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Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans

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A special issue of Microorganisms (ISSN 2076-2607). This special issue belongs to the section "Medical Microbiology".

Deadline for manuscript submissions: closed (1 January 2023) | Viewed by 16478

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Prof. Dr. Lidia Chomicz

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Department of Medical Biology, Medical University of Warsaw, Litewska 14/16, 00-575 Warsaw, Poland
Interests: infections, pathogenesis, pathogens, clinical and laboratory diagnosis, in vitro investigation, molecular biology examination, PCR, TEM, SEM, medical microbiology, medical .parasitology, nosocomial Infections
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Jacek P. Szaflik

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Head of the Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
Interests: diagnosis; diagnosis and treatment; cataract surgery; glaucoma surgery and glaucoma/cataract surgery; lens implants; corneal diseases
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Dr. Wanda Baltaza

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Clinical Dietitian, Department of Public Health, Faculty of Health Sciences, Medical University of Warsaw, 02-097 Warsaw, Poland
Interests: public health; food-associated infections; oral microorganisms; emerging infection; innovative technology; Molecular Diagnostic; clinical microbiology; hospital acquired infection; human behavior

Special Issue Information

Dear Colleagues,

Different strains of Acanthamoeba spp., widely distributed in natural and man-made environments are able to enter human body from different sources causing pathogenic effects. They are etiological agents of a rare, usually fatal granulomatous amoebic encephalitis developing in immunocompromised individuals. Pathogenic Acanthamoeba strains cause the vision-threatening corneal disease, difficult for diagnosis Acanthamoeba keratitis (AK). The progressive, devastating, considered a rare disease can result in loss of visual acuity and even blindness; successful treatment has not yet been fully established. In the last decades, incidents of AK are detected with increasing frequency especially in contact lenses wears. Threat for individual and public health caused by AK remains poorly investigated; it is worldwide medical problem however the knowledge and awareness of the threat is still insufficient. There are challenges in AK management: suitable clinical and laboratory diagnosis, in vivo / in vitro and molecular techniques, epidemiology aspects, chemotherapy, pathogenesis mechanisms, potential role of concomitant infections and endosymbiotic microorganisms as secondary diseases factors, an association with oral cavity microbiota, influence of various risk factors. In this special issue we would like to present up-to-date data and advanced research desirable for the prevention of health threat caused by Acanthamoeba spp. infections.

Prof. Dr. Lidia Chomicz
Prof. Dr. Jacek P. Szaflik
Dr. Wanda Baltaza
Guest Editors

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Keywords

Acanthamoeba
facultative parasites
epidemiological aspects
contact lens
diagnosis, treatment
Acanthamoeba keratitis
concomitant infections bacteria, fungi
endosymbiotic microorganisms
trophozoites, cysts
oral cavity microbiota
slit lamp
confocal microscopy
corneal isolates, cultivation methods
in vivo, in vitro and molecular techniques

Published Papers (9 papers)

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Editorial

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3 pages, 174 KiB

Open AccessEditorial

Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans

by Lidia Chomicz, Jacek P. Szaflik and Wanda Baltaza

Microorganisms 2024, 12(3), 581; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms12030581 - 14 Mar 2024

Viewed by 498

Abstract

Acanthamoeba spp [...] Full article

(This article belongs to the Special Issue Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans)

Research

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12 pages, 909 KiB

Open AccessArticle

Successive Acanthamoeba Corneal Isolates Identified in Poland Monitored in Terms of In Vitro Dynamics

by Lidia Chomicz, Jacek P. Szaflik, Beata Szostakowska, Justyna Izdebska, Wanda Baltaza, Monika Łazicka-Gałecka, Agnieszka Kuligowska, Anna Machalińska, Paweł J. Zawadzki and Jerzy Szaflik

Microorganisms 2023, 11(5), 1174; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms11051174 - 29 Apr 2023

Viewed by 1536

Abstract

Background: Amoebae of the genus Acanthamoeba cause a sight-threatening infection called Acanthamoeba keratitis. It is considered a rare disease in humans but poses an increasing threat to public health worldwide, including in Poland. We present successive isolates from serious keratitis preliminary examined in terms of the identification and monitoring of, among others, the in vitro dynamics of the detected strains. Methods: Clinical and combined laboratory methods were applied; causative agents of the keratitis were identified at the cellular and molecular levels; isolates were cultivated in an axenic liquid medium and regularly monitored. Results: In a phase-contrast microscope, Acanthamoeba sp. cysts and live trophozoites from corneal samples and in vitro cultures were assessed on the cellular level. Some isolates that were tested at the molecular level were found to correspond to A. mauritanensis, A. culbertsoni, A. castellanii, genotype T4. There was variability in the amoebic strain dynamics; high viability was expressed as trofozoites’ long duration ability to intense multiply. Conclusions: Some strains from keratitis under diagnosis verification and dynamics assessment showed enough adaptive capability to grow in an axenic medium, allowing them to exhibit significant thermal tolerance. In vitro monitoring that was suitable for verifying in vivo examinations, in particular, was useful to detect the strong viability and pathogenic potential of successive Acanthamoeba strains with a long duration of high dynamics. Full article

(This article belongs to the Special Issue Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans)

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14 pages, 5697 KiB

Open AccessArticle

Acanthamoeba castellanii Genotype T4: Inhibition of Proteases Activity and Cytopathic Effect by Bovine Apo-Lactoferrin

by Gerardo Ramírez-Rico, Moises Martinez-Castillo, Roberto Cárdenas-Zúñiga, Daniel Coronado-Velázquez, Angélica Silva-Olivares, Mireya De la Garza, Mineko Shibayama and Jesús Serrano-Luna

Microorganisms 2023, 11(3), 708; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms11030708 - 09 Mar 2023

Cited by 2 | Viewed by 1327

Abstract

Acanthamoeba castellanii genotype T4 is a clinically significant free-living amoeba that causes granulomatous amoebic encephalitis and amoebic keratitis in human beings. During the initial stages of infection, trophozoites interact with various host immune responses, such as lactoferrin (Lf), in the corneal epithelium, nasal mucosa, and blood. Lf plays an important role in the elimination of pathogenic microorganisms, and evasion of the innate immune response is crucial in the colonization process. In this study, we describe the resistance of A. castellanii to the microbicidal effect of bovine apo-lactoferrin (apo-bLf) at different concentrations (25, 50, 100, and 500 µM). Acanthamoeba castellanii trophozoites incubated with apo-bLf at 500 µM for 12 h maintained 98% viability. Interestingly, despite this lack of effect on viability, our results showed that the apo-bLf inhibited the cytopathic effect of A. castellanii in MDCK cells culture, and analysis of amoebic proteases by zymography showed significant inhibition of cysteine and serine proteases by interaction with the apo-bLf. From these results, we conclude that bovine apo-Lf influences the activity of A. castellanii secretion proteases, which in turn decreases amoebic cytopathic activity. Full article

(This article belongs to the Special Issue Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans)

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14 pages, 4194 KiB

Open AccessArticle

SLAMF7/STAT6 Pathway Inhibits Innate Immune Response in Late-Stage Human Acanthamoeba Keratitis: A Comparative Transcriptome Analysis

by Zhenyu Wei, Yuheng Zhang, Qiankun Chen, Xizhan Xu, Zhiqiang Pan, Zi-Bing Jin and Qingfeng Liang

Microorganisms 2023, 11(2), 365; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms11020365 - 01 Feb 2023

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Abstract

Acanthamoeba keratitis (AK) is a blinding corneal infection caused by the protozoan Acanthamoeba. The long-term course of AK suggests the host immunity could not kill Acanthamoeba rapidly. The immune status is still unclear in the late stage of AK. The comparative transcriptome analysis was made based on the bulk RNA sequencing of cornea tissues from AK patients and donors. Differentially expressed genes and enriched signaling pathways were calculated. CIBERSORT algorithm was used for immune infiltration analysis of cornea tissue between AK and normal controls. A total of 2668 differentially expressed genes, including 1477 upregulated genes and 1191 downregulated genes, were detected. Gene Ontology analysis revealed that the pathways were significantly enriched in leukocyte migration, regulation of T-cell activation, the external side of plasma membrane, collagen-containing extracellular matrix, immune receptor activity, and cytokine binding. The Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the pathways were significantly enriched in the cytokine–cytokine receptor interaction, hematopoietic cell lineage, and Staphylococcus aureus infection pathway. The immune infiltration profiles varied little between AK and normal controls. Compared with normal tissue, cornea tissue of AK contained a higher proportion of M0 macrophages and CD8 T cells, while resting memory CD4 T cells contributed to a relatively lower portion (p < 0.05). Finally, the expression levels of cell markers and SLAMF7/STAT6 pathway were confirmed by histopathology examinations, RT-qPCR, and Western blot. Full article

(This article belongs to the Special Issue Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans)

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12 pages, 2980 KiB

Open AccessArticle

Complete Recovery of Acanthamoeba Motility among Surviving Organisms after Contact Lens Care Disinfection

by Allison Campolo, Brian Patterson, Esther Lara, Paul Shannon and Monica Crary

Microorganisms 2023, 11(2), 299; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms11020299 - 23 Jan 2023

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Abstract

Acanthamoeba keratitis is a sight-threatening infection of the cornea which is extremely challenging to treat. Understanding this organism’s responses during contact lens contact and disinfection could enhance our understanding of how Acanthamoebae colonize contact lens cases, better inform us on contact lens care solution (CLC) efficacy, and help us better understand the efficacy required of CLC products. To explore this gap in knowledge, we used Acanthamoeba ATCC 30461 and ATCC 50370 trophozoites to examine Acanthamoeba behavior during and after CLC disinfection. Amoebae were added to sterile aluminum flow cells and flow cell solutions were changed to Ringer’s solution (control), or one of four CLCs based on biocides (PHMB, PAPB/Polyquad, Polyquad/Aldox, or Polyquad/Alexidine) for 6 h. Each flow cell solution was then changed to axenic culture media (AC6) for 12 h to determine the behavior of amoebae following disinfection. Distance, speed, and displacement were calculated for each organism. As compared to the control of one-quarter Ringer’s solution, each CLC significantly impacted Acanthamoeba motility in both the CLC and AC6 conditions. However, the amoebae challenged with the PHMB CLC traveled a significantly greater total distance than with the other three CLCs, indicating differences in effectiveness between biocides. Furthermore, amoebae regaining motility post-disinfection by CLCs were observed to travel considerable distances and thus could be considered dangerous to ocular health. We determined that while all CLCs produced a substantial or complete cessation of movement vs. the control condition during disinfection, those which relied on the Polyquad biocides were the most effective, and that any amoebae which survived disinfection were able to recover motility. Future examinations of these findings should include direct correlations between motility and viability, and how infectivity and motility may be related. Full article

(This article belongs to the Special Issue Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans)

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10 pages, 2075 KiB

Open AccessArticle

Efficacy of Off-Label Anti-Amoebic Agents to Suppress Trophozoite Formation of Acanthamoeba spp. on Non-Nutrient Agar Escherichia Coli Plates

by Vithusan Muthukumar, Lei Shi, Ning Chai, Achim Langenbucher, Sören L. Becker, Berthold Seitz, Erika Orosz, Tanja Stachon, Albrecht F. Kiderlen, Markus Bischoff and Nóra Szentmáry

Microorganisms 2022, 10(8), 1642; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms10081642 - 13 Aug 2022

Cited by 1 | Viewed by 1580

Abstract

Acanthamoeba keratitis (AK) is a dangerous infectious disease, which is associated with a high risk of blindness for the infected patient, and for which no standard therapy exists thus far. Patients suffering from AK are thus treated, out of necessity, with an off-label therapy, using drugs designed and indicated for other diseases/purposes. Here, we tested the capability of the off-label anti-amoebic drugs chlorhexidine (CH; 0.1%), dibromopropamidine diisethionate (DD; 0.1%), hexamidine diisethionate (HD; 0.1%), miltefosine (MF; 0.0065%), natamycin (NM; 5%), polyhexamethylene biguanide (PHMB; 0.02%), povidone iodine (PVPI; 1%), and propamidine isethionate (PD; 0.1%) to suppress trophozoite formation of Acantamoeba castellanii and Acanthamoeba hatchetti cysts on non-nutrient agar Escherichia coli plates. Of the eight off-label anti-amoebic drugs tested, only PVPI allowed for a complete suppression of trophozoite formation by drug-challenged cysts for all four Acanthamoeba isolates in all five biological replicates. Drugs such as NM, PD, and PHMB repeatedly suppressed trophozoite formation with some, but not all, tested Acanthamoeba isolates, while other drugs such as CH, DD, and MF failed to exert a relevant effect on the excystation capacities of the tested Acanthamoeba isolates in most, if not all, of our repetitions. Our findings suggest that pre-testing of the AK isolate with the non-nutrient agar E. coli plate assay against the anti-amoebic drug intended for treatment should be performed to confirm that the selected drug is cysticidal for the Acanthamoeba isolate. Full article

(This article belongs to the Special Issue Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans)

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12 pages, 1270 KiB

Open AccessArticle

The Activity of PHMB and Other Guanidino Containing Compounds against Acanthamoeba and Other Ocular Pathogens

by Dharanga Ratnayake, Michael Ansah, Enas Al Ani and Wayne Heaselgrave

Microorganisms 2022, 10(7), 1375; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms10071375 - 08 Jul 2022

Cited by 4 | Viewed by 2325

Abstract

In recent years, a rise in the number of contact lens users in the UK and worldwide coincided with an increased incidence of microbial keratitis. The aim of this study was to investigate the antimicrobial activities of polyhexamethylene guanidine (PHMG), polyaminopropyl biguanide (PAPB), and guazatine in comparison to the common contact lens disinfectant constituent, polyhexamethylene biguanide (PHMB). The study investigated these compounds against a broad range of organisms, including Acanthamoeba castellanii, Acanthamoeba polyphaga, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. This study demonstrated that PHMG, PAPB, and guazatine are equal in activity to PHMB against Acanthamoeba trophozoites and cysts. PHMG and PAPB are also equal in activity to PHMB against S. aureus and P. aeruginosa, whereas PHMG shows significantly better activity than PHMB against C. albicans (p < 0.001). To our knowledge, this is the first study to demonstrate the effectiveness of PHMB, PHMG, PAPB, and guazatine against Acanthamoeba and other ocular pathogens. As alternatives to PHMB, these compounds warrant further investigation for inclusion in contact lens solutions and for the treatment of keratitis. Full article

(This article belongs to the Special Issue Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans)

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7 pages, 1540 KiB

Open AccessArticle

Real-Time PCR for the Diagnosis of Acanthamoeba Genotype T4

by Aline Lamien-Meda, Martina Köhsler and Julia Walochnik

Microorganisms 2022, 10(7), 1307; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms10071307 - 28 Jun 2022

Cited by 4 | Viewed by 1839

Abstract

Acanthamoeba spp. are ubiquitous and opportunistic free-living amoebae (FLA) that can cause Acanthamoeba keratitis and other infections in the human host. A quick and efficient diagnosis is often challenging. Our study aimed to establish a qPCR assay to detect and, at the same time, quantify the predominant Acanthamoeba genotype T4. DNA from clinical corneal scrapings and Acanthamoeba reference strains, including genotypes T3, T4, T5, T6, T10, T11, and T12, were used to develop the new T4 assay and it was compared to published protocols and one commercial kit for evaluation. The T4 assay showed no amplification with Acanthamoeba genotypes T3, T5, T6, T10, T11, and T12. The efficiencies ranged from 92.01 to 97.59% (R² of 0.9768 to 0.9951). The calculated LOD range was 3.63 to 33.27 cells/µL. The protocol published by Qvarnstrom and colleagues was more sensitive compared to the other assays, and an overall good agreement was observed between the new T4 and the Qvarnstrom assays. We successfully developed and validated a genotype T4 assay that could be run in duplex with the Qvarnstrom assay to reliably and simultaneously diagnose Acanthamoeba genotype T4 and other genotypes from clinical samples. Full article

(This article belongs to the Special Issue Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans)

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Other

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11 pages, 2009 KiB

Open AccessPerspective

Tannic Acid-Modified Silver Nanoparticles in Conjunction with Contact Lens Solutions Are Useful for Progress against the Adhesion of Acanthamoeba spp. to Contact Lenses

by Marcin Padzik, Lidia Chomicz, Julita Bluszcz, Karolina Maleszewska, Jaroslaw Grobelny, David Bruce Conn and Edyta B. Hendiger

Microorganisms 2022, 10(6), 1076; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms10061076 - 24 May 2022

Cited by 5 | Viewed by 1922

Abstract

Acanthamoeba spp. are amphizoic amoebae that are widely distributed in the environment and capable of entering the human body. They can cause pathogenic effects in different tissues and organs, including Acanthamoeba keratitis (AK), which may result in a loss of visual acuity and blindness. The diagnostics, treatment, and prevention of AK are still challenging. More than 90% of AK cases are related to the irresponsible wearing of contact lenses. However, even proper lens care does not sufficiently protect against this eye disease, as amoebae have been also found in contact lens solutions and contact lens storage containers. The adhesion of the amoebae to the contact lens surface is the first step in developing this eye infection. To limit the incidence of AK, it is important to enhance the anti-adhesive activity of the most popular contact lens solutions. Currently, silver nanoparticles (AgNPs) are used as modern antimicrobial agents. Their effectiveness against Acanthamoeba spp., especially with the addition of plant metabolites, such as tannic acid, has been confirmed. Here, we present the results of our further studies on the anti-adhesion potential of tannic acid-modified silver nanoparticles (AgTANPs) in combination with selected contact lens solutions against Acanthamoeba spp. on four groups of contact lenses. The obtained results showed an increased anti-adhesion activity of contact lens solutions in conjunction with AgTANPs with a limited cytotoxicity effect compared to contact lens solutions acting alone. This may provide a benefit in improving the prevention of amoebae eye infections. However, there is still a need for further studies on different pathogenic strains of Acanthamoeba in order to assess the adhesion of the cysts to the contact lens surface and to reveal a more comprehensive picture of the activity of AgTANPs and contact lens solutions. Full article

(This article belongs to the Special Issue Acanthamoeba spp. as Factors for Severe Infectious Diseases in Humans)

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