An extraordinary endocytobiont in Acanthamoeba sp. isolated from a patient with keratitis

Scheid, Patrick; Zöller, Lothar; Pressmar, S.; Richard, Gisbert; Michel, R.

doi:10.1007/s00436-007-0858-3

Cited by 82 publications

(50 citation statements)

References 19 publications

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“…was detected in the raw and finished water of all DWTPs and WWTPs, indicating that the purification processes used in these treatment plants did not eliminate this opportunistic agent. This fact is important to highlight since such amoebae have been described as vectors or reservoirs of pathogenic microorganisms (Scheid et al 2008;Valster et al 2011;Huang et al 2011). Our results are not surprising, since similar data have been obtained by the previous reports from DWTP.…”

Section: Discussionsupporting

confidence: 90%

Molecular characterization of Acanthamoeba isolated in water treatment plants and comparison with clinical isolates

et al. 2012

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A total of 116 samples (44 clinical specimens and 72 environmental samples) have been analyzed for the presence of Acanthamoeba. The environmental samples (ESs) were collected from four drinking water treatment plants (DWTP, n=32), seven wastewater treatment plants (n=28), and six locations of influence (n=12) on four river basins from the central area of Spain (winter-spring 2008). Water samples were concentrated by using the IDEXX Filta-Max(®) system. Acanthamoeba was identified in 65 of the 72 ESs by culture isolation (90.3%) and 63 by real-time PCR (87.5%), resulting in all sampling points (100%) positive for Acanthamoeba when considering both techniques and all the time period analyzed. Nine of the 44 clinical specimens were positive for Acanthamoeba. Seventeen Acanthamoeba strains (eight from four DWTP and nine from clinical samples) were also established in axenic-PYG medium. Twenty-four of the ESs and the 17 Acanthamoeba sp. strains were genotyped as T4/1, T4/8, and T4/9. The eight strains isolated from the DWTP samples were inoculated in nude mouse to ascertain their potential pathogenicity in this model. Animals that were inoculated died or showed central nervous system symptoms 9 days post-inoculation. Examination of immunofluorescence-stained brain and lung tissue sections showed multiple organisms invading both tissues, and re-isolation of throphozoites was successful in these tissues of all infected animals. For the first time, potentially pathogenic Acanthamoeba T4 has been detected in 100% of different types of water samples including tap water and sewage effluents in the central area of Spain suggesting a potential health threat for humans especially for the contact lens wearers.

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Section: Discussionsupporting

confidence: 90%

Molecular characterization of Acanthamoeba isolated in water treatment plants and comparison with clinical isolates

et al. 2012

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“…recently isolated from the contact lens and inflamed eye of a patient with keratitis was described elsewhere (case report see Scheid et al 2008).…”

Section: Introductionmentioning

confidence: 98%

Investigations of an extraordinary endocytobiont in Acanthamoeba sp.: development and replication

Scheid¹,

Hauröder²,

Michel³

2010

Parasitol Res

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In this article, the results of investigations concerning a parasitic endocytobiont within the host amoebae (Acanthamoeba sp.) are presented. The endocytobiont was recently isolated from the contact lens and the inflamed eye of a patient with keratitis. Light microscopy and electron microscopy were performed to provide morphological details: Light microscopy revealed the presence of ovoid microorganisms developing and proliferating within the cytoplasm of the amoebic trophozoites. Details of the unusual development of these endocytobionts within the amoebae could be studied and demonstrated by means of electron microscopy. Foldings and morphological reorganization of the microorganisms took place exclusively within the host cytoplasm. The intracellularly aggregating organisms led to the rupture of the Acanthamoeba trophozoites after proliferation. Numerous microorganisms were released, which were infectious and were subsequently ingested by hitherto uninfected acanthamoebic trophozoites. To evaluate the in vitro growth of the isolated endocytobionts (without their hosts), they were transferred to several different culture plates. There was no growth of these unique organisms on five different common cultural plates suitable for the growth of bacteria and fungi.

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“…It is generally accepted that the predominant risk factor for Acanthamoeba sp. keratitis is contact lens wear and early diagnosis improves the final outcome (Claerhout et al 2004;Scheid et al 2008;Pens et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Efficacy of miltefosine for topical treatment of Acanthamoeba keratitis in Syrian hamsters

Polat

Obwaller²,

Vural

et al. 2011

Parasitol Res

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Acanthamoeba keratitis is a painful corneal infection and difficult to treat because no sufficiently efficient drug has yet been available. The aim of the study therefore was to assess the therapeutic potential of miltefosine on Acanthamoeba keratitis-infected hamster eyes. The cornea of hamsters were infected with Acanthamoeba hatchetti, a human corneal isolate. On the fifth day, all the cornea were microscopically examined in order to determine the degree of infections (G, from 0 to 3). Four groups were then prepared: miltefosine (160 μM); 0.1% propamidine isetionate plus 0.02% polyhexnide; infected control (0.05% ethanol in PBS) and a non-infected control (0.05% ethanol in PBS) groups. The treatment was continued for 28 days. After the treatment, the cornea were excised and used for Acanthamoeba culture to investigate the presence of Acanthamoeba growth. Miltefosine treatment yielded much higher cure scores than propamidine isetionate plus polyhexanide. On the last day of treatment, 85% of the miltefosine-treated eyes were graded as G0; no changes were observed in the uninfected control group eyes; G3 eyes showed only a partial improvement. Furthermore, no Acanthamoeba cells could be recovered from the miltefosine-treated eye samples. Miltefosine appeared to hold necessary therapeutic properties for the treatment of Acanthamoeba keratitis.

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An extraordinary endocytobiont in Acanthamoeba sp. isolated from a patient with keratitis

Cited by 82 publications

References 19 publications

Molecular characterization of Acanthamoeba isolated in water treatment plants and comparison with clinical isolates

Molecular characterization of Acanthamoeba isolated in water treatment plants and comparison with clinical isolates

Investigations of an extraordinary endocytobiont in Acanthamoeba sp.: development and replication

Efficacy of miltefosine for topical treatment of Acanthamoeba keratitis in Syrian hamsters

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