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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 -
The Lancet. Infectious Diseases Mar 2022Cutaneous infection by Balamuthia mandrillaris is a rare condition that is sometimes complicated by life-threatening CNS involvement. It often evades timely diagnosis... (Review)
Review
Cutaneous infection by Balamuthia mandrillaris is a rare condition that is sometimes complicated by life-threatening CNS involvement. It often evades timely diagnosis due to its rarity and non-specific clinical manifestations. Patients can be either immunocompetent or immunocompromised. It is probably transmitted via inhalation or inoculation through broken skin, and then spreads to the brain and other organs through haematogenous spread. It is important for clinicians to be aware of this disease because rapid diagnosis and subsequent therapy has, in some cases, been associated with survival. In this Grand Round, we report the case of a 7-year-old boy who presented with large, chronic plaques on his face. Several biopsies showed non-specific granulomatous inflammation. The patient deteriorated rapidly and died within 1 month of displaying abnormal symptoms in the CNS. Immunohistochemical staining of skin tissue identified B mandrillaris as the infectious agent. The diagnosis was confirmed with PCR, which detected B mandrillaris DNA in formalin-fixed skin tissue sections. B mandrillaris infection should be considered in the differential diagnosis of patients with chronic granulomatous lesions. We also reviewed the epidemiology, B mandrillaris in nature and in the laboratory, clinical manifestations, histopathology, diagnosis, and treatment of infection.
Topics: Amebiasis; Balamuthia mandrillaris; Brain; Child; Face; Granuloma; Humans; Male
PubMed: 34838200
DOI: 10.1016/S1473-3099(21)00334-0 -
FEMS Immunology and Medical Microbiology Jun 2007Among 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... (Review)
Review
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, lungs, sinuses and skin, mostly in immunocompromised humans. Balamuthia is also associated with disease in immunocompetent children, and Acanthamoeba spp. cause a sight-threatening infection, Acanthamoeba keratitis, mostly in contact-lens wearers. Of more than 30 species of Naegleria, only one species, N. fowleri, causes an acute and fulminating meningoencephalitis in immunocompetent children and young adults. In addition to human infections, Acanthamoeba, Balamuthia and Naegleria can cause central nervous system infections in animals. Because only one human case of encephalitis caused by Sappinia diploidea is known, generalizations about the organism as an agent of disease are premature. In this review we summarize what is known of these free-living amoebae, focusing on their biology, ecology, types of disease and diagnostic methods. We also discuss the clinical profiles, mechanisms of pathogenesis, pathophysiology, immunology, antimicrobial sensitivity and molecular characteristics of these amoebae.
Topics: Acanthamoeba; Amebiasis; Amoeba; Animals; Humans; Naegleria fowleri
PubMed: 17428307
DOI: 10.1111/j.1574-695X.2007.00232.x -
Diagnostic Microbiology and Infectious... Aug 2021Balamuthia mandrillaris encephalitis is a rare disease with high mortality in the children. Due to the lack of specificity in clinical manifestations, laboratory tests,... (Review)
Review
Balamuthia mandrillaris encephalitis is a rare disease with high mortality in the children. Due to the lack of specificity in clinical manifestations, laboratory tests, and neuroimaging, the diagnosis of the disease is difficult, especially the diagnosis of etiology. Currently, the evidence shows that the diagnosis of the disease depends on local brain biopsy or autopsy, and it is difficult to detect the pathogens by traditional etiological detection methods in blood and cerebrospinal fluid. We report a 9-year-old Chinese girl with B. mandrillaris encephalitis who was diagnosed with metagenomic next-generation sequencing (mNGS). The technology of mNGS can provide rapid, early etiological diagnosis without the need for a local brain biopsy, which can buy time for the early treatment of patients. We also provide a comprehensive literature review on this disease.
Topics: Amebiasis; Balamuthia mandrillaris; Brain; Central Nervous System Protozoal Infections; Child; Encephalitis; Fatal Outcome; Female; High-Throughput Nucleotide Sequencing; Humans; Magnetic Resonance Imaging; Metagenomics
PubMed: 33887622
DOI: 10.1016/j.diagmicrobio.2020.115180 -
Journal of Medical Microbiology Mar 2001
Topics: Amebiasis; Amoeba; Animals; Humans; Meningoencephalitis; Prognosis
PubMed: 11232763
DOI: 10.1099/0022-1317-50-3-205 -
Parasites & Vectors Jun 2022Environmental protozoa need an adaptation mechanism to survive drastic changes in niches in the human body. In the brain parenchyma, Balamuthia mandrillaris...
BACKGROUND
Environmental protozoa need an adaptation mechanism to survive drastic changes in niches in the human body. In the brain parenchyma, Balamuthia mandrillaris trophozoites, which are causative agents of fatal brain damage, must acquire nutrients through the ingestion of surrounding cells. However, the mechanism deployed by the trophozoites for cellular uptake remains unknown.
METHODS
Amoebic ingestion of human neural cell components was investigated using a coculture system of clinically isolated B. mandrillaris trophozoites and human neuroblastoma SH-SY5Y cells. Cell-to-cell interactions were visualized in a three-dimensional manner using confocal and holotomographic microscopes.
RESULTS
The B. mandrillaris trophozoites first attached themselves to human neuroblastoma SH-SY5Y cells and then twisted themselves around the cytoplasmic bridge. Based on fluorescence-based cell tracking, the B. mandrillaris trophozoites then inserted invadopodia into the cytoplasm of the human cells. Subsequently, the human protein-enriched components were internalized into the trophozoites in the form of nonmembranous granules, whereas the human lipids were dispersed in the cytoplasm. Intervention of trogocytosis, a process involving nibbling on parts of the target cells, failed to inhibit this cellular uptake.
CONCLUSIONS
Human cell ingestion by B. mandrillaris trophozoites likely differs from trogocytosis, suggesting that a pathogen-specific strategy can be used to ameliorate brain damage.
Topics: Amebiasis; Animals; Balamuthia mandrillaris; Brain; Humans; Neuroblastoma; Trogocytosis; Trophozoites
PubMed: 35761411
DOI: 10.1186/s13071-022-05306-7 -
Trends in Parasitology Oct 2013Balamuthia mandrillaris is an opportunistic, free-living amoeba that can cause skin lesions and the typically fatal Balamuthia amoebic encephalitis (BAE) both in... (Review)
Review
Balamuthia mandrillaris is an opportunistic, free-living amoeba that can cause skin lesions and the typically fatal Balamuthia amoebic encephalitis (BAE) both in immunocompromised and immunocompetent individuals. Available data for BAE cases indicate that this disease is difficult to detect because knowledge of predisposing factors is lacking, causing a challenge for diagnosing BAE. The number of reported BAE cases is increasing worldwide, and this is a major concern because little is known about the pathogen, no standardized detection tools are available, and most of the treatments are almost empirical. The recently reported cases, novel diagnostics tools, and successful therapeutic approaches against BAE infections are reviewed here.
Topics: Amebiasis; Amoebozoa; Animals; Communicable Diseases, Emerging; Encephalitis; Life Cycle Stages; Public Health
PubMed: 23988231
DOI: 10.1016/j.pt.2013.07.009 -
Laboratory Medicine Mar 2020Encephalitis is caused by infection, immune mediated diseases, or primary inflammatory diseases. Of all the causative infectious pathogens, 90% are viruses or bacteria.... (Review)
Review
BACKGROUND
Encephalitis is caused by infection, immune mediated diseases, or primary inflammatory diseases. Of all the causative infectious pathogens, 90% are viruses or bacteria. Granulomatous amoebic encephalitis (GAE), caused by Balamuthia mandrillaris, is a rare but life-threatening disease. Diagnosis and therapy are frequently delayed due to the lack of specific clinical manifestations.
METHOD
A healthy 2 year old Chinese male patient initially presented with a nearly 2 month history of irregular fever. We present this case of granulomatous amoebic encephalitis caused by B. mandrillaris. Next generation sequencing of the patient's cerebrospinal fluid (CSF) was performed to identify an infectious agent.
RESULT
The results of next generation sequencing of the CSF showed that most of the mapped reads belonged to Balamuthia mandrillaris.
CONCLUSION
Next generation sequencing (NGS) is an unbiased and rapid diagnostic tool. The NGS method can be used for the rapid identification of causative pathogens. The NGS method should be widely applied in clinical practice and help clinicians provide direction for the diagnosis of diseases, especially for rare and difficult cases.
Topics: Amebiasis; Balamuthia mandrillaris; Central Nervous System Protozoal Infections; Cerebrospinal Fluid; Child, Preschool; China; High-Throughput Nucleotide Sequencing; Humans; Infectious Encephalitis; Male; Molecular Diagnostic Techniques
PubMed: 31711180
DOI: 10.1093/labmed/lmz079 -
Case Reports in Infectious Diseases 2019is a rare cause of granulomatous meningoencephalitis associated with high mortality. We report a 69-year-old Caucasian female who presented with a 3-day history of...
is a rare cause of granulomatous meningoencephalitis associated with high mortality. We report a 69-year-old Caucasian female who presented with a 3-day history of worsening confusion and difficulty with speech. On admission, she was disoriented and had expressive dysphasia. Motor examination revealed a right arm pronator drift. Cerebellar examination showed slowing of finger-nose testing on the left. She was HIV-negative, but the absolute CD4 count was low. Neuroimaging showed three cavitary, peripherally enhancing brain lesions, involving the right frontal lobe, the left basal ganglia, and the left cerebellar hemisphere. She underwent right frontal craniotomy with removal of tan, creamy, partially liquefied necrotic material from the brain, consistent with granulomatous amoebic encephalitis on tissue staining. Immunohistochemical studies and PCR tests confirmed infection with . She was started on pentamidine, sulfadiazine, azithromycin, fluconazole, flucytosine, and miltefosine. The postoperative course was complicated by an ischemic stroke, and she died a few weeks later.
PubMed: 30838148
DOI: 10.1155/2019/9315756 -
The Journal of International Medical... May 2022is a free-living heterotrophic amoeba found in soil that causes a rare and usually fatal granulomatous amebic encephalitis. We report an immunocompetent patient...
is a free-living heterotrophic amoeba found in soil that causes a rare and usually fatal granulomatous amebic encephalitis. We report an immunocompetent patient infected with encephalitis diagnosed by next-generation sequencing (NGS). Clinical manifestations included sudden headache and epilepsy with disturbance of consciousness. The opening pressure of cerebrospinal fluid (CSF) was 220 mmHO, with mildly elevated white blood cell numbers and elevated protein levels. Cranial magnetic resonance imaging revealed abnormal signals in the right frontal lobe, left parietal lobe, and left occipital lobe. CSF NGS detected . Albendazole and metronidazole combined with fluconazole were administered to the patient immediately, but his condition deteriorated and he eventually died. Encephalitis caused by is rare and has a high mortality rate. Clinical manifestations are complex and diverse, but early diagnosis is very important for successful treatment. This can be aided by the metagenomic NGS of CSF.
Topics: Amebiasis; Balamuthia mandrillaris; Encephalitis; High-Throughput Nucleotide Sequencing; Humans; Magnetic Resonance Imaging; Male
PubMed: 35505464
DOI: 10.1177/03000605221093217