Displaying publications 1 - 20 of 37 in total

  1. Kamel AG, Norazah A
    Trans R Soc Trop Med Hyg, 1995 11 1;89(6):652.
    PMID: 8594684
    Matched MeSH terms: Acanthamoeba Keratitis/diagnosis*; Acanthamoeba Keratitis/etiology; Acanthamoeba Keratitis/epidemiology
  2. Mohamed Kamel Abd Ghani, Irdawati Azhar, Haliza Abdul Mutalib, Anisah Nordin, Yusof Suboh, Noraina Ab Rahim, et al.
    Sains Malaysiana, 2018;47:1563-1569.
    Acanthamoeba spp. merupakan ameba hidup bebas yang tersebar luas di persekitaran. Ameba ini menyebabkan penyakit
    keratitis terutamanya kepada individu yang memakai kanta sentuh terkontaminasi atau mempunyai sejarah trauma
    pada mata. Tujuh puluh empat sampel kikisan kornea pesakit keratitis daripada 4 buah hospital di sekitar Lembah
    Kelang telah dikultur untuk menemukan Acanthamoeba spp. Keputusan kajian mendapati Acanthamoeba spp. berjaya
    dipencilkan daripada 14.87% sampel kikisan kornea pesakit keratitis. Berdasarkan kajian ini, kesemua pesakit keratitis
    Acanthamoeba adalah merupakan pemakai kanta sentuh yang majoritinya (90.9%) terdiri daripada kaum wanita. Kanta
    sentuh lembut terlibat dalam 90.9% kes manakala jenis kanta separa keras cuma satu kes 9.1%. Kesemua 11 pencilan
    Acanthamoeba yang dipencilkan adalah daripada kumpulan polyphagids yang biasanya patogenik kepada manusia dan
    menyebabkan jangkitan ini. Kegagalan pengguna kanta sentuh mengamalkan tahap kebersihan kanta sentuh yang baik
    merupakan faktor risiko yang penting dalam kejadian keratitis Acanthamoeba di Malaysia.
    Matched MeSH terms: Acanthamoeba Keratitis
  3. Nurul Zarhana Jufri, Anisah Nordin, Mohamed Kamel Abd Ghani, Yusof Suboh, Noraina Abd Rahim
    Acanthamoeba is a free living protozoa that can cause keratitis and granulomatous amoebic encephalitis. Physiological characteristics of this amoeba are found to have a medical importance and related to the pathogenic potential of the organism. This study was carried out to investigate the physiological characteristic from the aspect of temperature tolerance. Six Acanthamoeba strains from three clinical isolates (HSB 1, HKL 48 and HKL 95) and three environmental isolates (PHS 2, PHS 11 and PHS 15) were used in this study. Test was done by culturing cysts at 30°C, 37°C and 42°C for two weeks and the ability of cysts to change to trophozoites were observed. The result showed all strain was able to change to trophozoites at 30°C and 37°C. However, no trophozoites were observed at 42°
    C. This indicate that there is a similarity in the physiological trait of strains from both isolates are the same and strains from the environment are able to show the pathogenic potential thus capable of causing infection to human.
    Keywords: Acanthamoeba; temperature tolerance; clinical; environmental isolates.
    Matched MeSH terms: Acanthamoeba Keratitis
  4. Ahmed U, Sivasothy Y, Khan KM, Khan NA, Wahab SMA, Awang K, et al.
    Acta Trop, 2023 Dec;248:107033.
    PMID: 37783284 DOI: 10.1016/j.actatropica.2023.107033
    Acanthamoeba castellanii is an opportunistic free-living amoeba (FLA) pathogen which can cause fatal central nervous system (CNS) infection, granulomatous amoebic encephalitis (GAE) and potentially blinding ocular infection, Acanthamoeba keratitis (AK). Acanthamoeba species remain a challenging protist to treat due to the unavailability of safe and effective therapeutic drugs and their ability to protect themselves in the cyst stage. Natural products and their secondary metabolites play a pivotal role in drug discovery against various pathogenic microorganisms. In the present study, the ethyl acetate extract of Myristica cinnamomea King fruit was evaluated against A. castellanii (ATCC 50492), showing an IC50 of 45.102 ± 4.62 µg/mL. Previously, the bio-guided fractionation of the extract resulted in the identification of three active compounds, namely Malabaricones (A-C). The isolated and thoroughly characterized acylphenols were evaluated for their anti-amoebic activity against A. castellanii for the first time. Among tested compounds, Malabaricone B (IC50 of 101.31 ± 17.41 µM) and Malabaricone C (IC50 of 49.95 ± 6.33 µM) showed potent anti-amoebic activity against A. castellanii trophozoites and reduced their viability up-to 75 and 80 %, respectively. Moreover, both extract and Malabaricones also significantly (p < 0.05) inhibit the encystation and excystation of A. castellanii, while showed minimal toxicity against human keratinocyte cells (HaCaT cells) at lower tested concentrations. Following that, the explanation of the possible mechanism of action of purified compounds were assessed by detection of the state of chromatin. Hoechst/PI 33342 double staining showed that necrotic cell death occurred in A. castellanii trophozoites after 8 h treatment of Malabaricones (A-C). These findings demonstrate that Malabaricones B and C could serve as promising therapeutic options against A. castellanii infections.
    Matched MeSH terms: Acanthamoeba Keratitis*
  5. Nurul Farhana Jufri, Anisah Nordin, Mohamed Kamel Abd. Ghani, Yusof Suboh, Noraina Abd. Rahim
    Acanthamoeba is a free living protozoa that can cause keratitis and granulomatous amoebic encephalitis. Physiological characteristics of this amoeba are found to have a medical importance in which it can be related to the pathogenicity potential of the organism. This study was carried out to investigate the physiological characteristics of survivability during axenization. Six Acanthamoeba strains from three clinical isolates (HSB 1, HKL 48 and HKL 95) and three environmental isolates (PHS 2, PHS 11 and PHS 15) were used in this study. Axenization test was done by treating cysts with hydrochloric acid (3%) and Page saline containing Gentamicin (100 μg/ml). Cysts were then cultured into PYG enrich media, incubated at 30oC and the presence and proliferation of trophozoites of Acanthamoeba were observed. This study showed that PHS 15, HSB 1, HKL 48 and HKL 95 could be axenized but they have poor proliferation rate in PYG enrich media. The result showed that the difference between both clinical and environmental isolates was observed in two strains; PHS 2 and PHS 11. This indicates that there is a possibility that the physiological traits of strains from both isolates are the same and strains from the environment are able to show the pathogenic potential and capable of causing infection to human.
    Keywords: Axenization, Survivability, Acanthamoeba, Clinical and environmental strains
    Matched MeSH terms: Acanthamoeba Keratitis
  6. Ithoi I, Mahmud R, Abdul Basher MH, Jali A, Abdulsalam AM, Ibrahim J, et al.
    Trop Biomed, 2013 Mar;30(1):131-40.
    PMID: 23665719 MyJurnal
    A total of 10 out of 65 cornea swab samples from cats with eye symptoms showed Acanthamoeba-like morphology after cultivation. By PCR and DNA sequencing of Acanthamoeba diagnostic fragment 3 (DF3), all 10 isolates from the positive samples were categorized into two homologous groups of AfC1 (PM1, PM2, PM3, PF6, KM7, KF8, KMK9) and AfC2 (PM4, PM5, KFK10) due to the presence of bases A(354) and G(354), respectively. Furthermore, DF3 of AfC1 and AfC2 showed 100% similarity with Genbank reference isolates with the accession numbers DQ087314, EU146073 and U07401, GU808323, which were Acanthamoeba castellanii strains genotype T4 originating from human keratitis. This finding suggests that A. castellani strains have the capability to infect cats and human under favorable conditions.
    Matched MeSH terms: Acanthamoeba Keratitis/parasitology; Acanthamoeba Keratitis/veterinary*
  7. Anwar A, Abdalla SAO, Aslam Z, Shah MR, Siddiqui R, Khan NA
    Parasitol Res, 2019 Jul;118(7):2295-2304.
    PMID: 31093751 DOI: 10.1007/s00436-019-06329-3
    Acanthamoeba castellanii belonging to the T4 genotype is an opportunistic pathogen which is associated with blinding eye keratitis and rare but fatal central nervous system infection. A. castellanii pose serious challenges in antimicrobial chemotherapy due to its ability to convert into resistant, hardy shell-protected cyst form that leads to infection recurrence. The fatty acid composition of A. castellanii trophozoites is known to be most abundant in oleic acid which chemically is an unsaturated cis-9-Octadecanoic acid and naturally found in animal and vegetable fats and oils. This study was designed to evaluate antiacanthamoebic effects of oleic acid against trophozoites, cysts as well as parasite-mediated host cell cytotoxicity. Moreover, oleic acid-conjugated silver nanoparticles (AgNPs) were also synthesized and tested against A. castellanii. Oleic acid-AgNPs were synthesized by chemical reduction method and characterized by ultraviolet-visible spectrophotometry, atomic force microscopy, dynamic light scattering analysis, and Fourier transform infrared spectroscopy. Viability, growth inhibition, encystation, and excystation assays were performed with 10 and 5 μM concentration of oleic acid alone and oleic acid-conjugated AgNPs. Bioassays revealed that oleic acid alone and oleic acid-conjugated AgNPs exhibited significant antiamoebic properties, whereas nanoparticle conjugation further enhanced the efficacy of oleic acid. Phenotype differentiation assays also showed significant inhibition of encystation and excystation at 5 μM. Furthermore, oleic acid and oleic acid-conjugated AgNPs also inhibited amoebae-mediated host cell cytotoxicity as determined by lactate dehydrogenase release. These findings for the first time suggest that oleic acid-conjugated AgNPs exhibit antiacanthamoebic activity that hold potential for therapeutic applications against A. castellanii.
    Matched MeSH terms: Acanthamoeba Keratitis/drug therapy*; Acanthamoeba Keratitis/parasitology
  8. Anwar A, Yi YP, Fatima I, Khan KM, Siddiqui R, Khan NA, et al.
    Parasitol Res, 2020 Jun;119(6):1943-1954.
    PMID: 32385711 DOI: 10.1007/s00436-020-06694-4
    Acanthamoeba causes diseases such as Acanthamoeba keratitis (AK) which leads to permanent blindness and granulomatous Acanthamoeba encephalitis (GAE) where there is formation of granulomas in the brain. Current treatments such as chlorhexidine, diamidines, and azoles either exhibit undesirable side effects or require immediate and prolonged treatment for the drug to be effective or prevent relapse. Previously, antifungal drugs amphotericin B, nystatin, and fluconazole-conjugated silver with nanoparticles have shown significantly increased activity against Acanthamoeba castellanii. In this study, two functionally diverse tetrazoles were synthesized, namely 5-(3-4-dimethoxyphenyl)-1H-tetrazole and 1-(3-methoxyphenyl)-5-phenoxy-1H-tetrazole, denoted by T1 and T2 respectively. These compounds were evaluated for anti-Acanthamoeba effects at different concentrations ranging from 5 to 50 μM. Furthermore, these compounds were conjugated with silver nanoparticles (AgNPs) to enhance their efficacy. Particle size analysis showed that T1-AgNPs and T2-AgNPs had an average size of 52 and 70 nm respectively. After the successful synthesis and characterization of tetrazoles and tetrazole-conjugated AgNPs, they were subjected to anti-Acanthamoeba studies. Amoebicidal assay showed that at concentration 10 μM and above, T2 showed promising antiamoebic activities between the two compounds while encystation and excystation assays reveal that both T1 and T2 have inhibited differentiation activity against Acanthamoeba castellanii. Conjugation of T1 and T2 to AgNP also increased efficacy of tetrazoles as anti-Acanthamoeba agents. This may be due to the increased bioavailability as AgNP allows better delivery of treatment compounds to A. castellanii. Human cell cytotoxicity assay revealed that tetrazoles and AgNPs are significantly less toxic towards human cells compared with chlorhexidine which is known to cause undesirable side effects. Cytopathogenicity assay also revealed that T2 conjugated with AgNPs significantly reduced cytopathogenicity of A. castellanii compared with T2 alone, suggesting that T2-conjugated AgNP is an effective and safe anti-Acanthamoeba agent. The use of a synthetic azole compound conjugated with AgNPs can be an alternative strategy for drug development against A. castellanii. However, mechanistic and in vivo studies are needed to explore further translational values.
    Matched MeSH terms: Acanthamoeba Keratitis/drug therapy; Acanthamoeba Keratitis/parasitology
  9. Kusrini E, Hashim F, Gunawan C, Mann R, Azmi WNNWN, Amin NM
    Parasitol Res, 2018 May;117(5):1409-1417.
    PMID: 29532220 DOI: 10.1007/s00436-018-5814-x
    This work investigated the anti-amoebic activity of two samarium (Sm) complexes, the acyclic complex [bis(picrato)(pentaethylene glycol)samarium(III)] picrate-referred to as [Sm(Pic)2(EO5)](Pic)-and the cyclic complex [bis(picrato)(18-crown-6)samarium(III)] picrate-referred to as [Sm(Pic)2(18C6)](Pic). Both Sm complexes caused morphological transformation of the protozoa Acanthamoeba from its native trophozoite form carrying a spine-like structure called acanthopodia, to round-shaped cells with loss of the acanthopodia structure, a trademark response to environmental stress. Further investigation, however, revealed that the two forms of the Sm complexes exerted unique cytotoxicity characteristics. Firstly, the IC50 of the acyclic complex (0.7 μg/mL) was ~ 10-fold lower than IC50 of the cyclic Sm complex (6.5 μg/mL). Secondly, treatment of the Acanthamoeba with the acyclic complex caused apoptosis of the treated cells, while the treatment with the cyclic complex caused necrosis evident by the leakage of the cell membrane. Both treatments induced DNA damage in Acanthamoeba. Finally, a molecular docking simulation revealed the potential capability of the acyclic complex to form hydrogen bonds with profilin-a membrane protein present in eukaryotes, including Acanthamoeba, that plays important roles in the formation and degradation of actin cytoskeleton. Not found for the cyclic complex, such potential interactions could be the underlying reason, at least in part, for the much higher cytotoxicity of the acyclic complex and also possibly, for the observed differences in the cytotoxicity traits. Nonetheless, with IC50 values of
    Matched MeSH terms: Acanthamoeba Keratitis/drug therapy; Acanthamoeba Keratitis/parasitology
  10. Abjani F, Khan NA, Yousuf FA, Siddiqui R
    Cont Lens Anterior Eye, 2016 Jun;39(3):239-43.
    PMID: 26675112 DOI: 10.1016/j.clae.2015.11.004
    Acanthamoeba cysts are highly resistant to contact lens disinfecting solutions. Acanthamoeba cyst wall is partially made of 1,4 β-glucan (i.e., cellulose) and other complex polysaccharides making it a hardy shell that protects the resident amoeba. Here, we hypothesize that targeting the cyst wall structure in addition to antiamoebic compound would improve the efficacy of marketed contact lens disinfecting solutions. Using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, the findings revealed that combination of both agents abolished viability of Acanthamoeba castellanii cysts and trophozoites. When tested alone, none of the agents nor contact lens disinfecting solutions completely destroyed A. castellanii cysts and trophozoites. The absence of cyst wall-degrading enzymes in marketed contact lens disinfecting solutions render them ineffective against Acanthamoeba cysts. It is concluded that the addition of cyst wall degrading molecules in contact lens disinfecting solutions will enhance their efficacy in decreasing the incidence of Acanthamoeba effectively.
    Matched MeSH terms: Acanthamoeba Keratitis/etiology; Acanthamoeba Keratitis/parasitology; Acanthamoeba Keratitis/prevention & control*
  11. Siddiqui R, Aqeel Y, Khan NA
    Cont Lens Anterior Eye, 2016 Oct;39(5):389-93.
    PMID: 27133448 DOI: 10.1016/j.clae.2016.04.004
    Acanthamoeba castellanii is the causative agent of blinding keratitis. Though reported in non-contact lens wearers, it is most frequently associated with improper use of contact lens. For contact lens wearers, amoebae attachment to the lens is a critical first step, followed by amoebae binding to the corneal epithelial cells during extended lens wear. Acanthamoeba attachment to surfaces (biological or inert) and migration is an active process and occurs during the trophozoite stage. Thus retaining amoebae in the cyst stage (dormant form) offers an added preventative measure in impeding parasite traversal from the contact lens onto the cornea. Here, we showed that as low as 3% DMSO, abolished A. castellanii excystation. Based on the findings, it is proposed that DMSO should be included in the contact lens disinfectants as an added preventative strategy against contracting Acanthamoeba keratitis.
    Matched MeSH terms: Acanthamoeba Keratitis/etiology; Acanthamoeba Keratitis/parasitology*; Acanthamoeba Keratitis/prevention & control*
  12. Kusrini E, Sabira K, Hashim F, Abdullah NA, Usman A, Putra N, et al.
    Acta Ophthalmol, 2021 Mar;99(2):e178-e188.
    PMID: 32701190 DOI: 10.1111/aos.14541
    PURPOSE: Contact lenses have direct contact with the corneal surface and can induce sight-threatening infection of the cornea known as Acanthamoeba keratitis. The objective of this study was to evaluate the dysprosium-based nanoparticles (Dy-based NPs), namely Fe3 O4 -PEG-Dy2 O3 nanocomposites and Dy(OH)3 nanorods, as an active component against Acanthamoeba sp., as well as the possibility of their loading onto contact lenses as the drug administering vehicle to treat Acanthamoeba keratitis (AK).

    METHODS: The Dy-based NPs were synthesized, and they were loaded onto commercial contact lenses. The loading content of the NPs and their release kinetics was determined based on the absorbance of their colloidal solution before and after soaking the contact lenses. The cytotoxicity of the NPs was evaluated, and the IC50 values of their antiamoebic activity against Acanthamoeba sp. were determined by MTT colorimetric assay, followed by observation on the morphological changes by using light microscopy. The mechanism of action of the Dy-based NPs against Acanthamoeba sp. was evaluated by DNA laddering assays.

    RESULTS: The loading efficiencies of the Dy-based NPs onto the contact lens were in the range of 30.6-36.1% with respect to their initial concentration (0.5 mg ml-1 ). The Dy NPs were released with the flux approximately 5.5-11 μg cm-2  hr-1 , and the release was completed within 10 hr. The emission of the NPs consistently showed a peak at 575 nm due to Dy3+ ion, offering the possible monitoring and tracking of the NPs. The SEM images indicated the NPs are aggregated on the surface of the contact lenses. The DNA ladder assay suggested that the cells underwent DNA fragmentation, and the cell death was due most probably to necrosis, rather than apoptosis. The cytotoxicity assay of Acanthamoeba sp. suggested that Fe3 O4 -PEG, Fe3 O4 -PEG-Dy2 O3 , Dy(NO3 )3 .6H2 O and Dy(OH)3 NPs have an antiamoebic activity with the IC50 value being 4.5, 5.0, 9.5 and 22.5 μg ml-1 , respectively.

    CONCLUSIONS: Overall findings in this study suggested that the Dy-based NPs can be considered as active antiamoebic agents and possess the potential as drugs against Acanthamoeba sp. The NPs could be loaded onto the contact lenses; thus, they can be potentially utilized to treat Acanthamoeba keratitis (AK).

    Matched MeSH terms: Acanthamoeba Keratitis/microbiology; Acanthamoeba Keratitis/pathology; Acanthamoeba Keratitis/prevention & control*
  13. Noradilah Samseh Abdullah, Mohamed Kamel Abd Ghani, Anisah Nordin, Yusof Suboh, Noraina Ab Rahim
    Acanthamoeba keratitis is a serious ocular problem and can cause blindness if not treated. This study was therefore performed to evaluate the effectiveness of eyedrop antibiotics on eight Acanthamoeba spp. isolates, of which four
    were clinical isolates and the remaining four from the environment. Three different eyedrop antibiotics (neomycin, ciprofloxacin and gentamicin) currently available in the market and ready for use were tested. Cyst suspension from all strains were tested against eyedrop antibiotics, respectively. After 48 hours of incubation period, the solutions were filtered and the filtered membranes were put onto non-nutrient agar lawn with E. coli. The plates were examined daily for Acanthamoeba trophozoites under inverted microscope until day 14. Neomycin, ciprofloxacin and gentamicin were found
    to be effective against Acanthamoeba spp. cysts for all test strains.
    Key words: Acanthamoeba Keratitis, Eyedrop Antibiotics, Effectiveness
    Matched MeSH terms: Acanthamoeba Keratitis
  14. Putri Noradyani Megat Hashim, Mohamed Kamel Abdul Ghani, Norhayati Moktar, Anisah Nordin, Yusof Suboh, Mimi Fazah Zainudin, et al.
    Keratitis Acanthamoeba merupakan sejenis inflamasi kornea yang dikaitkan dengan penggunaan kanta sentuh. la disebabkan oleh Acanthamoeba spp., ameba hidup bebas yang tersebar luas di pelbagai persekitaran manusia. Kontaminasi Acanthamoeba spp. pada bekas penyimpanan kanta sentuh merupakan faktor kehadiran ameba pada kanta seterusnya menjangkiti mata. Kajian ini bertujuan untuk melihat kehadiran Acanthamoeba spp. pada bekas penyimpanan kanta sentuh pengguna asimptomatik. Seramai 90 orang pengguna kanta sentuh asimptomatik terlibat dalam kajian ini. Sampel diambil secara swab pada bekas kanta sentuh dan dikulturkan ke atas agar bukan nutrien yang dilapisi Escherichia coli. Plat agar diperiksa setiap hart bagi mengesan kehadiran ameba. Kultur positif seterusnya disahkan di bawah 'Image Analysis with Video TesT 4.0'. Acanthamoeba spp. didapati positif pada lapan daripada 90 sampel (8. 7%) dan kesemua strain adalah kumpulan II (polyphagids). Penemuan ini membuktikan Acanthamoeba spp. boleh Nadir pada bekas penyimpanan kanta sentuh pengguna asimptomatik dan boleh menjadi risiko jangkitan keratitis Acanthamoeba.
    Matched MeSH terms: Acanthamoeba Keratitis
  15. Khan NA, Anwar A, Siddiqui R
    Curr Med Chem, 2018 May 10.
    PMID: 29745319 DOI: 10.2174/0929867325666180510125633
    BACKGROUND: First discovered in the early 1970s, Acanthamoeba keratitis has remained a major eye infection and presents a significant threat to the public health, especially in developing countries. The aim is to present a timely review of our current understanding of the advances made in this field in a comprehensible manner and includes novel concepts and provides clear directions for immediate research priorities.

    METHOD: We undertook a search of bibliographic databases for peer-reviewed research literature and also summarized our published results in this field.

    RESULTS: The present review focuses on novel diagnostic and therapeutic strategies in details which can provide access to management and treatment of Acanthamoeba keratitis. This coupled with the recently available genome sequence information together with high throughput genomics technology and innovative approaches should stimulate interest in the rational design of preventative and therapeutic measures. Current treatment of Acanthamoeba keratitis is problematic and often leads to infection recurrence. Better understanding of diagnosis, pathogenesis, pathophysiology and therapeutic regimens, would lead to novel strategies in treatment and prophylaxis.

    Matched MeSH terms: Acanthamoeba Keratitis
  16. Faizah, M. H., Anisah, N., Yusof, S., Noraina, A. R., Adibah, M. R.
    Medicine & Health, 2017;12(2):286-292.
    Acanthamoeba spp. merupakan ameba hidup bebas yang biasa ditemui
    di persekitaran. Ia merupakan agen penyebab keratitis Acanthamoeba (AK)
    dan ensefalitis ameba bergranuloma (GAE). Ameba ini juga mampu menjadi
    perumah kepada pelbagai bakteria termasuklah yang bersifat patogenik seperti
    Mycobacterium, Legionella dan Staphylococcus aureus rintang metisilin (MRSA).
    Berdasarkan maklumat ini, satu kajian dijalankan untuk mengesan kehadiran tiga
    bakteria endosimbion berkepentingan perubatan di dalam Acanthamoeba spp. yang
    telah dipencilkan dari bolong penghawa dingin yang terdapat di wad and dewan
    bedah di Pusat Perubatan Universiti Kebangsaan Malaysia. Kehadiran bakteria
    endosimbion ini disaring menggunakan pasangan primer khusus bagi setiap genus
    menggunakan reaksi rantai polimerase (PCR) konvensional dan disahkan dengan
    analisis penjujukan. Dua puluh sembilan (80.56%) pencilan Acanthamoeba spp.
    didapati mengandungi bakteria endosimbion patogenik yang disasarkan dengan
    sekurang-kurangnya satu genus bakteria bagi setiap pencilan. Mycobacterium
    (82.76 %) adalah bakteria yang paling banyak dikesan, diikuti dengan Legionella sp.
    (65.52 %) dan Pseudomonas spp. (62.07 %). Tiada bakteria MRSA dikesan daripada
    mana-mana pencilan dalam kajian ini. Dua endosimbion Mycobacterium yang
    dikenalpasti telah dikelompokkan ke dalam strain Mycobacterium tuberculosis.
    Kami membuat kesimpulan bahawa, kebanyakan Acanthamoeba berpotensi untuk
    menjadi perumah bagi pelbagai bakteria patogenik, namun implikasi interaksi ini
    terhadap patogenisiti kedua-dua organisma masih kurang jelas dan memerlukan
    penyelidikan yang lebih lanjut.
    Matched MeSH terms: Acanthamoeba Keratitis
  17. Siddiqui R, Aqeel Y, Khan NA
    Antimicrob Agents Chemother, 2016 11;60(11):6441-6450.
    PMID: 27600042 DOI: 10.1128/AAC.00686-16
    For the past several decades, there has been little improvement in the morbidity and mortality associated with Acanthamoeba keratitis and Acanthamoeba encephalitis, respectively. The discovery of a plethora of antiacanthamoebic compounds has not yielded effective marketed chemotherapeutics. The rate of development of novel antiacanthamoebic chemotherapies of translational value and the lack of interest of the pharmaceutical industry in developing such chemotherapies have been disappointing. On the other hand, the market for contact lenses/contact lens disinfectants is a multi-billion-dollar industry and has been successful and profitable. A better understanding of drugs, their targets, and mechanisms of action will facilitate the development of more-effective chemotherapies. Here, we review the progress toward phenotypic drug discovery, emphasizing the shortcomings of useable therapies.
    Matched MeSH terms: Acanthamoeba Keratitis/drug therapy*; Acanthamoeba Keratitis/parasitology
  18. Mungroo MR, Tong T, Khan NA, Anuar TS, Maciver SK, Siddiqui R
    Int Microbiol, 2021 Aug;24(3):363-371.
    PMID: 33754231 DOI: 10.1007/s10123-021-00171-3
    Acanthamoeba keratitis is a sight-endangering eye infection, and causative organism Acanthamoeba presents a significant concern to public health, given escalation of contact lens wearers. Contemporary therapy is burdensome, necessitating prompt diagnosis and aggressive treatment. None of the contact lens disinfectants (local and international) can eradicate Acanthamoeba effectively. Using a range of compounds targeting cellulose, ion channels, and biochemical pathways, we employed bioassay-guided testing to determine their anti-amoebic effects. The results indicated that acarbose, indaziflam, terbuthylazine, glimepiride, inositol, vildagliptin and repaglinide showed anti-amoebic effects. Compounds showed minimal toxicity on human cells. Therefore, effects of the evaluated compounds after conjugation with nanoparticles should certainly be the subject of future studies and will likely lead to promising leads for potential applications.
    Matched MeSH terms: Acanthamoeba Keratitis/drug therapy*; Acanthamoeba Keratitis/parasitology*
  19. Kusrini E, Hashim F, Azmi WN, Amin NM, Estuningtyas A
    PMID: 26474244 DOI: 10.1016/j.saa.2015.09.021
    The terbium trinitrate.trihydrate.18-crown ether-6, Tb(NO3)3(OH2)3.(18C6) complex has been characterized by elemental analysis, photoluminescence and single X-ray diffraction. The IC50 values were determined based on MTT assay while light and fluorescence microscopy imaging were employed to evaluate the cellular morphological changes. Alkaline comet assay was performed to analyze the DNA damage. The photoluminescence spectrum of the Tb complex excited at 325 nm displayed seven luminescence peaks corresponding to the (5)D4→(7)F(0, 1, 2, 3, 4, 5, 6) transitions. The cytotoxicity and genotoxicity studies indicated that the Tb(NO3)3(OH2)3.(18C6) complex and its salt form as well as the 18C6 molecule have excellent anti-amoebic activity with very low IC50 values are 7, 2.6 and 1.2 μg/mL, respectively, with significant decrease (p<0.05) in Acanthamoeba viability when the concentration was increased from 0 to 30 μg/mL. The mode of cell death in Acanthamoeba cells following treatment with the Tb complex was apoptosis. This is in contrast to the Tb(NO3)3.6H2O salt- and 18C6 molecule-treated Acanthamoeba, which exhibited necrotic type cells. The percentage of DNA damage following treatment with all the compounds at the IC25 values showed high percentage of type 1 with the % nuclei damage are 14.15±2.4; 46.00±4.2; 36.36±2.4; 45.16±0.6%, respectively for untreated, treated with Tb complex, Tb salt and 18C6 molecule. The work features promising potential of Tb(NO3)3(OH2)3.(18C6) complex as anti-amoebic agent, representing a therapeutic option for Acanthamoeba keratitis infection.
    Matched MeSH terms: Acanthamoeba Keratitis
  20. Anwar A, Ting ELS, Anwar A, Ain NU, Faizi S, Shah MR, et al.
    AMB Express, 2020 Feb 03;10(1):24.
    PMID: 32016777 DOI: 10.1186/s13568-020-0960-9
    Acanthamoeba spp. are the causative agent of Acanthamoeba keratitis and granulomatous amoebic encephalitis (GAE). The current options to treat Acanthamoeba infections have limited success. Silver nanoparticles show antimicrobial effects and enhance the efficacy of their payload at the specific biological targets. Natural folk plants have been widely used for treating diseases as the phytochemicals from several plants have been shown to exhibit amoebicidal effects. Herein, we used natural products of plant or commercial sources including quercetin (QT), kolavenic acid (PGEA) isolated from plant extracts of Polyalthia longifolia var pendula and crude plant methanolic extract of Caesalpinia pulcherrima (CPFLM) as antiacanthamoebic agents. Furthermore, these plant-based materials were conjugated with silver nanoparticles (AgNPs) to determine the effects of the natural compounds and their nanoconjugates against a clinical isolate of A. castellanii from a keratitis patient (ATCC 50492) belonging to the T4 genotype. The compounds were conjugated with AgNPs and characterized by using ultraviolet visible spectrophotometry and atomic force microscopy. Quercetin coated silver nanoparticles (QT-AgNPs) showed characteristic surface plasmon resonance band at 443 nm and the average size distribution was found to be around 45 nm. The natural compounds alone and their nanoconjugates were tested for the viability of amoebae, encystation and excystation activity against A. castellanii. The natural compounds showed significant growth inhibition of A. castellanii while QT-AgNPs specifically exhibited enhanced antiamoebic effects as well as interrupted the encystation and excystation activity of the amoebae. Interestingly, these compounds and nanoconjugates did not exhibit in vitro cytotoxic effects against human cells. Plant-based compounds and extracts could be an interesting strategy in development of alternative therapeutics against Acanthamoeba infections.
    Matched MeSH terms: Acanthamoeba Keratitis
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