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Annals of Parasitology 2018Amoebas from the genus Acanthamoeba are cosmopolitan organisms, which can exist as free-living organisms and as parasites within host tissue. Acanthamoeba infection... (Review)
Review
Amoebas from the genus Acanthamoeba are cosmopolitan organisms, which can exist as free-living organisms and as parasites within host tissue. Acanthamoeba infection present a serious risk to human health and are characterized by high mortality, especially in immunocompromised individuals. These protozoa are the etiological factors of granulomatous amoebic encephalitis (GAE) and Acanthamoeba keratitis (AK). They can also live in the lungs, adrenals glands, nose, throat, and bones of the host. Furthermore, the amoebas can be vectors of pathogenic bacteria. Acanthamoeba infection caused is a serious clinical problem mainly due to limited progress in diagnostics and treatment of this infection, which is associated with insufficient knowledge of pathogenesis, pathophysiology and the host immune response against Acanthamoeba antigens. This review study presents the biology of Acanthamoeba sp. as well as pathogenicity, diagnostics, and treatment of amoebas infections. It also presents data, including experimental results, concerning pathogenic properties and the host’s immunology response against Acanthamoeba sp.
Topics: Acanthamoeba; Amebiasis; Humans; Immunocompromised Host
PubMed: 30720249
DOI: 10.17420/ap6404.164 -
Indian Journal of Ophthalmology Apr 2024This is a comprehensive review after a thorough literature search in PubMed-indexed journals, incorporating current information on the pathophysiology, clinical... (Review)
Review
This is a comprehensive review after a thorough literature search in PubMed-indexed journals, incorporating current information on the pathophysiology, clinical features, diagnosis, medical and surgical therapy, as well as outcomes of Acanthamoeba keratitis (AK). AK is a significant cause of ocular morbidity, and early diagnosis with timely institution of appropriate therapy is the key to obtaining good outcomes. The varied presentations result in frequent misdiagnosis, and co-infections can increase the morbidity of the disease. The first line of therapy continues to be biguanides and diamidines, with surgery as a last resort.
Topics: Humans; Acanthamoeba Keratitis; Pentamidine; Biguanides
PubMed: 38454853
DOI: 10.4103/IJO.IJO_2627_23 -
Indian Journal of Ophthalmology Nov 2017The purpose of the study is to describe epidemiology, clinical features, diagnosis, and treatment of Acanthamoeba keratitis (AK) with special focus on the disease in... (Review)
Review
The purpose of the study is to describe epidemiology, clinical features, diagnosis, and treatment of Acanthamoeba keratitis (AK) with special focus on the disease in nonusers of contact lenses (CLs). This study was a perspective based on authors' experience and review of published literature. AK accounts for 2% of microbiology-proven cases of keratitis. Trauma and exposure to contaminated water are the main predisposing factors for the disease. Association with CLs is seen only in small fraction of cases. Contrary to classical description experience in India suggests that out of proportion pain, ring infiltrate, and radial keratoneuritis are seen in less than a third of cases. Majority of cases present with diffuse infiltrate, mimicking herpes simplex or fungal keratitis. The diagnosis can be confirmed by microscopic examination of corneal scraping material and culture on nonnutrient agar with an overlay of Escherichia coli. Confocal microscopy can help diagnosis in patients with deep infiltrate; however, experience with technique and interpretation of images influences its true value. Primary treatment of the infection is biguanides with or without diamidines. Most patients respond to medical treatment. Corticosteroids play an important role in the management and can be used when indicated after due consideration to established protocols. Surgery is rarely needed in patients where definitive management is initiated within 3 weeks of onset of symptoms. Lamellar keratoplasty has been shown to have good outcome in cases needing surgery. Since the clinical features of AK in nonusers of CL are different, it will be important for ophthalmologists to be aware of the scenario wherein to suspect this infection. Medical treatment is successful if the disease is diagnosed early and management is initiated soon.
Topics: Acanthamoeba Keratitis; Contact Lenses; Corneal Transplantation; Humans; India; Microscopy, Confocal; Risk Factors; Visual Acuity
PubMed: 29133630
DOI: 10.4103/ijo.IJO_826_17 -
Microorganisms Aug 2022Although the prevalence of keratitis (AK) is rare, its incidence in contact lens wearers has increased. infections can lead to the loss of vision if the diagnosis and...
Although the prevalence of keratitis (AK) is rare, its incidence in contact lens wearers has increased. infections can lead to the loss of vision if the diagnosis and treatment are delayed. In this study, we investigated the diagnostic potential of two antibodies raised against the adenylyl cyclase-associated protein (ACAP) and periplasmic binding protein (PBP) of in the AK mouse model. The specificity of ACAP and PBP antibodies to was confirmed by immunocytochemistry. AK mouse models were produced by corneal infections with trophozoites for 7 days and 21 days. Enzyme-linked immunosorbent assay results revealed that both ACAP and PBP antibodies successfully detected antigens in the tears and eyeball lysates of the AK mouse model. The detection levels of antigens were similar at both infection time points. Anti- IgG, IgA, and IgM antibodies were evaluated from the sera of the AK mouse model. Notably, IgM and IgA antibody responses were highest and lowest at both time points, respectively. Our findings revealed that both ACAP and PBP antibodies could detect antigens in the tears and eyeball lysates of the AK mouse model. These results provide important information for understanding infections and developing a new diagnostic tool for AK.
PubMed: 36144313
DOI: 10.3390/microorganisms10091711 -
The Israel Medical Association Journal... Apr 2013
Review
Topics: Acanthamoeba; Acanthamoeba Keratitis; Antiprotozoal Agents; Contact Lenses; Cornea; Humans; Incidence
PubMed: 23781754
DOI: No ID Found -
Parasitology Research Sep 2021Acanthamoeba spp. are among the most worldwide prevalent protozoa. It is the causative agent of a disease known as Acanthamoeba keratitis, a painful and severe... (Review)
Review
Acanthamoeba spp. are among the most worldwide prevalent protozoa. It is the causative agent of a disease known as Acanthamoeba keratitis, a painful and severe sight-threatening corneal infection that can lead to blindness. In recent years, the prevalence of Acanthamoeba keratitis has rapidly increased, growing its importance to human health. This systematic review aims to assess the distribution of Acanthamoeba sp. genotypes causing keratitis around the world, considering the sample collected type and the used identification method. Most of the cases were found in Asia and Europe. Not surprisingly, the T4 genotype was the most prevalent worldwide, followed by T3, T15, T11, and T5. Furthermore, the T4 genotype contains a higher number of species. Given the differences in pathology, susceptibility to treatment, and clinical outcome between distinct genotypes, it is essential to genotype isolates from Acanthamoeba keratitis cases to help to establish a better correlation between in vitro and in vivo activities, resulting in better drug therapies and successful treatment in cases of this important ocular infection.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Cornea; Genotype; Humans
PubMed: 34351492
DOI: 10.1007/s00436-021-07261-1 -
Parasites & Vectors Jan 2012Acanthamoeba is a free-living protist pathogen, capable of causing a blinding keratitis and fatal granulomatous encephalitis. The factors that contribute to Acanthamoeba... (Review)
Review
Acanthamoeba is a free-living protist pathogen, capable of causing a blinding keratitis and fatal granulomatous encephalitis. The factors that contribute to Acanthamoeba infections include parasite biology, genetic diversity, environmental spread and host susceptibility, and are highlighted together with potential therapeutic and preventative measures. The use of Acanthamoeba in the study of cellular differentiation mechanisms, motility and phagocytosis, bacterial pathogenesis and evolutionary processes makes it an attractive model organism. There is a significant emphasis on Acanthamoeba as a Trojan horse of other microbes including viral, bacterial, protists and yeast pathogens.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Amebiasis; Encephalitis
PubMed: 22229971
DOI: 10.1186/1756-3305-5-6 -
Iranian Journal of Parasitology 2020species are vision-threatening agents by causing cornea infections known as keratitis. A 5 year-old kid with the complaints of erythema, eyelid edema, inflammation,...
species are vision-threatening agents by causing cornea infections known as keratitis. A 5 year-old kid with the complaints of erythema, eyelid edema, inflammation, limitation of eye movements in the right eye, and having no history of wearing contact lenses or trauma, was diagnosed of conjunctivitis through laboratory examinations in the Ophthalmology clinic. The visual sharpness of the patient improved after the treatment. A 44 year-old female patient suffering from pain, stinging, irritation, and inability to see in the left eye with the history of wearing contact lenses or trauma was diagnosed of keratitis through laboratory examinations. The agent was isolated and identified as "" in the Genotype "T2". Examination of the left eye on the 15th day of treatment indicated that all complaints disappeared except for the cataract originated visual loss. However, the first diagnosis of keratitis appeared in the literature on a case with no history of wearing contact lenses and trauma it is found to be attention grabbing. We think that should not be ignored among microbial agents that cause eye infection with or without trauma and contact lens usage history.
PubMed: 32595719
DOI: No ID Found -
International Journal of Antimicrobial... Oct 2020Acanthamoebae are facultative parasites causing rare but serious infections such as keratitis and encephalitis and are also known as vectors for several bacterial...
Acanthamoebae are facultative parasites causing rare but serious infections such as keratitis and encephalitis and are also known as vectors for several bacterial pathogens, including legionellae and pseudomonads. Acanthamoeba cysts are particularly resilient and enable the amoebae to withstand desiccation and to resist disinfection and therapy. While the search for new therapeutic options has been intensified in the past years, hand and surface disinfectants as well as topical antiseptics for preventing infections have not been studied in detail to date. The aim of this study was to screen well-known and commonly used antimicrobial products in various formulations and different concentrations for their efficacy against Acanthamoeba trophozoites and cysts, including aliphatic alcohols, quaternary ammonium compounds (QACs), peracetic acid (PAA), potassium peroxymonosulfate sulfate (PPMS) and octenidine dihydrochloride (OCT). Of all products tested, OCT and QACs showed the highest efficacy, totally eradicating both trophozoites and cysts within 1 min. The determined 50% effective concentration (EC) for cysts was 0.196 mg/mL for OCT and 0.119 mg/mL for QACs after 1 min of exposure. PAA and PPMS showed reliable cysticidal efficacies only with prolonged incubation times of 30 min and 60 min, respectively. Aliphatic alcohols generally had limited efficacy, and only against trophozoites. In conclusion, OCT and QACs are potent actives against Acanthamoeba trophozoites and cysts at concentrations used in commercially available products, within contact times suitable for surface and hand disinfection as well as topical antisepsis.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Alcohols; Antiparasitic Agents; Disinfectants; Disinfection; Hand Disinfection; Humans; Imines; Peracetic Acid; Pyridines; Quaternary Ammonium Compounds; Sulfuric Acids; Trophozoites
PubMed: 32739477
DOI: 10.1016/j.ijantimicag.2020.106122 -
Antimicrobial Agents and Chemotherapy Nov 2016For the past several decades, there has been little improvement in the morbidity and mortality associated with Acanthamoeba keratitis and Acanthamoeba encephalitis,... (Review)
Review
For the past several decades, there has been little improvement in the morbidity and mortality associated with Acanthamoeba keratitis and Acanthamoeba encephalitis, respectively. The discovery of a plethora of antiacanthamoebic compounds has not yielded effective marketed chemotherapeutics. The rate of development of novel antiacanthamoebic chemotherapies of translational value and the lack of interest of the pharmaceutical industry in developing such chemotherapies have been disappointing. On the other hand, the market for contact lenses/contact lens disinfectants is a multi-billion-dollar industry and has been successful and profitable. A better understanding of drugs, their targets, and mechanisms of action will facilitate the development of more-effective chemotherapies. Here, we review the progress toward phenotypic drug discovery, emphasizing the shortcomings of useable therapies.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Amphotericin B; Animals; Antiprotozoal Agents; Azoles; Biguanides; Caspofungin; Cefazolin; Chlorhexidine; Echinocandins; Humans; Infectious Encephalitis; Lipopeptides; Meropenem; Natamycin; Polymyxin B; Thienamycins
PubMed: 27600042
DOI: 10.1128/AAC.00686-16