Adhesion of Acanthamoeba on Scleral Contact Lenses According to Lens Shape.

Purpose: To investigate the adhesion of Acanthamoeba to scleral contact lens (ScCL) surface according to lens shape. Methods: Two strains of A. polyphaga (CDC:V062 and ATCC 30461) and one clinical Acanthamoeba isolate, were inoculated onto five contact lens (CL): one first-generation silicone hydrogel (SHCL; lotrafilcon B; adhesion control) containing plasma surface treatment; two ScCL (fluorosilicone acrylate) one containing surface treatment composed of plasma and the other containing plasma with Hydra-PEG, and two CL designed with a flat shape having the same material and surface treatments of the ScCL. Trophozoites that adhered to the lens's surfaces were counted by inverted optical light microscopy. Possible alterations of the lens surface that could predispose amoeba adhesion and Acanthamoeba attached to these lens surfaces were evaluated by scanning electron microscopy (SEM). Results: All strains revealed greater adhesion to the ScCL when compared with the flat lenses (P < 0.001). The clinical isolate and the ATCC 30461 had a higher adhesion (P < 0.001) when compared with the CDC:V062. A rough texture was observed on the surface of the lenses that have been examined by SEM. Also, SEM revealed that the isolates had a rounded appearance on the surface of the ScCL in contrast with an elongated appearance on the surface of the silicone hydrogel. Conclusions: The findings revealed that the curved shape of the ScCL favors amoeba adhesion.

Three encephalitis-causing amoebae and their distinct interactions with the host.

Naegleria fowleri, Balamuthia mandrillaris, and Acanthamoeba spp. can cause devastating brain infections in humans which almost always result in death. The symptoms of the three infections overlap, but brain inflammation and the course of the disease differ, depending on the amoeba that is responsible. Understanding the differences between these amoebae can result in the development of strategies to prevent and treat these infections. Recently, numerous scientific advancements have been made in the understanding of pathogenicity mechanisms in general, and the basic biology, epidemiology, and the human immune response towards these amoebae in particular. In this review, we combine this knowledge and aim to identify which factors can explain the differences between the lethal brain infections caused by N. fowleri, B. mandrillaris, and Acanthamoeba spp.

The Acanthamoeba SBDS, a cytoskeleton-associated gene, is highly expressed during phagocytosis and encystation.

BACKGROUND/PURPOSE: Shwachman-Bodian-Diamond syndrome (SBDS) protein is widely present in eukaryotes from vertebrates to protozoa. However, there are several variants within species, and previous studies have shown evidence that they may have additional functions. There are two SBDS-related proteins in Acanthamoeba. One is an rRNA metabolism protein of the SBDS family (ACA1_142090), and the other is SBDS (ACA1_204560). Although there is a conserved SBDS domain in the Acanthamoeba SBDS (ACA1_204560; AcSBDS), its function has not been reported. The aims of this study were to characterize the expression of AcSBDS during phagocytosis and encystation. METHODS: AcSBDS-specific primer was designed to amplify the genomic AcSBDS of Acanthamoeba ATCC-30010. The AcSBDS expression was examined using reverse transcription polymerase chain reaction (RT-PCR) and immunostaining after phagocytosis and encystation treatment. RESULTS: In this study, we found that the mRNA expression level of AcSBDS increased rapidly and that alternative splice variants were detected during phagocytosis and encystation processes. The results of immunofluorescence staining showed that the AcSBDS proteins accumulated surrounding phagocytosed bacteria. CONCLUSION: Our results suggest that AcSBDS may not only have ribosomal maturation features but also have cytoskeleton-associated functions related to phagocytosis and encystation.

Acanthamoeba keratitis: a review of biology, pathophysiology and epidemiology.

Acanthamoeba keratitis is an infection caused by a unicellular protozoan of the genus Acanthamoeba that is universally widespread. Until now, most cases were reported in contact lens wearers, although it is also a reality for non-wearers, mostly connected to corneal trauma. There is also a variation in incidence regarding the aetiology of the disease between developed and developing countries. PURPOSE: This work is based on a literature review, and the main goal is to deepen the knowledge about Acanthamoeba keratitis, presenting the main risk factors and focusing on prevention actions for this type of corneal infection since the treatments are not always effective. It targets specialists in visual health to strengthen their knowledge in this area, as well as to allow them to better inform their patients about hygiene care, appropriate measures of disinfection and ways to minimise the risk of infection. At this stage, it is important to highlight the essential role that practitioners play in fitting, monitoring and following-up patients to minimise the danger of infection. RECENT FINDINGS: It is well recognised that corneal trauma facilitates invasion by leaving an open door for microorganisms to penetrate the cornea. In addition to trauma, risk factors are mostly associated with patients' behaviours, such as interaction of contact lenses with contaminated water in the shower, swimming pools and beaches, etc., lack of hygiene habits with contact lenses and respective cases, and the use of ineffective disinfecting solutions. The fact that a disinfecting solution is not completely effective against trophozoites and/or cysts, both forms of Acanthamoeba's lifecycle, can cause the infection since one cyst alone leads to the emergence of a whole new population of Acanthamoeba. SUMMARY: It is necessary to reduce the risk of infection and, beyond the need to promote patient education to encourage correct CL hygiene behaviours, it should also be highlighted that there is an urgent need to enhance the efficacy of CL disinfection systems against all strains and both stages of Acanthamoeba through the creation of standardised methods. The ease of purchasing CLs without any supervision must also be considered a concern, and, in the near future, it is also important to develop and implement effective diagnostic methods and treatments for Acanthamoeba keratitis.

Acanthamoeba species isolated from Philippine freshwater systems: epidemiological and molecular aspects.

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.

The expression of TLR2 and TLR4 in the kidneys and heart of mice infected with Acanthamoeba spp.

BACKGROUND: Acanthamoeba spp. are cosmopolitan protozoans that cause infections in the brain, as well as extracerebral infections in the cornea, lungs and skin. Little is known about the mechanisms of the immunological response to these parasites in organs which are not their main biotope. Therefore, the purpose of this study was to determine the expression of TLR2 and TLR4 in the kidneys and heart of Acanthamoeba spp.-infected mice, with respect to the host's immunological status. METHODS: The mice were grouped into four groups: immunocompetent control mice; immunosuppressed control mice; immunocompetent Acanthamoeba spp.-infected mice; and immunosuppressed Acanthamoeba spp. infected mice. In the study, we used the amoebae T16 genotype which was isolated from a patient. The TLRs expressions in the kidneys and heart of mice were assessed by quantitative real-time polymerase chain reaction. Moreover, we visualized TLR2 and TLR4 proteins in the organs by immunohistochemical staining. RESULTS: In the kidneys, we observed a higher TLR2 expression in immunosuppressed mice at 24 days post-Acanthamoeba spp. infection (dpi) compared to the uninfected mice. There were no statistically significant differences in TLR4 expression in the kidneys between the immunocompetent and immunosuppressed mice, both of infected and uninfected mice. In the heart, we observed a difference in TLR2 expression in immunocompetent mice at 24 dpi compared to immunocompetent mice at 8 dpi. The immunocompetent Acanthamoeba spp.-infected mice had higher TLR4 expression at 8 dpi compared to the immunocompetent uninfected mice. CONCLUSIONS: Our results indicate that TLR2 is involved in response to Acanthamoeba spp. infection in the kidneys, whereas in the heart, both studied TLRs are involved.

In vitro activity of isavuconazole against three species of Acanthamoeba.

Acanthamoeba keratitis due to a genus of free-living amoebae is a severe corneal infection. Treatment of this disease is based on the combined use of antiseptics and other drugs, including azoles. We tested isavuconazole, the latest marketed azole, in vitro, against A. castellanii, A. lenticulata and A. hatchetti. Our results show that isavuconazole presents slight amoebistatic activity against A. castellanii trophozoites but no cysticidal activity. Isavuconazole could be used only in association for management of AK due to A. castellanii.

In vitro effects of environmental isolates of Acanthamoeba T4 and T5 over human erythrocytes and platelets.

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.

Experimental keratitis in rats caused by Acanthamoeba griffini: A kinetic histopathological study.

The aim of this study was to evaluate the inflammation process that resulted from the inoculation of Wistar Rats with Acanthamoeba griffini, a virulent T3 Acanthamoeba genotype that produces keratitis. Haematoxylin and eosin, periodic acid stain, immunohistochemistry and morphometry were used to analyse tissues from rats of an Acanthamoeba keratitis (AK) model. Two weeks after inoculating the rats with A griffini trophozoites, the thickness of the stroma had diminished, followed by an increase in thickness at 4 weeks. At the latter time, an abundance of inflammatory infiltrate cells was observed, some found to express IL-1ß, IL-10 and/or caspase 3. Intercellular adhesion molecule-1 was expressed in corneal blood vessels amid the abundant vascularization characteristic of the development of AK. Through an immunohistochemical technique, trophozoites were detected at 2 and 4 weeks post-inoculation. By 8 weeks, there were a low number of trophozoites and cysts and the corneas of infected rats were similar in thickness to those of the controls. Thus, the rats were capable of healing experimental AK in the present rat model. Diverse immunological mechanisms regulated the inflammatory process in acute AK induced by A griffini in a murine model.

Interactions of free-living amoebae with the rice fungal pathogen, Rhizoctonia solani.

OBJECTIVE: Rhizoctonia solani is a soil-borne fungal pathogen of many important crop plants. In rice, R. solani causes sheath blight disease, which results in devastating grain yield and quality losses. Few methods are available to control this pathogen and classic single gene resistance mechanisms in rice plants have not been identified. We hypothesize that alternate means of control are available in the environment including free-living amoebae. Amoebae are soil-, water- and air-borne microorganisms that are predominantly heterotrophic. Many amoeba species are mycophagous, and several harm their prey using mechanisms other than phagocytosis. Here, we used light and scanning electron microscopy to survey the interactions of R. solani with four amoeba species, with the goal of identifying amoebae species with potential for biocontrol. RESULTS: We observed a wide range of responses during interactions of R. solani with four different free-living amoebae. Two Acanthamoeba species encyst in co-cultures with R. solani at higher rates than medium without R. solani. Vermamoeba vermiformis (formerly Hartmanella vermiformis) attach to R. solani mycelium and are associated with mycelial shriveling and perforations of fungal cell walls, indicating an antagonistic interaction. No phenotypic changes were observed in co-cultures of Dictyostelium discoideum and R. solani.

Acanthamoeba in Southeast Asia - Overview and Challenges.

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.

Corticosteroid eye drop instillation aggravates the development of Acanthamoeba keratitis in rabbit corneas inoculated with Acanthamoeba and bacteria.

The role of topical corticosteroids in management of Acanthamoeba keratitis (AK) remains controversial. Using a rabbit AK model, we investigated whether corticosteroid use is a risk factor of AK. Acanthamoeba (1 × 105/ml) was incubated with two densities of P. aeruginosa (PA; high-PA: 1 × 108/ml, low-PA: 3 × 105/ml) before corneal inoculation. Rabbit corneas were inoculated with Acanthamoeba alone or Acanthamoeba plus PA and administered levofloxacin and betamethasone sodium phosphate (BSP) eye drops for 5 or 7 days. Infected rabbit eyes were evaluated for clinical score and Acanthamoeba by histological examination. Acanthamoeba alone and BSP treatment did not produce keratitis. Corneas inoculated with Acanthamoeba plus low-PA treated immediately with levofloxacin and BSP remained clear with few infiltrates. Corneas inoculated with Acanthamoeba plus low-PA treated with levofloxacin immediately and BSP 12 h later developed severe keratitis. Corneas inoculated with Acanthamoeba plus high-PA treated immediately with levofloxacin and BSP also developed severe keratitis. Acanthamoebae were detected by PAS staining in corneas inoculated with Acanthamoeba plus high-PA treated with levofloxacin and BSP. Topical corticosteroids have the potential to aggravate AK when cornea is infected by Acanthamoeba with a critical number of bacteria or when corticosteroids are given after infection has established by Acanthamoeba with small number of bacteria.

Pathogenic free-living amoebic encephalitis in Japan.

Over 600 cases of amoebic encephalitis caused by pathogenic free-living amoebas (Balamuthia mandrillaris, Acanthamoeba spp., and Naegleria fowleri) have been reported worldwide, and in Japan, 24 cases have been reported from the first case in 1976 up to 2018. Among these cases, 18 were caused by B. mandrillaris, four by Acanthamoeba spp., one by N. fowleri, and one was of unknown etiology. Additionally, eight cases were diagnosed with encephalitis due to pathogenic free-living amoebas before death, but only three cases were successfully treated. Unfortunately, all other cases were diagnosed by autopsy. These facts indicate that an adequate diagnosis is difficult, because encephalitis due to pathogenic free-living amoebas does not show typical symptoms or laboratory findings. Moreover, because the number of cases is limited, other cases might have been missed outside of those diagnosed by autopsy. Cases of encephalitis caused by B. mandrillaris have been reported from all over Japan, with B. mandrillaris recently isolated from soil in Aomori prefecture. Therefore, encephalitis caused by pathogenic free-living amoebas should be added to the differential diagnosis of encephalitis patients.

Efficient therapeutic effect of Nigella sativa aqueous extract and chitosan nanoparticles against experimentally induced Acanthamoeba keratitis.

Acanthamoeba keratitis (AK) is a devastating, painful corneal infection, which may lead to loss of vision. The development of resistance and failure of the currently used drugs represent a therapeutic predicament. Thus, novel therapies with lethal effects on resistant Acanthamoeba are necessary to combat AK. In the present study, the curative effect of Nigella sativa aqueous extract (N. sativa) and chitosan nanoparticles (nCs) and both agents combined were assessed in experimentally induced AK. All inoculated corneas developed varying grades of AK. The study medications were applied on the 5th day postinoculation and were evaluated by clinical examination of the cornea and cultivation of corneal scraps. On the 10th day posttreatment, a 100% cure of AK was obtained with nCs (100 µg/ml) in grades 1 and 2 of corneal opacity as well as with N. sativa 60 mg/ml-nCs 100 µg/ml in grades 1, 2, and 3 of corneal opacity, highlighting a possible synergistic effect. On the 15th day posttreatment, a 100% cure was reached with N. sativa aqueous extract (60 mg/ml). Moreover, on the 20th day posttreatment, N. sativa (30 mg/ml) provided a cure rate of 87.5%, while nCs (50 µg/ml) as well as N. sativa 30 mg/ml-nCs 50 µg/ml yielded a cure rate of 75%; the lowest percentage of cure (25%) was obtained with chlorhexidine (0.02%), showing a non-significant difference compared to the parasite control. The clinical outcomes were in agreement with the results of corneal scrap cultivation. The results of the present study demonstrate the effectiveness of N. sativa aqueous extract and nCs (singly or combined) when used against AK, and these agents show potential for the development of new, effective, and safe therapeutic alternatives.

Molecular characterization of bacterial, viral and fungal endosymbionts of Acanthamoeba isolates in keratitis patients of Iran.

Free-living amoebae belong to the genus Acanthamoeba; can feed on microbial population by phagocytosis, and with the capability to act as a reservoir and a vehicle of microorganisms to susceptible host. Therefore, the role of endosymbiosis in the pathogenesis of Acanthamoeba is complex and not fully understood. The aim of the present study was to identify bacterial, fungal, and human adenovirus (HADV) endosymbionts as well as evaluating the endosymbionts role of such organisms in the pathogenesis of Acanthamoeba in keratitis patients living in Iran. Fifteen Acanthamoeba (T4 genotype) isolates were recovered from corneal scrapes and contact lenses of patients with keratitis. Cloning and purification was performed for all isolate. Gram staining was performed to identify bacterial endosymbionts. DNA extraction, PCR, and nested PCR was set up to identify endosymbiont of amoeba. Evaluation of pathogenicity was conducted by osmo-tolerance and thermo-tolerance assays and cell culture, and then CPE (cytopathic effect) was survey. Statistical analysis was used between Acanthamoeba associated endosymbionts and Acanthamoeba without endosymbiont at 24, 48, 72, and 96 h. A p value < 0.05 was considered as significant, statistically. A total of 9 (60%) Acanthamoeba (T4 genotypes) isolates were successfully cloned for detecting microorganism endosymbionts. The only isolate negative for the presence of endosymbiont was ICS9. ICS7 (Pseudomonas aeruginosa, Aspergillus sp., and human adenovirus endosymbionts) and ICS2 (Escherichia coli endosymbiont) isolates were considered as Acanthamoeba associated endosymbionts. ICS7 and ICS2 isolates were highly pathogen whereas ICS9 isolate showed low pathogenicity in pathogenicity evaluated. Positive CPE for ICS7 and ICS2 isolates and negative CPE for ICS9 isolate were observed in cell culture. The average number of cells, trophozoites, and cysts among ICS7, ICS2, and ICS9 isolates at 24, 48, 72, and 96 h was significant. This is the first survey on microbial endosymbionts of Acanthamoeba in keratitis patients of Iran, and also the first report of Aspergillus sp, Achromobacter sp., Microbacterium sp., Brevibacillus sp, Brevundimonas sp and Mastadenovirus sp in Acanthamoeba as endosymbionts. Our study demonstrated that microbial endosymbionts can affect the pathogenicity of Acanthamoeba; however, further research is required to clarify the exact pattern of symbiosis, in order to modify treatment protocol.

The modulatory effect of Artemisia annua L. on toll-like receptor expression in Acanthamoeba infected mouse lungs.

The genus Acanthamoeba, which may cause different infections in humans, occurs widely in the environment. Lung inflammation caused by these parasites induces pulmonary pathological changes such as pulmonary necrosis, peribronchial plasma cell infiltration, moderate desquamation of alveolar cells and partial destruction of bronchial epithelial cells, and presence of numerous trophozoites and cysts among inflammatory cells. The aim of this study was to assess the influence of plant extracts from Artemisia annua L. on expression of the toll-like receptors TLR2 and TLR4 in lungs of mice with acanthamoebiasis. A. annua, which belongs to the family Asteraceae, is an annual plant that grows wild in Asia. In this study, statistically significant changes of expression of TLR2 and TLR4 were demonstrated. In the lungs of infected mice after application of extract from A. annua the expression of TLRs was observed mainly in bronchial epithelial cells, pneumocytes (to a lesser extent during the outbreak of infection), and in the course of high general TLR expression. TLR4 in particular was also visible in stromal cells of lung parenchyma. In conclusion, we confirmed that a plant extract of A. annua has a modulatory effect on components of the immune system such as TLR2 and TLR4.

Lyophilisation as a simple and safe method for long-term storage of free-living amoebae at ambient temperature.

Free-living amoebae (FLA) are protozoa ubiquitously found in nature. As some species or strains of these FLA are pathogenic for humans and animals, they represent objects of medical and parasitological research worldwide. Storage of valuable FLA strains in laboratories is often time- and energy-consuming and expensive. The shipment of such strains as frozen stocks is cumbersome and challenging in terms of cooling requirements as well as of transport regulations. To overcome these difficulties and challenges in maintenance and transport, we present a new method to generate lyophilised samples of non-cyst-forming FLA (Ripella (Vannella) spp.) and cyst-forming FLA (Acanthamoeba spp.) strains which guarantees a simple mechanism for long-term storage at ambient temperature, as well as easy handling and/or shipment. The survival rate of all FLA lyophilisates after short-term storage (2 months) was comparable to the survival rate of freeze cultures of the respective strains. Furthermore, the viability of Acanthamoeba spp. cysts after storage for 29 months was 20 to 40% following lyophilisation and rehydration, with strain variation.

First report of Acanthamoeba genotype T8 human keratitis.

Acanthamoeba has a worldwide distribution in the environment and it is capable of causing a painful sight-threatening disease of the cornea designated as Acanthamoeba keratitis (AK). Nowadays, the cases of AK have surged all over the world along with its disease burden due to increasing use of contact lenses used not only for optical correction but also for cosmetic purposes. In our present work, epithelial abrasion of a 27-year-old female soft contact lens wearer with keratitis was examined. Genotype identification was carried out with a real-time fluorescence resonance energy transfer polymerase chain reaction (PCR) assay based on sequence analysis of the 18S rRNA gene. Genotyping allowed the identification of a T8 group isolate. The analysis confirmed the importance of a complete diagnostic protocol, including a PCR assay, for the clinical diagnosis of AK from human samples. Acanthamoeba T8 should be considered as potential causative organism in keratitis in human.

Expression and Activity of COX-1 and COX-2 in Acanthamoeba sp.-Infected Lungs According to the Host Immunological Status.

Little is known about the pathomechanism of pulmonary infections caused by Acanthamoeba sp. Therefore, the aim of this study was to determine whether Acanthamoeba sp. may affect the expression and activity of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), resulting in the altered levels of their main products, prostaglandins (PGE2) and thromboxane B2 (TXB2), in lungs of immunocompetent or immunosuppressed hosts. Acanthamoeba sp. induced a strong expression of COX-1 and COX-2 proteins in the lungs of immunocompetent mice, which, however, did not result in significant differences in the expression of PGE2 and TXB2. Our immunohistochemical analysis showed that immunosuppression induced by glucocorticoids in Acanthamoeba sp.-infected mice caused a decrease in COX-1 and COX-2 (not at the beginning of infection) in lung tissue. These results suggest that similar to COX-2, COX-1 is an important mediator of the pathophysiology in experimental pulmonary acanthamoebiasis. We suggest that the signaling pathways important for Acanthamoeba sp. induction of lung infection might interact with each other and depend on the host immune status.

Adhesion of Acanthamoeba on Cosmetic Contact Lenses.

BACKGROUND: This study aimed to evaluate the adhesion of Acanthamoeba trophozoites on cosmetic contact lenses (CLs) with and without CL care multipurpose solution (MPS) treatment. METHODS: Acanthamoeba lugdunensis L3a trophozoites were inoculated onto disks trimmed from CLs: 1-day Acuvue moist, 1-day Acuvue define, Acuvue 2, and Acuvue 2 define. After 18-hour inoculation, the number of adherent trophozoites was counted under phase contrast microscopy. The effects of MPS, Opti-Free Express, soaking CLs for 6 hours, on Acanthamoeba adhesion were analyzed. Scanning electron microscopic examination was performed for assessment of Acanthamoeba attached on the lens surface. RESULTS: Acanthamoeba trophozoites showed greater adhesion to cosmetic CL (P = 0.017 for 1-day CL and P = 0.009 for 2-week CL) although there was no significant difference between the types of cosmetic CL. On all lenses, the number of adherent Acanthamoeba was significantly reduced after treatment with MPS (P < 0.001 for 1-day Acuvue moist, P = 0.046 for 1-day Acuvue define, P < 0.001 for Acuvue 2, and P = 0.015 for Acuvue 2 define), but there was still significant difference between conventional and cosmetic CLs (P = 0.003 for 1-day CL and P < 0.001 for 2-week CL, respectively). More attachment of Acanthamoeba was observed on colored area and the acanthopodia of Acanthamoeba was placed on the rough surface of colored area. CONCLUSION: Acanthamoeba showed a greater affinity for cosmetic CL and mostly attached on colored area. Although MPS that contained myristamidopropyl dimethylamine reduced the adhesion rate, there was a significant difference between conventional and cosmetic CLs.