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Protozoan keratitis

Yen C Hsia, Caitlin A Moe, Thomas M Lietman, Jeremy D Keenan, Jennifer Rose-Nussbaumer
Objective: To assess the current opinion and practice patterns from cornea experts regarding the benefit of corneal cross-linking (CXL) for infectious keratitis (IK). Methods and analysis: An international survey was distributed to corneal specialists via an internet survey. The survey data collected were analysed with descriptive statistics. Results: A survey was sent to 190 recipients, and 29 (15%) respondents completed the survey with an average of 7 years' experience using CXL...
2018: BMJ open ophthalmology
Ana Montoya, Guadalupe Miró, José María Saugar, Beatriz Fernández, Rocío Checa, Rosa Gálvez, Begoña Bailo, Valentina Marino, José E Piñero, Jacob Lorenzo-Morales, Isabel Fuentes
Acanthamoeba spp. is a widespread protozoan that has been isolated from air, dust, soil, water and biological samples. An opportunistic pathogen of humans and animals, it may cause ocular keratitis, encephalitis, and even multisystem disease. The frequency of Acanthamoeba in animals is unknown. The aim of present study was determine the presence of Acanthamoeba spp. in immunocompromised stray cats - animals possibly more likely to harbour the infection given their immunocompromised status and frequenting of contaminated environments...
May 2018: Experimental Parasitology
M M Juárez, L I Tártara, A G Cid, J P Real, J M Bermúdez, V B Rajal, S D Palma
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...
December 19, 2017: Contact Lens & Anterior Eye: the Journal of the British Contact Lens Association
Atteneri López-Arencibia, María Reyes-Batlle, Mónica Blanco Freijo, Grant McNaughton-Smith, Patricia Martín-Rodríguez, Leandro Fernández-Pérez, Ines Sifaoui, Carolina Wagner, Ana B García-Méndez, Aitor Rizo Liendo, Carlos J Bethencourt-Estrella, Teresa Abad-Grillo, José E Piñero, Jacob Lorenzo-Morales
Acanthamoeba is an opportunistic pathogen which is the causal agent of a sight-threatening ulceration of the cornea known as Acanthamoeba keratitis (AK) and, more rarely, an infection of the central nervous system called "granulomatous amoebic encephalitis" (GAE). The symptoms of AK are non-specific, and so it can be misdiagnosed as a viral, bacterial, or fungal keratitis. Furthermore, current therapeutic measures against AK are arduous, and show limited efficacy against the cyst stage of Acanthamoeba...
December 2017: Experimental Parasitology
Muhammet Karakavuk, Mehmet Aykur, Esra Atalay Şahar, Mehmet Karakuş, Duygu Aldemir, Ömer Döndüren, Hüseyin Gökhan Özdemir, Hüseyin Can, Adnan Yüksel Gürüz, Hande Dağcı, Mert Döşkaya
Acanthamoeba is a free-living amoeba which can be isolated from environment and among others well known as an opportunist protozoan parasite causing infections in humans and animals. Eyes are extremely important for the wild birds and losing sight ability due to Acanthamoeba can be dangerous. The studies on Acanthamoeba infection in wild birds is very few in world and Turkey therefore we aimed to screen deceased wild birds found in İzmir and Manisa provinces located in western Turkey using PCR and non-nutrition agar (NNA) plate method...
December 2017: Experimental Parasitology
Viviane P Sant'Ana, Annette S Foronda, Denise de Freitas, Linda C Carrijo-Carvalho, Fábio Ramos de Souza Carvalho
Acanthamoeba is a free-living amoeba that causes severe corneal infection (Acanthamoeba keratitis) and produces a variety of extracellular enzymes, called exoproteome. Since physicochemical characters are suggested being associated with therapeutic profile and clinical severity of the infection, we investigated the physicochemical properties of proteolysis mediated by amoebic exoproteome. Corneal scraping was collected from a patient who showed typical symptoms of acute Acanthamoeba keratitis. Axenic amoeba was phylogenetically identified by 18S rDNA sequencing analysis...
November 2017: Current Microbiology
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
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