The Acanthamoeba–Fungal Keratitis Study

Raghavan, Anita; Baidwal, Shaffie; Narendran, Venkatapathy; Rammohan, Ram

doi:10.1016/j.ajo.2019.01.024

Cited by 31 publications

(37 citation statements)

References 21 publications

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“…Indeed, development of AK in rabbit corneas was shown to be reliant on the presence of the bacteria Pseudomonas aeruginosa, with bacterial density having an impact on development and severity of the infection while those inoculated in the absence of bacteria were unable to cause infection (Nakagawa et al, 2017). It is tempting to speculate from this study that the risk of AK in non-contact lens wearers is increased by the presence of a co-infectious agent and indeed this is a point that has been supported in recent investigations by Raghavan et al (2019) in which coinfections were found to be less restricted to contact lens use than what is observed in Acanthamoeba infections alone (Stapleton and Carnt, 2012;Nakagawa et al, 2017;Raghavan et al, 2019). Other research has found bacterial infection in AK can enhance binding of both Acanthamoeba and bacteria to the corneal endothelial cells (Clarke and Niederkorn, 2006).…”

Section: Complex Microbial Acanthamoeba Keratitissupporting

confidence: 71%

“…One issue that is often less considered is the connection between the environmental interactions of Acanthamoeba with bacterial symbionts and how this translates to synergistic pathogenicity against humans. Co-infections have been observed in all Acanthamoeba pathologies with multiple virus, bacteria and fungi species (Grayson, 2011;Pietrucha-Dilanchian et al, 2012;Scheid and Schwarzenberger, 2012;Guimaraes et al, 2016;Geith et al, 2018;Lau et al, 2019;Raghavan et al, 2019). However, the number of cases of CA and GAE is rare, with the latter proving fatal in ∼90% of cases (Król-Turmiñska and Olender, 2017).…”

Section: Acanthamoebamentioning

confidence: 99%

“…AK data has long been considered underreported, the reasoning for this is the ease in which misdiagnosis or partial diagnosis can occur given the similarities to other forms of keratitis. Raghavan et al (2019) note that in cases of Acanthamoeba co-infections, the need for corneal scrapings and diagnostic cultures were higher than those of AK alone (Raghavan et al, 2019), a factor that could impact treatment success given the rapid encystation Acanthamoeba can undergo when incorrect drug therapies are used. It is clear that more work is required to provide an accurate assessment of the direct risks of co-infection on patient outcome.…”

Section: Complex Microbial Acanthamoeba Keratitismentioning

confidence: 99%

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Paradigms of Protist/Bacteria Symbioses Affecting Human Health: Acanthamoeba species and Trichomonas vaginalis

et al. 2021

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Ever since the publication of the seminal paper by Lynn Margulis in 1967 proposing the theory of the endosymbiotic origin of organelles, the study of the symbiotic relationships between unicellular eukaryotes and prokaryotes has received ever-growing attention by microbiologists and evolutionists alike. While the evolutionary significance of the endosymbiotic associations within protists has emerged and is intensively studied, the impact of these relationships on human health has been seldom taken into account. Microbial endosymbioses involving human eukaryotic pathogens are not common, and the sexually transmitted obligate parasite Trichomonas vaginalis and the free-living opportunistic pathogen Acanthamoeba represent two unique cases in this regard, to date. The reasons of this peculiarity for T. vaginalis and Acanthamoeba may be due to their lifestyles, characterized by bacteria-rich environments. However, this characteristic does not fully explain the reason why no bacterial endosymbiont has yet been detected in unicellular eukaryotic human pathogens other than in T. vaginalis and Acanthamoeba, albeit sparse and poorly investigated examples of morphological identification of bacteria-like microorganisms associated with Giardia and Entamoeba were reported in the past. In this review article we will present the body of experimental evidences revealing the profound effects of these examples of protist/bacteria symbiosis on the pathogenesis of the microbial species involved, and ultimately their impact on human health.

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Section: Complex Microbial Acanthamoeba Keratitissupporting

confidence: 71%

Section: Acanthamoebamentioning

confidence: 99%

Section: Complex Microbial Acanthamoeba Keratitismentioning

confidence: 99%

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Paradigms of Protist/Bacteria Symbioses Affecting Human Health: Acanthamoeba species and Trichomonas vaginalis

et al. 2021

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“…AK should be taken into consideration in anyone exhibiting the risk factors as described above, especially contact lenses wearers, or anyone who is demonstrating severe ocular pain. To complicate the matters, there are also many reports of AK in mixed form with viral, bacterial, or fungal pathogens also present [34,35]. These forms of mixed keratitis have important implications for diagnosis and management of disease.…”

Section: Diagnosismentioning

confidence: 99%

Acanthamoeba Keratitis, Pathology, Diagnosis and Treatment

et al. 2021

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Acanthamoeba keratitis is an unusual corneal infection that is recently increasing in frequency and is often contracted by contact lens wearers, someone who experienced recent eye trauma, or someone exposed to contaminated waters. Acanthamoeba survive in air, soil, dust, and water. Therefore, eye trauma and poor contact lens hygiene practices lead to the entrapment of debris and thus infection. Acanthamoeba keratitis results in severe eye pain, inflammation, and defects of the epithelium and stroma that can potentially result in vision loss if not diagnosed early and treated promptly. The disease can be diagnosed using corneal scrape/biopsy, polymerase chain reactions, impression cytology, or in vivo confocal microscopy. Once diagnosed, it is usually treated with an antimicrobial combination therapy of biguanide and aromatic diadine eye drops for several months. Advanced stages of the disease result in vision loss and the need for corneal transplants. Avoiding the risk factors and diagnosing the disease early are the most effective ways to combat Acanthamoeba keratitis.

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“…Beide Substanzen sind auch gegen Akanthamöbenzysten wirksam (evtl. Koinfektion) [46]. Aufgrund des Molekulargewichts (5000 Da) sind wiederholte Epithelabrasiones notwendig [8].…”

Section: Antiseptikaunclassified