... Acanthamoeba causes Acanthamoeba keratitis when it infects the transparent outer covering of the eye called the cornea. ...
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Acanthamoeba and Naegleria are widely distributed in fresh water, soil and dust throughout the world, and cause meningoencephalitis or keratoconjunctivitis in humans and other mammals. Korean isolates, namely, Naegleria sp. YM-1 and Acanthamoeba sp. YM-2, YM-3, YM-4, YM-5, YM-6 and YM-7, were collected from sewage, ...
PubMed Central
A new species of Acanthamoeba was isolated from a freshwater fish in Korea and tentatively named Acanthamoeba sp. YM-4 (Korean isolate YM-4). The trophozoites were 11.0-23.0 micrometer in length and had hyaline filamentous projections. Cysts were similar to those of A. culbertsoni and A. royreba, which were previously designated as ...
PubMed
A new species of Acanthamoeba was isolated from a freshwater fish in Korea and tentatively named Acanthamoeba sp. YM-4 (Korean isolate YM-4). The trophozoites were 11.0-23.0 �m in length and had hyaline filamentous projections. Cysts were similar to those of A. culbertsoni and A. royreba, which were previously designated as ...
Members of the genus Acanthamoeba are usually free-living amoebae that are found in a variety of ecological niches including soil, fresh and brackish water, dust in the air, heating, ventilating, and air conditioning filters, swimming pools and hot tubs. Occasionally they are also known to cause central nervous system infections in humans and animals. We ...
... 9-tetrahydrocannabinol (THC), the major psychoactive component of marijuana, exacerbates brain infection by Acanthamoeba. J. Eukaryot. Microbiol ... ...
NBII National Biological Information Infrastructure
Acanthamoeba sp. is a free-living amoeba known to cause chronic central nervous system infection or eye infection in humans. Many cases remain undetected for want of a good detection system. We report for the first time a rapid staining method to facilitate the identification of Acanthamoeba ...
Free-living amebas are widely distributed in soil and water, particularly members of the genera Acanthamoeba and Naegleria. Since the early 1960s, they have been recognized as opportunistic human pathogens, capable of causing infections of the central nervous system (CNS) in both immunocompetent and immunocompromised hosts. Naegleria is the causal agent of ...
A patient with AIDS, treated with highly active antiretroviral therapy and trimethoprim-sulfamethoxazole, presented with confusion, a hemifield defect, and a mass lesion in the right occipital lobe. A brain biopsy confirmed granulomatous amebic encephalitis (GAE) due to Acanthamoeba castellanii. The patient was treated with fluconazole and sulfadiazine, and the lesion was ...
This book is the ninth in the Emerging Infections series from the American Society for Microbiology. The 18 chapters cover the following diseases and pathogens: influenza in 2009, human adenovirus 14, Acanthamoeba polyphaga mimivirus as a cause of pneumonia, hepatitis E, lymphocytic choriomeningitis virus-like arenavirus infections, ...
Naegleria fowleri, Acanthamoeba spp., Balamuthia mandrillaris, and Sappinia sp. are pathogenic free-living amoebae. N. fowleri causes Primary Amoebic Meningoencephalitis, a rapidly fatal disease of the central nervous system, while Acanthamoeba spp. and B. mandrillaris cause chronic granulomatous encephalitis. ...
Stable Mycobacterium avium infections of several Acanthamoeba strains were characterized by increased infection resistance of recent environmental isolates and reduced infectivity in the presence of other bacteria. Exposure of M. avium in coculture with Acanthamoeba castellanii to ...
A new species of amoeba, Acanthamoeba tubiashi, is described from the sediment of a fresh-water stream near Bishopville, Maryland. Living trophozoites have features characteristic of amoebae belonging to the family Acanthamoebidae Sawyer and Griffin, 1975...
National Technical Information Service (NTIS)
Acanthamoeba and Naegleria species are free-living amoebae (FLA) found in a large variety of natural habitats. The prevalence of such amoebae was determined from dust samples taken from public non-hospital internal environments with good standards of cleanliness from two campuses of the same University in the city of Santos (SP), Brazil, and where young ...
Acanthamoeba causes opportunistic eye infections in humans, which can lead to severe keratitis and may ultimately result in blindness. Current methods for identifying this organism rely on culture and microscopy. In this paper, we describe the isolation of antibody fragments that can be used for the unequivocal identification of ...
In this study, two free-living amoebae strains, Acanthamoeba genotype T4 and Paravahlkampfia sp., which were isolated from keratitis cases are presented. While the Acanthamoeba strain was isolated as a single agent, the Paravahlkampfia strain was found together with herpes simplex virus. Neither of the patients were contact lens ...
The recently proposed reorganization of the order Chlamydiales and description of new taxa are broadening our perception of this once narrowly defined taxon. We have recovered four strains of gram-negative cocci endosymbiotic in Acanthamoeba spp., representing 5% of the Acanthamoeba sp. isolates examined, which displayed developmental ...
Acanthamoeba is an opportunistic protozoan pathogen that can cause blinding keratitis as well as fatal granulomatous encephalitis. One of the distressing aspects in combating Acanthamoeba infections is the prolonged and problematic treatment. For example, current treatment against Acanthamoeba keratitis requires ...
The genus Acanthamoeba can cause severe infections such as granulomatous amebic encephalitis and amebic keratitis in humans. However, little genomic information of Acanthamoeba has been reported. Here, we constructed Acanthamoeba expressed sequence tags (EST) database (Acanthamoeba EST DB) ...
Case Description-A 10-month-old Boxer was evaluated for fever and signs of cervical pain. Clinical Findings-Physical examination revealed lethargy, fever, and mucopurulent ocular and preputial discharge. On neurologic examination, the gait was characterized by a short stride. The dog kept its head flexed and resisted movement of the neck, consistent with cervical pain. Clinicopathologic findings ...
Granulomatous amebic encephalitis (GAE), an infection of immunocompromised hosts, is almost uniformly fatal. A case of GAE in a patient who failed to mount a serologic response to Acanthamoeba polyphaga is presented. Although Acanthamoeba polyphaga that is sensitive to multiple antimicrobials grew from brain tissue, an inability to ...
to multiply in various Acanthamoeba hosts and even in the distantly related amoeba Dictyostelium discoideum host amoebae, and was therefore transferred to another host, Acanthamoeba sp. UWC1 (Fritsche et al by Everett et al. (1999) and comprises obligately intracellular symbionts of free-living amoebae
E-print Network
We describe a 66-year-old woman with therapy-refractory cryoglobulinemia treated with rituximab, plasmapheresis, and steroids; a case of fatal meningoencephalitis caused by Acanthamoeba spp. then developed. Such infections are rare and show an unusually rapid course (possibly related to rituximab).
As part of an epidemiological study on legionellosis, we attempted to isolate Legionella spp. from hot spring water and were able to isolate L. londiniensis HYKF-90505 (=JCM 16338), confirming that L. londiniensis inhabits hot spring water in Japan. To investigate the disease potential of L. londiniensis, we examined its ability to grow intracellularly within Acanthamoeba ...
... lobose or fine pseudopodia during locomotion, such as Amoeba proteus, Acanthamoeba sp., Mayorella sp., Vexillifera sp., Thecamoeba ... related biological studies on the free-living soil amoeba, Hartmannel...
The first medical cure of a corneal infection due to an Acanthamoeba species is reported. The 44-year-old patient developed a suppurative keratitis associated with an epithelial defect, hypopyon, and secondary glaucoma. Acanthamoeba was confirmed as the causative agent four months after presentation when positive cultures were obtained ...
Acanthamoeba is a free-living ameba that is found throughout the world and that causes encephalitis, keratitis, and cutaneous infections in humans. It has two stages in its life cycle: a trophic stage and a resistant cyst stage. We describe here the ability of Acanthamoeba cysts to survive desiccation for more than 20 years.
Mice were intranasally immunized with living and killed Acanthamoeba as well as culture supernatant, living Toxoplasma and BCG, and challenged with pathogenic A. culbertsoni strain A-1. The best protection was achieved with killed amoebae of the same strain. A high rate of mortality was observed in immunized mice treated with immunosuppressives and challenged with A. ...
Parachlamydia acanthamoebae is an obligately intracellular bacterium that infects free-living amoebae and is a potential human pathogen in hospital-acquired pneumonia. We examined whether the presence of P. acanthamoebae is related to the presence of Acanthamoeba in an actual hospital environment and assessed the ...
Acanthamoeba keratitis (AK) is an opportunistic protozoan infection caused by the pathogenic Acanthamoeba and associated with soft contact lens wear. If untreated, it can cause serious visual disability. A 23 year-old female wearing soft contact lenses applied to the Department of Ophthalmology of the Aydin Adnan Menderes University ...
Pathogenic strains of Acanthamoeba are causative agents of a serious sight-threatening infection of the eye known as Acanthamoeba keratitis. The prevalence of this infection has risen in the past 20years, mainly due to the increase in number of contact lens wearers. Bioclen FR One Step (Ophtecs Corporation) is the ...
Monoclonal antibodies to Naegleria fowleri and Acanthamoeba polyphaga were analyzed by enzyme-linked immunosorbent assay, indirect immunofluorescence microscopy, and fluorescence flow cytometry to assess specificity and cross-reactivity with axenically cultured N. fowleri and Acanthamoeba spp. Four monoclonal antibodies to N. fowleri were specific for N. ...
... Stamm (1972) from a patient undergoing chemotherapy for Hodgkin's disease. Recognizing two disease entities, Martinez (1980) proposed the ... of the genus Hartmanella in a patient with Hodgkin's disease. ...
... liposomes containing supernatants from Con A�stimulated spleen cell cultures resulted in rapid resolution of the corneal infection. Approximately 80% of animals treated with PBS- ... ...
Acanthamoeba infection occurred in a 4-year-old military working dog (German shepherd). The disease was manifested by multifocal necrohemorrhagic foci in the heart, lungs, liver, and pancreas. Numerous organisms morphologically compatible with Acanthamoeb...
Acanthamoebae produce a painful, sight-threatening corneal infection. The adhesion of parasites to the host cells is a critical first step in the pathogenesis of infection. Subsequent to adhesion, the parasites produce a potent cytopathic effect (CPE) leading to target cell death. Recent studies showing that ...
Acanthamoeba spp., free-living amoebae inhabited in moist soil, pond, freshwater, sewage, atmosphere and swimming pool, may be causative protozoa of the fatal primary amoebic meningoencephalitis in experimental animals and humans. In this study, Acanthamoeba spp., including Acanthamoeba sp. YM-4 (isolated strain ...
Among the many genera of free-living amoebae that exist in nature, members of only four genera have an association with human disease: Acanthamoeba spp., Balamuthia mandrillaris, Naegleria fowleri and Sappinia diploidea. Acanthamoeba spp. and B. mandrillaris are opportunistic pathogens causing infections of the central nervous system, ...
In a previous study, we reported our discovery of Acanthamoeba contamination in domestic tap water; in that study, we determined that some Acanthamoeba strains harbor endosymbiotic bacteria, via our molecular characterization by mitochondrial DNA restriction fragment length polymorphism (Mt DNA RFLP). Five (29.4%) among 17 Acanthamoeba ...
Acute ocular infection due to free-living amoebae of the genus Acanthamoeba is characterized by severe pain, loss of corneal transparency and, eventually, blindness. Proteolytic enzymes secreted by trophozoites of virulent Acanthamoeba strains have an essential role in the mechanisms of pathogenesis, including adhesion, invasion and ...
BackgroundVibrio cholerae O1 and V. cholerae O139 infect humans, causing the diarrheal and waterborne disease cholera, which is a worldwide health problem. V. cholerae and the free-living amoebae Acanthamoeba species are present in aquatic environments, including drinking water and it has shown that Acanthamoebae support bacterial ...
Parachlamydia acanthamoebae, belonging to the order Chlamydiales, is an obligately intracellular bacterium that infects free-living amoebae and is a potential human pathogen. However, no method exists to accurately quantify viable bacterial numbers. We present a novel quantification method for P. acanthamoebae based on coculture with ...
Early identification of Acanthamoeba in cerebrospinal fluid is mandatory to prevent fatal granulomatous amebic encephalitis. In the case presented here amebic trophozoites were detected in a routine cerebrospinal fluid sample. The antibiotic treatment and the apparently low virulence of this isolate were responsible for the benign progression of the ...
The amoebicidal and amoebistatic action in vitro of 24 compounds was tested on two strains of Acanthamoeba, A. polyphaga and A. castellanii, isolated from eye infections in this country. For comparison, the Ryan strain of A. castellanii and Naegleria gruberi L-1 were also examined. Nine compounds showed sufficient activity to merit further consideration, ...
... 1645/GE-2289.1 Persistence of Infection by Metacercariae of Apophallus sp., Neascus sp., and Nanophyetus salmincola ... the typ...
Parachlamydiaceae are potential emerging pathogens that naturally infect free-living amoebae. We investigated the affects of incubation temperature on the growth and cytopathic effect of P. acanthamoeba in Acanthamoeba polyphaga. A. polyphaga were infected with P. acanthamoeba and incubated at ...
Strains of Acanthamoeba sp. constitute a factor contributing to the occurrence of chronic granulomatous amoebic encephalitis, keratitis, pneumonia, as well as inflammations of other organs. Treatment of these diseases is very difficult and not always effective. A majority of these infections have been fatal. The aim of our study was to ...
During the last year we came across three cases of Acanthamoeba keratitis. They were all contact lens wearers. The diagnosis of Acanthamoeba keratitis was established by the history, clinical picture and the culture of corneal and conjunctival swabs. The patients were treated with metronidazole (Flagyl) 0.5% eyedrops, propamidine isethionate (Brolene) 0.1% ...
Acanthamoeba keratitis is a painful corneal infection and difficult to treat because no sufficiently efficient drug has yet been available. The aim of the study therefore was to assess the therapeutic potential of miltefosine on Acanthamoeba keratitis-infected hamster eyes. The cornea of hamsters were ...
We examined partial 18S ribosomal DNA (Rns) sequences of Acanthamoeba isolates cultured in a study of microbial keratitis in Hong Kong. Sequence differences were sufficient to distinguish closely related strains and were used to examine links between strains obtained from corneal scrape specimens, contact lenses, lens cases, lens case solutions, and home water-supply faucets ...
The visual outcomes of Acanthamoeba keratitis, a rare cause of corneal infection, can be devastating. This paper reports two contact lens wearers with severe pain and photophobia who presented to the emergency room. Biomicroscopy revealed radial keratoneuritis in both individuals. Tissue culture on a nonnutrient agar plate with Escherichia coli overlay ...
Acanthamoeba species can cause serious, debilitating, and sometimes life-threatening infections. Three groups have been identified using morphological and immunological comparisons. Previous serological studies have utilized a variety of antigen preparations and assay methods and reported disparate (3 to 100%) results. This study was designed to (i) ...
Cysts were traced to the water bath where paraffin sections are floated. Few were found in the surface film, but large numbers settled on the bottom. Their presence is attributed to aerosol contamination. Water baths can be considered as a possible source...
Acanthamoeba griffini, n. sp. was collected from Long Island Sound near New London, Conn. Experimental cultivation studies on agar media supplemented with Aerobacter aerogenes showed that A. griffini grew and encysted on seawater agar media ranging up to ...
Acanthamoeba spp. are free-living amebae that inhabit a variety of air, soil, and water environments. However, these amebae can also act as opportunistic as well as nonopportunistic pathogens. They are the causative agents of granulomatous amebic encephalitis and amebic keratitis and have been associated with cutaneous lesions and sinusitis. Immuno compromised individuals, ...
Acanthamoeba keratitis is a potentially devastating infection of the cornea caused by the free-living amoebae, Acanthamoeba species. During the period from 1997 to 2000, a total of 136 corneal scrapings from clinically suspected cases were screened and examined for the presence of the Acanthamoeba. On examination ...
Acanthamoeba keratitis (AK) is a serious infection of the cornea. At present, diagnosis of the disease is not straightforward and treatment is very demanding. While contact lens wear is the leading risk factor for A K, Acanthamoeba parasites are increasingly recognized as an important cause of keratitis in non-contact lens wearers. The ...
Acanthamoeba keratitis (AK) is a serious infection of the cornea. At present, diagnosis of the disease is not straightforward and treatment is very demanding. While contact lens wear is the leading risk factor for AK, Acanthamoeba parasites are increasingly recognized as an important cause of keratitis in non-contact lens wearers. The ...
An unusual case of peritonitis in a 61-year-old patient is reported where culture for bacteria and fungi were negative. Acanthamoeba was isolated and the patient was treated with Ceftazidine, Cefazolin, Levofloxacin, Fluconazole and Rifampicin with regular haemodialytic support. The patient was completely cured of the infection and continuous ambulatory ...
Free-living amoebae (FLA) belonging to Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris, and Sappinia pedata are known to cause infections in humans and animals leading to severe brain pathologies. Worldwide, warm aquatic environments have been found to be suitable habitats for pathogenic FLA. The present study reports on screening for ...
A 25-year-old active duty Army E-5 developed severe infectious keratitis in his left eye secondary to soft contact lens (CL) wear while deployed in Iraq, necessitating evacuation to Walter Reed Army Medical Center for further evaluation and treatment. Initial clinical examination at Walter Reed Army Medical Center was suggestive of Acanthamoeba keratitis, a serious corneal ...
Eleven Acanthamoeba isolates, obtained from Acanthamoeba keratitis patients, from contact lens cases of non-Acanthamoeba keratitis patients, from asymptomatic individuals, from necrotic tissue, and from tap water and two reference strains were investigated by morphological, molecular biological, and physiological means in order to ...
Acinetobacter baumanii, which may be found in water, is an important emerging hospital-acquired pathogen. Free-living amoebae can be recovered from the same water networks, and it has been shown that these protozoa may support the growth of other bacteria. In this paper, we have studied potential relationships between A. baumanii and Acanthamoeba species. Two strains of A. ...
The pathogenesis and pathophysiology of Acanthamoeba infections remain incompletely understood. Phos-pholipases are known to cleave phospholipids, suggesting their possible involvement in the host cell plasma membrane disruption leading to host cell penetration and lysis. The aims of the present study were to determine phospholipase activities in ...
Buruli ulcer disease caused by Mycobacterium ulcerans results in extensive destruction of skin and soft tissue and long-term functional disabilities that ultimately require surgery and rehabilitation. The disease is associated with aquatic and swampy environments with the mycobacterium occurring in biofilms, soil, aquatic insects, fish and wildlife however, the mode of transmission to humans ...
... have been typed as T5, however, come from sites, such as sewage treatment plants, which would normally be thought of as potential ... ...
Acanthamoebae are ubiquitous free-living amoebae and important predators of microbial communities. They frequently contain obligate intracellular bacterial symbionts, which show a worldwide distribution. All Acanthamoeba spp. described so far harboured no or only a single specific endosymbiont phylotype, and in some cases evidence for coevolution between ...
Limited evidence exists to suggest that the ability to invade and escape protozoan host cell bactericidal activity extends to members of the Chlamydiaceae, intracellular pathogens of humans and animals and evolutionary descendants of amoeba-resisting Chlamydia-like organisms. PCR and microscopic analyses of Chlamydophila abortus infections of Acanthamoeba ...
This review focuses on free-living amoebae, widely distributed in soil and water, causing opportunistic and non-opportunistic infections in humans: Acanthamoeba spp., Balamuthia mandrillaris, Naegleria fowleri, and Sappinia diploidea. Diseases include primary amoebic meningoencephalitis (N. fowleri), granulomatous amoebic encephalitis, cutaneous and ...
PurposeTo determine the presence of four clinically relevant bacterial endosymbionts in Acanthamoeba isolates obtained from patients with Acanthamoeba keratitis (AK) and the possible contribution of endosymbionts to the pathogenesis of AK.DesignExperimental studyParticipantsAcanthamoeba isolates (N=37) recovered from cornea and contact ...
An outbreak of Acanthamoeba keratitis, a rare, potentially blinding, corneal infection, was detected in the United States in 2007; cases had been increasing since 2004. A case-control study was conducted to investigate the outbreak. We interviewed 105 case-patients from 30 states and 184 controls matched geographically and by contact lens use. Available ...
An outbreak of Acanthamoeba keratitis, a rare, potentially blinding, corneal infection, was detected in the United States in 2007; cases had been increasing since 2004. A case�control study was conducted to investigate the outbreak. We interviewed 105 case-patients from 30 states and 184 controls matched geographically and by contact lens use. Available ...
Acanthamoeba spp. consists of free-living amoebae, widespread in nature, which occasionally can cause human infections including granulomatous amoebic encephalitis and amoebic keratitis. Acanthamoeba pathogenesis is not entirely known and correlations between pathogenic potential and taxonomy are complex issues. In order to decipher ...
To determine the pathogenicity of Acanthamoeba spp. isolated in Korea and to develop a isoenzymatic maker, the mortality rate of infected mice, in vitro cytotoxicity against target cells and isoenzyme band patterns were observed. Five isolates of Acanthamoeba spp. (YM-2, YM-3, YM-4, YM-5, and YM-7) were used in this study as well as ...
BackgroundMany aspects of Acanthamoeba granulomatous encephalitis remain poorly understood, including host susceptibility and chronic colonization which represent important features of the spectrum of host-pathogen interactions. Previous studies have suggested locusts as a tractable model in which to study Acanthamoeba pathogenesis. Here we determined the ...
The anticancer agent miltefosine and the antifungal drug voriconazole were tested in vitro against Balamuthia mandrillaris, Acanthamoeba spp., and Naegleria fowleri. All three amebas are etiologic agents of chronic (Balamuthia, Acanthamoeba) or fulminant (Naegleria) encephalitides in humans and animals and, in the case of Acanthamoeba, ...
Portable and stationary eye wash stations were tested for the presence of free-living amoebae. Such amoebae may be found in potable waters, and at least one genera, the Acanthamoebae, can cause severe infections when introduced into traumatized eyes. Concentrates or filtrates of water from eye wash stations were placed on nonnutrient agar plates seeded ...
Energy Citations Database
Recent reports indicate a higher frequency of brain infections with opportunistic amebae of the genus Acanthamoeba among immune compromised individuals, including AIDS patients. We have demonstrated, using a murine model of Granulomatous Amebic Encephalitis (GAE), that the major psychoactive and immune suppressive component in marijuana ...
