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Rayamajhee B, Willcox M, Sharma S, Mooney R, Petsoglou C, Badenoch PR, Sherchan S, Henriquez FL, Carnt N. Zooming in on the intracellular microbiome composition of bacterivorous Acanthamoeba isolates. ISME COMMUNICATIONS 2024; 4:ycae016. [PMID: 38500701 PMCID: PMC10945361 DOI: 10.1093/ismeco/ycae016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 11/29/2023] [Accepted: 01/22/2024] [Indexed: 03/20/2024]
Abstract
Acanthamoeba, a free-living amoeba in water and soil, is an emerging pathogen causing severe eye infection known as Acanthamoeba keratitis. In its natural environment, Acanthamoeba 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 Acanthamoeba spp. isolated in Australia and India through directly sequencing 16S rRNA amplicons from the amoebae. The presence of intracellular bacteria was further confirmed by in situ 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; Pseudomonas species was abundant in Australian corneal isolates (P < 0.007), Enterobacteriales showed higher abundance in Indian corneal isolates (P < 0.017), and Bacteroidota was abundant in Australian water isolates (P < 0.019). The bacterial beta diversity of Acanthamoeba isolates from keratitis patients in India and Australia significantly differed (P < 0.05), while alpha diversity did not vary based on the country of origin or source of isolation (P > 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 Acanthamoeba, thereby emphasizing its crucial role as a bunker and carrier of potential human pathogens.
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Affiliation(s)
- Binod Rayamajhee
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, NSW 2052, Australia
| | - Mark Willcox
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, NSW 2052, Australia
| | - Savitri Sharma
- Jhaveri Microbiology Centre, Prof Brien Holden Eye Research Centre, Hyderabad Eye Research Foundation, L. V. Prasad Eye Institute (LVPEI), Hyderabad, 500034, India
| | - Ronnie Mooney
- School of Health and Life Sciences, University of the West of Scotland, Blantyre, PA1 2BE, United Kingdom
| | - Constantinos Petsoglou
- Sydney and Sydney Eye Hospital, South-Eastern Sydney Local Health District, Sydney, NSW 2000, Australia
- Save Sight Institute, University of Sydney, Sydney, NSW 2000, Australia
| | - Paul R Badenoch
- College of Medicine and Public Health, Flinders University, Adelaide, 5042, Australia
| | - Samendra Sherchan
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112, United States
| | - Fiona L Henriquez
- School of Health and Life Sciences, University of the West of Scotland, Blantyre, PA1 2BE, United Kingdom
| | - Nicole Carnt
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, NSW 2052, Australia
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2
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Zhang J, Lu X, Cheng Z, Zou D, Shi W, Wang T. Alterations of conjunctival microbiota associated with orthokeratology lens wearing in myopic children. BMC Microbiol 2023; 23:397. [PMID: 38087200 PMCID: PMC10717905 DOI: 10.1186/s12866-023-03042-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 10/03/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Orthokeratology (OK) lens wear increases the risk of bacterial infection, but little is known about the microbiota of the conjunctival sac in myopic children wearing OK lenses. This study aimed to investigate the changes of conjunctival microbiota in children after treatment with OK lenses using 16 S rDNA sequencing. METHODS Twenty-eight myopic children who had been continuously wearing OK lenses for 12 to 13 months were enrolled in this prospective study. Twenty-two gender- and age-matched myopic children who had not worn OK lenses or discontinued OK lens wear at least 1 year ago were recruited as controls. Conjunctival swabs from each participant were collected for exploration of the microbiota profiles, targeting the V3-V4 regions of the 16 S rRNA gene by MiSeq sequencing. The differences in the microbial community structure and diversity were also compared between groups. RESULTS The bacterial alpha diversity indices in the OK lens group were not different from those in the non-wearer group (P > 0.05, Wilcoxon test), while beta diversity examined using principle coordinate analysis of unweighted UniFrac divided the two groups into different clusters. Proteobacteria, Bacteroidetes, and Firmicutes were the abundant phyla in the conjunctival sac microbiota in both groups (P < 0.05, Mann-Whitney U test). Among children in the OK lens group, the Linear discriminant analysis Effect Size identified the compositional changes in OK lens-associated bacteria. Key functional genera such as Blautia, Parasutterella, and Muribaculum were enriched, whereas Brevundimonas, Acinetobacter, Proteus, and Agathobacter decreased significantly (P < 0.05, Mann-Whitney U test). Phylogenetic investigation of communities by reconstruction of unobserved states also showed altered bacterial metabolic pathways in OK lens-associated microbiota. Moreover, using receiver operating characteristic curves, Brevundimonas, Acinetobacter, Proteus, and Agathobacter alone (the area under the curve was all > 0.7500) or in combination (the area under the curve was 0.9058) were revealed to discriminate OK lens wearers from controls. CONCLUSIONS The relative abundance of the microbial community in the conjunctival sac of myopic children can alter after OK lens wear. Brevundimonas, Acinetobacter, Proteus, and Agathobacter may be candidate biomarkers to distinguish between OK lens wearers and non-wearers.
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Affiliation(s)
- Ju Zhang
- Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Qingdao, China
| | - Xiuhai Lu
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, Jinan, 250021, China
| | - Zhiwei Cheng
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, Jinan, 250021, China
| | - Dulei Zou
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Qingdao, China
- Medical College, Qingdao University, Qingdao, China
| | - Weiyun Shi
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, Jinan, 250021, China.
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Qingdao, China.
| | - Ting Wang
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, Jinan, 250021, China.
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Qingdao, China.
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Huang L, Suhler EB, Rosenberg C, Ta Kim D, Winthrop KL, Doan T, Lin P. Acanthamoeba-associated retinitis successfully treated with intravitreal and systemic antimicrobials. Am J Ophthalmol Case Rep 2023; 32:101902. [PMID: 37663996 PMCID: PMC10474359 DOI: 10.1016/j.ajoc.2023.101902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 07/03/2023] [Accepted: 07/19/2023] [Indexed: 09/05/2023] Open
Abstract
Purpose To describe a case of unilateral Acanthamoeba-associated retinitis in the absence of concomitant corneal infection in an immunocompetent host without risk factors. Observations A 37-year-old woman presented with unilateral multifocal retinitis with minimal vitritis. Anterior segment was normal. Conventional diagnostics of bacterial, fungal, viral, Toxoplasma and Toxocara etiologies all returned negative. Empiric treatments were unsuccessful, including oral valacyclovir, oral fluconazole, as well as intravitreal injection of vancomycin and ceftazidime. Metagenomic deep sequencing (MDS) identified Acanthamoeba genomic fragments in the vitreous sample. Multiple intravitreal voriconazole injections were performed and achieved partial suppression of lesion growth. Subsequent dual therapy of oral voriconazole and trimethoprim-sulfamethoxazole led to resolution of the lesions and vision improvement without further injections. Conclusions and importance This is an unusual case of unilateral Acanthamoeba-associated retinitis without concomitant corneal infection, diagnosed via unbiased DNA and RNA deep sequencing, with other etiologies ruled out by conventional approaches. Treatment with systemic and intravitreal therapy led to a successful resolution of retinitis and vision improvement. Our case demonstrates the potential of MDS as an unbiased diagnostic tool for rare ocular pathogens and the therapeutic effect of oral voriconazole with trimethoprim-sulfamethoxazole for Acanthamoeba intraocular infection.
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Affiliation(s)
- Lingling Huang
- Casey Eye Institute, Oregon Health & Science University, 515 SW Campus Drive, Portland, OR, USA
| | - Eric B. Suhler
- Casey Eye Institute, Oregon Health & Science University, 515 SW Campus Drive, Portland, OR, USA
- Veterans Affairs Portland Health Care System, 3710 Southwest US Veterans Hospital Road, Portland, OR, USA
| | - Christopher Rosenberg
- Casey Eye Institute, Oregon Health & Science University, 515 SW Campus Drive, Portland, OR, USA
| | - David Ta Kim
- University of British Columbia, 2550 Willow Street, Vancouver, British Columbia, Canada
| | - Kevin L. Winthrop
- Division of Infectious Diseases, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, USA
| | - Thuy Doan
- Francis I. Proctor Foundation, University of California San Francisco, 490 Illinois Street, San Francisco, CA, USA
| | - Phoebe Lin
- Casey Eye Institute, Oregon Health & Science University, 515 SW Campus Drive, Portland, OR, USA
- Cole Eye Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, USA
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4
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Fatemi M, Niyyati M, Rouhani S, Karamati SA, Mirjalali H, Karanis P. Contamination of fresh vegetables in municipal stores with pathogenic Acanthamoeba genotypes; a public health concern. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2023; 33:1010-1021. [PMID: 35443833 DOI: 10.1080/09603123.2022.2067328] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 04/12/2022] [Indexed: 05/23/2023]
Abstract
Acanthamoeba spp. cause keratitis and encephalitis, and are a proper carrier of foodborne pathogens. A total of 70 samples including garden cress, chives, mint, parsley, and basil were collected. Samples were cultured onto a 2% non-nutrient agar medium. The cultures were analyzed using morphological and molecular techniques. In total, 18 (25.7%) out of 70 samples were positive including garden cress 10/22 (45.45%), chives 3/12 (25%), mint 2/13 (15.38%), basil 2/13 (15.38%), and parsley 1/10 (10%). The diagnostic fragment 3 was successfully sequenced in 15 samples and represented 11 (73.3%) T4, three (20%) T5, and one T9 genotypes. In addition, three, two, and one strains, belonging to the genotypes T4, T5, and T9 were ranked highly pathogenic. This is the first study reporting contamination of the most commonly consumed fresh vegetables with pathogenic Acanthamoeba genotypes. Our findings signify the public health concerns due the contamination of vegetables in municipal public markets.
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Affiliation(s)
- Marziye Fatemi
- Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Medical Parasitology and Mycology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Niyyati
- Department of Medical Parasitology and Mycology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Soheila Rouhani
- Department of Medical Parasitology and Mycology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed Ahmad Karamati
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamed Mirjalali
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Panagiotis Karanis
- University of Cologne, Medical Faculty and University Hospital, Cologne 50931, Germany
- Department of Basic and Clinical Sciences, Nicosia University Medical School, Nicosia, Cyprus
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5
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Huang JM, Sung KC, Lin WC, Lai HY, Wang YJ. Enhancement of capsular hypermucoviscosity in Klebsiella pneumoniae by Acanthamoeba. PLoS Negl Trop Dis 2023; 17:e0011541. [PMID: 37566587 PMCID: PMC10495012 DOI: 10.1371/journal.pntd.0011541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 09/11/2023] [Accepted: 07/18/2023] [Indexed: 08/13/2023] Open
Abstract
BACKGROUND Acanthamoeba and Klebsiella pneumoniae are both environmental commensals. Recently, clinical harm caused by hypermucoviscous K. pneumoniae has been observed. However, the interaction between these microbes and the origin of hypermucoviscous K. pneumoniae have not been reported. METHODOLOGY/PRINCIPAL FINDINGS Here, we report that the bacterial capsule is enlarged when co-cultured with Acanthamoeba using India ink staining, and this effect depends on the number of parasites present. This interaction results in an enhancement of capsular polysaccharide production in the subsequent generations of K. pneumoniae, even without co-culturing with Acanthamoeba. The hypermucoviscosity of the capsule was examined using the sedimentation assay and string test. We also screened other K. pneumoniae serotypes, including K1, K2, K5, and K20, for interaction with Acanthamoeba using India ink staining, and found the same interaction effect. CONCLUSIONS/SIGNIFICANCE These findings suggest that the interaction between Acanthamoeba and K. pneumoniae could lead to harmful consequences in public health and nosocomial disease control, particularly hypermucoviscous K. pneumoniae infections.
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Affiliation(s)
- Jian-Ming Huang
- School of Medicine, National Tsing Hua University, Hsinchu, Taiwan
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Ko-Chiang Sung
- Department of Clinical Laboratory, Chest Hospital, Ministry of Health and Welfare, Tainan, Taiwan
| | - Wei-Chen Lin
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Parasitology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Hong-Yue Lai
- Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan
| | - Yu-Jen Wang
- Department of Parasitology, School of Medicine, China Medical University, Taichung, Taiwan
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Rayamajhee B, Willcox MDP, Henriquez FL, Petsoglou C, Subedi D, Carnt N. Acanthamoeba, an environmental phagocyte enhancing survival and transmission of human pathogens. Trends Parasitol 2022; 38:975-990. [PMID: 36109313 DOI: 10.1016/j.pt.2022.08.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 01/13/2023]
Abstract
The opportunistic protist Acanthamoeba, which interacts with other microbes such as bacteria, fungi, and viruses, shows significant similarity in cellular and functional aspects to human macrophages. Intracellular survival of microbes in this microbivorous amoebal host may be a crucial step for initiation of infection in higher eukaryotic cells. Therefore, Acanthamoeba-microbe adaptations are considered an evolutionary model of macrophage-pathogen interactions. This paper reviews Acanthamoeba as an emerging human pathogen and different ecological interactions between Acanthamoeba and microbes that may serve as environmental training grounds and a genetic melting pot for the evolution, persistence, and transmission of potential human pathogens.
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Affiliation(s)
- Binod Rayamajhee
- School of Optometry and Vision Science, Faculty of Medicine and Health, University of New South Wales (UNSW), Sydney, Australia.
| | - Mark D P Willcox
- School of Optometry and Vision Science, Faculty of Medicine and Health, University of New South Wales (UNSW), Sydney, Australia.
| | - Fiona L Henriquez
- Institute of Biomedical and Environmental Health Research, School of Health and Life Sciences, University of the West of Scotland, Blantyre, South Lanarkshire, G72 0LH, UK
| | - Constantinos Petsoglou
- Sydney and Sydney Eye Hospital, Southeastern Sydney Local Health District, Sydney, Australia; Save Sight Institute, University of Sydney, Sydney, Australia
| | - Dinesh Subedi
- School of Biological Sciences, Monash University, Clayton, Australia
| | - Nicole Carnt
- School of Optometry and Vision Science, Faculty of Medicine and Health, University of New South Wales (UNSW), Sydney, Australia
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7
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Comparison of Microbial Sampling Sites and Donor-Related Factors on Corneal Graft Contamination. J Clin Med 2022; 11:jcm11216236. [PMID: 36362464 PMCID: PMC9655421 DOI: 10.3390/jcm11216236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/17/2022] [Accepted: 10/20/2022] [Indexed: 11/05/2022] Open
Abstract
Grafts used for corneal donation should be sterile to avoid transplantation failure and secondary infection. However, there are no clear and globally accepted specifications from eye banks on microbial sampling sites. The objective of this study was to analyze microbial contamination of corneal grafts collected from different sampling sites. We found that the contamination rates and strain compositions significantly differed at different sampling sites. To clarify the effect of the microbial sampling site on corneal graft contamination, microbial sampling was conducted using 30 corneal grafts at the extraocular and intraocular sides of the graft in 2020 from the National Eye Bank of Taiwan. Microbial contamination significantly differed (p < 0.05) between the different sampling sites on the graft according to McNemar’s test. Although the two sampling sites showed the same specificity (33.33%), the sensitivity of sampling on the extraocular side (82.35%) was higher than that on the intraocular side (17.65%) of the graft. Donor-associated factors, including the cause of death, operating place, and cold compression, were analyzed using chi-square statistics, which revealed no significant differences in microbial contamination. Thus, our data provide evidence for the microbial sampling site of donated grafts and clear specifications for maintaining the quality of corneal grafts.
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8
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Siddiqui R, Makhlouf Z, Akbar N, Khamis M, Ibrahim T, Khan AS, Khan NA. Antiamoebic properties of salicylic acid-based deep eutectic solvents for the development of contact lens disinfecting solutions against Acanthamoeba. Mol Biochem Parasitol 2022; 250:111493. [PMID: 35753525 DOI: 10.1016/j.molbiopara.2022.111493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 05/30/2022] [Accepted: 06/20/2022] [Indexed: 10/17/2022]
Abstract
Acanthamoeba castellanii is a protist pathogen that can cause sight-threatening keratitis and a fatal infection of the central nervous system, known as granulomatous amoebic encephalitis. In this study, effects of five malonic acid and salicylic acid-based deep eutectic solvents (DES) on A. castellanii were investigated. These are salicylic acid-trioctylphosphine (DES 1), salicylic acid- trihexylamine (DES 2), salicylic acid-trioctylamine (DES 3), malonic acid-trioctylphosphine (DES 4) and malonic acid-trihexylamine (DES 5). The experiments were done by performing amoebicidal, encystment, excystment, cytopathogenicity, and cytotoxicity assays. At micromolar dosage, the solvents DES 2 and DES 3 displayed significant amoebicidal effects (P<0.05), inhibited encystment and excystment, undermined the cell-mediated cytopathogenicity of A. castellanii, and also displayed minimal cytotoxicity to human cells. Conversely, the chemical components of these solvents: salicylic acid, trihexylamine, and trioctylamine showed minimal effects when tested individually. These results are very promising and to the best of our knowledge, are reported for the first time on the effects of deep eutectic solvents on amoebae. These results can be applied in the development of new formulations of novel contact lens disinfectants against Acanthamoeba castellanii.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah 26666, United Arab Emirates
| | - Zinb Makhlouf
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah 26666, United Arab Emirates
| | - Noor Akbar
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah 26666, United Arab Emirates
| | - Mustafa Khamis
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah 26666, United Arab Emirates
| | - Taleb Ibrahim
- Department of Chemical Engineering, College of Engineering, American University of Sharjah, P.O. Box 26666, Sharjah, United Arab Emirates
| | - Amir Sada Khan
- Department of Chemical Engineering, College of Engineering, American University of Sharjah, P.O. Box 26666, Sharjah, United Arab Emirates
| | - Naveed Ahmed Khan
- Department of Clinical Sciences, College of Medicine, University of Sharjah, University, City, Sharjah, 27272, United Arab Emirates.
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A Comparative Genomic Approach to Determine the Virulence Factors and Horizontal Gene Transfer Events of Clinical Acanthamoeba Isolates. Microbiol Spectr 2022; 10:e0002522. [PMID: 35416714 PMCID: PMC9045148 DOI: 10.1128/spectrum.00025-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acanthamoeba species are among the most ubiquitous protists that are widespread in soil and water and act as both a replicative niche and vectors for dispersal. They are the most important human intracellular pathogens, causing Acanthamoeba keratitis (AK) and severely damaging the human cornea. The sympatric lifestyle within the host and amoeba-resisting microorganisms (ARMs) promotes horizontal gene transfer (HGT). However, the genomic diversity of only A. castellanii and A. polyphaga has been widely studied, and the pathogenic mechanisms remain unknown. Thus, we examined 7 clinically pathogenic strains by comparative genomic, phylogenetic, and rhizome gene mosaicism analyses to explore amoeba-symbiont interactions that possibly contribute to pathogenesis. Genetic characterization and phylogenetic analysis showed differences in functional characteristics between the "open" state of T3 and T4 isolates, which may contribute to the differences in virulence and pathogenicity. Through comparative genomic analysis, we identified potential genes related to virulence, such as metalloprotease, laminin-binding protein, and HSP, that were specific to the genus Acanthamoeba. Then, analysis of putative sequence trafficking between Acanthamoeba and Pandoraviruses or Acanthamoeba castellanii medusaviruses provided the best hits with viral genes; among bacteria, Pseudomonas had the most significant numbers. The most parsimonious evolutionary scenarios were between Acanthamoeba and endosymbionts; nevertheless, in most cases, the scenarios are more complex. In addition, the differences in exchanged genes were limited to the same family. In brief, this study provided extensive data to suggest the existence of HGT between Acanthamoeba and ARMs, explaining the occurrence of diseases and challenging Darwin's concept of eukaryotic evolution. IMPORTANCE Acanthamoeba has the ability to cause serious blinding keratitis. Although the prevalence of this phenomenon has increased in recent years, our knowledge of the underlying opportunistic pathogenic mechanism maybe remains incomplete. In this study, we highlighted the importance of Pseudomonas in the pathogenesis pathway using comprehensive a whole genomics approach of clinical isolates. The horizontal gene transfer events help to explain how endosymbionts contribute Acanthamoeba to act as an opportunistic pathogen. Our study opens up several potential avenues for future research on the differences in pathogenicity and interactions among clinical strains.
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Wang YJ, Chen CH, Chen JW, Lin WC. Commensals Serve as Natural Barriers to Mammalian Cells during Acanthamoeba castellanii Invasion. Microbiol Spectr 2021; 9:e0051221. [PMID: 34935418 PMCID: PMC8693914 DOI: 10.1128/spectrum.00512-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 11/02/2021] [Indexed: 12/23/2022] Open
Abstract
Acanthamoeba castellanii is a free-living, pathogenic ameba found in the soil and water. It invades the body through ulcerated skin, the nasal passages, and eyes and can cause blinding keratitis and granulomatous encephalitis. However, the mechanisms underlying the opportunistic pathogenesis of A. castellanii remain unclear. In this study, we observed that commensal bacteria significantly reduced the cytotoxicity of the ameba on mammalian cells. This effect occurred in the presence of both Gram-positive and Gram-negative commensals. Additionally, commensals mitigated the disruption of cell junctions. Ex vivo experiments on mouse eyeballs further showed that the commensals protected the corneal epithelial layer. Together, these findings indicate that A. castellanii is pathogenic to individuals with a dysbiosis of the microbiota at infection sites, further highlighting the role of commensals as a natural barrier during parasite invasion. IMPORTANCE Acanthamoeba castellanii, an opportunistic protozoan widely present in the environment, can cause Acanthamoeba keratitis and encephalitis in humans. However, only a few reports describe how the ameba acts as an opportunistic pathogen. Our study showed that the normal microbiota interfered with the cytotoxicity of Acanthamoeba, persevered during Acanthamoeba invasion, and reduced corneal epithelium peeling in the mouse eyeball model. This suggests that commensals may act as a natural barrier against Acanthamoeba invasion. In future, individuals who suffer from Acanthamoeba keratitis should be examined for microbiota absence or dysbiosis to reduce the incidence of Acanthamoeba infection in clinical settings.
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Affiliation(s)
- Yu-Jen Wang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Clinical Laboratory, Chest Hospital, Ministry of Health and Welfare, Tainan, Taiwan
| | - Chun-Hsien Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jenn-Wei Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Chen Lin
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Parasitology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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11
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Borroni D, Rachwani-Anil R, González JMS, Rodríguez-Calvo-de-Mora M, Rocha de Lossada C. Metagenome techniques to reduce diagnostic delay in Acanthamoeba keratitis. Rom J Ophthalmol 2021; 65:307-308. [PMID: 35036659 PMCID: PMC8697792 DOI: 10.22336/rjo.2021.63] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2021] [Indexed: 01/08/2023] Open
Affiliation(s)
- Davide Borroni
- The Veneto Eye Bank Foundation, Venice, Italy.,Department of Doctoral Studies, Riga Stradins University, Riga, Latvia
| | - Rahul Rachwani-Anil
- Department of Ophthalmology, Regional University Hospital of Malaga, Malaga, Spain
| | - José María Sánchez González
- Department of Physics of Condensed Matter, University of Seville, Seville, Spain.,Department of Ophthalmology (Tecnolaser Clinic Vision®), Seville, Spain
| | | | - Carlos Rocha de Lossada
- Department of Ophthalmology (Qvision), VITHAS Hospital, Almería, Spain; Department of Ophthalmology, Hospital Virgen de las Nieves, Granada, Spain; Department of Ophthalmology, Ceuta Medical Center, Ceuta, Spain
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