Free-Living Amoebae Keratitis

Pinna, Antonio; Porcu, Tiziana; Boscia, Francesco; Cano, Antonella; Erre, G; Mattana, Antonella

doi:10.1097/ico.0000000000001226

Cited by 15 publications

(14 citation statements)

References 25 publications

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“…A limitation of this study is that the genus-level identification of FLA by molecular methods was not performed. FLA such as Hartmannella and Vahlkampfiid amoebae [4,5], although rare compared to Acanthamoeba, are also causative agents of keratitis. In addition, the significantly higher FLA positive samples in the patient cohort suggests that their identification in the genus-level will help to better understand the risk of keratitis associated with domestic tap water.…”

Section: Plos Onementioning

confidence: 99%

“…Free-living amoebae (FLA) are unicellular eukaryotic organisms that can grow independently in different environments, including natural and man-made bodies of water; lakes, ponds, swimming pools, and even treated water supplies [1][2][3]. Some genera of FLA such as Acanthamoeba, Vahlkampfia, Naegleria and Hartmannella are opportunistically pathogenic to humans [1,4].…”

Section: Introductionmentioning

confidence: 99%

“…The term Acanthamoeba keratitis (AK) refers to infection of the cornea by Acanthamoeba. However, other FLA such as Vahlkampfia and Hartmannella are also known causative agents of keratitis [4,5]. AK and other amoebal keratitis are increasingly being recognized as a severe ocular infection worldwide that occurs most often among contact lens (CL) wearers and can lead to blindness [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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The relationship between environmental sources and the susceptibility of Acanthamoeba keratitis in the United Kingdom

Carnt

Subedi

Connor³

et al. 2020

PLoS ONE

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To determine whether Acanthamoeba keratitis (AK) patients have higher rates of Acanthamoeba and free-living amoeba (FLA) colonising domestic sinks than control contact lens (CL) wearers, and whether these isolates are genetically similar to the corneal isolates from their CL associated AK. Methods 129 AK patients from Moorefield Eye Hospital, London and 64 control CL wearers from the Institute of Optometry were included in this study. The participants self-collected home kitchen and bathroom samples from tap-spouts, overflows and drains using an instructional kit. The samples were cultured by inoculating onto a non-nutrient agar plate seeded with Escherichia coli, incubated at 32˚C and examined for amoebae by microscopy for up to 2 weeks. Partial sequences of mitochondrial cytochrome oxidase genes (coxA) of Acanthamoeba isolates from four AK patients were compared to Acanthamoeba isolated from the patient's home. The association between sampling sites was analysed with the chi-square test. Results A total of 513 samples from AK patients and 189 from CL controls were collected. The yield of FLA was significantly greater in patients' bathrooms (72.1%) than CL controls' bathrooms (53.4%) (p<0.05). Spouts (kitchen 6.7%, bathroom 11%) had the lowest rate of Acanthamoeba isolation compared to drains (kitchen 18.2%, bathroom 27.9%) and overflow (kitchen 39.1%, bathroom 25.9%) either in kitchens or bathrooms (p<0.05). There was no statistically significant difference between the average prevalence of Acanthamoeba in all three sample sites in kitchens (16.9%) compared to all three sample sites in bathrooms (21.5%) and no association for Acanthamoeba prevalence between AK patients and CL controls. All four

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Section: Plos Onementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The relationship between environmental sources and the susceptibility of Acanthamoeba keratitis in the United Kingdom

Carnt

Subedi

Connor³

et al. 2020

PLoS ONE

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“…Já a ceratite amebiana está relacionada principalmente a Acanthamoeba spp. e o uso de lentes de contato (VISVESVARA, 2010;PINNA et al, 2017).…”

Section: Introductionunclassified

“…A partir daí casos esporádicos foram relatados em diferentes regiões do mundo, que aumentaram significamente após o uso indiscriminado de lentes de contato na década de 1980. As lentes de contato do tipo gelatinoso parecem facilitar a infecção devido a sua porosidade e por serem utilizadas diariamente em longo prazo(PINNA et al, 2017).Nos países desenvolvidos a ceratite por Acanthamoeba spp. pode atingir até 90% dos usuários de lentes de contato devido ao hábito de não retirar as lentes para dormir e/ou pela má higienização das mesmas, com utilização de água de torneira e outros compostos esterilizantes de baixa eficiência.…”

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O Que Sabemos Sobre as Amebas De Vida Livre Até O Momento?

Nunes

2020

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Introdução: Bactérias, vírus, fungos, protozoários e helmintos têm sido associados a infecções humanas em locais de assistência à saúde. Dentre eles: Naegleria fowleri, Balamuthia mandrillaris, Sappinia pedata e algumas espécies de Acanthamoeba spp. constituem o grupo das Amebas de Vida Livre (AVL) que podem causar doença grave no SNC, pele, órgãos internos e olhos. Objetivo: Estabelecer as principais características biológicas, clínicas e propedêuticas das infecções por AVL em humanos por meio de pesquisa literária. Metodologia: Foi realizada uma revisão de literatura do tipo narrativa a partir de artigos publicados em língua inglesa e portuguesa entre 2010 e 2020 nas bases científicas Scielo e Pubmed. A busca pelas produções científicas se deu a partir dos descritores DECS e MESH. Resultados e discussão: Acanthamoeba spp. e B. mandrillaris podem causar encefalite amebiana granulomatosa que é mais comum em imunodeprimidos. Enquanto, a meningoencefalite amebiana primária por N. fowleri atinge principalmente jovens adultos saudáveis com evolução rapidamente fatal em 7 dias do aparecimento dos sintomas. Para S. pedata a encefalite descrita ocorreu em imunocompetente, mas há apenas um caso relatado até o presente momento. Além disso, em imunocompetentes usuários de lentes de contato podem ocorrer ceratite amebiana por Acanthamoeba spp. O sítio de infecção por AVL é bastante diversificado e os sintomas observados são inespecíficos e similares a patógenos mais rotineiros nos ambientes hospitalares. Isso dificulta a suspeita clínica. Não há um esquema terapêutico específico, apesar de o diagnóstico precoce favorecer a diminuição de morbimortalidade. Conclusão: A complexidade da biologia, clínica e propedêutica das infecções causadas por AVL provavelmente está associada a uma subnotificação dos casos, os quais apesar de raros possuem altos índices de morbimortalidade, inferindo a necessidade de maior divulgação deste tema junto à sociedade.

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Impact of implementation of polymerase chain reaction on diagnosis, treatment, and clinical course of Acanthamoeba keratitis

Roth

Balasiu

Daas

et al. 2023

Graefes Arch Clin Exp Ophthalmol

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Purpose Acanthamoeba keratitis (AK) is a painful and possibly sight-threatening ocular infection. While the correct diagnosis and specific treatment in the early stages significantly improve the prognosis, the disease is often misdiagnosed and in clinical examination confused with other forms of keratitis. Polymerase chain reaction (PCR) for the detection of AK was first introduced in our institution in December 2013 to improve the timely diagnosis of AK. The aim of this study was to assess the impact of implementation of Acanthamoeba PCR on the diagnosis and treatment of the disease in a German tertiary referral center. Patients and methods Patients treated for Acanthamoeba keratitis between 1st of January 1993 and 31st of December 2021 in the Department of Ophthalmology of the University Hospital Duesseldorf were identified retrospectively via in-house registries. Evaluated parameters include age, sex, initial diagnosis, method of correct diagnosis, duration of symptoms until correct diagnosis, contact lens use, visual acuity, and clinical findings as well as medical and surgical therapy by keratoplasty (pKP). In order to assess the impact of implementation of Acanthamoeba PCR, the cases were divided into two groups (before (pre-PCR group) and after PCR implementation (PCR group). Results Seventy-five patients with Acanthamoeba keratitis were included (69.3% female, median age 37 years). Eighty-four percent (63/75) of all patients were contact lens wearers. Until PCR was available, 58 patients with Acanthamoeba keratitis were diagnosed either clinically (n = 28), by histology (n = 21), culture (n = 6), or confocal microscopy (n = 2) with a median duration until diagnosis of 68 (18; 109) days. After PCR implementation, in 17 patients, the diagnosis was established with PCR in 94% (n = 16) and median duration until diagnosis was significantly shorter with 15 (10; 30.5) days. A longer duration until correct diagnosis correlated with a worse initial visual acuity (p = 0.0019, r = 0.363). The number of pKP performed was significantly lower in the PCR group (5/17; 29.4%) than in the pre-PCR group (35/58; 60.3%) (p = 0.025). Conclusions The choice of diagnostic method and especially the application of PCR have a significant impact on the time to diagnosis and on the clinical findings at the time of confirmation of diagnosis and the need for penetrating keratoplasty. In contact lens–associated keratitis, the first crucial step is to take AK into consideration and perform a PCR test as timely confirmation of diagnosis of AK is imperative to prevent long-term ocular morbidity.

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Free-Living Amoebae Keratitis

Cited by 15 publications

References 25 publications

The relationship between environmental sources and the susceptibility of Acanthamoeba keratitis in the United Kingdom

The relationship between environmental sources and the susceptibility of Acanthamoeba keratitis in the United Kingdom

O Que Sabemos Sobre as Amebas De Vida Livre Até O Momento?

Impact of implementation of polymerase chain reaction on diagnosis, treatment, and clinical course of Acanthamoeba keratitis

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