AIM:To investigate the demographics,risk factors,clinical presentation,treatments and outcomes of Acanthamoeba keratitis(AK)in a tertiary referral hospital in central China.METHODS:In this noncomparative,retrospective...AIM:To investigate the demographics,risk factors,clinical presentation,treatments and outcomes of Acanthamoeba keratitis(AK)in a tertiary referral hospital in central China.METHODS:In this noncomparative,retrospective study,a total of 21 AK patients were enrolled between April 2020 and March 2023.All patients underwent anterior segment photography,in vivo confocal microscopy(IVCM),bestcorrected visual acuity(BCVA)and anterior segment optical coherence tomography(AS-OCT).RESULTS:The most common potential predisposing factors were contact lens wearing(71.4%),mostly were students,and organic trauma(23.8%),mainly by outdoor workers.And 80.9%of patients were initially misdiagnosed with herpes keratitis.The clinical features were radial keratoneuritis 42.8%(n=9),crude salt-like granular dense infiltration 28.6%(n=6),and corneal ring infiltration 28.6%(n=6).Fifteen patients were completely cured by medical therapy,and six patients with corneal ring infiltration feature were performed conjunctival flap covering surgery(CFCS),three of them later underwent secondary deep anterior lamellar keratoplasty(DALK).All patients completed their follow-up at the Union Hospital,with a total of 20 patients(95.2%)had improved visual acuity after treatment,1 had no change.Corneal scarring and vascularization were the two most common complications of AK in this study,with incidence rates of 85.7%and 28.6%,respectively.CONCLUSION:In central China,AK occurs predominantly in contact lens wearers,mainly in students with myopia prevention and control.The radial keratoneuritis with crude salt-like granular dense infiltration can generally be effectively managed with medications.In contrast,corneal ring infiltration necessitates immediate surgical intervention.The CFCS combined with secondary DALK is effective for patients with high-risk AK in this condition.展开更多
<i>Acanthamoeba</i> is free living amoeba consisting of many species that are naturally pathogenic and have been isolated from different environmental sources. The purpose of this study was to determine th...<i>Acanthamoeba</i> is free living amoeba consisting of many species that are naturally pathogenic and have been isolated from different environmental sources. The purpose of this study was to determine the prevalence and relative abundance of <i>Acanthamoeba species</i> in soil and water samples within the University of Jos environment and to create public health awareness on the dangers of this parasitic protozoan. The study was conducted in the eleven (11) Faculties of the University of Jos. Soil and water samples were collected from each of the faculties, cultured and morphologically identified for positive samples. In addition, quantitative data on occurrence were examined to help better understand the potential risk to the university community. The prevalence of <i>Acanthamoeba</i> based on the chi-square analysis indicates that there is a significant difference between the number of <i>Acanthamoeba</i> species in the soil and water samples collected (P < 0.05). Relative abundance of <i>Acanthamoeba</i> based on the Man-Whitney test indicates that there was no significant difference in the distribution of <i>Acanthamoeba</i> species in the water and soil samples between different faculties (P > 0.05). Morphological identification indicates the presence of probably <i>Acanthamoeba castellani</i>. The demonstration of the presence of <i>Acanthamoeba</i> species in soil and water sources calls for awareness among the clinical community, as cases of keratitis and granulomatous amoebic encephalitis might have never been recorded due to lack of expertise or unawareness amongst the clinical community. An improved treatment of water supply and strict adherence to water act needs to be strictly encouraged.展开更多
Rationale: Microbial keratitis caused by coinfection with more than one species of pathogens is a severe condition with an unfavorable prognosis. Patient concerns: An immunocompetent Nepali woman complained of pain in...Rationale: Microbial keratitis caused by coinfection with more than one species of pathogens is a severe condition with an unfavorable prognosis. Patient concerns: An immunocompetent Nepali woman complained of pain in the left eye, redness, watering and decreased vision for 5 months. Interventions: The patient was discarded and accurately diagnosed with coinfection with Fusarium sp. and Acanthamoeba sp. The habit of washing the eyes with tap water from a domestic storage tank was the most likely source of infection since it was found to be contaminated with cysts of Acanthamoeba sp. The woman received eye drops of fluconazole and natamycin(5%), cefazoline(50 mg/m L), atropine, and tablets of itraconazole(100 mg), which were later switched to eye drops of clotrimazole(1%), natamycin(5%) and voriconazole(1%), and tablets of itraconazole. A full thickness penetrating keratoplasty was performed followed by treatment with eye drops of voriconazole(1%), natamet(5%), ofloxacin, atropine and carboxymethylcellulose for one week.Outcomes: After treatment, the condition of the patient significantly improved and was discharged one week after keratoplasty. Lessons: This is the first report of Acanthamoeba keratitis in Nepal and the first report of coinfection with Fusarium in this country and highlights the importance of early diagnosis of microbial keratitis both in single microorganism infections and coinfections, even in no contact lens wearers.展开更多
Objective:To identify the prevalence of Acanthamoeba in drinking water treatment plants during the course of the purification processes.Methods:Samples were taken from two drinking water purification plants and monito...Objective:To identify the prevalence of Acanthamoeba in drinking water treatment plants during the course of the purification processes.Methods:Samples were taken from two drinking water purification plants and monitored for the presence of Acanthamoeba in order to estimate the removal capacity of treatment methods employed. Water samples were collected at each step in the purification,during the one year survey,and analysed for the presence of Acanthamoeba spp.by plating on bacterial-seeded plates.Results:The results showed that amoebae were present in surface raw waters in 100%of the samples tested.Acanthamoeba spp.were isolated from 71%and 57%of the water samples collected from post flat-bottom clarifier 1 and post-sedimentation plant respectively.Considering the outflow drinking waters,the removal capacity was 100%in both purification plants monitored.The occurrence of Acanthamoeba was not associated with seasonality.Conclusion: These findings confirm that water purification plants employing methods of flocculation,sedimentation,and filtration in combination with activated charcoal filtration,ozonisation and chlorination exhibited sufficient Acanthamoeba removal capacity and the presence of amoebae in the tap water may be due to older plumbing,water storage tanks,tap water hygiene,and/or environmental settings.展开更多
We analysed histologically two Acanthamoeba keratitis(AK) eyes with anterior and posterior segment inflammation and blindness. Two enucleated eyes of 2 patients(age 45 and 51y) with AK(PCR of epithelial abrasion posit...We analysed histologically two Acanthamoeba keratitis(AK) eyes with anterior and posterior segment inflammation and blindness. Two enucleated eyes of 2 patients(age 45 and 51y) with AK(PCR of epithelial abrasion positive) were analysed. Histological analysis was performed using hematoxylin-eosin, periodic acid-Schiff and G?m?rimethenamine silver staining. We could not observe Acanthamoeba trophozoites or cysts neither in the cornea nor in other ocular tissues. Meanwhile, we found uveitis, retinal vasculitis and scleritis in these eyes, due to the long-standing, recalcitrant AK. So in this stage of AK, systemic immune suppression may be necessary for a longer time period.展开更多
This study is to investigate the characteristic features of Acanthamoeba keratitis（AK） that differentiating it from herpetic epithelial keratitis（HEK） using anterior segment optical coherence tomography（AS-OCT）....This study is to investigate the characteristic features of Acanthamoeba keratitis（AK） that differentiating it from herpetic epithelial keratitis（HEK） using anterior segment optical coherence tomography（AS-OCT）. Medical records of three eyes of each AK and herpetic keratitis who had AS-OCT examination were reviewed in this study. Slitlamp biomicroscopy and AS-OCT was performed on the initial visit and on every follow-up visits in all patients. In all three AK cases, reflective bands in the corneal stroma that correspond to the area of radial keratoneuritis were observed. The depth of the reflective bands varied in each case. After AK treatment, slit-lamp biomicroscopy confirmed that radial keratoneuritis had resolved and AS-OCT confirmed that reflective bands in the corneal stroma had also disappeared in all patients. Unlike the AS-OCT results found in AK, highly reflective HEK lesions were observed only in the subepithelial area, not in the stroma. AS-OCT seems to be helpful analyzing the specific depth of the lesion which enables to distinguish AK from HEK.展开更多
Objective: To verify phylogeography and genetic structure of Acanthamoeba populations among the Iranian clinical isolates and natural/artificial environments distributed in various regions of the country.Methods: We s...Objective: To verify phylogeography and genetic structure of Acanthamoeba populations among the Iranian clinical isolates and natural/artificial environments distributed in various regions of the country.Methods: We searched electronic databases including Medline, Pub Med, Science Direct, Scopus and Google Scholar from 2005 to 2016. To explore the genetic variability of Acanthamoeba sp, 205 sequences were retrieved from keratitis patients, immunosuppressed cases and environmental sources as of various geographies of Iran.Results: T4 genotype was the predominant strain in Iran, and the rare genotypes belonged to T2, T3, T5(Acanthamoeba lenticulata), T6, T9, T11, T13 and T15(Acanthamoeba jacobsi).A total of 47 unique haplotypes of T4 were identified. A parsimonious network of the sequence haplotypes demonstrated star-like feature containing haplogroups IR6(34.1%) and IR7(31.2%) as the most common haplotypes. In accordance with the analysis of molecular variance, the high value of haplotype diversity(0.612–0.848) of Acanthamoeba T4 represented genetic variability within populations. Neutrality indices of the 18 S ribosomal RNA demonstrated negative values in all populations which represented a considerable divergence from neutrality. The majority of genetic diversity belonged to the infected contact lens and dust samples in immunodeficiency and ophthalmology wards, which indicated potential routes for exposure to a pathogenic Acanthamoeba sp. in at-risk individuals. A pairwise fixation index(FST) was from low to high values(0.024 33–0.418 92). The statistically FST points out that T4 is genetically differentiated between north-west, north-south and centralsouth metapopulations, but not differentiated between west-central, west-south, centralsouth, and north-central isolates.Conclusions: An occurrence of IR6 and IR7 displays that possibly a gene flow of Acanthamoeba T4 occurred after the founder effect or bottleneck experience through ecological changes or host mobility. This is the first systematic review and meta-analysis providing new approaches into gene migration and transmission patterns of Acanthamoeba sp, and targeting at the high-risk individuals/sources among the various regions of Iran.展开更多
Acanthamoeba keratitis, a vision-threatening disease, is caused by a free-living amoeba of genus Acanthamoeba. Amoeba is widely distributed all around the world. Several cases of Acanthamoeba keratitis have been repor...Acanthamoeba keratitis, a vision-threatening disease, is caused by a free-living amoeba of genus Acanthamoeba. Amoeba is widely distributed all around the world. Several cases of Acanthamoeba keratitis have been reported from the Middle East and Iran as well. The infection is mainly caused by inappropriate use of contact lens;therefore, it is more common among lens wearers. The number of reported cases worldwide is increasing annually due to the increasing number of contact lens wearers for medical or cosmetic reasons. It is known that early diagnosis and treatment can reduce consequent damages, while the delay in these processes will deteriorate the vision. Nowadays contact lens wearing, surgery and use of corticosteroids are known to predispose to Acanthamoeba keratitis, and it was also believed that trauma was the main cause. Increasing public knowledge about Acanthamoeba infection, inquiring the history of patients, clinical signs and laboratory findings can be helpful to early diagnosis and better treatment. Regardless of the increasing knowledge of diagnosis and treatment, this disease is still a challenge. Considering the long curative time, and insufficient efficacy of available treatments, it seems that the prevention is more important than the treatment. This review aimed to explain Acanthamoeba keratitis in the Middle East and Iran from the aspects of epidemiology, diagnosis, and therapeutic treatment.展开更多
Acanthamoeba keratitis is a serious infection that can lead to loss of vision. It is highly challenging and often poses a diagnostic dilemma, causing delay in diagnosis and treatment. We report herewith the clinical a...Acanthamoeba keratitis is a serious infection that can lead to loss of vision. It is highly challenging and often poses a diagnostic dilemma, causing delay in diagnosis and treatment. We report herewith the clinical and histopathology findings of a patient with an atypical presentation of acanthamoeba keratitis in Bahrain. The patient is a 16-year-old Bahraini teenager who was a cosmetic contact lens wearer. She presented with clinical signs and symptoms of microbial keratitis, which was initially misdiagnosed elsewhere as a case of herpetic corneal infection. Her corneal biopsy confirmed the clinical diagnosis as acanthamoeba keratitis. The patient was started on anti amoebic treatment. The infection got eradicated. The cornea healed with a central scar. Eventually, she underwent penetrating keratoplasty. This case report serves to raise awareness of this rare condition. Clinicians should have a high index of suspicion when diagnosing such cases among contact lens wearers. Early diagnosis and treatment are crucial to prevent serious complications.展开更多
Dear Sir,I am Dr. Yan-Long Bi, from the Department of Ophthalmology of the Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China. I write to present a case report of recurrent amoebic cor...Dear Sir,I am Dr. Yan-Long Bi, from the Department of Ophthalmology of the Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China. I write to present a case report of recurrent amoebic corneal abscess展开更多
In this review,recent studies regarding riboflavin-ultraviolet A(UVA)collagen cross-linking for the treatment of acanthamoeba keratitis(AK)were reviewed.English written studies about acanthamoeba,keratitis,riboflavin ...In this review,recent studies regarding riboflavin-ultraviolet A(UVA)collagen cross-linking for the treatment of acanthamoeba keratitis(AK)were reviewed.English written studies about acanthamoeba,keratitis,riboflavin and collagen cross-linking were retrieved from PubMed search engine(www.ncbi.nlm.nih.gov/pubmed).Although there were significant numbers of cases reporting the effectiveness of riboflavin-UVA collagen cross-linking in AK,experimental studies(in vivo and in vitro)failed to verify amoebicidal or cysticidal effect of riboflavin-UVA collagen cross-linking.In conclusion,the efficacy of riboflavin-UVA collagen cross-linking for the treatment of AK is still debatable.It is necessary to conduct a prospective case-control study for clear guidance for clinicians.展开更多
Pathogenic strains of Acanthamoeba cause keratitis (AK), granulomatous amoebic encephalitis (GAE), amoebic pneumonitis (AP), and skin infection in human and animals. The treatment of an Acanthamoeba infection is invar...Pathogenic strains of Acanthamoeba cause keratitis (AK), granulomatous amoebic encephalitis (GAE), amoebic pneumonitis (AP), and skin infection in human and animals. The treatment of an Acanthamoeba infection is invariably very difficult and not always effective, and compounds that are amebicidic or amebistatic are frequently toxic and/or irritating for humans. Squaramides and polyamine derivatives have been demonstrated to have antitumor and antiprotozoal activity. The aim of this study was to investigate the activity of 5 squaramides and 5 acyclic polyamines against trophozoites and cysts of A. castellanii Neff. Amoebicidal activity against the trophozoites and cytotoxicity against Vero cells were evaluated with a colorimetric assay, using Alamar Blue?, and chlorhexidine digluconate was assayed as the reference drug. The squaramides 3 and 5 and the acyclic polyamine 6 appeared to be the most active against the trophozoites and their cytotoxicity was low, showing selectivity indexes of 28.3, 26, and 25.7, respectively, similar to the control drug, chlorhexidine digluconate (27.6). But only the squaramide 3 showed complete cysticidal activity at the concentrations of 100 and 200 μM, as the chlorhexidine digluconate. Further studies of the mechanism of action and in vivo assays are needed, but squaramide 3 could be used for developing novel therapeutic approaches against Acanthamoeba infections.展开更多
Objective The objective of this article was to review the current advances in diagnostic methods for Acanthamoeba keratitis （AK）.Data sources Data used in this review were retrieved from PubMed （1970-2013）.The ter...Objective The objective of this article was to review the current advances in diagnostic methods for Acanthamoeba keratitis （AK）.Data sources Data used in this review were retrieved from PubMed （1970-2013）.The terms ＂Acanthamoeba keratitis＂ and ＂diagnosis＂ were used for the literature search.Study selection Data from published articles regarding AK and diagnosis in clinical trials were identified and reviewed.Results The diagnostic methods for the eight species implicated in AK were reviewed.Among all diagnostic procedures,corneal scraping and smear examination was an essential diagnostic method.Polymerase chain reaction was the most sensitive and accurate detection method.Culturing of Acanthamoeba was a reliable method for final diagnosis of AK.Confocal microscopy to detect Acanthamoeba was also effective,without any invasive procedure,and was helpful in the early diagnosis of AK.Conclusion Clinically,conjunction of various diagnostic methods to diagnose AK was necessary.展开更多
基金Supported by National Natural Science Foundation of China(No.82171025No.82070934)+3 种基金the Fundamental Research Funds for the Central Universities(HUST:2019kfyXMBZ065)the Key Research and Development Program of Hubei Province(No.2021BCA146)the Clinical Research Foundation of Wuhan Union Hospital(No.2021xhlcyj03)the Hubei Province Health and Family Planning Scientific Research Project(No.WJ2023M035).
文摘AIM:To investigate the demographics,risk factors,clinical presentation,treatments and outcomes of Acanthamoeba keratitis(AK)in a tertiary referral hospital in central China.METHODS:In this noncomparative,retrospective study,a total of 21 AK patients were enrolled between April 2020 and March 2023.All patients underwent anterior segment photography,in vivo confocal microscopy(IVCM),bestcorrected visual acuity(BCVA)and anterior segment optical coherence tomography(AS-OCT).RESULTS:The most common potential predisposing factors were contact lens wearing(71.4%),mostly were students,and organic trauma(23.8%),mainly by outdoor workers.And 80.9%of patients were initially misdiagnosed with herpes keratitis.The clinical features were radial keratoneuritis 42.8%(n=9),crude salt-like granular dense infiltration 28.6%(n=6),and corneal ring infiltration 28.6%(n=6).Fifteen patients were completely cured by medical therapy,and six patients with corneal ring infiltration feature were performed conjunctival flap covering surgery(CFCS),three of them later underwent secondary deep anterior lamellar keratoplasty(DALK).All patients completed their follow-up at the Union Hospital,with a total of 20 patients(95.2%)had improved visual acuity after treatment,1 had no change.Corneal scarring and vascularization were the two most common complications of AK in this study,with incidence rates of 85.7%and 28.6%,respectively.CONCLUSION:In central China,AK occurs predominantly in contact lens wearers,mainly in students with myopia prevention and control.The radial keratoneuritis with crude salt-like granular dense infiltration can generally be effectively managed with medications.In contrast,corneal ring infiltration necessitates immediate surgical intervention.The CFCS combined with secondary DALK is effective for patients with high-risk AK in this condition.
文摘<i>Acanthamoeba</i> is free living amoeba consisting of many species that are naturally pathogenic and have been isolated from different environmental sources. The purpose of this study was to determine the prevalence and relative abundance of <i>Acanthamoeba species</i> in soil and water samples within the University of Jos environment and to create public health awareness on the dangers of this parasitic protozoan. The study was conducted in the eleven (11) Faculties of the University of Jos. Soil and water samples were collected from each of the faculties, cultured and morphologically identified for positive samples. In addition, quantitative data on occurrence were examined to help better understand the potential risk to the university community. The prevalence of <i>Acanthamoeba</i> based on the chi-square analysis indicates that there is a significant difference between the number of <i>Acanthamoeba</i> species in the soil and water samples collected (P < 0.05). Relative abundance of <i>Acanthamoeba</i> based on the Man-Whitney test indicates that there was no significant difference in the distribution of <i>Acanthamoeba</i> species in the water and soil samples between different faculties (P > 0.05). Morphological identification indicates the presence of probably <i>Acanthamoeba castellani</i>. The demonstration of the presence of <i>Acanthamoeba</i> species in soil and water sources calls for awareness among the clinical community, as cases of keratitis and granulomatous amoebic encephalitis might have never been recorded due to lack of expertise or unawareness amongst the clinical community. An improved treatment of water supply and strict adherence to water act needs to be strictly encouraged.
文摘Rationale: Microbial keratitis caused by coinfection with more than one species of pathogens is a severe condition with an unfavorable prognosis. Patient concerns: An immunocompetent Nepali woman complained of pain in the left eye, redness, watering and decreased vision for 5 months. Interventions: The patient was discarded and accurately diagnosed with coinfection with Fusarium sp. and Acanthamoeba sp. The habit of washing the eyes with tap water from a domestic storage tank was the most likely source of infection since it was found to be contaminated with cysts of Acanthamoeba sp. The woman received eye drops of fluconazole and natamycin(5%), cefazoline(50 mg/m L), atropine, and tablets of itraconazole(100 mg), which were later switched to eye drops of clotrimazole(1%), natamycin(5%) and voriconazole(1%), and tablets of itraconazole. A full thickness penetrating keratoplasty was performed followed by treatment with eye drops of voriconazole(1%), natamet(5%), ofloxacin, atropine and carboxymethylcellulose for one week.Outcomes: After treatment, the condition of the patient significantly improved and was discharged one week after keratoplasty. Lessons: This is the first report of Acanthamoeba keratitis in Nepal and the first report of coinfection with Fusarium in this country and highlights the importance of early diagnosis of microbial keratitis both in single microorganism infections and coinfections, even in no contact lens wearers.
基金support provided by Three Valleys Water,UKVeolia Water, UK.funded by the Life Sciences Research Grant,University of London
文摘Objective:To identify the prevalence of Acanthamoeba in drinking water treatment plants during the course of the purification processes.Methods:Samples were taken from two drinking water purification plants and monitored for the presence of Acanthamoeba in order to estimate the removal capacity of treatment methods employed. Water samples were collected at each step in the purification,during the one year survey,and analysed for the presence of Acanthamoeba spp.by plating on bacterial-seeded plates.Results:The results showed that amoebae were present in surface raw waters in 100%of the samples tested.Acanthamoeba spp.were isolated from 71%and 57%of the water samples collected from post flat-bottom clarifier 1 and post-sedimentation plant respectively.Considering the outflow drinking waters,the removal capacity was 100%in both purification plants monitored.The occurrence of Acanthamoeba was not associated with seasonality.Conclusion: These findings confirm that water purification plants employing methods of flocculation,sedimentation,and filtration in combination with activated charcoal filtration,ozonisation and chlorination exhibited sufficient Acanthamoeba removal capacity and the presence of amoebae in the tap water may be due to older plumbing,water storage tanks,tap water hygiene,and/or environmental settings.
文摘We analysed histologically two Acanthamoeba keratitis(AK) eyes with anterior and posterior segment inflammation and blindness. Two enucleated eyes of 2 patients(age 45 and 51y) with AK(PCR of epithelial abrasion positive) were analysed. Histological analysis was performed using hematoxylin-eosin, periodic acid-Schiff and G?m?rimethenamine silver staining. We could not observe Acanthamoeba trophozoites or cysts neither in the cornea nor in other ocular tissues. Meanwhile, we found uveitis, retinal vasculitis and scleritis in these eyes, due to the long-standing, recalcitrant AK. So in this stage of AK, systemic immune suppression may be necessary for a longer time period.
基金Supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (No.NRF-2015R1C1A1A02037702)
文摘This study is to investigate the characteristic features of Acanthamoeba keratitis（AK） that differentiating it from herpetic epithelial keratitis（HEK） using anterior segment optical coherence tomography（AS-OCT）. Medical records of three eyes of each AK and herpetic keratitis who had AS-OCT examination were reviewed in this study. Slitlamp biomicroscopy and AS-OCT was performed on the initial visit and on every follow-up visits in all patients. In all three AK cases, reflective bands in the corneal stroma that correspond to the area of radial keratoneuritis were observed. The depth of the reflective bands varied in each case. After AK treatment, slit-lamp biomicroscopy confirmed that radial keratoneuritis had resolved and AS-OCT confirmed that reflective bands in the corneal stroma had also disappeared in all patients. Unlike the AS-OCT results found in AK, highly reflective HEK lesions were observed only in the subepithelial area, not in the stroma. AS-OCT seems to be helpful analyzing the specific depth of the lesion which enables to distinguish AK from HEK.
基金financially supported by Immunology Research Center,Tabriz University of Medical Sciences,Tabriz,Iran
文摘Objective: To verify phylogeography and genetic structure of Acanthamoeba populations among the Iranian clinical isolates and natural/artificial environments distributed in various regions of the country.Methods: We searched electronic databases including Medline, Pub Med, Science Direct, Scopus and Google Scholar from 2005 to 2016. To explore the genetic variability of Acanthamoeba sp, 205 sequences were retrieved from keratitis patients, immunosuppressed cases and environmental sources as of various geographies of Iran.Results: T4 genotype was the predominant strain in Iran, and the rare genotypes belonged to T2, T3, T5(Acanthamoeba lenticulata), T6, T9, T11, T13 and T15(Acanthamoeba jacobsi).A total of 47 unique haplotypes of T4 were identified. A parsimonious network of the sequence haplotypes demonstrated star-like feature containing haplogroups IR6(34.1%) and IR7(31.2%) as the most common haplotypes. In accordance with the analysis of molecular variance, the high value of haplotype diversity(0.612–0.848) of Acanthamoeba T4 represented genetic variability within populations. Neutrality indices of the 18 S ribosomal RNA demonstrated negative values in all populations which represented a considerable divergence from neutrality. The majority of genetic diversity belonged to the infected contact lens and dust samples in immunodeficiency and ophthalmology wards, which indicated potential routes for exposure to a pathogenic Acanthamoeba sp. in at-risk individuals. A pairwise fixation index(FST) was from low to high values(0.024 33–0.418 92). The statistically FST points out that T4 is genetically differentiated between north-west, north-south and centralsouth metapopulations, but not differentiated between west-central, west-south, centralsouth, and north-central isolates.Conclusions: An occurrence of IR6 and IR7 displays that possibly a gene flow of Acanthamoeba T4 occurred after the founder effect or bottleneck experience through ecological changes or host mobility. This is the first systematic review and meta-analysis providing new approaches into gene migration and transmission patterns of Acanthamoeba sp, and targeting at the high-risk individuals/sources among the various regions of Iran.
文摘Acanthamoeba keratitis, a vision-threatening disease, is caused by a free-living amoeba of genus Acanthamoeba. Amoeba is widely distributed all around the world. Several cases of Acanthamoeba keratitis have been reported from the Middle East and Iran as well. The infection is mainly caused by inappropriate use of contact lens;therefore, it is more common among lens wearers. The number of reported cases worldwide is increasing annually due to the increasing number of contact lens wearers for medical or cosmetic reasons. It is known that early diagnosis and treatment can reduce consequent damages, while the delay in these processes will deteriorate the vision. Nowadays contact lens wearing, surgery and use of corticosteroids are known to predispose to Acanthamoeba keratitis, and it was also believed that trauma was the main cause. Increasing public knowledge about Acanthamoeba infection, inquiring the history of patients, clinical signs and laboratory findings can be helpful to early diagnosis and better treatment. Regardless of the increasing knowledge of diagnosis and treatment, this disease is still a challenge. Considering the long curative time, and insufficient efficacy of available treatments, it seems that the prevention is more important than the treatment. This review aimed to explain Acanthamoeba keratitis in the Middle East and Iran from the aspects of epidemiology, diagnosis, and therapeutic treatment.
文摘Acanthamoeba keratitis is a serious infection that can lead to loss of vision. It is highly challenging and often poses a diagnostic dilemma, causing delay in diagnosis and treatment. We report herewith the clinical and histopathology findings of a patient with an atypical presentation of acanthamoeba keratitis in Bahrain. The patient is a 16-year-old Bahraini teenager who was a cosmetic contact lens wearer. She presented with clinical signs and symptoms of microbial keratitis, which was initially misdiagnosed elsewhere as a case of herpetic corneal infection. Her corneal biopsy confirmed the clinical diagnosis as acanthamoeba keratitis. The patient was started on anti amoebic treatment. The infection got eradicated. The cornea healed with a central scar. Eventually, she underwent penetrating keratoplasty. This case report serves to raise awareness of this rare condition. Clinicians should have a high index of suspicion when diagnosing such cases among contact lens wearers. Early diagnosis and treatment are crucial to prevent serious complications.
文摘Dear Sir,I am Dr. Yan-Long Bi, from the Department of Ophthalmology of the Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China. I write to present a case report of recurrent amoebic corneal abscess
基金The study is supported in part by a grant of Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2016R1D1A1B03931724).
文摘In this review,recent studies regarding riboflavin-ultraviolet A(UVA)collagen cross-linking for the treatment of acanthamoeba keratitis(AK)were reviewed.English written studies about acanthamoeba,keratitis,riboflavin and collagen cross-linking were retrieved from PubMed search engine(www.ncbi.nlm.nih.gov/pubmed).Although there were significant numbers of cases reporting the effectiveness of riboflavin-UVA collagen cross-linking in AK,experimental studies(in vivo and in vitro)failed to verify amoebicidal or cysticidal effect of riboflavin-UVA collagen cross-linking.In conclusion,the efficacy of riboflavin-UVA collagen cross-linking for the treatment of AK is still debatable.It is necessary to conduct a prospective case-control study for clear guidance for clinicians.
文摘Pathogenic strains of Acanthamoeba cause keratitis (AK), granulomatous amoebic encephalitis (GAE), amoebic pneumonitis (AP), and skin infection in human and animals. The treatment of an Acanthamoeba infection is invariably very difficult and not always effective, and compounds that are amebicidic or amebistatic are frequently toxic and/or irritating for humans. Squaramides and polyamine derivatives have been demonstrated to have antitumor and antiprotozoal activity. The aim of this study was to investigate the activity of 5 squaramides and 5 acyclic polyamines against trophozoites and cysts of A. castellanii Neff. Amoebicidal activity against the trophozoites and cytotoxicity against Vero cells were evaluated with a colorimetric assay, using Alamar Blue?, and chlorhexidine digluconate was assayed as the reference drug. The squaramides 3 and 5 and the acyclic polyamine 6 appeared to be the most active against the trophozoites and their cytotoxicity was low, showing selectivity indexes of 28.3, 26, and 25.7, respectively, similar to the control drug, chlorhexidine digluconate (27.6). But only the squaramide 3 showed complete cysticidal activity at the concentrations of 100 and 200 μM, as the chlorhexidine digluconate. Further studies of the mechanism of action and in vivo assays are needed, but squaramide 3 could be used for developing novel therapeutic approaches against Acanthamoeba infections.
基金This study was supported by grants from the National Natural Science Foundation of China （No. 81301450） and the Education Department of Jilin Province （No. 2014373）.
文摘Objective The objective of this article was to review the current advances in diagnostic methods for Acanthamoeba keratitis （AK）.Data sources Data used in this review were retrieved from PubMed （1970-2013）.The terms ＂Acanthamoeba keratitis＂ and ＂diagnosis＂ were used for the literature search.Study selection Data from published articles regarding AK and diagnosis in clinical trials were identified and reviewed.Results The diagnostic methods for the eight species implicated in AK were reviewed.Among all diagnostic procedures,corneal scraping and smear examination was an essential diagnostic method.Polymerase chain reaction was the most sensitive and accurate detection method.Culturing of Acanthamoeba was a reliable method for final diagnosis of AK.Confocal microscopy to detect Acanthamoeba was also effective,without any invasive procedure,and was helpful in the early diagnosis of AK.Conclusion Clinically,conjunction of various diagnostic methods to diagnose AK was necessary.
