RESUMO
Amoebic infections have been described in humans and animals, causing lesions in specific organs or as systemic infections. In both animals and humans, immunocompromised patients are predisposed to the infection. The present report described the macroscopic and histologic findings in a Quarter horse filly who presented with a systemic infection caused by Acanthamoeba spp. that was characterized by multinodular lesions in lung, kidney, heart, submandibular lymph node, and lip. Histopathology revealed dense inflammatory infiltrates composed of neutrophils, histiocytes, occasional multinucleated giant cells, and numerous intralesional trophozoites. Immunohistochemistry was positive for Acanthamoeba spp. trophozoites in lungs, kidneys, heart, submandibular lymph node, and lip. No predisposing conditions were identified.(AU)
Assuntos
Animais , Acanthamoeba/patogenicidade , Amebíase/diagnóstico , Amebíase/veterinária , Cavalos/microbiologia , Pulmão/microbiologia , AmoebaRESUMO
Amoebic infections have been described in humans and animals, causing lesions in specific organs or as systemic infections. In both animals and humans, immunocompromised patients are predisposed to the infection. The present report described the macroscopic and histologic findings in a Quarter horse filly who presented with a systemic infection caused by Acanthamoeba spp. that was characterized by multinodular lesions in lung, kidney, heart, submandibular lymph node, and lip. Histopathology revealed dense inflammatory infiltrates composed of neutrophils, histiocytes, occasional multinucleated giant cells, and numerous intralesional trophozoites. Immunohistochemistry was positive for Acanthamoeba spp. trophozoites in lungs, kidneys, heart, submandibular lymph node, and lip. No predisposing conditions were identified.
Assuntos
Animais , Acanthamoeba/patogenicidade , Amebíase/diagnóstico , Amebíase/veterinária , Cavalos/microbiologia , Pulmão/microbiologia , AmoebaRESUMO
Free-living amoebae of the genus Acanthamoeba have been associated with keratitis and encephalitis. Some factors related to their pathogenic potential have been described, including the release of hydrolytic enzymes, and the adhesion and phagocytosis processes. However, other factors such as their effect over the hemodynamics and microcirculation elements have not been fully investigated. This work determines the in vitro activity of potentially pathogenic environmental isolates of Acanthamoeba genotype T4 and T5 over erythrocytes and platelets. The hemolytic activity (dependent and independent of contact), as well as the production of ADP of ten environmental isolates of Acanthamoeba obtained from dental units, combined emergency showers, dust, and hospital water, were measured. Tests were carried out over erythrocytes in suspension and blood agar plates, incubated at 4 °C, room temperature and 37 °C. Erythrophagocytosis and platelet aggregation assays were also performed. Live trophozoites of all of the isolates tested showed a hemolytic activity that was temperature-dependent. Over erythrocytes in suspension, variable hemolysis percentages were obtained: a maximum of 41% and a minimum of 15%. Regarding hemolysis over agar plates, two patterns of hemolysis were observed: double and simple halos. Conditioned medium and crude extracts of trophozoites did not show hemolytic activity. Erythrophagocytosis by Acanthamoeba was also observed; however, no production of ADP was determined by the employed methodology.
Assuntos
Acanthamoeba/fisiologia , Plaquetas/parasitologia , Meio Ambiente , Eritrócitos/parasitologia , Acanthamoeba/classificação , Acanthamoeba/genética , Acanthamoeba/patogenicidade , Difosfato de Adenosina/metabolismo , Doenças Transmissíveis Emergentes/parasitologia , Meios de Cultivo Condicionados , Eritrócitos/fisiologia , Genótipo , Hemólise , Humanos , Fagocitose , Agregação Plaquetária , Temperatura , Trofozoítos/classificação , Trofozoítos/genética , Trofozoítos/patogenicidade , Trofozoítos/fisiologiaRESUMO
Acanthamoeba spp. are free-living amoebae with a worldwide distribution. These amoebae can cause granulomatous amoebic encephalitis and amoebic keratitis in humans. Proteases are considered virulence factors in pathogenic Acanthamoeba. The objective of this study was to evaluate the behavior of Acanthamoeba mauritaniensis, a nonpathogenic amoeba. We analyzed the cytopathic effect of A. mauritaniensis on RCE1(5â¯T5) and MDCK cells and compared it to that of Acanthamoeba castellanii. A partial biochemical characterization of proteases was performed in total crude extracts (TCE) and conditioned medium (CM). Finally, we evaluated the effect of proteases on tight junction (TJ) proteins and the transepithelial electrical resistance of MDCK cells. The results showed that this amoeba can induce substantial damage to RCE1(5T5) and MDCK cells. Moreover, the zymograms and Azocoll assays of amoebic TCE and CM revealed different protease activities, with serine proteases being the most active. Furthermore, A. mauritaniensis induced the alteration and degradation of MDCK cell TJ proteins with serine proteases. After genotyping this amoeba, we determined that it is an isolate of Acanthamoeba genotype T4D. From these data, we suggest that A. mauritaniensis genotype T4D behaves similarly to the A. castellanii strain.
Assuntos
Acanthamoeba/genética , Acanthamoeba/patogenicidade , Genótipo , Acanthamoeba/enzimologia , Animais , Cães , Células Epiteliais/parasitologia , Células Epiteliais/patologia , Células Madin Darby de Rim Canino , Serina Proteases/metabolismo , Proteínas de Junções Íntimas/metabolismoRESUMO
The epithelium represents the first and most extensive line of defence against pathogens, toxins and pollutant agents in humans. In general, pathogens have developed strategies to overcome this barrier and use it as an entrance to the organism. Entamoeba histolytica, Naegleriafowleri and Acanthamoeba spp. are amoebae mainly responsible for intestinal dysentery, meningoencephalitis and keratitis, respectively. These amoebae cause significant morbidity and mortality rates. Thus, the identification, characterization and validation of molecules participating in host-parasite interactions can provide attractive targets to timely intervene disease progress. In this work, we present a compendium of the parasite adhesins, lectins, proteases, hydrolases, kinases, and others, that participate in key pathogenic events. Special focus is made for the analysis of assorted molecules and mechanisms involved in the interaction of the parasites with epithelial surface receptors, changes in epithelial junctional markers, implications on the barrier function, among others. This review allows the assessment of initial host-pathogen interaction, to correlate it to the potential of parasite invasion.
Assuntos
Acanthamoeba/patogenicidade , Entamoeba histolytica/patogenicidade , Células Epiteliais/parasitologia , Interações Hospedeiro-Parasita , Naegleria fowleri/patogenicidade , Infecções por Protozoários/parasitologia , Acanthamoeba/metabolismo , Animais , Entamoeba histolytica/metabolismo , Células Epiteliais/metabolismo , Humanos , Naegleria fowleri/metabolismo , Infecções por Protozoários/metabolismoRESUMO
Acanthamoeba keratitis is an ophthalmic disease with no specific treatment that specially affects contact lens users. The silencing of serine phosphatase (SP) and glycogen phosphorylase (GP) proteins produced by Acanthamoeba has been shown to significantly reduce the cytopathic effect, although no vehicle was proposed yet to deliver the siRNA sequences to the trophozoites. In this study, PEGylated cationic liposomes were proposed and optimized using Box-Behnken design. The influence of DOTAP:DOPE ratio, DSPE-PEG concentration, and siRNA/DOTAP charge ratio were evaluated over both biological response and physicochemical properties of liposomes. The ratio of DOTAP:DOPE had an effect in the trophozoite activity whereas the charge ratio influenced both size and protease activity. The predicted values were very close to the observed values, yielding a formulation with good activity and toxicity profile, which was used in the following experiments. A murine model of ocular keratitis was treated with siGP + siSP-loaded liposomes, as well as their respective controls, and combined treatment of liposomes and chlorhexidine. After 15 days of eight daily administrations, the liposomal complex combined with chlorhexidine was the only treatment able to reverse the more severe lesions associated with keratitis. There was 60% complete regression in corneal damage, with histological sections demonstrating the presence of an integral epithelium, without lymphocytic infiltrate. The set of results demonstrate the efficacy of a combined therapy based on siRNA with classical drugs for a better prognosis of keratitis caused by Acanthamoeba.
Assuntos
Ceratite por Acanthamoeba/terapia , Acanthamoeba/efeitos dos fármacos , Clorexidina/farmacologia , Sistemas de Liberação de Medicamentos/métodos , Lipossomos/química , Proteínas de Protozoários/antagonistas & inibidores , Trofozoítos/efeitos dos fármacos , Acanthamoeba/enzimologia , Acanthamoeba/patogenicidade , Ceratite por Acanthamoeba/parasitologia , Ceratite por Acanthamoeba/patologia , Animais , Córnea/efeitos dos fármacos , Córnea/parasitologia , Córnea/patologia , Modelos Animais de Doenças , Esquema de Medicação , Composição de Medicamentos/métodos , Quimioterapia Combinada , Análise Fatorial , Ácidos Graxos Monoinsaturados/química , Regulação da Expressão Gênica , Glicogênio Fosforilase/antagonistas & inibidores , Glicogênio Fosforilase/genética , Glicogênio Fosforilase/metabolismo , Humanos , Lipossomos/metabolismo , Fosfatidiletanolaminas/química , Monoéster Fosfórico Hidrolases/antagonistas & inibidores , Monoéster Fosfórico Hidrolases/genética , Monoéster Fosfórico Hidrolases/metabolismo , Polietilenoglicóis/química , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Compostos de Amônio Quaternário/química , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Wistar , Trofozoítos/enzimologia , Trofozoítos/patogenicidadeRESUMO
Little is known about the prevalence of Balamuthia mandrillaris within the environment due to its difficult isolation, but once an axenic culture is established, it is relatively easy to maintain. As most of the time researchers are interested mainly in isolating B. mandrillaris from environmental samples, the flora that accompanies it becomes second in importance. Therefore, this study aimed to determine which potentially pathogenic free-living amoebae, in addition to B. mandrillaris, could be found co-inhabiting a source of natural thermal water called "Agua Caliente" (Mexico), where this amoeba has previously been detected twice by molecular methods. A third sampling from this same source was carried out to try to isolate B. mandrillaris and other free-living amoebae using 37 and 45⯰C as isolation temperatures. For PCR techniques, specific primers were used for B. mandrillaris, Naegleria fowleri, and Acanthamoeba species, plus a universal primer set for the eukaryotic 18S SSU rRNA gene for other isolated amoebae. PCR products were sequenced for final identification. 42 strains of the primary isolate were obtained, but only 34 could be kept in culture. Of them, 23 strains were identified as Naegleria lovaniensis, eight strains as Acanthamoeba jacobsi, two strains as Stenamoeba sp. and only one was identified as Vermamoeba vermiformis. The isolation of B. mandrillaris was once again not successful, but the presence of potentially pathogenic and nonpathogenic free-living amoebae is reported for the first time in this type of water in Mexico thanks to molecular methodology.
Assuntos
Amoeba/patogenicidade , Fontes Termais/parasitologia , Acanthamoeba/classificação , Acanthamoeba/genética , Acanthamoeba/isolamento & purificação , Acanthamoeba/patogenicidade , Amoeba/classificação , Amoeba/genética , Amoeba/isolamento & purificação , Balamuthia mandrillaris/classificação , Balamuthia mandrillaris/genética , Balamuthia mandrillaris/isolamento & purificação , Balamuthia mandrillaris/patogenicidade , DNA de Protozoário/química , DNA de Protozoário/isolamento & purificação , Genótipo , Fontes Termais/química , Concentração de Íons de Hidrogênio , México , Naegleria fowleri/classificação , Naegleria fowleri/genética , Naegleria fowleri/isolamento & purificação , Naegleria fowleri/patogenicidade , Filogenia , Reação em Cadeia da Polimerase , Espectrofotometria , TemperaturaRESUMO
Several strains of free-living amoebae belonging to the genus Acanthamoeba can cause a painful sight-threatening disease of the cornea known as Acanthamoeba keratitis (AK). The numbers of AK cases keep rising worldwide mainly due to an increase in contact lens wearers and lack of hygiene in the maintenance of contact lenses and their cases. We report a case of AK in a healthy young woman admitted to the Hospital de Clinicas in Porto Alegre, southern Brazil. Corneal scrapings were examined for the presence of Acanthamoeba strains. The initial isolate was characterized by morphological and genotypic properties. The isolate belonged to group III according to Pussard and Pons' cyst morphology. Analysis of its 18S rDNA sequence identified the isolate as genotype T4. The T4 genotype is the most commonly reported among keratitis isolates and the most common in environmental samples.
Assuntos
Ceratite por Acanthamoeba/parasitologia , Acanthamoeba/patogenicidade , Lentes de Contato/parasitologia , Córnea/parasitologia , Acanthamoeba/genética , Acanthamoeba/isolamento & purificação , Acanthamoeba/ultraestrutura , Ceratite por Acanthamoeba/epidemiologia , Ceratite por Acanthamoeba/etiologia , Adulto , Brasil/epidemiologia , Córnea/patologia , DNA de Protozoário/genética , DNA Ribossômico/genética , Feminino , Genótipo , Humanos , Microscopia , Análise de Sequência de DNA , NataçãoRESUMO
BACKGROUND: Acanthamoeba is the genus of free-living amoebae that is most frequently isolated in nature. To date, 20 Acanthamoeba genotypes have been described. Genotype T4 is responsible for approximately 90% of encephalitis and keratitis cases. Due to the ubiquitous presence of amoebae, isolation from environmental sources is not uncommon; to determine the clinical importance of an isolation, it is necessary to have evidence of the pathogenic potential of amoebae. OBJECTIVE: The aim of this study was to physiologically characterise 8 Acanthamoeba T4 isolates obtained from dental units and emergency combination showers and to determine their pathogenic potential by employing different laboratory techniques. METHODS: Eight axenic cultures of Acanthamoeba genotype T4 were used in pathogenic potential assays. Osmotolerance, thermotolerance, determination and characterisation of extracellular proteases and evaluation of cytopathic effects in MDCK cells were performed. FINDINGS: All of the isolates were osmotolerant, thermotolerant and had serine proteases from 44-122 kDa. Two isolates had cytopathic effects on the MDCK cell monolayer. MAIN CONCLUSION: The presence of Acanthamoeba T4 with pathogenic potential in areas such as those tested in this study reaffirms the need for adequate cleaning and maintenance protocols to reduce the possibility of infection with free-living amoebae.
Assuntos
Acanthamoeba , Microbiologia Ambiental , Acanthamoeba/genética , Acanthamoeba/isolamento & purificação , Acanthamoeba/patogenicidade , Genótipo , Humanos , FilogeniaRESUMO
BACKGROUND Acanthamoeba is the genus of free-living amoebae that is most frequently isolated in nature. To date, 20 Acanthamoeba genotypes have been described. Genotype T4 is responsible for approximately 90% of encephalitis and keratitis cases. Due to the ubiquitous presence of amoebae, isolation from environmental sources is not uncommon; to determine the clinical importance of an isolation, it is necessary to have evidence of the pathogenic potential of amoebae. OBJECTIVE The aim of this study was to physiologically characterise 8 Acanthamoeba T4 isolates obtained from dental units and emergency combination showers and to determine their pathogenic potential by employing different laboratory techniques. METHODS Eight axenic cultures of Acanthamoeba genotype T4 were used in pathogenic potential assays. Osmotolerance, thermotolerance, determination and characterisation of extracellular proteases and evaluation of cytopathic effects in MDCK cells were performed. FINDINGS All of the isolates were osmotolerant, thermotolerant and had serine proteases from 44-122 kDa. Two isolates had cytopathic effects on the MDCK cell monolayer. MAIN CONCLUSION The presence of Acanthamoeba T4 with pathogenic potential in areas such as those tested in this study reaffirms the need for adequate cleaning and maintenance protocols to reduce the possibility of infection with free-living amoebae.
Assuntos
Humanos , Acanthamoeba/isolamento & purificação , Acanthamoeba/genética , Acanthamoeba/patogenicidade , Microbiologia Ambiental , Filogenia , GenótipoRESUMO
This study was developed in order to describe the early morphological events observed during the invasion of two pathogenic strains of Acanthamoeba (genotype T4); A. castellanii and A. culbertsoni, at the olfactory meatus and cerebral, pulmonary, renal, hepatic and splenic tissues levels, an in vivo invasion study. Histological and immunohistochemical description of the events at 24, 48, 72, and 96 h postintranasal inoculations of BALB/c mice was performed. A. castellanii showed a higher invasion rate than A. culbertsoni, which was only able to reach lung and brain tissue in the in vivo model. The current study supports previous evidence of lack of inflammatory response during the early stages of infection. Acanthamoeba invasion of the CNS and other organs is a slow and contact-dependent process. The early morphological events during the invasion of amoebae include the penetration of trophozoites into different epithelia: olfactory, respiratory, alveolar space, and renal tubule, which resemble the process of amoebae invasion described in corneal tissue. The data suggest that after reaching the nasal epithelium, trophozoites continued invasion, separating and lifting the most superficial cells, then migrating and penetrating between the cell junctions without causing a cytolytic effect on adjacent cells. These results reaffirm the idea that contact-dependent mechanisms are relevant for amoebae of Acanthamoeba genus regardless of the invasion site.
Assuntos
Acanthamoeba/patogenicidade , Amebíase/patologia , Sistema Nervoso Central/parasitologia , Túbulos Renais/parasitologia , Mucosa Nasal/parasitologia , Mucosa Respiratória/parasitologia , Trofozoítos/metabolismo , Animais , Córnea/parasitologia , Modelos Animais de Doenças , Genótipo , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos BALB CRESUMO
T4 is the Acanthamoeba genotype most related to cases of granulomatous amoebic encephalitis (GAE) in immunocompromised patients and of keratitis in contact lens wearers. The determination of the pathogenic potential of Acanthamoeba clinical and environmental isolates using experimental models is extremely important to elucidate the capacity of free-living organisms to establish and cause disease in hosts. The aim of this study was to compare and evaluate the histopathology and culture between two different routes of experimental infection of T4 Acanthamoeba isolated from environmental and clinical source in mice (intracranial and intraperitoneal). Swiss isogenic healthy mice were inoculated with 10(4) trophozoites by intracranial (IC) and intraperitoneal (IP) routes and observed during 21 days. The brains from animals inoculated by the IC route were collected and from the animals of the IP inoculation group, the brains, livers, kidneys, spleens, and lungs were removed. The organs were prepared and appropriately divided to be evaluated with histopathology and culture. There was no significant difference between the inoculation routes in terms of isolates recovery (χ(2) = 0.09; p = 0.76). In the IC group, isolate recovery rate was significantly higher in histopathology than the one achieved by culture (χ(2) = 6.45; p < 0.01). Experimental infection revealed that all isolates inoculated could be considered invasive because it was possible to recover evolutive forms of Acanthamoeba in both routes. This work represents the first in vivo pathogenicity assay of primary isolation source in Central region of Brazil showing in vivo pathogenicity and hematogenous spread capacity of these protozoa, improving the knowledge on free-living amoebae isolates.
Assuntos
Acanthamoeba/genética , Acanthamoeba/patogenicidade , Amebíase/parasitologia , Ceratite/parasitologia , Acanthamoeba/classificação , Acanthamoeba/fisiologia , Ceratite por Acanthamoeba/parasitologia , Amebíase/patologia , Animais , Encéfalo/parasitologia , Brasil , Feminino , Genótipo , Humanos , Ceratite/patologia , Masculino , Camundongos , Trofozoítos/fisiologia , VirulênciaRESUMO
The virulence of various amoebic parasites has been correlated with the presence of electron-dense granules (EDGs) in the cytoplasm of trophozoites. Here, we report the finding by transmission electron microscopy of a large number of EDGs in a recent culture of Acanthamoeba culbertsoni, isolated from a severe case of human keratitis. When this isolate was maintained in culture for 6 mo, the granules almost disappeared. However, after induction of mice brain lesions with the long-term cultured isolate, recovered amoebas had abundant EDGs. Trophozoites of the original isolate, or those recovered from experimental lesions, secreted EDGs into the medium when incubated with MDCK cells. To analyze a possible cytotoxic effect the conditioned medium was incubated with MDCK monolayers. After 5 h, the media containing EDGs produced opening of the tight junctions; at 24 h, cell viability was compromised, and at 48 h most of the cells were detached from the monolayer. In contrast, trophozoites in long-term cultures did not release EDGs to the medium during incubation with MDCK cells, and the corresponding conditioned medium did not have any effect on MDCK monolayers. Our observations further support the hypothesis that EDGs play a role in the cytopathogenic mechanisms of A. culbertsoni.
Assuntos
Acanthamoeba/patogenicidade , Acanthamoeba/ultraestrutura , Amebíase/parasitologia , Ceratite/parasitologia , Acanthamoeba/genética , Acanthamoeba/isolamento & purificação , Animais , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Trofozoítos/crescimento & desenvolvimento , Trofozoítos/ultraestrutura , VirulênciaRESUMO
Pathogenic strains of Acanthamoeba genus are the causative agents of fatal granulomatous amoebic encephalitis and a serious sight-threatening infection of the eye known as Acanthamoeba keratitis. In a previous study, Acanthamoeba strains were isolated from nasal swabs collected from healthy individuals in Peru. In the present study, the pathogenic potential of the isolated strains was established based on temperature and osmotolerance assays as well as the secretion rate of extracellular proteases. Based on these experiments, four strains that showed the highest pathogenic potential were selected for sensitivity assays against two molecules (voriconazole and chlorhexidine) which are currently used for the treatment of Acanthamoeba infections. After performing sensitivity and activity assays, it was found that both drugs were active against the tested strains. However, voriconazole showed higher activity against the studied strains compared to chlorhexidine. Therefore, voriconazole should be established as a first-line treatment against Acanthamoeba infections at least in the studied region of Peru.
Assuntos
Acanthamoeba/efeitos dos fármacos , Amebicidas/farmacologia , Pirimidinas/farmacologia , Triazóis/farmacologia , Acanthamoeba/isolamento & purificação , Acanthamoeba/patogenicidade , Amebíase/tratamento farmacológico , Amebíase/parasitologia , Amebicidas/uso terapêutico , Clorexidina/farmacologia , Clorexidina/uso terapêutico , Humanos , Testes de Sensibilidade Parasitária , Peru , Pirimidinas/uso terapêutico , Triazóis/uso terapêutico , VoriconazolRESUMO
Free Living Amoebae (FLA) of Acanthamoeba genus are widely distributed in the environment and can be found in the air, soil and water; and have also been isolated from air-conditioning units. In humans, they are causative agents of a sight-threating infection of the cornea, Acanthamoeba keratitis (AK) and a fatal infection of the central nervous system known as Granulomatous Amoebic Encephalitis (GAE). In this study, a survey was conducted in order to determine the presence and pathogenic potential of free-living amoebae of Acanthamoeba genus in nasal swabs from individuals in two regions of Peru. Identification of isolates was based on cyst morphology and PCR-sequencing of the Diagnostic Fragment 3 to identify strains at the genotype level. The pathogenic potential of the isolates was also assayed using temperature and osmotolerance assays and extracellular proteases zymograms. The obtained results revealed that all isolated strains exhibited pathogenic potential. After sequencing the highly variable DF3 (Diagnostic Fragment 3) region in the 18S rRNA gene as previously described, genotype T4 was found to be the most common one in the samples included in this study but also genotype T15 was identified. To the best of our knowledge, this is the first study on the characterization of Acanthamoeba strains at the genotype level and the first report of genotype T4 and T15 in Peru.
Assuntos
Acanthamoeba/classificação , Mucosa Nasal/parasitologia , Acanthamoeba/genética , Acanthamoeba/patogenicidade , Genótipo , HumanosRESUMO
OBJETIVO: Investigar sazonalidade de ceratities infecciosas em serviço terciário no Brasil. MÉTODOS: Estudo retrospectivo de dados coletados do Laboratório de Microbiologia Ocular do Departamento de Oftalmologia da Universidade Federal de São Paulo de 2005 a 2009. Foram definidas como ceratites infecciosas aquelas com cultura positiva para o agente. Dados foram distribuídos de acordo com os meses do ano e modelos de regressão linear com variáveis "dummy" foram utilizados para testar sazonalidade. RESULTADOS: Foram diagnosticados 1.468 casos de ceratite infecciosa durante o período do estudo. Bactérias foram responsáveis por 80,3% dos casos seguidas por fungos (7%), Acanthamoeba (6%) e casos mistos (6,7%). Testes estatísticos não mostraram sazonalidade para bactérias (p=0,064), fungos (p=0,379), Acanthamoeba (p=0,062) ou casos mistos (p=0,441). CONCLUSÃO: Não foi observada sazonalidade nas ceratites infecciosas em nossa amostra.
PURPOSE: To investigate the seasonality of infectious keratitis in a tertiary hospital in Brazil. METHODS: Charts from the Ocular Microbiology Laboratory of the Department of Ophthalmology of the Federal University of Sao Paulo were reviewed from 2005 to 2009. Infectious keratitis were defined as those with positive culture. Data were distributed monthly and linear regressions with seasonal dummy models were used to test for seasonal trends. RESULTS: Total of 1,468 cases of keratitis was diagnosed during the study period. Bacterial keratitis were reponsible for 80.3% of all cases, followed by fungal (7%), and Acanthamoeba (6%); 6.7% were mixed cases. Statistical tests showed that there were no seasonal trends for bacteria (p=0.064), fungi (p=0.379), Acanthamoeba (p=0.062) or mixed infections (p=0.441). Conclusions: No seasonal trends for infectious keratitis were observed in our sample.
Assuntos
Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Infecções Oculares Bacterianas/epidemiologia , Infecções Oculares Fúngicas/epidemiologia , Infecções Oculares Parasitárias/epidemiologia , Ceratite/epidemiologia , Centros de Atenção Terciária/estatística & dados numéricos , Acanthamoeba/patogenicidade , Brasil/epidemiologia , Infecções Oculares Bacterianas/microbiologia , Infecções Oculares Fúngicas/microbiologia , Infecções Oculares Parasitárias/microbiologia , Ceratite/microbiologia , Estudos Retrospectivos , Estações do Ano , Fatores de TempoRESUMO
Prolonged culturing of many microorganisms leads to the loss of virulence and a reduction of their infective capacity. However, little is known about the changes in the pathogenic strains of Acanthamoeba after long culture periods. Our study evaluated the effect of prolonged culturing on the invasiveness of different isolates of Acanthamoeba in an in vivo rat model. ATCC strains of Acanthamoeba, isolates from the environment and clinical cases were evaluated. The in vivo model was effective in establishing the infection and differentiating the pathogenicity of the isolates and re-isolates. The amoebae cultured in the laboratory for long periods were less virulent than those that were recently isolated, confirming the importance of passing Acanthamoeba strains in animal models.
Assuntos
Acanthamoeba/patogenicidade , Amebíase/parasitologia , Cultura Axênica , Virulência/efeitos dos fármacos , Acanthamoeba/efeitos dos fármacos , Animais , Masculino , Ratos Wistar , Fatores de TempoRESUMO
Prolonged culturing of many microorganisms leads to the loss of virulence and a reduction of their infective capacity. However, little is known about the changes in the pathogenic strains of Acanthamoeba after long culture periods. Our study evaluated the effect of prolonged culturing on the invasiveness of different isolates of Acanthamoeba in an in vivo rat model. ATCC strains of Acanthamoeba, isolates from the environment and clinical cases were evaluated. The in vivo model was effective in establishing the infection and differentiating the pathogenicity of the isolates and re-isolates. The amoebae cultured in the laboratory for long periods were less virulent than those that were recently isolated, confirming the importance of passing Acanthamoeba strains in animal models.
Assuntos
Animais , Masculino , Cultura Axênica , Acanthamoeba/patogenicidade , Amebíase/parasitologia , Virulência/efeitos dos fármacos , Acanthamoeba/efeitos dos fármacos , Ratos Wistar , Fatores de TempoRESUMO
Among free-living amoeba in nature, species of the genus Acanthamoeba have been associated with human disease. These amoeba are among the most abundant protozoa in nature due to its cosmopolitan distribution and are able to survive in a wide variety of habitats because its low demand for food and in harsh environments by forming structures known as cysts. However, ecological changes and incursion of its different habitats have made this organism can invade a host and live as parasites within him. That's why this type of protozoa are known as amphizoic organism, because human can be constituted as its host, causing infections in the central nervous system, disseminated infections in skin and lungs, and keratitis. Thus, since an increase in the number of cases of Acanthamoeba infections has occurred worldwide, these protozoa have become increasingly important as agents of human disease. This review summarizes what is known of this kind of free-living amoeba, focusing on the biology, ecology, pathogenesis, diagnosis, treatment and human defense mechanism against infection by the amoeba.
Assuntos
Acanthamoeba , Amebíase/parasitologia , Infecções Oportunistas/parasitologia , Acanthamoeba/classificação , Acanthamoeba/patogenicidade , Acanthamoeba/fisiologia , Interações Hospedeiro-Parasita , HumanosRESUMO
Species of Acanthamoeba are frequently isolated from distinct environmental sources such as water, soil, dust and air. They are responsible to cause infections and disease in humans and animals. In addition, Acanthamoeba sp. are considered an important reservoir of bacteria, virus and fungi, which act as "Trojan horses" to protect these microorganisms of harsh environmental conditions. In this study, nine Acanthamoeba isolates from bromeliads phylloplane were identified based on the morphology of cyst and trophozoite forms. The genotype level was accessed by the sequence analysis of Acanthamoeba small-subunit rRNA gene. Genotypic characterization grouped five isolates in the genotype T2/T6, three in the T4 genotype and one in the genotype T16. The results obtained indicate that the genotype T2/T6 is common on phylloplane. To predict the pathogenic potential of the Acanthamoeba isolates, thermo and osmotolerance assays were employed, although all isolates were capable of surviving at temperatures of 37°C, other tests will be conducted in the future to determine the potential pathogenic of the isolates. Altogether, our results revealed the importance of the presence of Acanthamoeba associated with bromeliads in Rio Grande do Sul, Brazil, and the necessity for further studies to determine the environmental distribution and the role of these species.