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Protozoan keratitis

Fu-Chin Huang, Tao-Shen Liu, Sung-Chou Li, Min-Hsiu Shih, Jyh-Wei Shin, Wei-Chen Lin
Acanthamoeba castellanii is a free-living protozoan pathogen capable of causing a blinding keratitis and fatal granulomatous encephalitis. Current treatment generally involves an hourly application of polyhexamethylene biguanide (PHMB) over a period of several days but this is not entirely effective against all strains/isolates. The tolerance mechanisms of PHMB in Acanthamoeba cells remain unclear. In this study, we found that the mRNA expression level of disulfideisomerase domain containing protein (PDI) increased rapidly in surviving cells of the highly PHMB-tolerant Acanthamoeba castellanii strain, NCKH_D, during PHMB treatment, but not in the ATCC standard strain...
December 2016: International Journal for Parasitology, Drugs and Drug Resistance
Linda Christian Carrijo-Carvalho, Viviane Peracini Sant'ana, Annette Silva Foronda, Denise de Freitas, Fabio Ramos de Souza Carvalho
Acanthamoeba keratitis is a sight-threatening infectious disease. Resistance of the cystic form of the protozoan to biocides and the potential toxicity of chemical compounds to corneal cells are the main concerns related to long-term treatment with the clinically available ophthalmic drugs. Currently, a limited number of recognized antimicrobial agents are available to treat ocular amoebic infections. Topical application of biguanide and diamidine antiseptic solutions is the first-line therapy. We consider the current challenges when treating Acanthamoeba keratitis and review the chemical properties, toxicities, and mechanisms of action of the available biocides...
March 2017: Survey of Ophthalmology
Fatemeh Memari, Maryam Niyyati, Jacob Lorenzo-Morales, Zaynab Jonaydi
Acanthamoeba spp. is an opportunistic protozoan parasite which is the causative agent of granulomatous amoebic encephalitis (GAE) and Acanthamoeba keratitis (AK). GAE usually occurs in immunocompromised patients which in most cases is fatal. The present study was conducted to determine the genotypes of Acanthamoeba isolated from patients with compromised immunological status. For this purpose, 90 samples from the oral cavity of these individuals were collected in different hospitals of Tehran, Iran using sterile cotton swabs...
September 1, 2016: Acta Parasitologica
Tanitta Sampaotong, Usa Lek-Uthai, Jantima Roongruangchai, Kosol Roongruangchai
Acanthamoeba is a free-living opportunistic protozoan parasite that is found in diverse environments. It can cause keratitis, mostly related to inappropriate use of contact lenses, as well as life threatening diseases including encephalitis, disseminated sinusitis, and skin ulcers. This study investigated morphological changes and fine structures of the cyst form of Acanthamoeba spp. after treatment with effective microorganisms (EM™) using light and scanning electron microscopies. Acanthamoeba cysts treated with 1:2, 1:4, 1:6, and undiluted EM™ showed higher percentages of non-viable cysts than those treated with 1:8, 1:10, 1:100, 1:200, and 1:400 EM™ and at 5 days post-treatment developed from cystic stage to trophozoite stage...
June 2016: Journal of Parasitic Diseases: Official Organ of the Indian Society for Parasitology
Muhammad Imran, Ambreen Gul Muazzam, Amir Habib, Abdul Matin
Acanthamoeba is an opportunistic protozoan pathogen that plays a pivotal role in the ecosystem. It may cause blinding keratitis and fatal encephalitis involving the central nervous system. Here we synthesized pure and Zn doped TiO2 nanoparticles (~10-30nm) via sol-gel and sol-hydrothermal methods and demonstrated its impact on the biological characteristics of pathogenic Acanthamoeba castellanii. Our results revealed that pure and Zn doped TiO2 nanoparticles synthesized by sol-hydrothermal methods (ranging 5, 10, 25 and 50μg/ml) exhibited amoebicidal effects i...
June 2016: Journal of Photochemistry and Photobiology. B, Biology
Wayne Heaselgrave, Gilbert Shama, Peter W Andrew, Michael G Kong
Currently there are estimated to be approximately 3.7 million contact lens wearers in the United Kingdom and 39.2 million in North America. Contact lens wear is a major risk factor for developing an infection of the cornea known as keratitis due to poor lens hygiene practices. While there is an international standard for testing disinfection methods against bacteria and fungi (ISO 14729), no such guidelines exist for the protozoan Acanthamoeba, which causes a potentially blinding keratitis most commonly seen in contact lens wearers, and as a result, many commercially available disinfecting solutions show incomplete disinfection after 6 and 24 h of exposure...
May 15, 2016: Applied and Environmental Microbiology
Nicholas J R Maycock, Rakesh Jayaswal
PURPOSES: A literature review to describe the current diagnosis and management of Acanthamoeba keratitis. RESULTS: Acanthamoeba is a ubiquitous protozoan: 8 species, 5 genotypic classes have been reported to cause keratitis. It is potentially a sight-threatening infection, and there is often a poor prognosis because of a significant delay in diagnosis and frequently a lack of effective medical management. Main risk factors are contact lens wear, poor hygiene, and contact with contaminated water...
May 2016: Cornea
Maryam Niyyati, Mostafa Rezaeian
BACKGROUND: Free-living amoebae belonging to the genus Acanthamoeba have an environmental distribution. Amoebic keratitis due to these protozoan parasites continue to rise in Iran and worldwide. In Iran, there are various researches regarding both morphological and molecular identification of Acanthamoeba spp. in environmental and clinical samples. However, there is no thorough review about Acanthamoeba genotypes and their distribution in environmental sources such as water, dust and biofilm in Iran...
April 2015: Iranian Journal of Parasitology
Tania Tanveer, Abdul Hameed, Asma Gul, Abdul Matin
Acanthamoeba is an opportunistic protozoan pathogen which is widely distributed in nature and plays a pivotal role in ecosystem. Acanthamoeba species may cause blinding keratitis and fatal granulomatous encephalitis involving central nervous system. In this study, we investigated the presence of Acanthamoeba in soil and water resources of Pakistan. Here, Acanthamoeba were recovered on non-nutrient agar plate lawn with E. coli and identified by morphological characteristics of the cyst. Furthermore PCR was performed with genus-specific primers followed by direct sequencing of the PCR product for molecular identification...
2015: Annals of Agricultural and Environmental Medicine: AAEM
Yihong Deng, Wei Ran, Suqin Man, Xueping Li, Hongjian Gao, Wei Tang, Hiroshi Tachibana, Xunjia Cheng
Acanthamoeba sp. parasites are the causative agents of Acanthamoeba keratitis, fatal granulomatous amoebic encephalitis, and cutaneous infections. However, there are currently no effective drugs for these organisms. Here, we evaluated the activity of the antimalarial agent artemether against Acanthamoeba castellanii trophozoites and identified potential targets of this agent through a proteomic approach. Artemether exhibited in vitro amoebicidal activity in a time- and dose-dependent manner and induced ultrastructural modification and cell apoptosis...
August 2015: Antimicrobial Agents and Chemotherapy
Avi Peretz, Yuval Geffen, Soergiu D Socea, Nina Pastukh, Shmuel Graffi
Acanthamoeba keratitis (AK), a potentially blinding infection of the cornea, is caused by a free-living protozoan. Culture and microscopic examination of corneal scraping tissue material is the conventional method for identifying Acanthamoeba. In this article, we compared several methods for AK diagnosis of 32 patients: microscopic examination using fluorescent dye, specific culture on growth media-non-nutrient agar (NNA), culture on liquid growth media-peptone yeast glucose (PYG), and TYI-S-33. AK was found in 14 patients...
August 2015: American Journal of Tropical Medicine and Hygiene
Bijay Kumar Jha, Incheol Seo, Hyun-Hee Kong, Seong-Il Suh, Min-Ho Suh, Won-Ki Baek
Acanthamoeba is an opportunistic protozoan parasite responsible for different diseases in humans, such as granulomatous amoebic encephalitis and amoebic keratitis. Tigecycline, a third-generation tetracycline antibiotic, has potential activity to treat most of the antibiotic resistant bacterial infections. The effects of tigecycline in eukaryotic cells as well as parasites are less well studied. In the present study, we tested the effects of tigecycline on trophozoites of Acanthamoeba castellanii. The inhibitory effect of tigecycline on Acanthamoeba was determined by resazurin reduction and trypan blue exclusion assays...
March 2015: Parasitology Research
Karin Silva Caumo, Karina Mariante Monteiro, Thiely Rodrigues Ott, Vinicius José Maschio, Glauber Wagner, Henrique Bunselmeyer Ferreira, Marilise Brittes Rott
Acanthamoeba polyphaga is a free-living protozoan pathogen, whose infective trophozoite form is capable of causing a blinding keratitis and fatal granulomatous encephalitis in humans. The damage caused by A. polyphaga trophozoites in human corneal or brain infections is the result of several different pathogenic mechanisms that have not yet been elucidated at the molecular level. We performed a comprehensive analysis of the proteins expressed by A. polyphaga trophozoites, based on complementary 2-DE MS/MS and gel-free LC-MS/MS approaches...
December 2014: Acta Tropica
Marta Palusinska-Szysz, Magdalena Kania, Anna Turska-Szewczuk, Witold Danikiewicz, Ryszard Russa, Beate Fuchs
Acanthamoeba are opportunistic protozoan pathogens that may lead to sight-threatening keratitis and fatal granulomatous encephalitis. The successful prognosis requires early diagnosis and differentiation of pathogenic Acanthamoeba followed by aggressive treatment regimen. The plasma membrane of Acanthamoeba consists of 25% phospholipids (PL). The presence of C20 and, recently reported, 28- and 30-carbon fatty acyl residues is characteristic of amoeba PL. A detailed knowledge about this unusual PL composition could help to differentiate Acanthamoeba from other parasites, e...
2014: PloS One
Lidia Chomicz, Marcin Padzik, Jacek P Szaflik, Wacław L Nahorski, Tomasz Kryczka, Jerzy Szaflik
Free-living amoebae of Acanthamoeba genus are ubiquitous in various parts of the world. Some species of these amoebozoans present a serious risk to human health as the causative agents of vision-threatening diseases, Acanthamoeba keratitis. Correct diagnosis requires both a clinical examination of the cornea and amoebic form identification in affected eyes. Despite advances in pharmacotherapy, the infection is difficult to diagnose and to threat. Population dynamics of five different Acanthamoeba strains cultured in vitro under bacteria-free condition in BSC medium, was monitored in terms of diagnostic and therapeutic management...
November 2014: Experimental Parasitology
Hayam Mohamed Ezz Eldin, Rania Mohamed Sarhan
Acanthamoeba castellanii is a protozoan parasite that may cause sight-threatening keratitis in some individuals. Its eradication is difficult because the trophozoites encyst making organisms highly resistant to anti-amoebic drugs. To test new anti-Acanthamoeba agents, usually having low water solubility, organic solvents and surfactant agents should be used. Therefore, the lethal effect of different concentrations of the solvents acetone, methanol, ethanol, and DMSO and surfactant agents Tween 20, Tween 80, and Triton X-100 was tested...
May 2014: Parasitology Research
Prashant Garg
Microsporidia are a diverse group of obligate, intracellular, eukaryotic, spore-forming parasites. Traditionally, these were considered as protozoans but recently have been reclassified as fungi. Microsporidia behave as opportunistic pathogens causing systemic infections. In the eye, Microsporidia cause keratoconjunctivitis, corneal stromal keratitis, scleritis, and endophthalmitis. This review shares our experiences with anterior segment infections caused by this pathogen. Keratoconjunctivitis is a common form of ocular infection caused by the parasite...
November 2013: Cornea
Md Moshiur Rahman, Kenji Yagita, Akira Kobayashi, Yosaburo Oikawa, Amjad I A Hussein, Takahiro Matsumura, Masaharu Tokoro
Because of an increased number of Acanthamoeba keratitis (AK) along with associated disease burdens, medical professionals have become more aware of this pathogen in recent years. In this study, by analyzing both the nuclear 18S small subunit ribosomal RNA (18S rRNA) and mitochondrial 16S rRNA gene loci, 27 clinical Acanthamoeba strains that caused AK in Japan were classified into 3 genotypes, T3 (3 strains), T4 (23 strains), and T5 (one strain). Most haplotypes were identical to the reference haplotypes reported from all over the world, and thus no specificity of the haplotype distribution in Japan was found...
August 2013: Korean Journal of Parasitology
I Heredero-Bermejo, J L Copa-Patiño, J Soliveri, R Gómez, F J de la Mata, J Pérez-Serrano
The species of the genus Acanthamoeba are opportunistic protozoan parasites that cause different diseases in humans, such as amoebic keratitis and granulomatous encephalitis. The rise in the rate of Acanthamoeba keratitis, mainly due to the increase in contact lens wearers, turns the development of viability assays using a multi-well plate reader as a tool for screening new antiamoebic agents in vitro into an important goal. In our study, the viability assays PrestoBlue®, resazurin sodium salt, 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) and CellTiter96® were tested for their suitability as time-saving alternatives to the classical manual or direct-counting method, assessing the effect of the antiamoebic agent chlorhexidine digluconate and temperature on Acanthamoeba castellanii (ATCC® 30234™) and Acanthamoeba polyphaga 2961...
December 2013: Parasitology Research
Trivendra Tripathi, Mahshid Abdi, Hassan Alizadeh
The aim of this study is to determine if the mannose-induced protein (MIP-133) from Acanthamoeba castellanii trophozoites induces apoptosis of corneal epithelial cells through a cytosolic phospholipase A2α (cPLA2α)-mediated pathway. The efficacy of cPLA2α inhibitors to provide protection against Acanthamoeba keratitis was examined in vivo. Chinese hamster corneal epithelial (HCORN) cells were incubated with or without MIP-133. MIP-133 induces significant increase in cPLA2α and macrophage inflammatory protein-2 (MIP-2/CXCL2) levels from corneal cells...
August 2013: Experimental Eye Research
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