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Emerging Infectious Diseases Apr 2024We describe 10 patients with nonkeratitis Acanthamoeba infection who reported performing nasal rinsing before becoming ill. All were immunocompromised, 7 had chronic...
We describe 10 patients with nonkeratitis Acanthamoeba infection who reported performing nasal rinsing before becoming ill. All were immunocompromised, 7 had chronic sinusitis, and many used tap water for nasal rinsing. Immunocompromised persons should be educated about safe nasal rinsing to prevent free-living ameba infections.
Topics: Humans; United States; Nose; Amebiasis; Immunocompromised Host
PubMed: 38526242
DOI: 10.3201/eid3004.231076 -
ISME Communications Jan 2024, a free-living amoeba in water and soil, is an emerging pathogen causing severe eye infection known as keratitis. In its natural environment, performs a dual function...
, a free-living amoeba in water and soil, is an emerging pathogen causing severe eye infection known as keratitis. In its natural environment, performs a dual function as an environmental heterotrophic predator and host for a range of microorganisms that resist digestion. Our objective was to characterize the intracellular microorganisms of phylogenetically distinct spp. isolated in Australia and India through directly sequencing 16S rRNA amplicons from the amoebae. The presence of intracellular bacteria was further confirmed by hybridization and electron microscopy. Among the 51 isolates assessed, 41% harboured intracellular bacteria which were clustered into four major phyla: Pseudomonadota (previously known as Proteobacteria), Bacteroidota (previously known as Bacteroidetes), Actinomycetota (previously known as Actinobacteria), and Bacillota (previously known as Firmicutes). The linear discriminate analysis effect size analysis identified distinct microbial abundance patterns among the sample types; species was abundant in Australian corneal isolates ( < 0.007), Enterobacteriales showed higher abundance in Indian corneal isolates ( < 0.017), and Bacteroidota was abundant in Australian water isolates ( < 0.019). The bacterial beta diversity of isolates from keratitis patients in India and Australia significantly differed ( < 0.05), while alpha diversity did not vary based on the country of origin or source of isolation ( > 0.05). More diverse intracellular bacteria were identified in water isolates as compared with clinical isolates. Confocal and electron microscopy confirmed the bacterial cells undergoing binary fission within the amoebal host, indicating the presence of viable bacteria. This study sheds light on the possibility of a sympatric lifestyle within , thereby emphasizing its crucial role as a bunker and carrier of potential human pathogens.
PubMed: 38500701
DOI: 10.1093/ismeco/ycae016 -
International Journal of Hygiene and... May 2024Free living amoeba (FLA) are among the organisms commonly found in wastewater and are well-established hosts for diverse microbial communities. Despite its clinical...
Free living amoeba (FLA) are among the organisms commonly found in wastewater and are well-established hosts for diverse microbial communities. Despite its clinical significance, there is little knowledge on the FLA microbiome and resistome, with previous studies relying mostly on conventional approaches. In this study we comprehensively analyzed the microbiome, antibiotic resistome and virulence factors (VFs) within FLA isolated from final treated effluents of two wastewater treatment plants (WWTPs) using shotgun metagenomics. Acanthamoeba has been identified as the most common FLA, followed by Entamoeba. The bacterial diversity showed no significant difference (p > 0.05) in FLA microbiomes obtained from the two WWTPs. At phylum level, the most dominant taxa were Proteobacteria, followed by Firmicutes and Actinobacteria. The most abundant genera identified were Enterobacter followed by Citrobacter, Paenibacillus, and Cupriavidus. The latter three genera are reported here for the first time in Acanthamoeba. In total, we identified 43 types of ARG conferring resistance to cephalosporins, phenicol, streptomycin, trimethoprim, quinolones, cephalosporins, tigecycline, rifamycin, and kanamycin. Similarly, a variety of VFs in FLA metagenomes were detected which included flagellar proteins, Type IV pili twitching motility proteins (pilH and rpoN), alginate biosynthesis genes AlgI, AlgG, AlgD and AlgW and Type VI secretion system proteins and general secretion pathway proteins (tssM, tssA, tssL, tssK, tssJ, fha, tssG, tssF, tssC and tssB, gspC, gspE, gspD, gspF, gspG, gspH, gspI, gspJ, gspK, and gspM). To the best of our knowledge, this is the first study of its kind to examine both the microbiomes and resistome in FLA, as well as their potential pathogenicity in treated effluents. Additionally, this study showed that FLA can host a variety of potentially pathogenic bacteria including Paenibacillus, and Cupriavidus that had not previously been reported, indicating that their relationship may play a role in the spread and persistence of antibiotic resistant bacteria (ARBs) and antibiotic resistance genes (ARGs) as well as the evolution of novel pathogens.
Topics: Wastewater; Anti-Bacterial Agents; Amoeba; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Microbiota; Bacteria; Genes, Bacterial; Drug Resistance, Microbial; Cephalosporins
PubMed: 38471337
DOI: 10.1016/j.ijheh.2024.114345 -
PloS One 2024Infectious Keratitis is one of the most common ocular emergencies seen by ophthalmologists. Our aim is to identify the risk factors and clinical features of Acanthamoeba...
INTRODUCTION
Infectious Keratitis is one of the most common ocular emergencies seen by ophthalmologists. Our aim is to identify the risk factors and clinical features of Acanthamoeba Keratitis (AK).
METHODS
This retrospective chart review study was conducted at King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia, and included all the microbial keratitis cases, male and female patients of all ages. The main outcome is the differentiation between various microbial keratitis types.
RESULTS
We included 134 consecutive eyes of 126 persons. We had 24 cases of acanthamoeba keratitis, 22 bacterial keratitis, 24 fungal keratitis, 32 herpetic keratitis, and 32 bacterial co-infection. Contact lens wear was found in 33 eyes (24.6%). Among acanthamoeba keratitis patients, 73% were ≤ 39 years of age, and 73% were females (P <0.001). Also, in AK cases, epithelial defect was found in all cases (100%), endothelial plaques were found in 18 eyes (69.2%), 12 cases had radial keratoneuritis (46.2%), and ring infiltrate was found in 53.8% of AK cases.
CONCLUSIONS
We determined the factors that increase the risk of acanthamoeba infection and the clinical characteristics that help distinguish it from other types of microbial keratitis. Our findings suggest that younger females and patients who wear contact lenses are more likely to develop acanthamoeba keratitis. The occurrence of epitheliopathy, ring infiltrate, radial keratoneuritis, and endothelial plaques indicate the possibility of acanthamoeba infection. Promoting education on wearing contact lenses is essential to reduce the risk of acanthamoeba infection, as it is the most significant risk factor for this infection.
Topics: Humans; Male; Female; Acanthamoeba Keratitis; Retrospective Studies; Cornea; Contact Lenses; Bacterial Infections; Risk Factors
PubMed: 38470877
DOI: 10.1371/journal.pone.0299492 -
Indian Journal of Ophthalmology Apr 2024This is a comprehensive review after a thorough literature search in PubMed-indexed journals, incorporating current information on the pathophysiology, clinical... (Review)
Review
This is a comprehensive review after a thorough literature search in PubMed-indexed journals, incorporating current information on the pathophysiology, clinical features, diagnosis, medical and surgical therapy, as well as outcomes of Acanthamoeba keratitis (AK). AK is a significant cause of ocular morbidity, and early diagnosis with timely institution of appropriate therapy is the key to obtaining good outcomes. The varied presentations result in frequent misdiagnosis, and co-infections can increase the morbidity of the disease. The first line of therapy continues to be biguanides and diamidines, with surgery as a last resort.
Topics: Humans; Acanthamoeba Keratitis; Pentamidine; Biguanides
PubMed: 38454853
DOI: 10.4103/IJO.IJO_2627_23 -
Turkiye Parazitolojii Dergisi Mar 2024The aim of this study was to evaluate the pathogenicity of strains with T4, T5, T11, and T12 genotypes by comparing the osmotolerance and thermotolerance...
OBJECTIVE
The aim of this study was to evaluate the pathogenicity of strains with T4, T5, T11, and T12 genotypes by comparing the osmotolerance and thermotolerance characteristics of strains isolated from genotype groups, within species with the same genotype, and from environmental and keratitis cases.
METHODS
In this study, after axenic cultures of 22 strains with T4 (Neff, A, B, D, E), T5, T11, and T12 genotypes isolated from clinical and environmental samples, thermotolerance (37 °C, 39 °C and 41 °C) and osmotolerance (0.5 M, 1 M) tests were performed.
RESULTS
All strains showed growth ability at 37 °C and 0.5 M osmolarity. While all five strains isolated from patients with keratitis showed growth ability at 37 °C and 0.5 M osmolarity, no growth was detected at 41 °C and 1 M osmolarity. When the tolerance characteristics of the strains with the same genotype were evaluated, the strains with the T5 and T4E genotypes showed the same characteristics. When strains with the T4 genotype were evaluated in general, 31.25% of the strains were found to grow at 39 °C and 6.25% at 41 °C. Of the T4Neff strains, only one strain did not show the ability to reproduce at 39 °C and showed a different feature from the other strains. While the strain with the T11 genotype grew at all temperatures, the strain with the T12 genotype did not grow at 41 °C.
CONCLUSION
According to our research results, we believe that tolerance to 39 °C and 1 M mannitol is not an indicator of pathogenicity. More studies with strains are required to clarify this issue.
Topics: Humans; Acanthamoeba; Virulence; Thermotolerance; Genotype; Mannitol
PubMed: 38449362
DOI: 10.4274/tpd.galenos.2024.92408 -
Parasites, Hosts and Diseases Feb 2024Acanthamoeba infection is associated with keratitis in humans; however, its association with keratitis in dogs remains unclear. To investigate this possibility, we...
Acanthamoeba infection is associated with keratitis in humans; however, its association with keratitis in dogs remains unclear. To investigate this possibility, we collected 171 conjunctival swab samples from dogs with eye-related diseases (65 with keratitis and 106 without keratitis) at Chungbuk National University Veterinary Teaching Hospital, Korea, from August 2021 to September 2022. Polymerase chain reaction identified 9 samples (5.3%) as Acanthamoeba positive; of these, 3 were from dogs with keratitis (4.6%) and 6 were from dogs without keratitis (5.7%). Our results indicated no significant association between Acanthamoeba infection and keratitis, season, sex, or age. All Acanthamoeba organisms found in this study had the genotype T4, according to 18S ribosomal RNA analysis. Acanthamoeba infection in dogs might have only a limited association with keratitis.
Topics: Humans; Dogs; Animals; Hospitals, Animal; Hospitals, Teaching; Amebiasis; Keratitis; Acanthamoeba; Republic of Korea
PubMed: 38443777
DOI: 10.3347/PHD.23112 -
BMC Infectious Diseases Mar 2024To compare the outcomes of big-bubble deep anterior lamellar keratoplasty (BB-DALK) and penetrating keratoplasty (PKP) in the management of medically unresponsive...
PURPOSE
To compare the outcomes of big-bubble deep anterior lamellar keratoplasty (BB-DALK) and penetrating keratoplasty (PKP) in the management of medically unresponsive Acanthamoeba keratitis (AK).
METHODS
This retrospective study included 27 eyes of BB-DALK and 24 eyes of PKP from a tertiary ophthalmology care centre. Glucocorticoid eye drops were subsequently added to the treatment plan 2 months postoperatively based on the evaluation using confocal laser scanning microscopy. The clinical presentations, best-corrected visual acuity (BCVA), postoperative refractive outcomes, graft survival, and Acanthamoeba recurrence were analyzed.
RESULTS
The AK patients included in the study were in stage 2 or stage 3, and the percentage of patients in stage 3 was higher in the PKP group (P = 0.003). Clinical presentations were mainly corneal ulcers and ring infiltrates, and endothelial plaques, hypopyon, uveitis and glaucoma were more common in the PKP group (P = 0.007). The BCVA and the graft survival rate showed no statistically significant differences between the two groups at 1 year after surgery. However, 3 years postoperatively, the BCVA of 0.71 ± 0.64 logMAR, the graft survival rate of 89.5%, and the endothelial cell density of 1899 ± 125 cells per square millimeter in the BB-DALK group were significantly better than those of the PKP group (P = 0.010, 0.046, and 0.032, respectively). 3 eyes (11.1%) in the BB-DALK group and 2 eyes (8.3%) in the PKP group experienced Acanthamoeba recurrence, but the rates showed no statistically significant difference between the two groups (P = 1.000). In the PKP group, immune rejection and elevated intraocular pressure were observed in 5 and 6 eyes, respectively.
CONCLUSION
Corneal transplantation is recommended for AK patients unresponsive to antiamoebic agents. The visual acuity and graft survival can be maintained after BB-DALK surgery. Acanthamoeba recurrence is not related to the surgical approach performed, whereas complete dissection of the infected corneal stroma and delayed prescribing of glucocorticoid eye drops were important to prevent recurrence.
Topics: Humans; Acanthamoeba Keratitis; Keratoplasty, Penetrating; Glucocorticoids; Retrospective Studies; Corneal Transplantation; Glaucoma; Ophthalmic Solutions
PubMed: 38438857
DOI: 10.1186/s12879-024-09147-w -
Frontiers in Microbiology 2024Free-living amoebae are an extensive group of protistans that can be found in a wide variety of environments. Among them, the genus and stand out as two of the most...
INTRODUCTION
Free-living amoebae are an extensive group of protistans that can be found in a wide variety of environments. Among them, the genus and stand out as two of the most pathogenic amoebae and with a higher number of reported cases. is mainly found in warm freshwater water bodies whereas amoebae of the genus are broadly distributed through natural and anthropogenic environments. In this regard, the management and the control of the amoebic populations in swimming pools has become a major public health challenge for institutions.
METHODS
The aim of this work was to evaluate the growth pattern of trophozoites of and at different temperatures and salt concentrations.
RESULTS AND DISCUSSION
Our results showed that resisted a higher concentration of salt than . Moreover, no trophozoites could withstand the salt levels of the sea in conditions. This work supports the contention that salinity could represent an important and useful tool for the control of the most pathogenic amoebic populations in recreational water bodies.
PubMed: 38426057
DOI: 10.3389/fmicb.2024.1356452 -
Nanoscale Advances Feb 2024extract (GME) has severe pharmacokinetic deficiencies and is made up of a variety of bioactive components. GME has proven its anti- effectiveness. In this...
extract (GME) has severe pharmacokinetic deficiencies and is made up of a variety of bioactive components. GME has proven its anti- effectiveness. In this investigation, a GME-loaded niosome was developed to increase its potential therapeutic efficacy. A GME-loaded niosome was prepared by encapsulation in a mixture of span60, cholesterol, and chloroform by the thin film hydration method. The vesicle size, zeta potential, percentage of entrapment efficiency, and stability of GME-loaded niosomes were investigated. The values for GME-loaded niosome size and zeta potential were 404.23 ± 4.59 and -32.03 ± 0.95, respectively. The delivery system enhanced the anti- activity, which possessed MIC values of 0.25-4 mg mL. In addition, the niosomal formulation decreased the toxicity of GME by 16 times. GME-loaded niosome must be stored at 4 °C, as the quantity of remaining GME encapsulated is greater at this temperature than at room temperature. SEM revealed the damage to the cell membrane caused by trophozoites and cysts, which led to dead cells. In light of the above, it was found that GME-loaded niosomes had better anti- activity. The study suggested that GME-loaded niosomes could be used as an alternative to 's therapeutic effects.
PubMed: 38419876
DOI: 10.1039/d3na01016c