histolytica is common in low- and middle-income countries, and up to 100,000 people with severe disease die every year. Adequate therapy for amoebic colitis is necessary to reduce illness, prevent development of complicated disease and extraintestinal spread, and decrease transmission., Objectives: To evaluate antiamoebic drugs for treating amoebic colitis., Search Methods: We searched the available literature up to 22 March 2018. We searched the Cochrane Infectious Diseases Group Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, mRCT, and conference proceedings. We contacted individual researchers, organizations, and pharmaceutical companies, and we checked reference lists., Selection Criteria: Randomized controlled trials of antiamoebic drugs given alone or in combination, compared with placebo or another antiamoebic drug, for treating adults and children with a diagnosis of amoebic colitis., Data Collection and Analysis: Two review authors independently assessed the eligibility and methodological quality of trials and extracted and analysed the data. We calculated clinical and parasitological failure rates and rates of relapse and adverse events as risk ratios (RRs) with 95% confidence intervals (CIs), using a random-effects model. We determined statistical heterogeneity and explored possible sources of heterogeneity using subgroup analyses. We carried out sensitivity analysis by using trial quality to assess the robustness of reported results., Main Results: In total, 41 trials (4999 participants) met the inclusion criteria of this review. In this update, we added four trials to the 37 trials included in the first published review version. Thirty trials were published over 20 years ago. Only one trial used adequate methods of randomization and allocation concealment, was blinded, and analysed all randomized participants. Only one trial used an E histolytica stool antigen test, and two trials used amoebic culture.Tinidazole may be more effective than metronidazole for reducing clinical failure (RR 0.28, 95% CI 0.15 to 0.51; 477 participants, eight trials; low-certainty evidence) and is probably associated with fewer adverse events (RR 0.65, 95% CI 0.46 to 0.92; 477 participants, 8 trials; moderate-certainty evidence). Compared with metronidazole, combination therapy may result in fewer parasitological failures (RR 0.36, 95% CI 0.15 to 0.86; 720 participants, 3 trials; low-certainty evidence), but we are uncertain which combination is more effective than another. Evidence is insufficient to allow conclusions regarding the efficacy of other antiamoebic drugs., Authors' Conclusions: Compared with metronidazole, tinidazole may be more effective in reducing clinical failure and may be associated with fewer adverse events. Combination drug therapy may be more effective for reducing parasitological failure compared with metronidazole alone. However, these results are based mostly on small trials conducted over 20 years ago with a variety of poorly defined outcomes. Tests that detect E histolytica more accurately are needed, particularly in countries where concomitant infection with other bacteria and parasites is common.

Introduction: In Mexico, seroprevalence of Entamoeba histolytica is 8.4%. The intestinal amebiasis in patients with acute leukemia of novo, after the start of chemotherapy (CT) in the Hematology Service of the CMN 20 de Noviembre is 12%, even if patients show a negative baseline coprological test., Objective: To find out if the administration of tinidazole, in patients with acute leukemia and negative coprological test, at the beginning of the CT, decreases the incidence of amoebic colitis during the induction to remission., Method: Prospective and not comparative study. Patients with de novo diagnosis of acute leukemia who initiate induction and initial coprological CT. Tinidazole was indicated, 2 g/day for 5 days in the first week of CT started. They were monitored until the induction was concluded and hematopoietic recovery started., Results: 38 patients, 15 women and 23 men with a mean age of 44 years (16-72), with acute lymphoblastic leukemia 19, myeloblastic 16 and promyelocytic 3. Cases without and with intestinal amebiasis were 35 and 3, respectively. Patients with amebiasis only received tinidazole for 3 days and it was given 2 days after the CT started., Conclusion: Tinidazole, in patients with acute de novo leukemia who initiate induction CT, is effective in the prevention of intestinal amebiasis, during the induction stage, if administered at 2 g/day, for five days, starting on day 1 of the CT., (Copyright: © 2019 Permanyer.)

Primary amoebic meningoencephalitis is rare but fatal disease encountered in immunocompetent individuals. Here, we present a case of a previously healthy 8-month-old female child, who presented with features of meningoencephalitis of 2 days' duration. Rapidly moving trophozoites of amoeba were observed in cerebrospinal fluid, which were confirmed to be Naegleria fowleri on polymerase chain reaction. Broad-spectrum antimicrobial therapy with ceftriaxone, vancomycin, amphotericin B and acyclovir was initiated. However, the patient deteriorated and left the hospital against medical advice. The isolation of N. fowleri in this case demands for increased awareness for prompt diagnosis and management in view of its high mortality., Competing Interests: None

Clinical Cases: Cases are presented of 10 patients with Acanthamoeba keratitis treated between 2008 and 2017. All were contact lens wearers. All of them received treatment with a biguanide combined with a diamidine. In 3 cases the infestation did not exceed the superficial stroma, responding to topical treatment. In 7, the infection reached the deep stroma, with 6 of these cases requiring penetrating keratoplasty (PKP), 3 of them therapeutic PKP because of perforation risk or ocular spreading. The visual acuity improved in all the cases., Conclusion: The infestation depth at the time of diagnosis appears to be the main risk factor for requiring a PKP., (Copyright © 2018 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.)

Acanthamoeba spp. is a free living protozoan in the environment, but can cause serious diseases. Acanthamoeba keratitis (AK), a severe and painful eye infection, must be treated as soon as possible to prevent ulceration of the cornea, loss of visual acuity, and eventually blindness or enucleation. Although the disease affects principally contact lens (CLs) wearers, it is recognized nowadays as a cause of keratitis also in non-CLs wearers. Although the number of infections caused by these amoebae is low, AK is an emerging disease presenting an extended number of cases each year worldwide mostly due to the increasing use of CLs, but also to better diagnostic methods and awareness. There are two principal causes that lead to severe outcomes: misdiagnosis or late diagnosis of the causal agent, and lack of a fully effective therapy due to the existence of a highly resistant cyst stage of Acanthamoeba. Recent studies have reported different genotypes that have not been previously associated with this disease. In addition, Acanthamoeba can act as a reservoir for phylogenetically diverse microorganisms. In this regard, recently giant viruses called Pandoravirus have been found within genotypes producing keratitis. What potential risk this poses is not yet known. This review focuses on an overview of the present status and future prospects of this re-emerging pathology, including features of the parasite, epidemiology, clinical aspects, diagnosis, and treatment., (Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To report a series of cases of Acanthamoeba keratitis (AK) in scleral lens wearers with keratoconus to determine whether this type of contact lens presents a greater risk for development of infection., Methods: This study reports three patients who wore scleral contact lenses to correct keratoconus and developed AK. The diagnoses of AK were established based on cultures of the cornea, scleral contact lenses, and contact lens paraphernalia. This study investigated the risk factors for infections., Results: The possible risks for AK in scleral contact lens wearers are hypoxic changes in the corneal epithelium because of the large diameter and minimal tear exchange, use of large amounts of saline solution necessary for scleral lens fitting, storing the scleral lens overnight in saline solution rather than contact lens multipurpose solutions, not rubbing the contact lens during cleaning, and the space between the cornea and the back surface of the scleral lens that might serve as a fluid reservoir and environment for Acanthamoeba multiplication. Two patients responded well to medical treatment of AK; one is still being treated., Conclusions: The recommendations for use and care of scleral contact lenses should be emphasized, especially regarding use of sterile saline (preferably single use), attention to rubbing the lens during cleaning, cleaning of the plunger, and overnight storage in fresh contact lens multipurpose solutions without topping off the lens solution in the case., (Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Acanthamoeba infections are difficult to diagnose and treat. We present a renal transplant patient who developed Acanthamoeba endophthalmitis on therapy with posaconazole and miltefosine for cutaneous acanthamobiasis. The patient was maintained on intracameral voriconazole injections, and oral azithromycin, fluconazole, and flucytosine. This case highlights novel presentations and treatments for acanthamoebic infection., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Osteo-cutaneous form is a rare presentation of acanthamoebiasis. We present the first such case from India in an apparently healthy male who developed cutaneous lesion with bone involvement after traumatic inoculation of Acanthamoeba cysts. The diagnosis was established by routine microbiological techniques and confirmed by 18SrRNA gene sequencing. Aggressive therapy with terbinafine, chlorhexidine, rifampicin and co-trimoxazole was successful in clearing the lesion and preventing encephalitis., (Copyright © 2017 Elsevier B.V. All rights reserved.)

A 23-year-old Japanese woman presented with abdominal distention following fever, diarrhea, and abdominal pain during a stay in Taiwan. Serology for the detection of amebic-antibodies and stool microscopic examination were both negative. A computed tomography scan showed a 13 cm diameter abscess spreading from the lower abdominal wall to the pelvic retroperitoneal space. Needle aspiration of the abscess was done under computed tomography guidance, and microscopy of the aspirated fluid revealed trophozoites of Entamoeba. The patient was diagnosed as amebiasis with negative serologic markers that caused intra-abdominal abscess. Intravenous metronidazole treatment for two weeks did not result in any improvement of the abscess. After irrigation and drainage of the abscess, her symptoms resolved. This case report highlights that amebiasis should be considered when indicated by patient history, including travelers returning from endemic areas, and that further evaluation is necessary for diagnosis, even if the serology and stool test are negative., (Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Entamoeba histolytica is considered endemic in Australia; however, cases are rare, occurring almost exclusively in high-risk individuals. We describe a series of locally acquired, complicated cases in low-risk individuals from Far North Queensland in whom the diagnosis was delayed. Amebiasis may pose a greater local threat than is currently recognized.

Disseminated acanthamoebiasis is a rare, often fatal, infection most commonly affecting immunocompromised patients. We report a case involving sinuses, skin, and bone in a 60-year-old woman 5 months after heart transplantation. She improved with a combination of flucytosine, fluconazole, miltefosine, and decreased immunosuppression. To our knowledge, this is the first case of successfully treated disseminated acanthamoebiasis in a heart transplant recipient and only the second successful use of miltefosine for this infection among solid organ transplant recipients. Acanthamoeba infection should be considered in transplant recipients with evidence of skin, central nervous system, and sinus infections that are unresponsive to antibiotics. Miltefosine may represent an effective component of a multidrug therapeutic regimen for the treatment of this amoebic infection., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Acanthamoeba infections are rare and mostly occur in immunocompromised patients. Most of the reported cases after stem cell transplantation have been diagnosed postmortem. We present the case of a 3-year-old boy with chronic graft versus host disease post hematopoietic transplantation, who was successfully treated for Acanthamoeba.

Visceral Leishmaniasis (VL) is a chronic infectious disease endemic in tropical and sub-tropical areas including the Mediterranean basin, caused by a group of protozoan parasites of the genus Leishmania and transmitted by phlebotomine sandflies. Typically, VL is classified as a zoonotic infection when Leishmania infantum is the causative agent and as an anthroponotic one when L. donovani is the causative agent. Immunocompromised patients, in particular HIV positive, are considered at risk of VL. They may present atypical signs and poor response to the treatment due to a compromission of T-helper and regulatory cells activity. Also pregnancy can be considered a condition predisposing to Leishmania reactivation and to the changes in immune response, due to a switch toward a Th2 response reported in this condition of the life. Laboratory diagnosis is based on microscopy for parasites detection on bone-marrow or spleen aspirates. Value of serology remains high in term of sensibility, but a positive test has to be confirmed by microscopy or molecular tests. Hypergammaglobulinemia and pancytopenia are the main alteration identified by blood examination. Treatment is based on use of liposomal amphotericin B (L-AmB) whose administration is associated to lower incidence of side effects, in respect to antimonials and other formulations of AmB. Use of Miltefosine needs further investigation when L. infantum is the causative agent. Relapses to treatment are observed in coinfected HIV patients. They can benefit of a second cycle, but cumulative efficacy of the treatment can be low.

Amoebiasisis an infectious disease, which originated with the single-celled parasitic protozoan Entamoeba histolytica. The parasitic amoeba infects the liver and intestine and may cause mild diarrhea and serious dysentery with bloody and mucoid stool. A study was conducted to evaluate the efficacy of Amoebex (400mg), a herbal formulation for the treatment of amoebiasis infections as compared to that of Metronidazole (400mg). The therapeutic evaluations of these medicines were carried out on 184 clinically diagnosed cases of the amoebiasis infection. Sample sizes of Ameobex for this study included a total of 93 patients and for Metronidazole a total of 91 were registered and treated. Comparison of the data recorded for the participants relating to sign and symptoms variables showed significant differences of efficacy between test and control groups (p<0.0357) and no side effects were at all recorded in test group. According to observation, there was a difference in the overall clinical success of both treatment groups, however, the efficacy of the test treated medication (Amoebex) was superior to that of Metronidazole as (p<0.03), and on the basis of the statistical analysis done by the chi square test, the null hypothesis was rejected. `It is clearly evident that Amoebex possesses therapeutic value for the treatment of amoebiasis associated symptoms but also the eradication rate of amoebiasis is superior by Amoebex as compared to that of Metronidazole (Control drug).

The first case of cholecystitis acalculous by Cryptosporidium in onco-hematology pediatric patient was described in this work.

Entamoeba being an internal parasite is the causative organism of many human and animal infections with lethal consequences. Chemotherapy against Entamoeba was well established by both synthetic and natural products. Vigorous attainments were made by different researchers all over the world for discovering better chemical entities and the potent formulations. Preexisting compounds were developed into non-cytotoxic and with an enhanced therapeutic compounds by usage of multiparametric optimization techniques like QSAR, and molecular docking. The present review is therefore an aerial perspective of importance of medicinal chemistry in anti-amoebic chemotherapy. The review elucidates the existing synthetic compounds, their analogues, natural products, in silico studies and some novel methods adopted for the drug design as anti-amoebic agents which would be of assured benefit in the future drug design.

Objective: Visceral leishmaniasis (VL) in north-west Ethiopia is causing an overwhelming case load among adult migrant workers that masked the disease burden in children. This study describes the clinical profile and explores comorbidities in paediatric VL patients., Methods: A prospective study at two hospitals in this region (Gondar and Humera) was conducted in a year period, 2011-2012. The clinical manifestations and comorbidities such as malnutrition, intestinal parasitosis and vitamin D deficiency and HIV infection were assessed, and treatment outcomes noted., Results: A total of 122 children with VL were detected during the study period with median age of 8.5 years (IQR 5-12 years); 23% were under 5 years. Eighty-five (69.7%) cases were male. The clinical manifestations were similar to the adult patients. High rates of malnutrition, intestinal parasitosis (47.5%) and hypovitaminosis D (56.4%) were detected. The proportion of stunting and wasting was 63% and 22.2% in children aged under five years, and 50.5% and 75.9% in 5-year and older children, respectively, using WHO standard growth curves. Only one child had HIV infection. In 95% of the cases, sodium stibogluconate (20 mg/kg/day for 30 days) was used for treatment. The treatment success rate at end of therapy was 98.3%, but the definitive outcome at 6 months could not be determined because of a high loss to follow-up (80.2%)., Conclusion: While HIV co-infection was rare, malnutrition, intestinal parasitosis and vitamin D deficiency were frequent indicating the need for further research on their role in the pathophysiology. Meanwhile, systematic assessment and management of malnutrition and intestinal parasitosis in VL programmes is recommended., (© 2014 John Wiley & Sons Ltd.)

Free-living amoebae of the genus Acanthamoeba are causal agents of a severe sight-threatening infection of the cornea known as Acanthamoeba keratitis. Moreover, the number of reported cases worldwide is increasing year after year, mostly in contact lens wearers, although cases have also been reported in non-contact lens wearers. Interestingly, Acanthamoeba keratitis has remained significant, despite our advances in antimicrobial chemotherapy and supportive care. In part, this is due to an incomplete understanding of the pathogenesis and pathophysiology of the disease, diagnostic delays and problems associated with chemotherapeutic interventions. In view of the devastating nature of this disease, here we present our current understanding of Acanthamoeba keratitis and molecular mechanisms associated with the disease, as well as virulence traits of Acanthamoeba that may be potential targets for improved diagnosis, therapeutic interventions and/or for the development of preventative measures. Novel molecular approaches such as proteomics, RNAi and a consensus in the diagnostic approaches for a suspected case of Acanthamoeba keratitis are proposed and reviewed based on data which have been compiled after years of working on this amoebic organism using many different techniques and listening to many experts in this field at conferences, workshops and international meetings. Altogether, this review may serve as the milestone for developing an effective solution for the prevention, control and treatment of Acanthamoeba infections., (© J. Lorenzo-Morales et al., published by EDP Sciences, 2015.)

Amebic liver abscess is a tropical disease. It is not uncommon in Bangladesh. Given the often nonspecific nature of complains related to amebic liver abscess, this study was carried out to identify the most common presentation. This hospital based cross sectional study was carried out in 30 cases of amebic liver abscess in the Department of Medicine, Gastroenterology and Hepatology, Comilla Medical College Hospital, Bangladesh. Clinical and laboratory informations were recorded including symptoms, signs, location and number of abscess. Among 30 patients, 27 were male (90%) and 3 female (10%), mean age of male and female were 42±11 and 52±8 respectively. Common clinical symptoms were fever (93%) and abdominal pain (93%). Common signs were right upper quadrant tenderness (60%), hepatomegaly (67%). Most of the patient had single abscess (80%) and location of abscess was predominantly in the right lobe (77%). Radiological abnormality on x-ray chest was present in 30% cases. Common clinical presentation of amebic liver abscess patients were fever and right upper abdominal pain. Duration of symptoms was more than two weeks in most cases.

Early diagnosis and appropriate therapy are key elements for a good prognosis in Acanthamoeba keratitis (AK). AK should be considered in any case of corneal trauma complicated by exposure to soil or contaminated water, and in all contact lens (CL) wearers. A presumptive diagnosis of AK can be made clinically and with in vivo confocal microscopy, although a definitive diagnosis requires identification of Acanthamoeba on direct scraping, histology, or identification of Acanthamoeba DNA by polymerase chain reaction (PCR). We use cysticidal drugs for treating AK because encysted forms are more resistant than trophozoites to treatment. The treatment protocol used a biguanide (PHMB 0.02% or chlorhexidine 0.02%) and a diamidine (propamidine 0.1% or hexamidine 0.1%). New diagnostic modalities and more specific topical anti-amoebic treatments would substantially benefit patients with AK., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Background/aims: Many parasites induce changes in the lipid profiles of the host. Cholesterol increases the virulence of Entamoeba histolytica in animal models and in vitro culture. This study aimed to determine, in patients with an amebic liver abscess, the correlation between cholesterol and other features, such as the size and number of abscesses, standard hematological and serum chemistry profiles, liver tests, and duration of hospital stay., Methods: A total of 108 patients with an amebic liver abscess and 140 clinically healthy volunteers were investigated. Cholesterol and triglycerides were measured in the sera. The data from medical observations and laboratory tests were obtained from the clinical records., Results: A total of 93% of patients with an amebic liver abscess showed hypocholesterolemia not related to any of the studied parameters. Liver function tests correlated with the size of the abscess. The most severe cases of amebic liver disease or death were found in patients whose cholesterol levels continued to decrease despite receiving antiamebic treatment and hospital care., Conclusions: Our results show that the hypocholesterolemia observed in patients with an amebic liver abscess is not related to any of the clinical and laboratory features analyzed. This is the first study relating hypocholesterolemia to severity of hepatic amebiasis.

Naegleria fowleri is a free living parasite which habitats in fresh water reservoirs. It causes a fatal nervous system infection known as primary amoebic meningoencephalitis by invading through cribriform plate of nose and gaining entry into brain. We report a case of primary amoebic meningoencephalitis caused by Naegleria fowleri in Karachi, Pakistan, in a 42 years old male poultry farm worker having no history of swimming. Clinical course was fulminant and death occurred within one week of hospital admission. Naegleria fowleri was detected by wet mount technique in the sample of cerebrospinal fluid collected by lumbar puncture of patient. This is a serious problem and requires immediate steps to prevent general population to get affected by this lethal neurological infection.

We report the case of an 83-year-old man who presented with a history of fluctuating delirium of insidious onset, secondary to an amoebic liver abscess more than 30 years after acute exposure. We describe a 2-year clinical journey that started with a fall and was additionally complicated by severe weight loss and acute kidney injury (AKI). The likely prognosis for such a combination of comorbidities in an older person is for lasting morbidity, institutionalisation and significant mortality. However, the case demonstrates that with timely assessment and care complete recovery is possible though it may take many months. It reminds us of the catalytic implications of falls for older persons and to maintain a differential diagnostic approach to delirium of insidious onset avoiding misdiagnosis as dementia with which it may be associated. Our case report includes extracts from the patient's own account providing added insight into such experiences.

We present a case of amoebic colitis, misdiagnosed as inflammatory bowel disease and treated with corticosteroids, leading to severe necrotizing enterocolitis. We review the literature on the epidemiology, pathogenesis, diagnosis, and treatment of amoebic dysentery, with special emphasis on the association between immunosuppressive treatment and the development of severe invasive amoebiasis.