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Pathogens and Global Health Mar 2022Pathogenic free-living amoebae affecting the central nervous system are known to cause granulomatous amoebic encephalitis (GAE) or primary amoebic meningoencephalitis...
Pathogenic free-living amoebae affecting the central nervous system are known to cause granulomatous amoebic encephalitis (GAE) or primary amoebic meningoencephalitis (PAM). Although hosts with impaired immunity are generally at a higher risk of severe disease, amoebae such as and can instigate disease in otherwise immunocompetent individuals, whereas species mostly infect immunocompromised people. also cause a sight-threatening eye infection, mostly in contact lens wearers. Although infections due to pathogenic amoebae are considered rare, recently, these deadly amoebae were detected in water supplies in the USA. This is of particular concern, especially with global warming further exacerbating the problem. Herein, we describe the epidemiology, presentation, diagnosis, and management of free-living amoeba infections.
Topics: Acanthamoeba; Amebiasis; Amoeba; Balamuthia mandrillaris; Humans; Naegleria fowleri
PubMed: 34602025
DOI: 10.1080/20477724.2021.1985892 -
Journal of Clinical Microbiology Jan 2022Infections caused by Naegleria fowleri, Acanthamoeba spp., and Balamuthia mandrillaris result in a variety of clinical manifestations in humans. These amoebae are found...
Infections caused by Naegleria fowleri, Acanthamoeba spp., and Balamuthia mandrillaris result in a variety of clinical manifestations in humans. These amoebae are found in water and soil worldwide. spp. and B. mandrillaris cause granulomatous amoebic encephalitis (GAE), which usually presents as a mass, while N. fowleri causes primary amoebic meningoencephalitis (PAM). spp. can also cause keratitis, and both spp. and can cause lesions in skin and respiratory mucosa. These amoebae can be difficult to diagnose clinically as these infections are rare and, if not suspected, can be misdiagnosed with other more common diseases. Microscopy continues to be the key first step in diagnosis, but the amoeba can be confused with macrophages or other infectious agents if an expert in infectious disease pathology or clinical microbiology is not consulted. Although molecular methods can be helpful in establishing the diagnosis, these are only available in referral centers. Treatment requires combination of antibiotics and antifungals and, even with prompt diagnosis and treatment, the mortality for neurological disease is extremely high.
Topics: Acanthamoeba; Amebiasis; Amoeba; Balamuthia mandrillaris; Humans; Naegleria fowleri
PubMed: 34133896
DOI: 10.1128/JCM.00228-21 -
Annals of Agricultural and... May 2017[b]Abstract Introduction[/b]. Among free-living amoebae that are widely distributed in nature only four genera/species are known as agents of human infections:[i]... (Review)
Review
[b]Abstract Introduction[/b]. Among free-living amoebae that are widely distributed in nature only four genera/species are known as agents of human infections:[i] Acanthamoeba spp., Naegleriafowleri, Balamuthia mandrillaris[/i] and[i] Sappiniapedata[/i]. These amoebae are not well adapted to parasitism, and could exist in the human environment without the need for a host. Infections due to these amoebae, despite low morbidity, are characterized by relatively high mortality rate and pose serious clinical problems. [b]Objectve[/b]. This review study presents and summarizes current knowledge about infections due to pathogenic and opportunistic free-living amoebae focused on epidemiology, clinical manifestations, diagnosis and treatment based on global literature. [b]State of knowledge[/b]. All four genera have been recognized as etiologic factors of fatal central nervous system infections and other serious diseases in humans. [i]N. fowleri[/i] causes an acute fulminating meningoencephalitis in children and young adults. [i]Acanthamoeba spp[/i]. and [i]B.mandrillaris[/i] are opportunistic pathogens causing granulomatous amoebic encephalitis and disseminated or localized infections which could affect the skin, sinuses, lungs, adrenals and/or bones. [i]Acanthamoeba spp[/i]. is also the main agent of acute eye infection -[i] Acanthamoeba keratitis, [/i]mostly in contact lens wearers. However, there is only one recognized case of encephalitis caused by [i]S. pedata. [/i] [b]Conclusions[/b]. Amoebic diseases are difficult to diagnose which leads to delayed treatment, and result in a high mortality rate. Considering those issues, there is an urgent need to draw more attention to this type of diseases.
Topics: Amebiasis; Amoeba; Animals; Humans
PubMed: 28664704
DOI: 10.5604/12321966.1233568 -
JMM Case Reports Jun 2016This case report describes a human survivor of infection. This is a free-living amoeba that can cause infection with the devastating consequence of near universally...
INTRODUCTION
This case report describes a human survivor of infection. This is a free-living amoeba that can cause infection with the devastating consequence of near universally fatal encephalitis. We report this case to demonstrate the possibility of recovery.
CASE PRESENTATION
A 26-year-old Hispanic male, a landscape gardener, presented to the hospital in March 2010 with a two month history of headache, visual disturbances and new-onset seizures. Brain imaging identified two enhancing central lesions and was later identified by brain biopsy. He received several months of various antimicrobials including miltefosine, a novel use of the drug in this disease at the time. Seven weeks into therapy, considerations were made to switch him to 'comfort care' because of worsening clinical status and seemingly lack of response to treatment. The patient finally demonstrated clinical and radiological improvement after eight weeks with modified therapy, despite experiencing some debilitating toxic effects likely to be related to antibiotics. Two years after his initial presentation he made a complete recovery.
CONCLUSION
amoebic encephalitis is considered an almost universally fatal disease; this case demonstrates the possibility of recovery. This report outlines his treatment, drug toxicities and includes additional information regarding the therapeutic use of the drug miltefosine. Whether his survival is related to the specific antimicrobials used in this case is unknown and further investigation is warranted.
PubMed: 28348755
DOI: 10.1099/jmmcr.0.005031 -
JAAD International Mar 2022Balamuthia mandrillaris, a free-living amoeba, causes an uncommon infection that is characterized by cutaneous and neurological involvement, which carries a poor...
INTRODUCTION
Balamuthia mandrillaris, a free-living amoeba, causes an uncommon infection that is characterized by cutaneous and neurological involvement, which carries a poor prognosis.
METHODS
This is a retrospective observational study including patients with clinical suspicion of cutaneous balamuthiasis, their skin biopsies, and/or a positive direct immunofluorescence test. The data were collected from the Dermatology and Pathology service of the Hospital Cayetano Heredia and the Instituto Tropical Alexander von Humboldt, Lima, Peru, from January 1985 to June 2007. We identified 60 biopsies from 35 patients, from which clinical data were available in 30.
RESULTS
Twenty-two (73%) patients had centrofacial lesions, mostly located on the nose. The classical lesion was an asymptomatic, erythematous, or violaceous infiltrated plaque. Twenty-two (73%) patients had neurologic involvement. Fifty (83%) biopsies showed granulomatous dermatitis and 75% showed ill-defined tuberculoid granulomas without caseous necrosis. Multinucleated giant cells were observed in 52 (87%) biopsies. Trophozoite forms were identified in the biopsies of 25 (71%) patients. Direct immunofluorescence was positive in 25 (71%) patients.
CONCLUSION
is a pathogen that is capable of inducing a characteristic skin lesion with a reaction pattern of ill-defined tuberculoid granulomas and many giant cells.
PubMed: 35059659
DOI: 10.1016/j.jdin.2021.11.005 -
Antibiotics (Basel, Switzerland) Sep 2022and are opportunistic protists, responsible for fatal central nervous system infections such as primary amoebic meningoencephalitis (PAM) and granulomatous amoebic...
and are opportunistic protists, responsible for fatal central nervous system infections such as primary amoebic meningoencephalitis (PAM) and granulomatous amoebic encephalitis (GAE) with mortality rates higher than 90%. Threatening a rise in cases is the increase in temperature due to global warming. No effective treatment is currently available. Herein, nanotechnology was used to conjugate Zinc oxide with Ampicillin, Ceftrixon, Naringin, Amphotericin B, and Quericitin, and the amoebicidal activity and host cell cytotoxicity of these resulting compounds were investigated. The compounds ZnO-CD-AMPi, ZnO-CD-CFT, ZnO-CD-Nar, ZnO-CD-AMB, and ZnO-CD-QT were found to reduce viability to 35.5%, 39.6%, 52.0%, 50.8%, 35.9%, and 69.9%, respectively, and viability to 40.9%, 48.2%, 51.6%, 43.8%, and 62.4%, respectively, when compared with their corresponding controls. Furthermore, the compounds reduced -mediated and -mediated host cell death significantly. Additionally, the compounds showed limited cytotoxicity against human cells; cell toxicity was 35.5%, 36.4%, 30.9%, 36.6%, and 35.6%, respectively, for the compounds ZnO-CD-AMPi, ZnO-CD-CFT, ZnO-CD-Nar, ZnO-CD-AMB, and ZnO-CD-QT. Furthermore, the minimum inhibitory concentrations to inhibit amoeba growth by 50% were determined for and The MIC for were determined to be 69.52 µg/mL, 82.05 µg/mL, 88.16 µg/mL, 95.61 µg/mL, and 85.69 µg/mL, respectively; the MIC of the compounds for were determined to be 113.9 µg/mL, 102.3 µg/mL, 106.9 µg/mL, 146.4 µg/mL, and 129.6 µg/mL, respectively. Translational research to further develop therapies based on these compounds is urgently warranted, given the lack of effective therapies currently available against these devastating infections.
PubMed: 36289939
DOI: 10.3390/antibiotics11101281 -
ACS Chemical Neuroscience Apr 2017Brain infections due to Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri often lead to death. Despite differences in the preferential sites of infection...
Brain infections due to Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri often lead to death. Despite differences in the preferential sites of infection in the brain, the mode of delivery of drugs is often intravenous. Here, we discuss targeted therapeutic approach to affect parasite viability without affecting the host cells, with an eye to improve formulation of drugs and/or administration of drugs against brain-eating amoebae.
Topics: Antiprotozoal Agents; Central Nervous System Protozoal Infections; Humans
PubMed: 28225265
DOI: 10.1021/acschemneuro.7b00049 -
Tropical Parasitology 2021is an opportunistic, free-living ameba that is pathogenic to humans. It has a worldwide distribution but is mainly detected in warmer regions. infections are rare but... (Review)
Review
is an opportunistic, free-living ameba that is pathogenic to humans. It has a worldwide distribution but is mainly detected in warmer regions. infections are rare but have been reported in both immunocompetent and immunocompromised individuals of all ages. can enter through wounds on the skin or the nose and cause cutaneous lesions and the usually fatal amebic encephalitis (BAE). Infection usually spreads from the lungs or through nerve fibers, and attacks the central nervous system, forming granulomatous lesions and necrosis in the brain. infection is usually chronic, and patients initially present with nonspecific symptoms, including headache, nausea, myalgia, and low-grade fever. As the disease progresses, the patient becomes paralyzed and comatose, often leading to death. Lack of knowledge of predisposing factors, specific treatment, and standardized detection tools have resulted in a nearly cent percent fatality rate. Although only about 200 cases have been reported worldwide since its characterization in the 1990s, the number of reported cases has increased over the years. BAE is an emerging disease and a major health concern. Few patients have survived infections with antimicrobial treatment that has largely been empirical. Early diagnosis is the key and requires familiarity with the disease and a high degree of suspicion on the part of the diagnostician. There are currently no specific treatment and prevention recommendations. This review highlights our current understanding of in terms of its pathogenicity, genomics, and novel diagnostic and therapeutic approaches against BAE infections.
PubMed: 34765527
DOI: 10.4103/tp.tp_36_21 -
Frontiers in Neurology 2023Free-living amoebae (FLA) including spp., and can become pathogenic and cause severe cerebral infections, named primary amoebic meningoencephalitis (PAM),... (Review)
Review
BACKGROUND
Free-living amoebae (FLA) including spp., and can become pathogenic and cause severe cerebral infections, named primary amoebic meningoencephalitis (PAM), granulomatous amoebic encephalitis (GAE), and balamuthia amoebic encephalitis (BAE), respectively. FLA encephalitis has been reported across China, but the clinical data descriptions and analytical results of these different reports vary widely. Currently, no consensus treatment has been established. We conduct a systematic review to evaluate the exposure location, clinical symptoms, diagnosis, treatment, and prognosis of three FLA encephalitis and aim to reveal the differences between three FLA encephalitis in China.
METHODS
We used MEDLINE (PubMed interface), EMBASE, China National Knowledge Infrastructure (CNKI), Wanfang database, and China Biology Medicine disc (CBMdisc) databases for literatures published and manually retrieve the hospital records of our hospital. The search time was up to August 30, 2022, with no language restrictions.
RESULTS
After excluding possible duplicate cases, a total of 48 patients of three FLA encephalitis were collected. One from the medical records of our hospital and 47 patients from 31 different studies. There were 11 patients of PAM, 10 patients of GAE, and 27 patients of BAE. The onset of PAM is mostly acute or subacute, and the clinical symptoms are acute and fulminant hemorrhagic meningoencephalitis. Most patients with GAE and BAE have an insidious onset and a chronic course. A total of 21 BAE patients (77.8%) had skin lesions before onset of symptoms. Additionally, 37 cases (77.1%) were diagnosed with FLA encephalitis before death. And there were 4 of PAM, 2 of GAE, and 10 of BAE diagnosed using next generation sequencing. No single agent can be proposed as the ideal therapy by itself. Only 6 cases were successfully treated.
CONCLUSIONS
This review provides an overview of the available data and studies of FLA encephalitis in China and identify some potential differences. FLA encephalitis is a rare but pathogenic infection, and physicians should early identify this encephalitis to improve survival.
PubMed: 36846140
DOI: 10.3389/fneur.2023.1100785