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Frontiers in Medicine 2024infection is a rare condition primarily occurring in immunocompromised patients with extremely high mortality. Currently, there is no standard treatment for this...
BACKGROUND
infection is a rare condition primarily occurring in immunocompromised patients with extremely high mortality. Currently, there is no standard treatment for this condition, and successful treatment reports are scarce.
CASE PRESENTATION
We present a case of infection in a 63-year-old female patient with AIDS, who was admitted to our hospital with symptoms of fever, skin ulcers, subcutaneous nodules, and food regurgitation from the nose while eating. After initial empirical treatment failed, a biopsy of the subcutaneous nodule was performed, and metagenomic next-generation sequencing (mNGS) technology was used to detect pathogenic microorganisms in both the biopsy specimen and blood samples. The results revealed infection. Additionally, histopathological examination of the biopsy specimen and cytological examination of the secretions from the ulcer surface also confirmed this pathogenic infection. The patient's symptoms significantly improved upon discharge after adjusting the treatment regimen to a combination of anti-amebic therapy.
CONCLUSION
Immunocompromised patients presenting with unexplained fever and skin or sinus lesions should be evaluated for infection. Multi-drug combination therapy is required for this organism infection, and a standard treatment protocol still needs further research. Metagenomic next-generation sequencing is a valuable tool for early diagnosis of unknown pathogen infections.
PubMed: 38952864
DOI: 10.3389/fmed.2024.1377302 -
Pharmaceuticals (Basel, Switzerland) Jun 2024spp. can cause a sight threatening disease. At present, the current treatments used to treat spp. Infections, such as biguanide-based antimicrobials, remain...
spp. can cause a sight threatening disease. At present, the current treatments used to treat spp. Infections, such as biguanide-based antimicrobials, remain inefficacious, with the appearance of resistant forms and high cytotoxicity to host cells. In this study, an initial screening was conducted against Neff and murine macrophages J774A.1 using alamarBlue™. Among the 160 compounds included in the cited box, 90% exhibited an inhibition of the parasite above 80%, while only 18.75% of the compounds inhibited the parasite with a lethality towards murine macrophage lower than 20%. Based on the amoebicidal activity, the cytotoxicity assay, and availability, Terconazole was chosen for the elucidation of the action mode in two clinical strains, and L10. A fluorescence image-based system and proteomic techniques were used to investigate the effect of the present azole on the cytoskeleton network and various programmed cell death features, including chromatin condensation and mitochondria dysfunction. Taking all the results together, we can suggest that Terconazole can induce programmed cell death (PCD) via the inhibition of sterol biosynthesis inhibition.
PubMed: 38931475
DOI: 10.3390/ph17060808 -
Pathogens (Basel, Switzerland) May 2024keratitis (AK) is a severe infection of the cornea. Prevention and treatment are difficult due to the inefficacy of currently available compounds. The impact of many...
keratitis (AK) is a severe infection of the cornea. Prevention and treatment are difficult due to the inefficacy of currently available compounds. The impact of many commonly used compounds for routine examinations of is unexplored but might offer insight useful in combatting AK. In this study, we demonstrate that sodium metabisulfite, a common preservation constituent of eye care solutions, was found to be active against trophozoites at concentrations lower than that commonly found in eye drops (IC 0.03 mg/mL). We demonstrate that sodium metabisulfite depletes thiamine from growth medium and that is a thiamine auxotroph, requiring thiamine salvage for growth. The inhibitory effects of sodium metabisulfite can be overcome by thiamine supplementation. These results are consistent with the lack of key enzymes for thiamine biosynthesis in the genome of , an area which might prove exploitable using new or existing compounds. Indeed, this study highlights sodium metabisulfite as a useful inhibitor of trophozoites in vitro and that it acts, at least in part, by limiting available thiamine.
PubMed: 38921729
DOI: 10.3390/pathogens13060431 -
PloS One 2024Exploration of interspecies interactions between microorganisms can have taxonomic, ecological, evolutionary, or medical applications. To better explore interactions...
Exploration of interspecies interactions between microorganisms can have taxonomic, ecological, evolutionary, or medical applications. To better explore interactions between microorganisms it is important to establish the ideal conditions that ensure survival of all species involved. In this study, we sought to identify the ideal biotic and abiotic factors that would result in high co-culture viability of two interkingdom species, Pseudomonas aeruginosa and Acanthamoeba castellanii, two soil dwelling microbes. There have been limited studies showing long-term interactions between these two organisms as co-culture can result in high mortality for one or both organisms suggesting a predator-predator interaction may exist between them. In this study, we identified biotic and abiotic conditions that resulted in a high viability for both organisms in long-term co-culture, including optimizing temperature, nutrient concentration, choice of bacterial strains, and the initial ratio of interacting partners. These two species represent ideal partners for studying microbial interactions because amoebae act similarly to mammalian immune cells in many respects, and this can allow researchers to study host-pathogen interactions in vitro. Therefore, long-term interaction studies between these microbes might reveal the evolutionary steps that occur in bacteria when subjected to intense predation, like what occurs when pathogens enter the human body. The culture conditions characterized here resulted in high viability for both organisms for at least 14-days in co-culture suggesting that long-term experimental studies between these species can be achieved using these culture conditions.
Topics: Acanthamoeba castellanii; Pseudomonas aeruginosa; Coculture Techniques; Microbial Interactions; Temperature; Soil Microbiology
PubMed: 38913685
DOI: 10.1371/journal.pone.0305973 -
Acta Tropica Jun 2024Soluble factors in the secretome of Acanthamoeba castellanii play crucial roles in the pathogenesis of Acanthamoeba keratitis (AK). Investigating the pathological...
Soluble factors in the secretome of Acanthamoeba castellanii play crucial roles in the pathogenesis of Acanthamoeba keratitis (AK). Investigating the pathological effects of A. castellanii-derived conditioned medium (ACCM) on ocular cells can provide insights into the damage inflicted during AK. This study examined ACCM-induced cytotoxicity in primary human corneal stromal cells (CSCs) and a human SV40 immortalized corneal epithelial cell line (ihCECs) at varying ACCM concentrations (25 %, 50 %, 75 %, and 100 %). MTT, AlamarBlue, Sulforhodamine B, lactate dehydrogenase, and Caspase-3/7 activation assays were used to assess the impact of ACCM on the cell viability, proliferation and apoptosis. Additionally, fluorescent staining was used to reveal actin cytoskeleton changes. ACCM exposure significantly decreased cell viability, increased apoptosis, and disrupted the actin cytoskeleton, particularly at higher concentrations and longer exposures. Proteases were found to mediate these cytopathogenic effects, highlighting the need for characterization of A. castellanii proteases as key virulence factors in AK pathogenesis.
PubMed: 38901524
DOI: 10.1016/j.actatropica.2024.107288 -
Scientific Reports Jun 2024Natural products play a significant role in providing the current demand as antiparasitic agents, which offer an attractive approach for the discovery of novel drugs....
Natural products play a significant role in providing the current demand as antiparasitic agents, which offer an attractive approach for the discovery of novel drugs. The present study aimed to evaluate in vitro the potential impact of seaweed Padina pavonica (P. pavonica) extract in combating Acanthamoeba castellanii (A. castellanii). The phytochemical constituents of the extract were characterized by Gas chromatography-mass spectrometry. Six concentrations of the algal extract were used to evaluate its antiprotozoal activity at various incubation periods. Our results showed that the extract has significant inhibition against trophozoites and cysts viability, with complete inhibition at the high concentrations. The IC of P. pavonica extract was 4.56 and 4.89 µg/mL for trophozoites and cysts, respectively, at 24 h. Morphological alterations of A. castellanii trophozoites/cysts treated with the extract were assessed using inverted and scanning electron microscopes and showed severe damage features upon treatment with the extract at different concentrations. Molecular Docking of extracted compounds against Acanthamoeba cytochrome P450 monooxygenase (AcCYP51) was performed using Autodock vina1.5.6. A pharmacokinetic study using SwissADME was also conducted to investigate the potentiality of the identified bioactive compounds from Padina extract to be orally active drug candidates. In conclusion, this study highlights the in vitro amoebicidal activity of P. pavonica extract against A. castellanii adults and cysts and suggests potential AcCYP51 inhibition.
Topics: Acanthamoeba castellanii; Molecular Docking Simulation; Acanthamoeba Keratitis; Plant Extracts; Antiprotozoal Agents; Trophozoites; Animals; Humans
PubMed: 38871751
DOI: 10.1038/s41598-024-63691-8 -
Virology Journal Jun 2024The discovery of mimivirus in 2003 prompted the search for novel giant viruses worldwide. Despite increasing interest, the diversity and distribution of giant viruses is...
The discovery of mimivirus in 2003 prompted the search for novel giant viruses worldwide. Despite increasing interest, the diversity and distribution of giant viruses is barely known. Here, we present data from a 2012-2022 study aimed at prospecting for amoebal viruses in water, soil, mud, and sewage samples across Brazilian biomes, using Acanthamoeba castellanii for isolation. A total of 881 aliquots from 187 samples covering terrestrial and marine Brazilian biomes were processed. Electron microscopy and PCR were used to identify the obtained isolates. Sixty-seven amoebal viruses were isolated, including mimiviruses, marseilleviruses, pandoraviruses, cedratviruses, and yaraviruses. Viruses were isolated from all tested sample types and almost all biomes. In comparison to other similar studies, our work isolated a substantial number of Marseillevirus and cedratvirus representatives. Taken together, our results used a combination of isolation techniques with microscopy, PCR, and sequencing and put highlight on richness of giant virus present in different terrestrial and marine Brazilian biomes.
Topics: Brazil; Giant Viruses; Phylogeny; Polymerase Chain Reaction; Acanthamoeba castellanii; Soil Microbiology; Sewage; Sequence Analysis, DNA; Seawater; Water Microbiology
PubMed: 38858684
DOI: 10.1186/s12985-024-02404-z -
International Journal For Parasitology.... May 2024Acanthamoeba, a free-living amoeba, is commonly found in various natural environments, such as rivers and soil, as well as in public baths, swimming pools, and sewers....
Acanthamoeba, a free-living amoeba, is commonly found in various natural environments, such as rivers and soil, as well as in public baths, swimming pools, and sewers. Acanthamoeba can cause severe illness such as granulomatous amoebic encephalitis and Acanthamoeba keratitis (AK) in humans. AK, the most recognized disease, can cause permanent visual impairment or blindness by affecting the cornea. AK commonly affects contact lens wearers who neglect proper cleaning habits. The symptoms of AK include epithelial and stromal destruction, corneal infiltrate, and intense ocular pain, occasionally necessitating surgical removal of the entire eyeball. Current AK treatment involves the hourly application of eye drops containing polyhexamethylene biocide (PHMB). However, studies have revealed their ineffectiveness against drug-resistant strains. Acanthamoeba can form cysts as a survival mechanism in adverse environments, though the exact mechanism remains unknown. Our experiments revealed that sodium P-type ATPase (ACA1_065450) is closely linked to encystation. In addition, various encystation buffers, such as MgCl or NaCl, induced the expression of P-type ATPase. Furthermore, we used ouabain, an ATPase inhibitor, to inhibit the Na/K ion pump, consequently decreasing the encystation rate of Acanthamoeba. Our primary objective is to develop an advanced treatment for AK. We anticipate that the combination of ouabain and PHMB may serve as an effective therapeutic approach against AK in the future.
PubMed: 38821038
DOI: 10.1016/j.ijpddr.2024.100550 -
Parasites & Vectors May 2024Proteases produced by Acanthamoeba spp. play an important role in their virulence and may be the key to understanding Acanthamoeba pathogenesis; thus, increasing...
Characterization of novel extracellular proteases produced by Acanthamoeba castellanii after contact with human corneal epithelial cells and their relevance to pathogenesis.
BACKGROUND
Proteases produced by Acanthamoeba spp. play an important role in their virulence and may be the key to understanding Acanthamoeba pathogenesis; thus, increasing attention has been directed towards these proteins. The present study aimed to investigate the lytic factors produced by Acanthamoeba castellanii during the first hours of in vitro co-culture with human corneal epithelial cells (HCECs).
METHODS
We used one old and one recent Acanthamoeba isolate, both from patients with severe keratitis, and subsets of these strains with enhanced pathogenic potential induced by sequential passaging over HCEC monolayers. The proteolytic profiles of all strains and substrains were examined using 1D in-gel zymography.
RESULTS
We observed the activity of additional proteases (ranging from 33 to 50 kDa) during the early interaction phase between amoebae and HCECs, which were only expressed for a short time. Based on their susceptibilities to protease inhibitors, these proteases were characterized as serine proteases. Protease activities showed a sharp decline after 4 h of co-incubation. Interestingly, the expression of Acanthamoeba mannose-binding protein did not differ between amoebae in monoculture and those in co-culture. Moreover, we observed the activation of matrix metalloproteinases in HCECs after contact with Acanthamoeba.
CONCLUSIONS
This study revealed the involvement of two novel serine proteases in Acanthamoeba pathogenesis and suggests a pivotal role of serine proteases during Acanthamoeba-host cell interaction, contributing to cell adhesion and lysis.
Topics: Humans; Acanthamoeba castellanii; Epithelial Cells; Coculture Techniques; Epithelium, Corneal; Peptide Hydrolases; Acanthamoeba Keratitis; Serine Proteases; Protozoan Proteins; Virulence
PubMed: 38812022
DOI: 10.1186/s13071-024-06304-7 -
Frontiers in Microbiology 2024Giant viruses, categorized under are believed to exist ubiquitously in natural environments. However, comprehensive reports on isolated giant viruses remain scarce,...
Giant viruses, categorized under are believed to exist ubiquitously in natural environments. However, comprehensive reports on isolated giant viruses remain scarce, with limited information available on unrecoverable strains, viral proliferation sites, and natural hosts. Previously, the author highlighted , , and sp. styx, isolated from brackish water soil, as potential hotspots for giant virus multiplication. This study presents findings from nearly a year of monthly sampling within the same brackish water region after isolating the three aforementioned strains. This report details the recurrent isolation of a wide range of giant viruses. Each month, four soil samples were randomly collected from an approximately 5 × 10 m plot, comprising three soil samples and one water sample containing sediment from the riverbed. was used as a host for virus isolation. These efforts consistently yielded at least one viral species per month, culminating in a total of 55 giant virus isolates. The most frequently isolated species was (24 isolates), followed by (23 isolates), (6 isolates), and singular isolates of and . Notably, viruses were not consistently isolated from any of the four samples every month, with certain sites yielding no viruses. Cluster analysis based on isolate numbers revealed that soil samples from May and water and sediment samples from January produced the highest number of viral strains. These findings underscore brackish coastal soil as a significant site for isolating numerous giant viruses, highlighting the non-uniform distribution along coastlines.
PubMed: 38756730
DOI: 10.3389/fmicb.2024.1402690