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Cardoso IR, de Lima CS, dos Reis RB, Pinto ACA, Pissinatti T, Kugelmeier T, Neto SFDC, da Silva FA, Santos HLC. Occurrence of Free-Living Amoebae in Non-Human Primate Gut. Trop Med Infect Dis 2024; 9:108. [PMID: 38787041 PMCID: PMC11125615 DOI: 10.3390/tropicalmed9050108] [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: 10/28/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 05/25/2024] Open
Abstract
The gut microbiome reflects health and predicts possible disease in hosts. A holistic view of this community is needed, focusing on identifying species and dissecting how species interact with their host and each other, regardless of whether their presence is beneficial, inconsequential, or detrimental. The distribution of gut-associated eukaryotes within and across non-human primates is likely driven by host behavior and ecology. To ascertain the existence of free-living amoebae (FLA) in the gut of wild and captive non-human primates, 101 stool samples were collected and submitted to culture-dependent microscopy examination and DNA sequencing. Free-living amoebae were detected in 45.4% (46/101) of fecal samples analyzed, and their morphological characteristics matched those of Acanthamoeba spp., Vermamoeba spp., heterolobosean amoeboflagellates and fan-shaped amoebae of the family Vannellidae. Sequence analysis of the PCR products revealed that the suspected amoebae are highly homologous (99% identity and 100% query coverage) with Acanthamoeba T4 genotype and Vermamoeba vermiformis amoebae. The results showed a great diversity of amoebae in the non-human primate's microbiome, which may pose a potential risk to the health of NHPs. To our knowledge, this is the first report of free-living amoebae in non-human primates that are naturally infected. However, it is unknown whether gut-borne amoebae exploit a viable ecological niche or are simply transient residents in the gut.
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Affiliation(s)
- Igor Rodrigues Cardoso
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro 21040-360, Brazil; (I.R.C.); (C.S.d.L.); (R.B.d.R.)
| | - Clezia Siqueira de Lima
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro 21040-360, Brazil; (I.R.C.); (C.S.d.L.); (R.B.d.R.)
- Instituto de Saúde de Nova Friburgo, da Universidade Federal Fluminense, Nova Friburgo 28625-650, Brazil
| | - Rhagner Bonono dos Reis
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro 21040-360, Brazil; (I.R.C.); (C.S.d.L.); (R.B.d.R.)
| | - Ana Cristina Araujo Pinto
- Instituto de Ciência e Tecnologia em Biomodelos/FIOCRUZ, Rio de Janeiro 26382-462, Brazil; (A.C.A.P.); (T.P.); (T.K.); (F.A.d.S.)
| | - Thalita Pissinatti
- Instituto de Ciência e Tecnologia em Biomodelos/FIOCRUZ, Rio de Janeiro 26382-462, Brazil; (A.C.A.P.); (T.P.); (T.K.); (F.A.d.S.)
| | - Tatiana Kugelmeier
- Instituto de Ciência e Tecnologia em Biomodelos/FIOCRUZ, Rio de Janeiro 26382-462, Brazil; (A.C.A.P.); (T.P.); (T.K.); (F.A.d.S.)
| | | | - Fabio Alves da Silva
- Instituto de Ciência e Tecnologia em Biomodelos/FIOCRUZ, Rio de Janeiro 26382-462, Brazil; (A.C.A.P.); (T.P.); (T.K.); (F.A.d.S.)
| | - Helena Lúcia Carneiro Santos
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro 21040-360, Brazil; (I.R.C.); (C.S.d.L.); (R.B.d.R.)
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Chomicz L, Szaflik JP, Szostakowska B, Izdebska J, Baltaza W, Łazicka-Gałecka M, Kuligowska A, Machalińska A, Zawadzki PJ, Szaflik J. Successive Acanthamoeba Corneal Isolates Identified in Poland Monitored in Terms of In Vitro Dynamics. Microorganisms 2023; 11:1174. [PMID: 37317148 DOI: 10.3390/microorganisms11051174] [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: 03/31/2023] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 06/16/2023] Open
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.
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Affiliation(s)
- Lidia Chomicz
- Department of Medical Biology, Medical University of Warsaw, 00-575 Warsaw, Poland
| | - Jacek P Szaflik
- Department of Ophthalmology, Independent Public Clinical Ophthalmology Hospital, Medical University of Warsaw, 00-576 Warsaw, Poland
| | - Beata Szostakowska
- Department of Tropical Parasitology, Faculty of Health Sciences, Medical University of Gdansk, 80-210 Gdańsk, Poland
| | - Justyna Izdebska
- Department of Ophthalmology, Independent Public Clinical Ophthalmology Hospital, Medical University of Warsaw, 00-576 Warsaw, Poland
| | - Wanda Baltaza
- Department of Public Health, Medical University of Warsaw, 02-097 Warsaw, Poland
| | - Monika Łazicka-Gałecka
- Department of Ophthalmology, Independent Public Clinical Ophthalmology Hospital, Medical University of Warsaw, 00-576 Warsaw, Poland
| | - Agnieszka Kuligowska
- First Department of Ophthalmology, Pomeranian Medical University, 70-111 Szczecin, Poland
| | - Anna Machalińska
- First Department of Ophthalmology, Pomeranian Medical University, 70-111 Szczecin, Poland
| | - Paweł J Zawadzki
- Clinic of Cranio-Maxillo-Facial and Oral Surgery and Implantology, Medical University of Warsaw, 02-005 Warsaw, Poland
| | - Jerzy Szaflik
- Laser Eye Microsurgery Centre Clinic of Prof. Jerzy Szaflik, Brand Med Medical Research Centre, 00-215 Warsaw, Poland
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Diehl MLN, Paes J, Rott MB. Genotype distribution of Acanthamoeba in keratitis: a systematic review. Parasitol Res 2021; 120:3051-3063. [PMID: 34351492 PMCID: PMC8339388 DOI: 10.1007/s00436-021-07261-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 07/20/2021] [Indexed: 12/16/2022]
Abstract
Acanthamoeba spp. are among the most worldwide prevalent protozoa. It is the causative agent of a disease known as Acanthamoeba keratitis, a painful and severe sight-threatening corneal infection that can lead to blindness. In recent years, the prevalence of Acanthamoeba keratitis has rapidly increased, growing its importance to human health. This systematic review aims to assess the distribution of Acanthamoeba sp. genotypes causing keratitis around the world, considering the sample collected type and the used identification method. Most of the cases were found in Asia and Europe. Not surprisingly, the T4 genotype was the most prevalent worldwide, followed by T3, T15, T11, and T5. Furthermore, the T4 genotype contains a higher number of species. Given the differences in pathology, susceptibility to treatment, and clinical outcome between distinct genotypes, it is essential to genotype isolates from Acanthamoeba keratitis cases to help to establish a better correlation between in vitro and in vivo activities, resulting in better drug therapies and successful treatment in cases of this important ocular infection.
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Affiliation(s)
- Maria Luisa Nunes Diehl
- Departamento de Microbiologia, Imunologia E Parasitologia, Instituto de Ciências, Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul (UFRGS), Rua Sarmento Leite, 500, Porto Alegre, RS, 90050-170, Brazil
| | - Júlia Paes
- Departamento de Microbiologia, Imunologia E Parasitologia, Instituto de Ciências, Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul (UFRGS), Rua Sarmento Leite, 500, Porto Alegre, RS, 90050-170, Brazil
| | - Marilise Brittes Rott
- Departamento de Microbiologia, Imunologia E Parasitologia, Instituto de Ciências, Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul (UFRGS), Rua Sarmento Leite, 500, Porto Alegre, RS, 90050-170, Brazil.
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Russello G, Moramarco A, Vizzini L, Farina C, Fontana L, Carretto E. Diagnostic approach and epidemiology of Microbial Keratitis: findings from an Italian Tertiary Care center. Diagn Microbiol Infect Dis 2021; 101:115470. [PMID: 34352436 DOI: 10.1016/j.diagmicrobio.2021.115470] [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: 01/20/2021] [Revised: 06/17/2021] [Accepted: 06/19/2021] [Indexed: 11/30/2022]
Abstract
Rapid identification of causative microorganisms of microbial keratitis (MK) and knowledge of the most common local pathogens are prerequisites for rational antimicrobial therapy. We retrospectively reviewed the characteristics of MK diagnosed at the IRCCS Arcispedale Santa Maria Nuova of Reggio Emilia (Italy) in a 5-years period, where the Ophthalmologist Unit is a reference center for corneal infections. During the study period, 183 MK were evaluated through corneal scrapings cultures. The positivity rate was 54,1%. A total of 107 microorganisms have been isolated: Acanthamoeba species was the etiologic agent in 19 cases. Pseudomonas aeruginosa and Staphylococcus aureus were more frequently isolated in bacterial keratitis, while Fusarium spp., Candida albicans, and Alternaria alternata were predominant among the fungal isolates. Strict cooperation between ophthalmologists and clinical microbiologists is advisable to allow the best diagnostic approach for MK.
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Affiliation(s)
- Giuseppe Russello
- Clinical Microbiology Laboratory, IRCCS Arcispedale S. Maria Nuova, AUSL Reggio Emilia, Italy
| | - Antonio Moramarco
- Ophthalmology Unit, IRCCS Arcispedale S. Maria Nuova, AUSL Reggio Emilia, Italy
| | - Loredana Vizzini
- Clinical Microbiology Laboratory, IRCCS Arcispedale S. Maria Nuova, AUSL Reggio Emilia, Italy
| | - Claudio Farina
- Clinical Microbiology and Virology Laboratory, ASST "Papa Giovanni XXIII", Bergamo, Italy
| | - Luigi Fontana
- Ophthalmology Unit, IRCCS Arcispedale S. Maria Nuova, AUSL Reggio Emilia, Italy
| | - Edoardo Carretto
- Clinical Microbiology Laboratory, IRCCS Arcispedale S. Maria Nuova, AUSL Reggio Emilia, Italy.
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Practical Guidance for Clinical Microbiology Laboratories: Diagnosis of Ocular Infections. Clin Microbiol Rev 2021; 34:e0007019. [PMID: 34076493 DOI: 10.1128/cmr.00070-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The variety and complexity of ocular infections have increased significantly in the last decade since the publication of Cumitech 13B, Laboratory Diagnosis of Ocular Infections (L. D. Gray, P. H. Gilligan, and W. C. Fowler, Cumitech 13B, Laboratory Diagnosis of Ocular Infections, 2010). The purpose of this practical guidance document is to review, for individuals working in clinical microbiology laboratories, current tools used in the laboratory diagnosis of ocular infections. This document begins by describing the complex, delicate anatomy of the eye, which often leads to limitations in specimen quantity, requiring a close working bond between laboratorians and ophthalmologists to ensure high-quality diagnostic care. Descriptions are provided of common ocular infections in developed nations and neglected ocular infections seen in developing nations. Subsequently, preanalytic, analytic, and postanalytic aspects of laboratory diagnosis and antimicrobial susceptibility testing are explored in depth.
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Challenges in Acanthamoeba Keratitis: A Review. J Clin Med 2021; 10:jcm10050942. [PMID: 33804353 PMCID: PMC7957573 DOI: 10.3390/jcm10050942] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/15/2021] [Accepted: 02/17/2021] [Indexed: 02/07/2023] Open
Abstract
To review challenges in the diagnosis and management of Acanthamoeba keratitis (AK), along with prognostic factors, in order to help ophthalmologists avoid misdiagnosis, protracted treatment periods, and long-term negative sequelae, with an overarching goal of improving patient outcomes and quality of life, we examined AK studies published between January 1998 and December 2019. All manuscripts describing clinical manifestations, diagnosis, treatment, prognosis, and challenges in short- and long-term management were included. The diagnosis of AK is often challenging. An increased time between symptom onset and the initiation of appropriate therapy is associated with poorer visual outcomes. The timely initiation of standardized antiamoebic therapies improves visual outcomes, decreases the duration of treatment, and reduces the chances of needing surgical intervention. In clinical practice, AK diagnosis is often missed or delayed, leading to poorer final visual outcomes and a negative impact on patient morbidity and quality of life.
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Rammohan R, Hajib Naraharirao M, Veerappan S, Vijayaraghavan P, Rajaraman R, Manayath GJ, Dsouza P, Radhakrishnan S, Venkatapathy N, Lakshmipathi D, Madhuravasal Krishnan J, Raghavan A. Cluster of Post-Operative Endophthalmitis Caused by Acanthamoeba T10 Genotype - A First Report. Cornea 2021; 40:232-241. [PMID: 33201060 DOI: 10.1097/ico.0000000000002603] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 09/27/2020] [Indexed: 11/27/2022]
Abstract
PURPOSE To report a cluster of postoperative Acanthamoeba endophthalmitis after routine cataract surgeries. METHODS A brief summary of sentinel events leading to the referral of 4 patients of postoperative endophthalmitis to our hospital is followed by clinical descriptions and the various diagnostic approaches and interventions used. Genotyping and phylogenetic analysis are also discussed. RESULTS Four cases of postoperative cluster endophthalmitis, presumed to be bacterial and treated as such, were referred to our hospital. The presence of an atypical ring infiltrate in the first case facilitated the diagnosis of Acanthamoeba endophthalmitis. All patients had vitritis, corneal involvement, and scleral inflammation. Multiple diagnostic methods, such as corneal scrapings, confocal microscopy, aqueous and vitreous taps, scleral abscess drainage, histopathological studies, polymerase chain reaction, and genotyping and phylogenetic analyses of isolated Acanthamoeba, were used to confirm the diagnosis of endophthalmitis and to establish the extent of ocular involvement. Various medical and therapeutic interventions used to control the infections were also documented. The isolated Acanthamoeba were confirmed as belonging to the T10 genotype, an environmentally and clinically rare variety. CONCLUSIONS This is the first report of a cluster of postoperative T10 genotype Acanthamoeba endophthalmitis, occurring after routine cataract surgery in immunocompetent individuals. Contrary to current perceptions, a rapidly evolving infection can occur with Acanthamoeba.
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Affiliation(s)
- Ram Rammohan
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | | | - Saravanan Veerappan
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - Prabhu Vijayaraghavan
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - Revathi Rajaraman
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - George J Manayath
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - Palmeera Dsouza
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - Shanthi Radhakrishnan
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Madurai, Tamil Nadu, India
| | - Narendran Venkatapathy
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
| | - Dhanurekha Lakshmipathi
- Sankara Nethralaya Referral Laboratory (Medical Research Foundation), Chennai, Tamil Nadu, India; and
| | | | - Anita Raghavan
- Aravind Eye Hospital and Post-Graduate Institute of Ophthalmology, Coimbatore, Tamil Nadu, India
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8
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Detection and Identification of Acanthamoeba and Other Nonviral Causes of Infectious Keratitis in Corneal Scrapings by Real-Time PCR and Next-Generation Sequencing-Based 16S-18S Gene Analysis. J Clin Microbiol 2021; 59:JCM.02224-20. [PMID: 33239372 PMCID: PMC8111161 DOI: 10.1128/jcm.02224-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/16/2020] [Indexed: 01/29/2023] Open
Abstract
Acanthamoeba is a free-living amoeba of extensive genetic diversity. It may cause infectious keratitis (IK), which can also be caused by bacteria, fungi, and viruses. Acanthamoeba is a free-living amoeba of extensive genetic diversity. It may cause infectious keratitis (IK), which can also be caused by bacteria, fungi, and viruses. High diagnostic sensitivity is essential to establish an early diagnosis of Acanthamoeba-associated keratitis. Here, we investigated the applicability of next-generation sequencing (NGS)-based ribosomal gene detection and differentiation (16S-18S) compared with specific real-time PCR for the detection of Acanthamoeba. Two hundred DNAs extracted from corneal scrapings and screened by Acanthamoeba-specific real-time PCR were analyzed using an in-house 16S-18S NGS assay. Of these, 24 were positive by specific real-time PCR, of which 21 were positive by the NGS assay. Compared with real-time PCR; the specificity and sensitivity of the NGS assay were 100% and 88%, respectively. Genotypes identified by the NGS assay included T4 (n = 19) and T6 (n = 2). Fungal and bacterial species of potential clinical relevance were identified in 31 of the samples negative for Acanthamoeba, exemplified by Pseudomonas aeruginosa (n = 11), Moraxella spp. (n = 6), Staphylococcus aureus (n = 2), Fusarium spp. (n = 4), and Candida albicans (n = 1). In conclusion, the 16S-18S assay was slightly less sensitive than real-time PCR in detecting Acanthamoeba-specific DNA in corneal scrapings. Robust information on genotypes was provided by the NGS assay, and other pathogens of potential clinical relevance were identified in 16% of the samples negative for Acanthamoeba. NGS-based detection of ribosomal genes in corneal scrapings could be an efficient screening method for detecting nonviral causes of IK, including Acanthamoeba.
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Gabr NS, Mohamed RM, Belal US, Abdel-Fatah MM, Ahmed RF, Abdel Gaber NAT, Abdel-Hafeez EH. Isolation and Identification of Pathogenic Acanthamoeba Species from Air Conditioning Systems, Egypt. Jpn J Infect Dis 2020; 74:180-186. [PMID: 32999181 DOI: 10.7883/yoken.jjid.2020.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Acanthamoeba are free-living amoebae that cause granulomatous amoebic encephalitis and keratitis. In this study, we aimed to isolate and identify Acanthamoeba from air conditioning systems using in vitro cell culture and polymerase chain reaction assays. We also estimated the pathogenicity of the isolates by measuring their thermotolerance and studying mice models inoculated with these isolates. Of the 80 dust samples acquired, 41 (51.25%) were found to be positive for Acanthamoeba spp. using in vitro cell culture and the results were validated using PCR. Out of these 41 samples, 27 (65.9%) were thermotolerant and 16 (39%) samples could infect mice and cause histopathological effects. Highly pathogenic Acanthamoeba isolates were characterized by their thermotolerance and the ability to disseminate in all organs after infection, causing early death of infected animals. Our study thus validated the presence of pathogenic isolates of Acanthamoeba in air conditioners that may be potentially infectious to humans.
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Affiliation(s)
- Nabil Shokrany Gabr
- Parasitology Department, Faculty of Pharmacy, Deraya University, Egypt.,Parasitology Department, Faculty of Medicine, Minia University, Egypt
| | | | - Usama Salah Belal
- Parasitology Department, Faculty of Medicine, Minia University, Egypt
| | | | - Rasha Fouad Ahmed
- Biochemistry Department, Faculty of Medicine, Minia University, Egypt
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Rice CA, Troth EV, Russell AC, Kyle DE. Discovery of Anti-Amoebic Inhibitors from Screening the MMV Pandemic Response Box on Balamuthia mandrillaris, Naegleria fowleri, and Acanthamoeba castellanii. Pathogens 2020; 9:E476. [PMID: 32560115 PMCID: PMC7344389 DOI: 10.3390/pathogens9060476] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/05/2020] [Accepted: 06/09/2020] [Indexed: 02/06/2023] Open
Abstract
Pathogenic free-living amoebae, Balamuthia mandrillaris, Naegleria fowleri, and several Acanthamoeba species are the etiological agents of severe brain diseases, with case mortality rates > 90%. A number of constraints including misdiagnosis and partially effective treatments lead to these high fatality rates. The unmet medical need is for rapidly acting, highly potent new drugs to reduce these alarming mortality rates. Herein, we report the discovery of new drugs as potential anti-amoebic agents. We used the CellTiter-Glo 2.0 high-throughput screening methods to screen the Medicines for Malaria Ventures (MMV) Pandemic Response Box in a search for new active chemical scaffolds. Initially, we screened the library as a single-point assay at 10 and 1 µM. From these data, we reconfirmed hits by conducting quantitative dose-response assays and identified 12 hits against B. mandrillaris, 29 against N. fowleri, and 14 against A. castellanii ranging from nanomolar to low micromolar potency. We further describe 11 novel molecules with activity against B. mandrillaris, 22 against N. fowleri, and 9 against A. castellanii. These structures serve as a starting point for medicinal chemistry studies and demonstrate the utility of phenotypic screening for drug discovery to treat diseases caused by free-living amoebae.
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Affiliation(s)
- Christopher A. Rice
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
- Center for Tropical and Emerging Global Diseases, Athens, GA 30602, USA; (E.V.T.); (A.C.R.)
| | - Emma V. Troth
- Center for Tropical and Emerging Global Diseases, Athens, GA 30602, USA; (E.V.T.); (A.C.R.)
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA
| | - A. Cassiopeia Russell
- Center for Tropical and Emerging Global Diseases, Athens, GA 30602, USA; (E.V.T.); (A.C.R.)
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA
| | - Dennis E. Kyle
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
- Center for Tropical and Emerging Global Diseases, Athens, GA 30602, USA; (E.V.T.); (A.C.R.)
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA
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Alkyl-carbon chain length of two distinct compounds and derivatives are key determinants of their anti-Acanthamoeba activities. Sci Rep 2020; 10:6420. [PMID: 32286337 PMCID: PMC7156471 DOI: 10.1038/s41598-020-62934-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 03/05/2020] [Indexed: 02/06/2023] Open
Abstract
The opportunistic pathogen, Acanthamoeba castellanii is the causative agent for the sight threatening infection Acanthamoeba keratitis (AK). It is commonly associated with contact lens wearers, and prevalence is increasing at an alarming rate due to an inadequate preventive strategy to protect the lens from this protist. This problem is compounded by the lack of an effective acanthamoebocide, particularly with cysticidal activity in the contact lens solutions. We have used cytotoxicity assays and a variety of biophysical approaches to show that two molecules with tails made of alkyl carbon, alkylphosphocholines (APCs) and quaternary ammonium compounds (QACs) had significant chain-length dependent efficacy against A. castellanii trophozoites, the latter producing death via permeabilization, and DNA complexing. QACs were more effective than APCs and had activity against cysts. Conversely, the QAC with 12 alkyl carbon chain, was non toxic, its presence increased A. castellanii trophozoites biomass and delayed encystation by 96 h. Interestingly, it was unable to induce excystation and increased trophozoite sensitivity to APC16. These results present a mono- and multi-inhibitor management strategy effective against trophozoites and cysts that may be useful for formulating into contact lense cleaning solutions and reducing AK incidence.
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12
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Carnt NA, Subedi D, Lim AW, Lee R, Mistry P, Badenoch PR, Kilvington S, Dutta D. Prevalence and seasonal variation of Acanthamoeba in domestic tap water in greater Sydney, Australia. Clin Exp Optom 2020; 103:782-786. [PMID: 32227362 DOI: 10.1111/cxo.13065] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 11/17/2019] [Accepted: 02/28/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND This study examined the prevalence of free-living Acanthamoeba in domestic tap water in the greater Sydney region, Australia, and determined any seasonal variation in prevalence. METHODS Fifty-four participants were included in this study following approval from an institutional human research ethics committee. Each participant self-collected two samples (one in summer and another in winter) from the surface of the drain of the bathroom sink using an instructional kit. The samples were cultured by inoculating onto a non-nutrient agar plate seeded with Escherichia coli and incubation at 32°C for two weeks. The plates were microscopically examined for the presence of free-living amoeba. DNA was isolated from 20 samples and a polymerase chain reaction (PCR) assay was performed for amplification of the partial sequence of the 18S ribosomal RNA gene. The PCR amplified products were sequenced using Sanger sequencing and genotyping was performed based on the variation in nucleotide sequences. RESULTS A total of 97 samples were collected over the two collection periods, with 28.6 per cent of samples morphologically classified as Acanthamoeba. The summer period yielded 16 of 54 (29.6 per cent) samples classified as Acanthamoeba, while the winter period yielded 12 of 43 (27.9 per cent) samples classified as Acanthamoeba. There was no statistically significant difference (p = 0.85) between the prevalence of free-living Acanthamoeba in summer compared to winter. Phylogenetic analysis showed that 15 of 20 (75 per cent) isolates belonged to genotype T4, the most frequent genotype isolated in Acanthamoeba keratitis. CONCLUSION The prevalence of free-living Acanthamoeba characterised morphologically in domestic tap water of the greater Sydney region was higher than expected, especially considering the low incidence of Acanthamoeba keratitis in Australia. However, this study did not find variation between seasons. As the T4 genotype was most common, Sydney-based practitioners must always consider Acanthamoeba as a possible causative organism in cases of microbial keratitis, regardless of the season.
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Affiliation(s)
- Nicole A Carnt
- School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia.,Centre for Vision Research, Westmead Institute for Medical Research, The University of Sydney, Sydney, Australia.,Institute of Ophthalmology, University College London, London, UK
| | - Dinesh Subedi
- School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia
| | - Ann W Lim
- School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia
| | - Rebecca Lee
- School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia
| | - Priyal Mistry
- School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia
| | - Paul R Badenoch
- Department of Ophthalmology, Flinders Medical Centre, Adelaide, Australia.,College of Medicine and Public Health, Flinders University, Adelaide, Australia
| | - Simon Kilvington
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Debarun Dutta
- School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia.,Optometry and Vision Science, Life and Health Sciences, Aston University, Birmingham, UK
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Li W, Wang Z, Qu J, Zhang Y, Sun X. Acanthamoeba keratitis related to contact lens use in a tertiary hospital in China. BMC Ophthalmol 2019; 19:202. [PMID: 31533675 PMCID: PMC6751601 DOI: 10.1186/s12886-019-1210-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 08/30/2019] [Indexed: 12/17/2022] Open
Abstract
Background To report the clinical and microbiological features of Acanthamoeba keratitis (AK) related to contact lens use in a tertiary hospital in China. Methods In this retrospective study, the medical results of 61 cases of AK related to contact lens use from January 2000 to December 2017 were reviewed. The data included patients’ demographics, lens type, history, risk factors, disease stages, corneal scraping and culture reports, and treatments. Moreover, genotypic identification of some of the isolates was carried out with a PCR assay and sequence analysis of the 18S ribosomal DNA gene. Results There were 64 eyes included in the study. A total of 32.8% of the patients wore soft contact lenses, and 67.2% of patients used overnight orthokeratology. In the cases (20 eyes) in the early stage, 65% (13 eyes) had positive results according to Giemsa-stained smears, and 0.9% sodium chloride (NaCl) wet mounts revealed trophozoites in 7 eyes (35%). Six eyes (30%) were diagnosed by confocal microscopy combined with clinical signs. In the orthokeratology patients, 87.8% (36/41) rinsed their lenses and/or cases with tap water; 55% of soft-lens wearers wore their lenses while showering. The genotype of 9 isolates was determined, and all the strains belonged to genotype T4. In the orthokeratology group, the number of patients who required therapeutic penetrating keratoplasty after 2005 was less than that before 2005 (chi-square test, χ2 = 4.209, P = 0.04). Conclusions More than two-thirds of the cases were associated with orthokeratology. Examinations with Giemsa-stained smears, 0.9% NaCl wet mounts and confocal microscopy should be performed for patients who are highly suspected of having early-stage AK to help with early diagnosis. In the orthokeratology group, the rate of therapeutic keratoplasty after 2005 was less than that before 2005. Electronic supplementary material The online version of this article (10.1186/s12886-019-1210-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Weiwei Li
- Tianjin Eye Hospital, Tianjin Ophthalmology and Visual Development Key Laboratory, Clinical College of Ophthalmology, Tianjin Medical University, Address: 4, Gansu Road, Heping District, Tianjin, 300020, China
| | - Zhiqun Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Address: 17 Hou Gou Lane, Chong Nei Street, Beijing, 100005, China
| | - Jinghao Qu
- Tianjin Eye Hospital, Tianjin Ophthalmology and Visual Development Key Laboratory, Clinical College of Ophthalmology, Tianjin Medical University, Address: 4, Gansu Road, Heping District, Tianjin, 300020, China
| | - Yang Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Address: 17 Hou Gou Lane, Chong Nei Street, Beijing, 100005, China
| | - Xuguang Sun
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Address: 17 Hou Gou Lane, Chong Nei Street, Beijing, 100005, China.
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Mohamed MSM, Abdallah AA, Mahran MH, Shalaby AM. Potential Alternative Treatment of Ocular Bacterial Infections by Oil Derived from Syzygium aromaticum Flower (Clove). Curr Eye Res 2018; 43:873-881. [PMID: 29634373 DOI: 10.1080/02713683.2018.1461907] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Purpose/Aim: This study aims to evaluate the predisposing risk factors and antibiotic resistance of bacterial corneal ulcer to commonly used antibiotics. In addition, assess the in vitro efficacy of plant-derived essential oils (EOs) as safe and effective antimicrobial agents. METHODS Demographic features and predisposing risk factors of corneal ulcer patients were recorded. Isolation and identification of bacteria was performed using conventional microbiological methods. Antibacterial activity was determined by disk diffusion and the micro-dilution broth methods. EOs were extracted by steam distillation and were analyzed by gas chromatography mass spectrometry technique. RESULTS Out of the 200 patients with corneal ulcer evaluated in this study, the main predisposing factor of bacterial corneal ulcer was trauma (26.5%) and 96.7% isolates were multidrug resistant. Staphylococcus aureus was the predominant isolate 33 cases. Antibiotic susceptibility of bacterial isolates showed that the fourth-generation fluoroquinolones, gatifloxacin was the most effective antibiotic with sensitivity rate 81.3%. Seven selected EOs showed significant activity against most of the tested bacteria. Syzygium aromaticum oil showed high activity against all tested bacterial species with highest sensitivity rate (97.5%) and low minimal inhibitory concentration values against S. aureus (0.10 µl/ml). The chemical composition of the EOs showed that the monoterpenes were predominant. The main constituent of S. aromaticum oil was eugenol (76%). CONCLUSIONS The current study showed that S. aromaticum oil had high antibacterial activity that could be helpful in the treatment of ocular bacterial infections to minimizing the possible side effects of commonly used antibiotic.
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Affiliation(s)
- Mahmoud S M Mohamed
- a Department of Botany and Microbiology, Faculty of Science , Cairo University , Giza , Egypt
| | - Asmaa A Abdallah
- a Department of Botany and Microbiology, Faculty of Science , Cairo University , Giza , Egypt
| | - Magda H Mahran
- b Department of Microbiology and Immunology , Research Institute of Ophthalmology , Giza , Egypt
| | - Ahmed M Shalaby
- a Department of Botany and Microbiology, Faculty of Science , Cairo University , Giza , Egypt
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15
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Isolation and molecular characterization of Acanthamoeba from patients with keratitis in Spain. Eur J Protistol 2017; 61:244-252. [PMID: 28756938 DOI: 10.1016/j.ejop.2017.06.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/23/2017] [Accepted: 06/28/2017] [Indexed: 11/22/2022]
Abstract
In order to improve our knowledge on the epidemiology of amoebic keratitis, as well as the identification of Acanthamoeba isolates, we have isolated Acanthamoeba spp. from five symptomatic patients in Spain in the present study. All isolates were grown in axenic liquid medium, with only one exception. The morphology of these isolates were characterized by optical and scanning electron microscopy. Their structural features corresponded to those of amphizoic amoebae (namely Acanthamoeba spp.). The molecular characterization of the five Acanthamoeba isolates yielded six sequences. Almost complete 18S rRNA gene sequences (>2000bp) were obtained from three isolates and partial sequences (∼1500bp) from the other two. A robust phylogenetic analysis based on the almost complete 18S rRNA sequence showed that four isolates belonged to the T4 genotype and the other one to the T3 genotype. However, all isolates were identified as T4 genotype using the ASA.S1 fragment. As previously suggested by other researchers, only a robust phylogenetic approach may be helpful in identifying Acanthamoeba genotypes. In addition, new data on the phylogenetic relationships among the Acanthamoeba genotypes is provided and discussed.
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16
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Del Chierico F, Di Cave D, Accardi C, Santoro M, Masotti A, D'Alfonso R, Berrilli F, Urbani A, Putignani L. Identification and typing of free-living Acanthamoeba spp. by MALDI-TOF MS Biotyper. Exp Parasitol 2016; 170:82-89. [DOI: 10.1016/j.exppara.2016.09.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/07/2016] [Accepted: 09/20/2016] [Indexed: 01/08/2023]
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17
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Genotypic, physiological, and biochemical characterization of potentially pathogenic Acanthamoeba isolated from the environment in Cairo, Egypt. Parasitol Res 2016; 115:1871-81. [PMID: 26841771 DOI: 10.1007/s00436-016-4927-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/14/2016] [Indexed: 10/22/2022]
Abstract
Acanthamoebae are the most common opportunistic amphizoic protozoa that cause life-threatening granulomatous amoebic encephalitis in immunocompromised individuals and sight-threatening amoebic keratitis (AK) in contact lens wearers. The present work aimed to determine the presence of Acanthamoeba isolates in different environmental sources: water, soil, and dust in Cairo, Egypt and to characterize the pathogenic potential of the isolated Acanthamoeba using physiological and biochemical assays as well as determination of the genotypes in an attempt to correlate pathogenicity with certain genotypes. The study included the collection of 22 corneal scrapings from patients complaining of symptoms and signs indicative of acanthamoeba keratitis (AK) and 75 environmental samples followed by cultivation on non-nutrient agar plates preseeded with E. coli. Positive samples for Acanthamoeba were subjected to osmo- and thermo-tolerance assays and zymography analysis. Potentially pathogenic isolates were subjected to PCR amplification using genus-specific primer pair. Isolates were classified at the genotype level based on the sequence analysis of Acanthamoeba 18S rRNA gene (diagnostic fragment 3). The total detection rate for Acanthamoeba in environmental samples was 33.3 %, 31.4 % in water, 40 % in soil, and 20 % in dust samples. Three and two Acanthamoeba isolates from water and soil sources, respectively, had the potential for pathogenicity as they exhibited full range of pathogenic traits. Other 12 isolates were designated as weak potential pathogens. Only ten of the environmental isolates were positive in PCR and were classified by genotype analysis into T4 genotype (70 %), T3 (10 %) and T5 (20 %). Potential pathogens belonged to genotypes T4 (from water) and T5 (from soil) while weak potential pathogens belonged to genotypes T3 (from water) and T4 (from water and soil). Additionally, T7 genotype was isolated from keratitis patients. There is a considerable variation in the response of Acanthamoeba members of the same genotype to pathogenicity indicator assays making correlation of pathogenicity with certain genotypes difficult. Presence of potentially pathogenic Acanthamoeba isolates in habitats related directly to human populations represent a risk for human health. Isolation of Acanthamoeba genotype T7 from AK cases, which is commonly considered as nonpathogenic, might draw the attention to other Acanthamoeba genotypes considered as non pathogenic and reevaluate their role in production of human infections. To our knowledge, this is the first study on the presence and distribution of Acanthamoeba genotypes in the environment, Cairo, Egypt.
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Carnt N, Stapleton F. Strategies for the prevention of contact lens-relatedAcanthamoebakeratitis: a review. Ophthalmic Physiol Opt 2015; 36:77-92. [DOI: 10.1111/opo.12271] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 11/23/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Nicole Carnt
- Save Sight Institute; University of Sydney; Sydney Australia
- School of Optometry and Vision Science; University of New South Wales; Sydney Australia
| | - Fiona Stapleton
- School of Optometry and Vision Science; University of New South Wales; Sydney Australia
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Emerging Threats for Human Health in Poland: Pathogenic Isolates from Drug Resistant Acanthamoeba Keratitis Monitored in terms of Their In Vitro Dynamics and Temperature Adaptability. BIOMED RESEARCH INTERNATIONAL 2015; 2015:231285. [PMID: 26682216 PMCID: PMC4670850 DOI: 10.1155/2015/231285] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/25/2015] [Accepted: 10/27/2015] [Indexed: 11/27/2022]
Abstract
Amphizoic amoebae generate a serious human health threat due to their pathogenic potential as facultative parasites, causative agents of vision-threatening Acanthamoeba keratitis (AK). Recently, AK incidences have been reported with increasing frequency worldwide, particularly in contact lens wearers. In our study, severe cases of AK in Poland and respective pathogenic isolates were assessed at clinical, morphological, and molecular levels. Misdiagnoses and the unsuccessful treatment in other ophthalmic units delayed suitable therapy, and resistance to applied chemicals resulted in severe courses and treatment difficulties. Molecular assessment indicated that all sequenced pathogenic corneal isolates deriving from Polish patients with AK examined by us showed 98–100% homology with Acanthamoeba genotype T4, the most prevalent genotype in this human ocular infection worldwide. In vitro assays revealed that the pathogenic strains are able to grow at elevated temperature and have a wide adaptive capability. This study is our subsequent in vitro investigation on pathogenic Acanthamoeba strains of AK originating from Polish patients. Further investigations designed to foster a better understanding of the factors leading to an increase of AK observed in the past years in Poland may help to prevent or at least better cope with future cases.
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Feng X, Zheng W, Wang Y, Zhao D, Jiang X, Lv S. A Rabbit Model ofAcanthamoebaKeratitis That Better Reflects the Natural Human Infection. Anat Rec (Hoboken) 2015; 298:1509-17. [DOI: 10.1002/ar.23154] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 12/20/2014] [Indexed: 01/04/2023]
Affiliation(s)
- Xianmin Feng
- School of Laboratory Medicine, Jilin Medical College; Jilin China
| | - Wenyu Zheng
- Department of Hand Microsurgery; Central Hospital of Jilin City; Jilin China
| | - Yuehua Wang
- School of Laboratory Medicine, Jilin Medical College; Jilin China
- School of Basical Medicine, Jilin Medical College; Jilin China
| | - Donghai Zhao
- School of Basical Medicine, Jilin Medical College; Jilin China
| | - Xiaoming Jiang
- School of Laboratory Medicine, Jilin Medical College; Jilin China
| | - Shijie Lv
- School of Basical Medicine, Jilin Medical College; Jilin China
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21
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Montalbano Di Filippo M, Santoro M, Lovreglio P, Monno R, Capolongo C, Calia C, Fumarola L, D'Alfonso R, Berrilli F, Di Cave D. Isolation and molecular characterization of free-living amoebae from different water sources in Italy. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:3417-27. [PMID: 25811766 PMCID: PMC4410193 DOI: 10.3390/ijerph120403417] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/13/2015] [Accepted: 03/16/2015] [Indexed: 12/18/2022]
Abstract
Free-living amoebae (FLA) are protozoa ubiquitous in Nature, isolated from a variety of environments worldwide. In addition to their natural distribution, some species have been found to be pathogenic to humans. In the present study a survey was conducted in order to evaluate the presence and to characterize at molecular level the isolates of amoebic organisms collected from different water sources in Italy. A total of 160 water samples were analyzed by culture and microscopic examination. FLA were found in 46 (28.7%) of the investigated water samples. Groundwater, well waters, and ornamental fountain waters were the sources with higher prevalence rates (85.7%, 50.0%, and 45.9%, respectively). Identification of FLA species/genotypes, based on the 18S rDNA regions, allowed to identify 18 (39.1%) Acanthamoeba isolates (genotypes T4 and T15) and 21 (45.6%) Vermamoeba vermiformis isolates. Other FLA species, including Vahlkampfia sp. and Naegleria spp., previously reported in Italy, were not recovered. The occurrence of potentially pathogenic free-living amoebae in habitats related to human population, as reported in the present study, supports the relevance of FLA as a potential health threat to humans.
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Affiliation(s)
| | - Maristella Santoro
- Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy.
| | - Piero Lovreglio
- Interdisciplinary Department of Medicine, University of Bari, Piazza G. Cesare 11, 70124 Bari, Italy.
| | - Rosa Monno
- Department of Basic Medical Science, Neuroscience and Sense Organ, University of Bari, Piazza G. Cesare 11, 70124 Bari, Italy.
| | - Carmen Capolongo
- Department of Basic Medical Science, Neuroscience and Sense Organ, University of Bari, Piazza G. Cesare 11, 70124 Bari, Italy.
| | - Carla Calia
- Department of Basic Medical Science, Neuroscience and Sense Organ, University of Bari, Piazza G. Cesare 11, 70124 Bari, Italy.
| | - Luciana Fumarola
- Department of Basic Medical Science, Neuroscience and Sense Organ, University of Bari, Piazza G. Cesare 11, 70124 Bari, Italy.
| | - Rossella D'Alfonso
- Department of Systems Medicine, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy.
| | - Federica Berrilli
- Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy.
| | - David Di Cave
- Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy.
- Laboratory of Parasitology, Foundation Polyclinic Tor Vergata, Viale Oxford 81, 00133 Rome, Italy.
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Walochnik J, Scheikl U, Haller-Schober EM. Twenty years of acanthamoeba diagnostics in Austria. J Eukaryot Microbiol 2015; 62:3-11. [PMID: 25047131 PMCID: PMC4342769 DOI: 10.1111/jeu.12149] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/03/2014] [Accepted: 06/17/2014] [Indexed: 11/27/2022]
Abstract
Acanthamoebae are the causative agents of an often seriously progressing keratitis (AK) occurring predominantly in contact lens wearers and can cause several disseminating infections potentially resulting in granulomatous amoebic encephalitis (GAE) in the immunocompromised host. Our institution is the Austrian reference laboratory for Acanthamoeba diagnostics and the aim of this study was to give an overview of proven cases of Acanthamoeba infections in Austria during the past 20 yr. All samples of patients with suspected AK or GAE were screened for Acanthamoeba spp. by culture and/or PCR and the detected amoebae were genotyped. Altogether, 154 cases of AK and three cases of GAE were diagnosed. Age of the AK patients ranged from 8 to 82 yr (mean 37.8) and 58% of the patients were female. Approximately 89% of the AK patients were contact lens wearers, almost all cases were unilateral and 19% of the patients required a keratoplasty. Age of the GAE patients ranged from 2 to 25 yr (mean 14.7), all were HIV-negative, but two were severely immunosuppressed at the time of diagnosis. The predominant genotype in the AK cases was T4, other genotypes found were T3, T5, T6, T10 and T11. The three GAE cases involved genotypes T2, T4 and T5.
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Affiliation(s)
- Julia Walochnik
- Molecular Parasitology, Institute of Specific Prophylaxis and Tropical Medicine, Centre for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
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Characterization of a human-pathogenic Acanthamoeba griffini isolated from a contact lens-wearing keratitis patient in Spain. Parasitology 2014; 142:363-73. [PMID: 25068502 DOI: 10.1017/s0031182014001140] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Amoebae were isolated from contact lenses of a symptomatic lens wearer in Spain. Protozoa were characterized by studying their morphology, biology, protease activity and the 18S rRNA gene sequence. Morphology of the organism was observed by light microscopy, scanning electron microscopy and transmission electron microscopy. Its structure corresponded to an amphizoic amoeba. The protozoa grew well at 37 °C and poorly at lower temperatures. In addition, it was capable of lysing mammalian cells in vitro. A major 56 kDa proteolytic enzyme was observed in amoeba crude extracts by gelatin-sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Most proteolytic enzymes in protozoa extracts showed significant activity over a wide range of pH (3-9) and temperature (8-45 °C) values. The assays on inhibition of protease activity indicated strongly that enzymes detected in amoeba extracts corresponded to serine proteases and, to a lesser extent, cysteine proteases. The use of proteinase inhibitors on a tissue culture model proved that the proteinase activity is critical for developing focal lesions in HeLa cell monolayers. Finally, partial sequencing of the 18S ribosomal RNA gene and phylogenetic analyses indicated that the isolate is closely related to Acanthamoeba griffini H37 from the UK (T3 genotype).
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Acanthamoeba DNA can be directly amplified from corneal scrapings. Parasitol Res 2014; 113:3267-72. [PMID: 24951167 DOI: 10.1007/s00436-014-3989-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 06/06/2014] [Indexed: 10/25/2022]
Abstract
This study evaluated the performance of direct amplification of Acanthamoeba-DNA bypassing DNA extraction in the diagnosis of Acanthamoeba keratitis in clinically suspected cases in comparison to direct microscopic examination and in vitro culture. Corneal scrapings were collected from 110 patients who were clinically suspected to have Acanthamoeba keratitis, 63 contact lens wearers (CLW), and 47 non-contact lens wearers (NCLW). Taken samples were subjected to direct microscopic examination, cultivation onto the non-nutrient agar plate surface seeded with Escherichia coli, and PCR amplification. The diagnostic performance of these methods was statistically compared. The results showed that Acanthamoeba infection was detected in 21 (19.1%) of clinically suspected cases (110); 17 (81%) of them were CLW and the remaining 4 (19%) positive cases were NCLW. Regarding the used diagnostic methods, it was found that direct amplification of Acanthamoeba DNA bypassing nucleic acid extraction was superior to microscopy and culture in which 21 cases (19.1%) were positive for Acanthamoeba by PCR compared to 19 positive cases by culture (17.3%) and one case (0.9%) by direct smear. The difference in detection rates between culture and direct smear was highly statistically significant (P = 0.001). On the other hand, there was no significant difference in detection rates between culture and PCR (P = 0.86). On using culture as the gold standard, PCR showed three false-positive samples that were negative by culture and one false-negative sample that was positive by culture. At the same time, direct smear showed 18 false-negative samples. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of PCR were 94.7, 96.7, 85.7, 98.9, and 96.4, respectively, while those of direct smear were 5.3, 100, 100, 83.5, and 83.6, respectively. In conclusion, direct amplification of Acanthamoeba-DNA bypassing DNA extraction is a reliable, specific, sensitive method in the diagnosis of Acanthamoeba keratitis in clinically suspected cases. It should set up in ophthalmological centers as an easy diagnostic tool.
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Genotypic heterogeneity based on 18S-rRNA gene sequences among Acanthamoeba isolates from clinical samples in Italy. Exp Parasitol 2014; 145 Suppl:S46-9. [PMID: 24858926 DOI: 10.1016/j.exppara.2014.05.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 04/11/2014] [Accepted: 05/07/2014] [Indexed: 11/23/2022]
Abstract
Acanthamoeba keratitis (AK) is an ocular disease caused by members of a genus of free-living amoebae and it is associated predominantly with contact lens (CL) use. This study reports 55 cases of AK diagnosed in Italy. Genotype identification was carried out by PCR assay followed by sequence analysis of the 18S rRNA gene using the genus specific primers JDP1 and JDP2. Genotype assignment was based on phenetic analysis of the ASA.S1 subset of the small-subunit rRNA gene sequences. The material has been collected at the Polyclinic Tor Vergata of Rome for a total of 19 isolates and at the Polyclinic Hospital of Bari (36 isolates). Thirty-three out of the 55 genetically characterized isolates were assigned to the genotype T4. Ten isolates were identified as belonging to the genotype T15 thus confirming the first association between the genotype T15 and human amoebic keratitis previously described from the same area. We underline the occurrence of the genotype T3 and T11 identified for the first time in the country.
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Influence of Acanthamoeba genotype on clinical course and outcomes for patients with Acanthamoeba keratitis in Spain. J Clin Microbiol 2014; 52:1213-6. [PMID: 24430449 DOI: 10.1128/jcm.00031-14] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Genotype T4 is by far the most frequent genotype of Acanthamoeba keratitis (AK) and therefore has been considered the most virulent. This study included 14 cases of AK of genotype T4 and three cases of non-T4 genotype. We found that cases of non-T4 genotype had a worse response to medical therapy, greater need for surgical intervention, greater risk of extracorneal involvement, and remarkably poorer final visual outcome than those of T4 genotype, suggesting an association between Acanthamoeba virulence and genotype that requires additional case investigation.
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Duarte JL, Furst C, Klisiowicz DR, Klassen G, Costa AO. Morphological, genotypic, and physiological characterization of Acanthamoeba isolates from keratitis patients and the domestic environment in Vitoria, Espírito Santo, Brazil. Exp Parasitol 2013; 135:9-14. [DOI: 10.1016/j.exppara.2013.05.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 05/06/2013] [Accepted: 05/17/2013] [Indexed: 11/25/2022]
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28
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Garcia A, Goñi P, Cieloszyk J, Fernandez MT, Calvo-Beguería L, Rubio E, Fillat MF, Peleato ML, Clavel A. Identification of free-living amoebae and amoeba-associated bacteria from reservoirs and water treatment plants by molecular techniques. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:3132-3140. [PMID: 23444840 DOI: 10.1021/es400160k] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The occurrence of free-living amoebae (FLA) was investigated in 83 water samples from reservoirs and water treatment plants, with culture positive in 64 of them (77.1%). Polymerase chain reaction (PCR) of partial 18S rRNA gene and ITS region was performed in order to identify amoeba isolates, and the presence of Legionella pneumophila , Mycobacterium spp., Pseudomonas spp., and Microcystis aeruginosa was investigated in 43 isolates of amoebae by multiplex PCR. Of the isolated amoebae, 31 were Acanthamoeba spp., 21 were Hartmannella vermiformis, 13 were Naegleria spp., and one was Vanella spp. T2, T4, and T5 genotypes of Acanthamoeba have been identified, and T4 isolates were grouped into five subgenotypes and graphically represented with a Weblog application. Inside amoebae, L. pneumophila was detected in 13.9% (6/43) of the isolates, and Pseudomonas spp. and Mycobacterium spp. were detected in 32.6% (14/43) and 41.9% (18/43), respectively. No statistical correlation was demonstrated between FLA isolation and seasonality, but the presence of intracellular bacteria was associated with warm water temperatures, and also the intracellular presence of Mycobacterium spp. and Pseudomonas spp. were associated. These results highlight the importance of amoebae in natural waters as reservoirs of potential pathogens and its possible role in the spread of bacterial genera with interest in public and environmental health.
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Affiliation(s)
- Alicia Garcia
- Area of Parasitology and §Area of Biomedicine and Public Health Biostatistics, Department of Microbiology, Preventive Medicine and Public Health, Faculty of Medicine, University of Zaragoza, 50009 Zaragoza, Spain
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Leduc A, Gravel S, Abikhzer J, Roy S, Barbeau J. Polymerase chain reaction detection of potentially pathogenic free-living amoebae in dental units. Can J Microbiol 2012; 58:884-6. [PMID: 22716087 DOI: 10.1139/w2012-071] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several genera of amoebae can be found in water from dental units and on the inner surface of waterlines. The presence of bacterial biofilms on these surfaces is thought to favor the proliferation of amoebae. Potentially pathogenic Acanthamoeba and Naegleria spp. may be an infection risk for patients through contact with open surgical sites or aerosolization. A polymerase chain reaction of DNA extracted from pelleted samples showed that Acanthamoeba spp. and Naegleria spp. were present in water from dental units, suction lines, and suction filters at the dental clinic of the Université de Montréal. Acanthamoeba spp. were detected in 24.2% of 66 samples and Naegleria spp. in 3.0%. We discuss the infection risk associated with these results.
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Affiliation(s)
- Annie Leduc
- Faculté de médecine dentaire, Université de Montréal, QC, Canada
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Siddiqui R, Khan NA. Biology and pathogenesis of Acanthamoeba. Parasit Vectors 2012; 5:6. [PMID: 22229971 PMCID: PMC3284432 DOI: 10.1186/1756-3305-5-6] [Citation(s) in RCA: 359] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 01/10/2012] [Indexed: 12/18/2022] Open
Abstract
Acanthamoeba is a free-living protist pathogen, capable of causing a blinding keratitis and fatal granulomatous encephalitis. The factors that contribute to Acanthamoeba infections include parasite biology, genetic diversity, environmental spread and host susceptibility, and are highlighted together with potential therapeutic and preventative measures. The use of Acanthamoeba in the study of cellular differentiation mechanisms, motility and phagocytosis, bacterial pathogenesis and evolutionary processes makes it an attractive model organism. There is a significant emphasis on Acanthamoeba as a Trojan horse of other microbes including viral, bacterial, protists and yeast pathogens.
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