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Journal of Medical Microbiology Jan 2020keratitis is a sight-threatening corneal infection that is commonly reported among contact lens users and those suffering from corneal trauma. The prevalence of...
keratitis is a sight-threatening corneal infection that is commonly reported among contact lens users and those suffering from corneal trauma. The prevalence of species or genotypes in causing keratitis infection is not well known. This study was conducted to identify and genotype isolates from keratitis patients, targeting the ribosomal nuclear subunit () region, and describe the associated clinical presentation and treatment outcome. Thirty culture-confirmed patients with keratitis, identified in a tertiary eye care centre in South India during the period from December 2016 to December 2018, were included in this study. The data collected from patient records include demographic details, history of illness, mode of trauma, treatment history and follow-up status. The genotype and species were identified based on the sequence and phylogenetic tree analysis. was the most predominant keratitis-causing species, followed by and . Three major genotypes were identified (T4, T11 and T12), with the T4 genotype being the most predominant, with four subclusters, i.e. T4A, T4B, T4D and T4E. This is the first report on corneal infection by the T11 genotype and the T12 genotype. No significant correlation was observed between the clinical outcomes of corneal disease and the genotypes or species. genotyping is very effective in identifying the species and genotype in keratitis. Genotyping of spp. will help to advance our understanding of genotype-specific pathogenesis and geographical distribution.
Topics: Acanthamoeba Keratitis; Acanthamoeba castellanii; Genes, rRNA; Genotype; Genotyping Techniques; Humans; India; Phylogeny; Tertiary Care Centers
PubMed: 31846414
DOI: 10.1099/jmm.0.001121 -
Antibiotics (Basel, Switzerland) Feb 2022is a ubiquitous opportunistic protozoan pathogen that is known to cause blinding keratitis and rare, but usually fatal, granulomatous encephalitis. The difficulty in...
is a ubiquitous opportunistic protozoan pathogen that is known to cause blinding keratitis and rare, but usually fatal, granulomatous encephalitis. The difficulty in treating infections and the toxicity issues of the current treatments emphasize the need to use alternative agents with amoebicidal activity. The aim of this study was to evaluate the in vitro antiamoebic activity of three third-generation statins-cerivastatin, pitavastatin and rosuvastatin-against both cysts and trophozoites of the following four strains of Neff, and . Furthermore, programmed cell death (PCD) induction traits were evaluated by measuring chromatin condensation, damages at the mitochondrial level, production of reactive oxygen species (ROS) and the distribution of actin cytoskeleton fibers. Neff was the strain most sensitive to all the statins, where cerivastatin showed the lowest amoebicidal activity for both trophozoite and cyst forms (0.114 ± 0.050 and 0.704 ± 0.129 µM, respectively). All the statins were able to cause DNA condensation, collapse in the mitochondrial membrane potential and a reduction in ATP level production, and disorganization of the total actin fibers in the cytoskeleton of all the evaluated strains. Our results showed that the tested statins were able to induce PCD compatible events in the treated amoebae, including chromatin condensation, collapse in the mitochondrial potential and ATP levels, cytoskeleton disassembly and ROS generation.
PubMed: 35203882
DOI: 10.3390/antibiotics11020280 -
European Journal of Pharmaceutics and... Nov 2022Statins are effective sterol lowering agents with high amoebicidal activity. Nevertheless, due to their poor aqueous solubility, they remain underused especially in eye...
Statins are effective sterol lowering agents with high amoebicidal activity. Nevertheless, due to their poor aqueous solubility, they remain underused especially in eye drop formulation. The aim of the present study is to develop Pitavastatin loaded nanoparticles suitable for ophthalmic administration and designed for the management of Acanthamoeba Keratitis. These nanocarriers are aimed to solve both the ophthalmic route-associated problems and the limited aqueous drug solubility issues of Pitavastatin. Nanoparticles were obtained by a nanoprecipitation-solvent displacement method and their amoebicidal activity was evaluated against four strains of Acanthamoeba: A. castellanii Neff, A. polyphaga, A. griffini and A. quina. In Acanthamoeba polyphaga, the effect of the present nanoparticles was investigated with respect to the microtubule distribution and several programmed cell death features. Nanoparticles were able to eliminate all the tested strains and Acanthamoeba polyphaga was determined to be the most resistance strain. Nanoparticles induced chromatin condensation, autophagic vacuoles and mitochondria dysfunction.
Topics: Humans; Acanthamoeba Keratitis; Administration, Ophthalmic; Acanthamoeba; Amebicides; Cell Death; Autophagy; Nanoparticles
PubMed: 36162636
DOI: 10.1016/j.ejpb.2022.09.020 -
Acta Tropica Apr 2021Amoebae of the genus Acanthamoeba are worldwide distributed causative agents of serious human infections such as granulomatous amoebic encephalitis (GAE) and...
Amoebae of the genus Acanthamoeba are worldwide distributed causative agents of serious human infections such as granulomatous amoebic encephalitis (GAE) and Acanthamoeba keratitis (AK). To date, treatment of these infections is non-uniform and frequently unsuccessful. Recently, the phosphonium salts were studied for their high levels of antimicrobial activity. This work was aimed to investigate the cytotoxic effect of metronidazole and two phosphonium salts (PS1, PS2) on two clinical Acanthamoeba isolates. The isolates showed distinctly higher susceptibility to both phosphonium salts than to metronidazole. The highest susceptibility was noted to PS1 after 48 h of incubation. Metronidazole derivate PS2 showed higher susceptibility than metronidazole. The values of EC of PS2 were approximately twenty times lower than EC of metronidazole for Acanthamoeba lugdunensis strain and sixteen times lower for Acanthamoeba quina strain after 48 h. Although the therapeutic effect of metronidazole in Acanthamoeba infections is usually insufficient, its derivatisation can result in a significantly higher amoebicidal effect. Cytomorphological changes of trophozoites after exposure to tested compounds included rounding up of the cells, damage of membrane integrity, presence of pathological protrusions, elongation of the cells or pseudocyst-like stages. Obtained results indicate possible therapeutic potential of studied phosphonium salts.
Topics: Acanthamoeba; Amebicides; Animals; Genotype; Humans; Metronidazole; Trophozoites
PubMed: 33465352
DOI: 10.1016/j.actatropica.2021.105830 -
Parasite Epidemiology and Control Nov 2021spp. are commonest opportunistic amoebae, which ubiquitous in various environmental resources. species are the causative agents of amoebic keratitis, granulomatous...
BACKGROUND
spp. are commonest opportunistic amoebae, which ubiquitous in various environmental resources. species are the causative agents of amoebic keratitis, granulomatous amoebic encephalitis and i.e. in immunocompromised and immunocompetent patients. Moreover spp. can act as reservoir and transmission agent of bacterial pathogens. Due to this issue the aim of this study was to characterized spp. genotypes in dust and soil of hospital samples from Khomein of Iran.
METHODS
In a cross sectional study, a total of 100 soil and dust samples were collected from hospital environment of Khomein Iran, and analyzed for the presence of spp. based on phenotypic and molecular methods including PCR amplification and sequence analysis of 18SrRNA. A total of 5 isolates were sequenced, and different genotypes of isolates were detected via direct sequence analysis.
RESULTS
The results showed that 20% of samples (20/100) were positive for while only 5 cases were successfully cultured in NNM medium and were subjected to molecular assay. were the prevalent identified species that were belonged to T4 and T5 genotypes.
CONCLUSIONS
spp. are the most prevalent free living amoeba in the dust and soil of hospital environment. Moreover, due to the presence of potentially pathogenic T4 genotypes in our hospital, it is recommended that in health and hygienic programs elimination of FLA should be considered.
PubMed: 34584991
DOI: 10.1016/j.parepi.2021.e00224 -
International Journal For Parasitology.... Dec 2021Free-living amoebae of Acanthamoeba spp. are causative agents of human infections such as granulomatous amoebic encephalitis (GAE) and Acanthamoeba keratitis (AK). The...
Free-living amoebae of Acanthamoeba spp. are causative agents of human infections such as granulomatous amoebic encephalitis (GAE) and Acanthamoeba keratitis (AK). The exploration of innovative chemical entities from natural sources that induce intrinsic apoptotic pathway or a Programmed Cell Death (PCD) in Acanthamoeba protozoa is essential to develop new therapeutic strategies. In this work, the antiamoeboid activity of squamins C-F (1-4), four cyclooctapeptides isolated from Annona globiflora was tested in vitro against Acanthamoeba castellanii Neff, A. polyphaga, A. quina, and A. griffini, and a structure-activity relationship was also established. The most sensitive strain against all tested cyclooctapeptides was A. castellanii Neff being the R conformers of the S-oxo-methionine residue, squamins D (2) and F (4), the most active against the trophozoite stage. It is remarkable that all four peptides showed no cytotoxic effects against murine macrophages cell line J774A.1. The analysis of the mode of action of squamins C-F against A. castellanii indicate that these cyclopeptides induced the mechanisms of programmed cell death (PCD). All peptides trigger mitochondrial damages, significant inhibition of ATP production compared to the negative control, chromatin condensation and slight damages in membrane that affects its permeability despite it conserves integrity at the IC for 24 h. An increase in reactive oxygen species (ROS) was observed in all cases.
Topics: Acanthamoeba Keratitis; Acanthamoeba castellanii; Amebiasis; Animals; Annona; Humans; Mice; Trophozoites
PubMed: 34411895
DOI: 10.1016/j.ijpddr.2021.08.003 -
The Korean Journal of Parasitology Jun 1998Subgenus classification of Acanthamoeba remains uncertain. Twenty-three reference strains of Acanthamoeba including 18 (neo)type-strains were subjected for...
Subgenus classification of Acanthamoeba remains uncertain. Twenty-three reference strains of Acanthamoeba including 18 (neo)type-strains were subjected for classification at the subgenus level by riboprinting. PCR/RFLP analysis of 18S rRNA gene (rDNA). On the dendrogram reconstructed on the basis of riboprint analyses, two type-strains (A. astronyxis and A. tubiashi) of morphological group 1 diverged early from the other strains and were quite distinct from each other. Four type-strains of morphological group 3, A. culbertsoni, A. palestinensis, A. healyi were considered taxonomically valid, but A. pustulosa was regarded as an invalid synonym of A. palestinensis. Strains of morphological group 2 were classified into 6 subgroups. Among them, A. griffini which has an intron in its 18S rDNA was the most divergent from the remaining strains. Acanthamoeba castellanii Castellani, A. quina Vil3, A. lugdunensis L3a, A. polyphaga Jones, A. triangularis SH621, and A. castellanii Ma strains belonged to a subgroup, A. castellanii complex. However, A. quina and A. lugdunensis were regarded as synonyms of A. castellanii. The Chang strain could be regarded as A. hatchetti. Acanthamoeba mauritaniensis, A. divionensis, A. paradivionensis could be considered as synonyms of A. rhysodes. Neff strain was regarded as A. polyphaga rather than as A. castellanii. It is likely that riboprinting can be applied for rapid identification of Acanthamoeba isolated from the clinical specimens and environments.
Topics: Acanthamoeba; Animals; DNA, Protozoan; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; RNA, Protozoan; RNA, Ribosomal, 18S
PubMed: 9637824
DOI: 10.3347/kjp.1998.36.2.69 -
Parasitology Research 1991The isoenzyme pattern of an Acanthamoeba, stock H-1, isolated from a patient with keratitis (Krankenhaus Heidberg, Hamburg) was compared with that of two strains of A....
The isoenzyme pattern of an Acanthamoeba, stock H-1, isolated from a patient with keratitis (Krankenhaus Heidberg, Hamburg) was compared with that of two strains of A. quina-A. lugdunensis (302-2, 312-1), two stocks of A. lenticulata (45, 89-1) and one strain of A. rhysodes (302-1). The isolated stock showed glucose-6-phosphate dehydrogenase (G-6-PDH), beta-hydroxybutyric dehydrogenase (beta-HBDH), alcohol dehydrogenase (ADH) and superoxide dismutase (SOD) isoenzyme patterns similar to those of A. quina-A. lugdunensis but their acid phosphatase (AP) patterns differed. Furthermore, cyst morphology showed that the patient-isolated stock belongs to group II of the taxonomic classification of Acanthamoeba. This stock was not thermophilic and exhibited non-pathogenic properties after its intranasal instillation into NMRI mice, whereas it killed BALB/c mice. Immunofluorescent studies revealed the presence of antibodies against Acanthamoeba in the patient's serum. Immunoblotting experiments showed that a 45-kDa protein reacted with this serum. Such an antigen was also detected in A. quina-A. lugdunensis and A. lenticulata. Lectin reactions with Canavalia ensiformis, Ricinus communis-120, Lotus tetragonolobus, Ulex europaeus I, Helix pomatia, Arachis hypogaea, Triticum vulgaris, Glycine maxima, Bauhinia purpurea and Mycoplasma gallisepticum demonstrated that only the A. lenticulata stocks could not be distinguished and that the H-1 stock was more similar to the A. lugdunensis 302-2 strain than to the other acanthamoebae.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Adult; Agglutination Tests; Animals; Biological Assay; Cell Nucleus; Cornea; Humans; Isoenzymes; Male; Mice
PubMed: 1924251
DOI: 10.1007/BF00928411 -
International Journal of Pharmaceutics Feb 2012Synthesis of five alkylphosphocholines with branched alkyl chains (Isophol-PCs) with different length of alkyl chains was described. Isophol(8)-PC and Isophol(12)-PC...
Synthesis of five alkylphosphocholines with branched alkyl chains (Isophol-PCs) with different length of alkyl chains was described. Isophol(8)-PC and Isophol(12)-PC represent new compounds. The physico-chemical properties of Isophol-PCs were determined, critical micelle concentration and types of formed aggregates in aqueous solutions were investigated. The biological activities of Isophol-PCs have been studied for the first time in the present study. Antimicrobial activities of alkylphosphocholines were studied against bacteria (Staphylococcus aureus, Escherichia coli), yeast (Candida albicans) and pathogenic free-living amoebae (Acanthamoeba lugdunensis and Acanthamoeba quina). A. lugdunensis and A. quina are relatively insusceptible to action of miltefosine (standard compound of alkylphosphocholines) and therefore they are good models for studies of amoebicidal action of the investigated compounds. Relationship between structure, physico-chemical and biological activities of Isophol-PCs was discussed. S. aureus and C. albicans were sensitive to action of Isophol(16)-PC, Isophol(20)-PC. E. coli was not sensitive to action of all studied alkylphosphocholines in the concentrations equal to, or less than 10mM. Among all the synthesized compounds, Isophol(16)-PC had the highest level of activity against both strains of Acanthamoeba. The minimum trophocidal concentrations of Isophol(16)-PC against A. lugdunensis and A. quina are about four times lower than the minimum trophocidal concentrations of miltefosine against both strains.
Topics: Acanthamoeba; Anti-Infective Agents; Candida albicans; Escherichia coli; Micelles; Microbial Sensitivity Tests; Molecular Structure; Phosphorylcholine; Staphylococcus aureus; Structure-Activity Relationship; Time Factors
PubMed: 22178895
DOI: 10.1016/j.ijpharm.2011.11.047 -
The Korean Journal of Parasitology Sep 1999We investigated the value of mitochondrial small subunit rRNA gene (mt SSU rDNA) PCR-RFLP as a taxonomic tool for Acanthamoeba isolates with close inter-relationships....
We investigated the value of mitochondrial small subunit rRNA gene (mt SSU rDNA) PCR-RFLP as a taxonomic tool for Acanthamoeba isolates with close inter-relationships. Twenty-five isolates representing 20 species were included in the analysis. As in nuclear 18S rDNA analysis, two type strains (A. astronyxis and A. tubiashi) of morphological group 1 diverged earliest from the other strains, but the divergence between them was less than in 18S riboprinting. Acanthamoeba griffini of morphological group 2 branched between pathogenic (A. culbertsoni A-1 and A. healyi OC-3A) and nonpathogenic (A. palestinensis Reich, A. pustulosa GE-3a, A. royreba Oak Ridge, and A lenticulata PD2S) strains of morphological group 3. Among the remaining isolates of morphological group 2, the Chang strain had the identical mitochondrial riboprints as the type strain of A. hatchetti. AA2 and AA1, the type strains of A. divionensis and A. paradivionensis, respectively, had the identical riboprints as A. quina Vil3 and A. castellanii Ma. Although the branching orders of A. castellanii Neff, A. polyphaga P23, A. triangularis SH621, and A. lugdunensis L3a were different from those in 18S riboprinting analysis, the results obtained from this study generally coincided well with those from 18S riboprinting. Mitochondrial riboprinting may have an advantage over nuclear 18S rDNA riboprinting because the mt SSU rDNAs do not seem to have introns that are found in the 18S genes of Acanthamoeba and that distort phylogenetic analyses.
Topics: Acanthamoeba; Animals; DNA, Mitochondrial; DNA, Protozoan; DNA, Ribosomal; Phylogeny; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length
PubMed: 10507226
DOI: 10.3347/kjp.1999.37.3.181