Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 769
Filtrar
1.
Parasitol Res ; 119(11): 3755-3761, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32918603

RESUMO

Free-living amoeba (FLA) research in the Philippines is still in its infancy but has, by far, demonstrated the presence of potentially pathogenic species. Acanthamoeba may cause sight-threatening and central nervous system infections to humans, yet its epidemiologic distribution from local environmental sources is yet to be defined. The present study aimed to provide a baseline epidemiologic distribution of Acanthamoeba spp. in freshwater systems in the Philippines and establish potential pathogenicity of isolates through thermo-tolerance assay. A total of 63 water samples were collected from 13 freshwater systems all over the Philippine archipelago. The low-volume (50 ml) water samples were processed and cultured on non-nutrient agar lawned with Escherichia coli and observed for amoebic growth using light microscopy. Amoebic culture demonstrated 14.28% (9/63) positivity while further molecular testing of culture-positive plates using Acanthamoeba-specific primers demonstrated 100% (9/9) confirmation of Acanthamoeba species. Genotyping of Acanthamoeba isolates revealed T1, T3, T4, T5, T7, T11, and T15 genotypes. Thermo-tolerance assay demonstrated that T5 and T7 genotypes were potentially pathogenic strains. The evidence of environmental distribution of Acanthamoeba spp. in the freshwater systems in the Philippines and thermo-tolerance profile of isolates are significant aspects of amoeba study in public health and calls for initiatives in the dissemination of relevant information and the expansion of knowledge, awareness, and policies on pathogenic waterborne amoeba to mitigate, prevent, detect, and report cases of human infections.


Assuntos
Acanthamoeba/isolamento & purificação , Acanthamoeba/fisiologia , Água Doce/parasitologia , Acanthamoeba/genética , Acanthamoeba/crescimento & desenvolvimento , DNA de Protozoário/genética , Monitoramento Ambiental , Genótipo , Humanos , Filipinas , Termotolerância
2.
J Water Health ; 18(2): 118-126, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32300086

RESUMO

Water reservoirs are important manmade structures providing water security to deliver clean and safe water for drinking and other purposes to the community. Eighty water samples were collected from Magat and Ipo water reservoirs using purposive sampling between November 2018 and January 2019. Water samples were collected in sterile containers for testing. The samples were cultured in non-nutrient agar and lawned with Escherichia coli and incubated at 33 °C. Twelve out of the 80 (15%) water samples were positive for amoebic growth. Light and scanning electron microscopy (SEM) revealed double-walled cystic stages and were initially identified as Acanthamoeba spp. based on morphological characteristic in reference to Page's established criteria. Their extracted DNAs were used in polymerase chain reaction using JDP1 and JDP2 primers and confirmed the presence of Acanthamoeba DNA in agarose gel electrophoresis. Aligned sequences from PCR products were deposited in GenBank under accession numbers MK886460, MK909919, MK905437, MK910997, MK911021 and MK886514. The presence of potentially pathogenic Acanthamoeba spp. in water reservoirs is considered a potential risk for public health, requiring appropriate processing of water in treatment plants.


Assuntos
Acanthamoeba/isolamento & purificação , Água Doce/parasitologia , Abastecimento de Água , Filipinas , Reação em Cadeia da Polimerase
3.
J Water Health ; 18(2): 186-199, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32300091

RESUMO

The present study aims to investigate the occurrence of free living amoeba (FLA) in water resources (rivers and tap water) in Samsun in the Black Sea. The presence of Acanthamoeba spp. was confirmed in 98 of 192 water samples collected from 32 sites of Samsun province (Samsun centre, Terme, Carsamba, Tekkekoy, Bafra) by PCR. Acanthamoeba spp. were found in 15/36 river samples from Samsun, in 58/90 from Terme, in 12/30 from Carsamba, in 7/18 from Tekkekoy and in 6/18 from Bafra. No Acanthamoeba species were detected in tap water samples. The highest rate in river waters contaminated with Acanthamoeba species was in Terme followed by Samsun centre (41.7%), Carsamba (40%), Tekkekoy (38.9%) and Bafra districts (33.3%), respectively. The result of the subsequent sequence analysis showed Haplotype I (A. triangularis) in 5%, Haplotype II (A. polyphaga) in 29.6%, Haplotype III (Acanthamoeba spp.) in 62% and Haplotype IV (A. lenticulata) in 3%. The most common genotype was Acanthamoeba T4 (Acanthamoeba spp., A. polyphaga, A. triangularis) and T5 genotype was also found in 3%. The T4 genotype is the most common genotype associated with Acanthamoeba keratitis (AK) worldwide; therefore, humans and animals living in the area are at risk after contact with such waters.


Assuntos
Acanthamoeba/isolamento & purificação , Monitoramento Ambiental , Rios/parasitologia , Mar Negro , Genótipo , Turquia
4.
J Water Health ; 18(2): 244-251, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32300097

RESUMO

Free-living amoeba (FLA), including Acanthamoeba and Naegleria are facultative parasites in humans. The amoeba have widespread distribution in various water sources. The aim of this study was isolation and molecular identification of Acanthamoeba and Naegleria isolated from swimming pools and also hot and cold tub waters in Qazvin province. The samples (166 water samples) were cultured to isolate and identify positive specimens. PCR (polymerase chain reaction) amplification, sequencing and phylogenetic analysis were conducted to confirm the isolated species and genotypes of amoeba. According to morphological characterizations, 18.6% of specimens were identified as FLA, which in 71% were Acanthamoeba by PCR method. Molecular analysis revealed that 36.3%, 18.1% and 4.5% of Acanthamoeba specimens were identified as T3, T4 and T11 Acanthamoeba genotypes, respectively. Protacanthamoeba bohemica (27.2%) and Acanthamoeba sp. (4.5%) were found among the specimens. The results of osmo-tolerance and thermo-tolerance assays demonstrated that 50% of T3 and 25% of T4 genotypes of Acanthamoeba were highly pathogenic parasites. The molecular approach showed the presence of Naegleria lovaniensis (9%) in hot tub water of swimming pools. This study demonstrated that the swimming pools and hot tub water in Qazvin province were contaminated with Acanthamoeba and Naegleria species.


Assuntos
Acanthamoeba/isolamento & purificação , Naegleria/isolamento & purificação , Piscinas , Água/parasitologia , Genótipo , Irã (Geográfico) , Filogenia
5.
PLoS One ; 15(3): e0229681, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32160218

RESUMO

PURPOSE: To determine whether Acanthamoeba keratitis (AK) patients have higher rates of Acanthamoeba and free-living amoeba (FLA) colonising domestic sinks than control contact lens (CL) wearers, and whether these isolates are genetically similar to the corneal isolates from their CL associated AK. METHODS: 129 AK patients from Moorefield Eye Hospital, London and 64 control CL wearers from the Institute of Optometry were included in this study. The participants self-collected home kitchen and bathroom samples from tap-spouts, overflows and drains using an instructional kit. The samples were cultured by inoculating onto a non-nutrient agar plate seeded with Escherichia coli, incubated at 32°C and examined for amoebae by microscopy for up to 2 weeks. Partial sequences of mitochondrial cytochrome oxidase genes (coxA) of Acanthamoeba isolates from four AK patients were compared to Acanthamoeba isolated from the patient's home. The association between sampling sites was analysed with the chi-square test. RESULTS: A total of 513 samples from AK patients and 189 from CL controls were collected. The yield of FLA was significantly greater in patients' bathrooms (72.1%) than CL controls' bathrooms (53.4%) (p<0.05). Spouts (kitchen 6.7%, bathroom 11%) had the lowest rate of Acanthamoeba isolation compared to drains (kitchen 18.2%, bathroom 27.9%) and overflow (kitchen 39.1%, bathroom 25.9%) either in kitchens or bathrooms (p<0.05). There was no statistically significant difference between the average prevalence of Acanthamoeba in all three sample sites in kitchens (16.9%) compared to all three sample sites in bathrooms (21.5%) and no association for Acanthamoeba prevalence between AK patients and CL controls. All four corneal isolates had the same coxA sequence as at least one domestic water isolate from the patients' sink of the kitchen and the bathroom. CONCLUSION: The prevalence of Acanthamoeba and FLA was high in UK homes. FLA colonisation was higher in AK patients compared to controls but the prevalence of Acanthamoeba between AK patients and CL controls domestic sinks was similar. This study confirms that domestic water isolates are probably the source of AK infection. Advice about avoiding water contact when using CL's should be mandatory.


Assuntos
Ceratite por Acanthamoeba/epidemiologia , Ceratite por Acanthamoeba/parasitologia , Acanthamoeba/isolamento & purificação , Acanthamoeba/genética , Acanthamoeba/patogenicidade , Amebozoários/isolamento & purificação , Estudos de Casos e Controles , Lentes de Contato/efeitos adversos , Lentes de Contato/parasitologia , Suscetibilidade a Doenças , Meio Ambiente , Habitação , Humanos , Londres/epidemiologia , Fatores de Risco , Engenharia Sanitária , Água/parasitologia
6.
Ann Parasitol ; 66(1): 111­114, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32199003

RESUMO

Acanthamoeba spp. are ubiquitous in both natural and man-made environments and have been isolated in lakes, recreational pools, tap water, and air conditioning systems. Twenty surface water (SW) samples were collected from different sampling areas of Lake Buhi. Water samples were pelleted, cultured in NNA lawned with Escherichia coli and observed microscopically. 10% of samples (2/20) were positive for amoebic growth and were furthered tested using molecular techniques. Polymerase chain reaction showed the presence of Acanthamoeba sp. DNA. The presence of potentially pathogenic Acanthamoeba sp. poses a public health concern. The formulation of policies for proper information dissemination and control measures to avert the contraction of pathogenic FLA as well as other WBPP should be seriously considered.


Assuntos
Acanthamoeba , Lagos , Acanthamoeba/classificação , Acanthamoeba/genética , Acanthamoeba/isolamento & purificação , DNA de Protozoário/genética , Lagos/parasitologia , Filipinas , Reação em Cadeia da Polimerase
8.
Acta Parasitol ; 65(1): 36-43, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31571139

RESUMO

PURPOSE: Free-living amoeba (FLA) including Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria are among the soil-born parasites. There are reports of FLA-related keratitis with a history of contact with soil and dust sources, particularly among the farmers. Due to lack of the previous studies on the farmland soils and a limited number of researches conducted on recreational soils in Iran, the present study was conducted. METHODS: A total of 93 soil samples including farming lands and recreational places were tested for the presence of Acanthamoeba spp. Balamuthia mandrillaris, Naegleria, and Vermamoeba using morphological key and sequencing-based tools. Pathogenicity of Acanthamoeba positive strains was also evaluated. To verify genetic associations and taxonomic status of isolated amoeba, a phylogenetic tree was built by MEGA 5.05 software inferred by the 18S rRNA gene based on maximum likelihood algorithm. RESULTS: Overall, 28 samples (30%) were contaminated with potentially pathogenic FLA, and according to the sequencing data, 17 strains were successfully sequenced. The isolated Acanthamoeba belonged to T2, T4, T5, mixed T4 and T5 contaminations, and T11. ITS sequencing revealed the occurrence of one strain of Naegleria canariensis. Four strains of Vermamoeba vermiformis were also confirmed. Morphological survey and PCR assay failed to show any positive results for Balamuthia mandrillaris. Pathogenic potential of the Acanthamoeba strains showed that T2, T4, and T11 genotypes were highly pathogenic, whereas T5 genotypes demonstrated lower pathogenic potential. CONCLUSION: The results indicate that soil could be a serious hazard to human health, and therefore, further studies are expected to investigate the source of infection in patients developing FLA-related diseases. The present study is the first to investigate FLA in the farmland soils in Iran and the first to report the presence of N. canariensis in the country.


Assuntos
Amoeba/classificação , Fazendas/estatística & dados numéricos , Genótipo , Filogenia , Solo/parasitologia , Acanthamoeba/classificação , Acanthamoeba/isolamento & purificação , Amebíase/epidemiologia , Amebíase/parasitologia , Amoeba/isolamento & purificação , Amoeba/patogenicidade , DNA de Protozoário/genética , Humanos , Irã (Geográfico)/epidemiologia , Naegleria/classificação , Naegleria/isolamento & purificação , Parques Recreativos , Saúde Pública , RNA Ribossômico 18S/genética , Abastecimento de Água
9.
Korean J Parasitol ; 57(5): 505-511, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31715691

RESUMO

Acanthamoeba keratitis (AK) is a rare sight-threatening corneal infection, often reporting from contact lens wearers. An asymptomatic human immunodeficiency virus (HIV)-infected Thai male without history of contact lens use complained foreign body sensation at his left eye during motorbike riding. He had neither specific keratitis symptoms nor common drugs responding, which contributed to delayed diagnosis. By corneal re-scraping, Acanthamoeba-like cysts were detected by calcofluor white staining and agar culture. The etiological agent obtained from the culture was molecularly confirmed by Acanthamoeba spp.-specific PCR, followed by DNA sequencing. The results from BLAST and phylogenetic analysis based on the DNA sequences, revealed that the pathogen was Acanthamoeba T4, the major genotype most frequently reported from clinical isolates. The infection was successfully treated with polyhexamethylene biguanide resulting in corneal scar. This appears the first reported AK case from a non-contact lens wearer with HIV infection in Thailand. Although AK is sporadic in developing countries, a role of free-living Acanthamoeba as an opportunistic pathogen should not be neglected. The report would increase awareness of AK, especially in the case presenting unspecific keratitis symptoms without clinical response to empirical antimicrobial therapy.


Assuntos
Ceratite por Acanthamoeba/parasitologia , Acanthamoeba/isolamento & purificação , Infecções por HIV/complicações , Acanthamoeba/classificação , Acanthamoeba/genética , Ceratite por Acanthamoeba/etiologia , Adulto , Doenças Assintomáticas , Olho/parasitologia , Humanos , Masculino , Filogenia , Tailândia
10.
Artigo em Inglês | MEDLINE | ID: mdl-31685474

RESUMO

Miltefosine is an alkylphosphocholine compound that is used primarily for treatment of leishmaniasis and demonstrates in vitro and in vivo antiamebic activity against Acanthamoeba species. Recommendations for treatment of amebic encephalitis generally include miltefosine therapy. Data indicate that treatment with an amebicidal concentration of at least 16 µg/ml of miltefosine is required for most Acanthamoeba species. Although there is a high level of mortality associated with amebic encephalitis, a paucity of data regarding miltefosine levels in plasma and cerebrospinal fluid in vivo exists in the literature. We found that despite aggressive dosing (oral miltefosine 50 mg every 6 h) and therapeutic plasma levels, the miltefosine concentration in cerebrospinal fluid was negligible in a patient with AIDS and Acanthamoeba encephalitis.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Amebíase/tratamento farmacológico , Amebicidas/sangue , Amebicidas/líquido cefalorraquidiano , Infecções Protozoárias do Sistema Nervoso Central/tratamento farmacológico , Encefalite Infecciosa/tratamento farmacológico , Fosforilcolina/análogos & derivados , Infecções Oportunistas Relacionadas com a AIDS/sangue , Infecções Oportunistas Relacionadas com a AIDS/líquido cefalorraquidiano , Acanthamoeba/efeitos dos fármacos , Acanthamoeba/isolamento & purificação , Adulto , Amebíase/sangue , Amebíase/líquido cefalorraquidiano , Amebicidas/administração & dosagem , Encéfalo/parasitologia , Infecções Protozoárias do Sistema Nervoso Central/sangue , Infecções Protozoárias do Sistema Nervoso Central/líquido cefalorraquidiano , Humanos , Encefalite Infecciosa/sangue , Encefalite Infecciosa/líquido cefalorraquidiano , Masculino , Fosforilcolina/administração & dosagem , Fosforilcolina/sangue , Fosforilcolina/líquido cefalorraquidiano
11.
J Water Health ; 17(5): 813-825, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31638031

RESUMO

This study aimed to identify the Acanthamoeba genotypes and their pathogenic potential in five recreational hot springs in Peninsular Malaysia. Fifty water samples were collected between April and September 2018. Physical parameters of water quality were measured in situ while chemical and microbiological analyses were performed in the laboratory. All samples were filtered through the nitrocellulose membrane and tested for Acanthamoeba using both cultivation and polymerase chain reaction (PCR) by targeting the 18S ribosomal RNA gene. The pathogenic potential of all positive isolates was identified using thermo- and osmotolerance tests. Thirty-eight (76.0%) samples were positive for Acanthamoeba. Water temperature (P = 0.035), chemical oxygen demand (P = 0.026), sulphate (P = 0.002) and Escherichia coli (P < 0.001) were found to be significantly correlated with the presence of Acanthamoeba. Phylogenetic analysis revealed that 24 samples belonged to genotype T4, nine (T15), two (T3) and one from each genotype T5, T11 and T17. Thermo- and osmotolerance tests showed that 6 (15.79%) of the Acanthamoeba strains were highly pathogenic. The existence of Acanthamoeba in recreational hot springs should be considered as a health threat among the public especially for high-risk people. Periodic surveillance of hot spring waters and posting warning signs by health authorities is recommended to prevent disease related to pathogenic Acanthamoeba.


Assuntos
Acanthamoeba/crescimento & desenvolvimento , Fontes Termais/parasitologia , Acanthamoeba/isolamento & purificação , Genótipo , Malásia , Filogenia , RNA Ribossômico 18S
12.
Parasitol Res ; 118(10): 3061-3066, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31502076

RESUMO

The burden of HIV/AIDS in Iran is not as high as in the other countries with high prevalence; however, the number of cases of HIV/AIDs is increasing in this region. According to a recent report, Iran had 5000 (1400-13,000) new cases of HIV infection with 4000 (2500-6200) AIDS-related deaths. Individuals affected by HIV/AIDS are highly susceptible for developing opportunistic infections, e.g. the cerebral complications related to pathogenic free-living amoebae and colonization of free-living amoebae (FLA) can be a serious hazard for patients living with HIV/AIDS. In the present study, a total of 70 oral and nasal mucosal samples were obtained from HIV/AIDS patients referred to the reference hospitals in Iran and tested for the presence of potentially pathogenic FLA using culture and PCR/sequencing-based methods. To discern the taxonomic status of Acanthamoeba genotypes a maximum likelihood phylogenetic tree was constructed and tolerance assays were performed for the positive Acanthamoeba strains. Among the patients with HIV/AIDS referred to the reference hospitals from 2017 to 2019, 7.1% were found positive for pathogenic free-living amoebae. Three strains (HA3, HA4, and HA5) belonged to the T4 genotype, one strain (HA1) was related to the T5 genotype assigned as A. lenticulata, and another strain (HA2) had high homology to Vermamoeba vermiformis. The tolerance assay used for Acanthamoeba strains (HA1, HA3, and HA4) classified these amoebae as highly pathogenic strains. For the most part, the encephalitis cases occurring in HIV/AIDS patients in Iran remain undiagnosed due to lack of awareness of the practitioners on the available diagnostic tools for this lethal infection; therefore, the true incidence of GAE in this region is unknown. A possible colonization with FLA should be considered in the differential diagnosis of suspected cases of CNS infections among HIV/AIDS patients. This study is the first worldwide comprehensive study attempting to isolate and identify the FLA colonization in HIV/AIDS patients. This study highlights the fact that clinicians should be aware of the differential diagnosis of cerebral disease related to FLA in patients with HIV/AIDS.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/parasitologia , Acanthamoeba/classificação , Acanthamoeba/isolamento & purificação , Amebíase/parasitologia , Mucosa Bucal/parasitologia , Filogenia , Infecções Oportunistas Relacionadas com a AIDS/complicações , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Acanthamoeba/genética , Acanthamoeba/patogenicidade , Adulto , Idoso , Amebíase/complicações , Amebíase/epidemiologia , Feminino , Genótipo , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Mucosa Nasal/parasitologia
13.
Acta Parasitol ; 64(4): 911-915, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31552581

RESUMO

BACKGROUND: Acanthamoeba is a genus of the free-living amoeba that is widespread in the environment and is a causative agent of opportunistic infections in human. This study aimed to investigate the existence and genotyping of Acanthamoeba species in hemodialysis units in Iran. METHODS: In the present study, forty water samples of hydraulic systems and twenty dust samples were collected from two hemodialysis units in Mazandaran Province, northern Iran. The samples were cultivated on non-nutrient agar and genotyping was performed by targeting the 18S rRNA gene. RESULTS: Both morphology and molecular analyses showed that 17.5% (7/40) of water samples and 50% (10/20) of dust samples were positive for Acanthamoeba spp. The sequencing analysis of these isolates was found to be T3, T4 and T5 genotypes. DISCUSSION: To the best of our knowledge, this is the first investigation to identify of Acanthamoeba species in hydraulic system of hemodialysis units in Iran. High contamination of hemodialysis units with virulent T4 genotype of Acanthamoeba may poses a risk for biofilm formation. Our results support urgent need to improve filtration methods in dialysis units and monitoring hemodialysis patients for Acanthamoeba infections.


Assuntos
Acanthamoeba/genética , Acanthamoeba/isolamento & purificação , Genótipo , Unidades Hospitalares de Hemodiálise , Água/parasitologia , Acanthamoeba/patogenicidade , DNA de Protozoário/genética , Poeira/análise , Irã (Geográfico) , RNA Ribossômico 18S/genética , Diálise Renal , Análise de Sequência de DNA
14.
Korean J Parasitol ; 57(4): 341-357, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31533401

RESUMO

Acanthamoeba, one of free-living amoebae (FLA), remains a high risk of direct contact with this protozoan parasite which is ubiquitous in nature and man-made environment. This pathogenic FLA can cause sight-threatening amoebic keratitis (AK) and fatal granulomatous amoebic encephalitis (GAE) though these cases may not commonly be reported in our clinical settings. Acanthamoeba has been detected from different environmental sources namely; soil, water, hot-spring, swimming pool, air-conditioner, or contact lens storage cases. The identification of Acanthamoeba is based on morphological appearance and molecular techniques using PCR and DNA sequencing for clinico-epidemiological purposes. Recent treatments have long been ineffective against Acanthamoeba cyst, novel anti-Acanthamoeba agents have therefore been extensively investigated. There are efforts to utilize synthetic chemicals, lead compounds from medicinal plant extracts, and animal products to combat Acanthamoeba infection. Applied nanotechnology, an advanced technology, has shown to enhance the anti-Acanthamoeba activity in the encapsulated nanoparticles leading to new therapeutic options. This review attempts to provide an overview of the available data and studies on the occurrence of pathogenic Acanthamoeba among the Association of Southeast Asian Nations (ASEAN) members with the aim of identifying some potential contributing factors such as distribution, demographic profile of the patients, possible source of the parasite, mode of transmission and treatment. Further, this review attempts to provide future direction for prevention and control of the Acanthamoeba infection.


Assuntos
Acanthamoeba , Amebíase/epidemiologia , Acanthamoeba/classificação , Acanthamoeba/isolamento & purificação , Acanthamoeba/fisiologia , Amebíase/diagnóstico , Amebíase/terapia , Amebíase/transmissão , Ásia Sudeste/epidemiologia , Solo/parasitologia , Água/parasitologia
15.
BMC Ophthalmol ; 19(1): 202, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31533675

RESUMO

BACKGROUND: To report the clinical and microbiological features of Acanthamoeba keratitis (AK) related to contact lens use in a tertiary hospital in China. METHODS: In this retrospective study, the medical results of 61 cases of AK related to contact lens use from January 2000 to December 2017 were reviewed. The data included patients' demographics, lens type, history, risk factors, disease stages, corneal scraping and culture reports, and treatments. Moreover, genotypic identification of some of the isolates was carried out with a PCR assay and sequence analysis of the 18S ribosomal DNA gene. RESULTS: There were 64 eyes included in the study. A total of 32.8% of the patients wore soft contact lenses, and 67.2% of patients used overnight orthokeratology. In the cases (20 eyes) in the early stage, 65% (13 eyes) had positive results according to Giemsa-stained smears, and 0.9% sodium chloride (NaCl) wet mounts revealed trophozoites in 7 eyes (35%). Six eyes (30%) were diagnosed by confocal microscopy combined with clinical signs. In the orthokeratology patients, 87.8% (36/41) rinsed their lenses and/or cases with tap water; 55% of soft-lens wearers wore their lenses while showering. The genotype of 9 isolates was determined, and all the strains belonged to genotype T4. In the orthokeratology group, the number of patients who required therapeutic penetrating keratoplasty after 2005 was less than that before 2005 (chi-square test, χ2 = 4.209, P = 0.04). CONCLUSIONS: More than two-thirds of the cases were associated with orthokeratology. Examinations with Giemsa-stained smears, 0.9% NaCl wet mounts and confocal microscopy should be performed for patients who are highly suspected of having early-stage AK to help with early diagnosis. In the orthokeratology group, the rate of therapeutic keratoplasty after 2005 was less than that before 2005.


Assuntos
Ceratite por Acanthamoeba/etiologia , Lentes de Contato/parasitologia , Úlcera da Córnea/etiologia , Infecções Oculares Parasitárias/etiologia , Acanthamoeba/genética , Acanthamoeba/isolamento & purificação , Ceratite por Acanthamoeba/diagnóstico , Ceratite por Acanthamoeba/terapia , Adolescente , Adulto , Anti-Infecciosos Locais/uso terapêutico , Biguanidas/uso terapêutico , Criança , China , Clorexidina/uso terapêutico , Úlcera da Córnea/diagnóstico , Úlcera da Córnea/terapia , DNA de Protozoário/genética , Desinfetantes/uso terapêutico , Combinação de Medicamentos , Infecções Oculares Parasitárias/diagnóstico , Infecções Oculares Parasitárias/terapia , Feminino , Humanos , Ceratoplastia Penetrante , Masculino , Microscopia Confocal , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , RNA Ribossômico 18S/genética , Estudos Retrospectivos , Centros de Atenção Terciária , Adulto Jovem
16.
Cornea ; 38(10): 1309-1313, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31306283

RESUMO

PURPOSE: To determine whether combinations of commonly used antiamoebic agents display synergy in their ability to kill Acanthamoeba cysts in vitro. METHODS: Synergy testing was performed with a microdilution checkerboard assay on 10 clinical Acanthamoeba keratitis isolates collected at the Proctor Foundation from 2008 to 2012. Each isolate was exposed to pairwise combinations of chlorhexidine, propamidine, and voriconazole. The minimum cysticidal concentration (MCC) for each drug pair was estimated for each isolate, and the summed fractional cysticidal concentration (ΣFCC) was calculated for each drug combination in the checkerboard, with synergy defined as a lack of growth at a ΣFCC ≤ 0.5 and antagonism as growth at a ΣFCC > 4. RESULTS: Chlorhexidine and propamidine were cysticidal, with median MCCs of 12.5 (range 1.5-50) and 11.7 (range 0.2-250), respectively. Voriconazole was not cysticidal, with a median MCC of >10,000 µg/mL. The combination of chlorhexidine and propamidine did not markedly change the cysticidal activity compared with either drug alone. By contrast, voriconazole antagonized the cysticidal activity of both chlorhexidine and propamidine, with Acanthamoeba growth observed at antagonistic ΣFCCs in 27 of 49 (55.1%, 95% confidence interval 35.7%-78.6%) checkerboard combinations of voriconazole and chlorhexidine and in 58 of 147 (39.5%, 95% confidence interval 14.3%-50.3%) combinations of voriconazole and propamidine. CONCLUSIONS: In an in vitro assay, voriconazole reduced the cysticidal activity of 2 commonly used antiamoebic drugs. Although the in vivo drug interactions could be different, these observations may be useful in cases of nonhealing Acanthamoeba keratitis being treated with combination therapies that include voriconazole.


Assuntos
Ceratite por Acanthamoeba/tratamento farmacológico , Acanthamoeba/isolamento & purificação , Amebicidas/farmacologia , Infecções Oculares Parasitárias/tratamento farmacológico , Voriconazol/farmacologia , Acanthamoeba/efeitos dos fármacos , Ceratite por Acanthamoeba/diagnóstico , Ceratite por Acanthamoeba/parasitologia , Animais , Antifúngicos/farmacologia , Sinergismo Farmacológico , Infecções Oculares Parasitárias/parasitologia , Humanos , Testes de Sensibilidade Parasitária
18.
Parasitol Res ; 118(6): 1865-1874, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31065830

RESUMO

Acanthamoeba is a free-living pathogenic protozoan that is distributed in different environmental reservoirs, including lakes and soil. Pathogenic Acanthamoeba can cause severe human diseases, such as blinding keratitis and granulomatous encephalitis. Therefore, it is important to understand the pathogenic relationship between humans and Acanthamoeba. By comparison of systemic analysis results for Acanthamoeba isolates, we identified a novel secreted protein of Acanthamoeba, an M28 aminopeptidase (M28AP), which targets of the human innate immune defense. We investigated the molecular functions and characteristics of the M28AP protein by anti-M28 antibodies and a M28AP mutant strain generated by the CRISPR/Cas9 system. Human complement proteins such as C3b and iC3b were degraded by Acanthamoeba M28AP. We believe that M28AP is an important factor in human innate immunity. This study provides new insight for the development of more efficient medicines to treat Acanthamoeba infection.


Assuntos
Acanthamoeba/metabolismo , Aminopeptidases/imunologia , Aminopeptidases/metabolismo , Complemento C3/metabolismo , Proteínas de Protozoários/imunologia , Proteínas de Protozoários/metabolismo , Acanthamoeba/isolamento & purificação , Amebíase/parasitologia , Aminopeptidases/genética , Sistemas CRISPR-Cas , Humanos , Lagos/parasitologia , Proteínas de Protozoários/genética , Solo/parasitologia
19.
Parasitol Res ; 118(6): 1953-1961, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31069536

RESUMO

The genus Acanthamoeba can cause Acanthamoeba keratitis (AK) and granulomatous amoebic encephalitis (GAE). The treatment of these illnesses is hampered by the existence of a resistance stage that many times causes infection relapses. In an attempt to add new agents to our chemotherapeutic arsenal against acanthamebiasis, two Acanthamoeba isolates were treated in vitro with newly synthesized biguanide dendrimers. Trophozoite viability analysis and ultrastructural studies showed that dendrimers prevent encystment by lysing the cellular membrane of the amoeba. Moreover, one of the dendrimers showed low toxicity when tested on mammalian cell cultures, which suggest that it might be eventually used as an amoebicidal drug or as a disinfection compound in contact lens solutions.


Assuntos
Ceratite por Acanthamoeba/tratamento farmacológico , Acanthamoeba/efeitos dos fármacos , Amebicidas/farmacologia , Biguanidas/farmacologia , Clorexidina/análogos & derivados , Dendrímeros/farmacologia , Encefalite/tratamento farmacológico , Acanthamoeba/classificação , Acanthamoeba/isolamento & purificação , Animais , Linhagem Celular Tumoral , Clorexidina/farmacologia , Soluções para Lentes de Contato , Encefalite/parasitologia , Células HeLa , Humanos , Trofozoítos/efeitos dos fármacos
20.
Ned Tijdschr Geneeskd ; 1632019 05 16.
Artigo em Holandês | MEDLINE | ID: mdl-31120209

RESUMO

Infectious keratitis in contact lens wearers Infectious keratitis is a sight-threatening complication in contact lens wearers. The infection is most frequently caused by bacteria (Pseudomonas aeruginosa). However, fungi or Acanthamoeba are found in increasing frequency. Three cases illustrate a characteristic course: patient A (11-year-old male) was treated for three weeks before the characteristic aspect of Acanthamoeba keratitis was recognized and confirmed. Patient B (45-year-old female) developed a severe corneal ulcer within 4 days; microbiological diagnostics confirmed Pseudomonas aeruginosa keratitis. Examination of patient C (27-year-old female) showed an infiltrate with satellites, typical of fungal keratitis. It is important to check the use of contact lenses in patients with keratitis. Referral to the ophthalmologist is mandatory: immediate in cases with an infiltrate. A dentritiform epithelial lesion in a contact lens wearer is indicative of Acanthamoeba keratitis, whereas fungal keratitis shows satellites or feathering edges. Steroids may only be prescribed by an ophthalmologist after confirmation of the causative agent.


Assuntos
Ceratite por Acanthamoeba/diagnóstico , Lentes de Contato/efeitos adversos , Ceratite/microbiologia , Infecções por Pseudomonas/complicações , Acanthamoeba/isolamento & purificação , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pseudomonas aeruginosa/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...