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Fulltext Bacterial and fungal keratitis in Upper Egypt: in vitro screening of enzymes, toxins and antifungal activity

Gharamah AA, Moharram AM, Ismail MA, Al-Hussaini AK

Indian J Ophthalmol, 2014 Feb;62(2):196-203.
PMID: 24008795 DOI: 10.4103/0301-4738.116463

This work was conducted to study the ability of bacterial and fungal isolates from keratitis cases in Upper Egypt to produce enzymes, toxins, and to test the isolated fungal species sensitivity to some therapeutic agents.

Matched MeSH terms: Keratitis/drug therapy; Keratitis/microbiology; Keratitis/epidemiology*
Assessment of polymerase chain reaction in the detection of pseudomonas aeruginosa in contact lens-induced severe infectious keratitis

Subrayan V, Peyman M, Lek Yap S, Mohamed Ali NA, Devi S

Eye Contact Lens, 2010 Jul;36(4):201-3.
PMID: 20531205 DOI: 10.1097/ICL.0b013e3181e3efa3

PURPOSE: The aim of this study is to evaluate the role of real-time polymerase chain reaction (PCR) and conventional bacterial culture methods in the detection of Pseudomonas aeruginosa in contact lens-induced severe, partially treated corneal ulcers referred to a tertiary center.
METHODS: The study duration was 6 months. All patients with contact lens-related corneal ulcer, requiring admission during the study period were recruited. Samples from corneal scrapings were simultaneously sent at the time of admission for PCR and culture testing. An in-house real-time PCR was developed to detect the P. aeruginosa lasA gene. The results of PCR and culture were compared using McNemar's chi2 test.
RESULTS: Ten patients were recruited. The mean age was 33 years (20-45 years). All the patients had contact lens-related keratitis (>4 mm) of which eight (80%) were found positive for P. aeruginosa by PCR or culture. There was no significant difference between PCR and culture in detecting P. aeruginosa (P<0.05).
CONCLUSIONS: PCR is, at least, as good as conventional cultures in detecting P. aeruginosa. It is a rapid assay as compared with culture, and early detection enables prompt treatment thus reducing the destructive effect of the organism on the cornea.

Matched MeSH terms: Keratitis/diagnosis*; Keratitis/drug therapy; Keratitis/microbiology
A novel antiamoebic agent against Acanthamoeba sp.--A causative agent for eye keratitis infection

Kusrini E, Hashim F, Azmi WN, Amin NM, Estuningtyas A

Spectrochim Acta A Mol Biomol Spectrosc, 2016 Jan 15;153:714-21.
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
Fulltext Microbial profile of culture-proven cases of endophthalmitis in hospital Universiti Sains Malaysia: a 7-year retrospective study

Norhayaty S., Sangeetha, T, Tai, Evelyn L.M., Wan Hazabbah W.H., Zaidah A.R., Azhany Y.

Journal of Biomedical and Clinical Sciences, 2017;2(1):69-73.
MyJurnal

nfectious endophthalmitis is a devastating and potentially sight-threatening condition.The objective is toanalyse the microbiological profile and visual outcome of culture positive endophthalmitis seen in Hospital Universiti Sains Malaysia. All patients with endophthalmitis admitted to Hospital Universiti Sains Malaysia over a 7-year period from January 2007 until December 2013 were recruited into this study. Retrospective review of medical and microbiology records was conducted among patients clinically diagnosed with endophthalmitis in Hospital Universiti Sains Malaysia from January 2007 until December 2013. Sixteen patients were admitted with endophthalmitis during this study period. Seven (43%) were culture-positive, in which five (71%) cases were from vitreous culture and two (29%) from blood specimens. The mean age for culture positive patients of presentation was44 years. The most common bacterial isolate was Pseudomonas spp., while the most common fungus was Candida spp. Other organisms isolated were Fusariumsp., Aspergillus sp., Staphylococcus sp.and Enterococcus sp. The risk factors for culture-positive cases were ocular trauma, corneal keratitis, ocular chemical injury, severe urinary tract infection and retropharyngeal abscess. Only three of the affected eyes could be salvaged. The final visual acuity waspoor in all the culture-positive eyes. Two cases underwent evisceration while one case underwent enucleation. As a conclusion,Culture-positive endophthalmitis in this study were mainly attributed to Pseudomonas spp. and Candida spp. The visual outcome of culture-positive endophthalmitis was poor.

Matched MeSH terms: Keratitis
Fulltext Antiamoebic activity of plant-based natural products and their conjugated silver nanoparticles against Acanthamoeba castellanii (ATCC 50492)

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
Fulltext Metronidazole conjugated magnetic nanoparticles loaded with amphotericin B exhibited potent effects against pathogenic Acanthamoeba castellanii belonging to the T4 genotype

Abdelnasir S, Anwar A, Kawish M, Anwar A, Shah MR, Siddiqui R, et al.

AMB Express, 2020 Jul 17;10(1):127.
PMID: 32681358 DOI: 10.1186/s13568-020-01061-z

Acanthamoeba castellanii can cause granulomatous amoebic encephalitis and Acanthamoeba keratitis. Currently, no single drug has been developed to effectively treat infections caused by Acanthamoeba. Recent studies have shown that drugs conjugated with nanoparticles exhibit potent in vitro antiamoebic activity against pathogenic free-living amoebae. In this study, we have developed a nano drug delivery system based on iron oxide nanoparticles conjugated with metronidazole which were further loaded with amphotericin B to produce enhanced antiamoebic effects against Acanthamoeba castellanii. The results showed that metronidazole-nanoparticles-amphotericin B (Met-MNPs-Amp) significantly inhibited the viability of these amoebae as compared to the respective controls including drugs and nanoparticles alone. Met-MNPs-Amp exhibited IC50 at 50 μg/mL against both A. castellanii trophozoites and cysts. Furthermore, these nanoparticles did not affect the viability of rat and human cells and showed safe hemolytic activity. Hence, the results obtained in this study have potential utility in drug development against infections caused by Acanthamoeba castellanii. A combination of drugs can lead to successful prognosis against these largely neglected infections. Future studies will determine the value of conjugating molecules with diagnostic and therapeutic potential to provide theranostic approaches against these serious infections.

Matched MeSH terms: Acanthamoeba Keratitis
Fulltext In vitro effects of multi-purpose contact lens disinfecting solutions towards survivability of Acanthamoeba genotype T4 in Malaysia

Mohd Hussain RH, Afiqah WN, Abdul Ghani MK, Khan NA, Siddiqui R, Anuar TS

Saudi J Biol Sci, 2021 Apr;28(4):2352-2359.
PMID: 33911949 DOI: 10.1016/j.sjbs.2021.01.030

The incidence of Acanthamoeba keratitis has been increasing since the previous decades, especially among contact lens users. This infection is majorly caused by the use of ineffective contact lens disinfecting solution. Thus, this study was conducted to evaluate the in vitro effects of multi-purpose disinfecting solutions (MPDS) against Acanthamoeba trophozoites and cysts. Acanthamoeba genotype T4 isolated from contact lens paraphernalia and an environmental strains were propagated for trophozoite or cyst-containing culture and adjusted in final concentration of 1 × 105 cells/ml. Amoebicidal and cysticidal assays were conducted by incubating trophozoites and cysts with OPTI-FREE® Express®, ReNu® Fresh™, Complete® Multi-Purpose Solution and AVIZOR Unica® Sensitive according to the manufacturer's minimum recommended disinfectant time (MMRDT) for up to 12 h at 30 ⁰C. Trypan blue hemocytometer-based microscopic counts determined amoebicidal and cysticidal effects. The viability of Acanthamoeba trophozoites and cysts was confirmed by re-inoculated them in the 1.5% non-nutrient agar plates. It was found that none of the MPDS showed amoebicidal and cysticidal effects during the MMRDT. However, OPTI-FREE® Express® demonstrated a significant differences in average cell reduction for both stages within MMRDT. When subjected to 12 h exposure, both OPTI-FREE® Express® and ReNu® Fresh™ led to significant reduction in the number of trophozoite and cyst cells. Notably, Complete® Multi-Purpose Solution and AVIZOR Unica® Sensitive did appreciably improve the solution effectiveness towards trophozoite cells when incubated for 12 h. All MPDS were largely ineffective, with 100% survival of all isolates at MMRDT, while OPTI-FREE® Express® showed limited amoebicidal activity against the contact lens paraphernalia isolate, however, it was more against the environmental strains after 12 h incubation time. The commercially available MPDS employed in this research offered minimal effectiveness against the protozoa despite the contact time. Improvement or development of new solution should consider the adjustment of the appropriate disinfectant concentration, adequate exposure time or the incorporation of novel chemical elements, which are effective against Acanthamoeba for accelerated disinfecting and more reduction of potential exposure of contact lens users to Acanthamoeba keratitis.

Matched MeSH terms: Acanthamoeba Keratitis
Fulltext Relationship between Routine Handling Practices with Potential Pathogenic Bacteria Isolated from Contact Lenses Among Students in UiTM Negeri Sembilan

Adam Zafdri Md Zali, Rashidah Iberahim

Journal of Academia Universiti Teknologi MARA Negeri Sembilan, 2021;9(1):106-116.
MyJurnal

Pseudomonas aeruginosa and Staphylococcus aureus are types of bacteria known to cause bacterial keratitis. Pseudomonas aeruginosa causes bacterial keratitis by adhering to the surface of the contact lenses, when the P. aeruginosa are in contact with the eye, resulting in infectious keratitis. As for Staphylococcus aureus, when there is a predisposing factor such as wearing expired or extended use of contact lenses (contact lenses that can be used continually for up to one week even while sleeping) weaken the individual defences and leads to the development of bacterial keratitis. Both bacteria are capable to infect eye cornea and lead to bacterial keratitis through contact lenses wearer. The findings of this study provide information on the importance of routine practices in handling contact lenses to help reduce the incidence of bacterial keratitis caused by wear contact lenses in an individual. The side effect of wearing contact lenses such as redness of the eye and keratitis due to the infection by pathogenic bacteria which comes from the behavior and low hygiene level management of individual had led the study to create awareness to contact lenses wearer. In this study, 25 soft and hard contact lenses with purposed for colored or toric contact lenses were obtained among UiTM Negeri Sembilan students. The users required to answer the questionnaire form regarding the type, behavior, and routine practices of their contact lenses. Pathogenic bacteria were isolated using the cotton swab technique and cultured on nutrient broth. The streak technique was used to cultured bacteria from broth to nutrient agar, blood agar, and MacConkey agar. Later, the identification of bacteria was carried out using biochemical tests and microscopic observation. From the laboratory results, 84% of the tested contact lenses contained pathogenic bacteria on their surface. These findings concluded that the presences of pathogenic microorganisms on the contact lenses used closely related to the behavior in handling and hygenic practices level by the contact lenses users.

Matched MeSH terms: Keratitis
Fulltext Management and treatment of contact lens-related Pseudomonas keratitis

Willcox MD

Clin Ophthalmol, 2012;6:919-24.
PMID: 22791973 DOI: 10.2147/OPTH.S25168

Pubmed and Medline were searched for articles referring to Pseudomonas keratitis between the years 2007 and 2012 to obtain an overview of the current state of this disease. Keyword searches used the terms "Pseudomonas" + "Keratitis" limit to "2007-2012", and ["Ulcerative" or "Microbial"] + "Keratitis" + "Contact lenses" limit to "2007-2012". These articles were then reviewed for information on the percentage of microbial keratitis cases associated with contact lens wear, the frequency of Pseudomonas sp. as a causative agent of microbial keratitis around the world, the most common therapies to treat Pseudomonas keratitis, and the sensitivity of isolates of Pseudomonas to commonly prescribed antibiotics. The percentage of microbial keratitis associated with contact lens wear ranged from 0% in a study from Nepal to 54.5% from Japan. These differences may be due in part to different frequencies of contact lens wear. The frequency of Pseudomonas sp. as a causative agent of keratitis ranged from 1% in Japan to over 50% in studies from India, Malaysia, and Thailand. The most commonly reported agents used to treat Pseudomonas keratitis were either aminoglycoside (usually gentamicin) fortified with a cephalosporin, or monotherapy with a fluoroquinolone (usually ciprofloxacin). In most geographical areas, most strains of Pseudomonas sp. (≥95%) were sensitive to ciprofloxacin, but reports from India, Nigeria, and Thailand reported sensitivity to this antibiotic and similar fluoroquinolones of between 76% and 90%.

Matched MeSH terms: Keratitis
Fulltext Gold Nanoparticle Conjugation Enhances the Antiacanthamoebic Effects of Chlorhexidine

Aqeel Y, Siddiqui R, Anwar A, Shah MR, Khan NA

Antimicrob Agents Chemother, 2015;60(3):1283-8.
PMID: 26666949 DOI: 10.1128/AAC.01123-15

Acanthamoeba keratitis is a serious infection with blinding consequences and often associated with contact lens wear. Early diagnosis, followed by aggressive topical application of drugs, is a prerequisite in successful treatment, but even then prognosis remains poor. Several drugs have shown promise, including chlorhexidine gluconate; however, host cell toxicity at physiologically relevant concentrations remains a challenge. Nanoparticles, subcolloidal structures ranging in size from 10 to 100 nm, are effective drug carriers for enhancing drug potency. The overall aim of the present study was to determine whether conjugation with gold nanoparticles enhances the antiacanthamoebic potential of chlorhexidine. Gold-conjugated chlorhexidine nanoparticles were synthesized. Briefly, gold solution was mixed with chlorhexidine and reduced by adding sodium borohydride, resulting in an intense deep red color, indicative of colloidal gold-conjugated chlorhexidine nanoparticles. The synthesis was confirmed using UV-visible spectrophotometry that shows a plasmon resonance peak of 500 to 550 nm, indicative of gold nanoparticles. Further characterization using matrix-assisted laser desorption ionization-mass spectrometry showed a gold-conjugated chlorhexidine complex at m/z 699 ranging in size from 20 to 100 nm, as determined using atomic force microscopy. To determine the amoebicidal and amoebistatic effects, amoebae were incubated with gold-conjugated chlorhexidine nanoparticles. For controls, amoebae also were incubated with gold and silver nanoparticles alone, chlorhexidine alone, neomycin-conjugated nanoparticles, and neomycin alone. The findings showed that gold-conjugated chlorhexidine nanoparticles exhibited significant amoebicidal and amoebistatic effects at 5 μM. Amoebicidal effects were observed by parasite viability testing using a Trypan blue exclusion assay and flow-cytometric analysis using propidium iodide, while amoebistatic effects were observed using growth assays. In contrast, chlorhexidine alone, at a similar concentration, showed limited effects. Notably, neomycin alone or conjugated with nanoparticles did not show amoebicidal or amoebistatic effects. Pretreatment of A. castellanii with gold-conjugated chlorhexidine nanoparticles reduced amoeba-mediated host cell cytotoxicity from 90% to 40% at 5 μM. In contrast, chlorhexidine alone, at similar concentrations, had no protective effects for the host cells. Similarly, amoebae treated with neomycin alone or neomycin-conjugated nanoparticles showed no protective effects. Overall, these findings suggest that gold-conjugated chlorhexidine nanoparticles hold promise in the improved treatment of A. castellanii keratitis.

Matched MeSH terms: Acanthamoeba Keratitis
Fulltext A case of trauma related Acanthamoeba keratitis

Kamel AG, Faridah H, Yusof S, Norazah A, Nakisah MA

Trop Biomed, 2004 Dec;21(2):135-8.
PMID: 16493405 MyJurnal

Acanthamoeba is an uncommon cause of keratitis but one of the most severe because of the prolonged and painful course of the disease and poor visual outcome. Although contact lens use is the principal risk factor, about 10% of cases occur following trauma and exposure to contaminated soil or water. Two cases of Acanthamoeba keratitis involving women contact lens wearers have previously been reported in Malaysia but this is the first time, a non contact lens related Acanthamoeba keratitis is reported. The case involved a 28 year old Indonesian male construction worker who had a trauma of the right eye during work. His eye was struck by sand and dust particles after which he quickly washed with water from an open tank at the construction site. He experienced pain, redness, glaring and blurring of vision of the right eye three days later. The diagnosis was missed at initial presentation but culture of the corneal scraping had proven Acanthamoeba as the aetiological agent. The history and clinical findings of this trauma related Acanthamoeba keratitis are briefly discussed.

Matched MeSH terms: Acanthamoeba Keratitis
Effect of non-steroidal anti-inflammatory drugs on biological properties of Acanthamoeba castellanii belonging to the T4 genotype

Siddiqui R, Lakhundi S, Iqbal J, Khan NA

Exp Parasitol, 2016 Jul 2;168:45-50.
PMID: 27381503 DOI: 10.1016/j.exppara.2016.06.011

Non-steroidal anti-inflammatory drug, Diclofenac, targeting COX have shown promise in the treatment of Acanthamoeba keratitis, but the underlying mechanisms remain unknown. Using various NSAIDs, Diclofenac sodium, Indomethacin, and Acetaminophen, here we determined the effects of NSAIDs on the biological properties of Acanthamoeba castellanii belonging to the T4 genotype. Using amoebicidal assays, the results revealed that Diclofenac sodium, and Indomethacin affected growth of A. castellanii. In contrast, none of the compounds tested had any effect on the viability of A. castellanii. Importantly, all NSAIDs tested abolished A. castellanii encystation. This is a significant finding as the ability of amoebae to transform into the dormant cyst form presents a significant challenge in the successful treatment of infection. The NSAIDs inhibit production of cyclo-oxegenase, which regulates the synthesis of prostaglandins suggesting that cyclooxygenases (COX-1 and COX-2) and prostaglandins play significant role(s) in Acanthamoeba biology. As NSAIDs are routinely used in the clinical practice, these findings may help design improved preventative strategies and/or of therapeutic value to improve prognosis, when used in combination with other anti-amoebic drugs.

Matched MeSH terms: Acanthamoeba Keratitis
Fulltext Sensitivity of Acanthamoeba cyst to antimicrobial agents

Noradilah, S. A., Mohamed Kamel, A. G., Anisah, N., Noraina, A. R., Yusof, S.

Malaysian Journal of Medicine and Health Sciences, 2010;6(1):111-117.
MyJurnal

Introduction: Acanthamoeba is an ubiquitous free-living protozoa which causes serious ocular problems. Acanthamoeba keratitis is becoming more prevalent amongst contact lens wearers. The disease can cause loss of vision and blindness if not treated properly. The objective of this research is to study the sensitivity of six Acanthamoeba spp. isolates, of which three were from the clinical isolates (HKL 95, HTH 40 and HS 6) and the remaining three from environmental isolates (TTT 9, TL 3 and SMAL 8) to antimicrobial agents. Methods: The antimicrobial agents chosen for this purpose were polyhexamethylene biguanide (PHMB) and chlorhexidine. Serial dilutions were perfomed for polyhexamethylene biguanide and chlorhexidine. Cyst suspensions from the chosen isolates were exposed to PHMB and chlorhexidine respectively. After 48 hours incubation time at 30°C, each mixture was filtered and filtration membrane was put onto non-nutrient agar laid with Escherichia coli. The agar plates were incubated for three days at 30°C and examined daily until day 14 to detect the presence of Acanthamoeba trophozoites under the inverted microscope. The presence of trophozoites indicated the ineffectiveness of the antimicrobial agents. Results: Both of the antimicrobial agents tested were found to be effective against Acanthamoeba cysts from all the test strains. Polyhexamethylene biguanide gave a minimum cysticidal concentration (MCC) mean value of 2.848 μg/mL while chlorhexidine showed
MCC mean value at a concentration of 3.988 μg/mL. Conlusion: It can be concluded that the Acanthamoeba cysts were sensitive to polyhexamethylene biguanide and chlorhexidine.

Matched MeSH terms: Acanthamoeba Keratitis
Fulltext The effectiveness of gentamicin against acanthamoeba cysts in vitro

Noradilah, S.A., Mohamd Kamel, A.G., Anisah, N., Noraina, A.R., Yusof, S.

Malaysian Journal of Medicine and Health Sciences, 2012;8(2):51-54.
MyJurnal

Acanthamoeba is a free-living protozoa which causes serious ocular problem. Acanthamoeba keratitis is becoming more prevalent amongst contact lens wearers and it can cause loss of vision and blindness if not treated properly. The objective of this research is to determine the effectiveness of gentamicin against six Acanthamoeba spp. isolates, of which three were clinical isolates (HS 6, HKL 95, HTH 73) and three environmental isolates (SMAL 7, SMAL 8, TTT 9). Cyst suspension from the chosen isolates were exposed to gentamicin. After 48 hours of incubation at temperature of 30°C and 37oC, each mixture was filtered and filtration membrane was put onto non-nutrient agar laid with Escherichia coli. The agar plates were incubated for three days at 30oC and 37oC and the plates were examined daily until day 14 to look for the presence of Acanthamoeba trophozoites under inverted microscope. The presence of trophozoites indicated the ineffectiveness of gentamicin. Gentamicin was found to be effective against Acanthamoeba cysts from all the test strains at both incubation temperatures. The minimum cysticidal concentration (MCC) mean value of gentamicin was 0.193 mg/mL at 30oC and 0.229 mg/mL at 37oC. So, we concluded that gentamicin has cysticidal potential towards Acanthamoeba.

Matched MeSH terms: Acanthamoeba Keratitis
Fulltext Survivability of Acanthamoeba strains isolated from clinical and environmental specimens during axenization

Nurul Farhana Jufri, Anisah Nordin, Mohamed Kamel Abd Ghani, Yusof Suboh, Noraina Abd Rahim

Jurnal Sains Kesihatan Malaysia, 2011;9(1):1-3.
MyJurnal

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.

Matched MeSH terms: Acanthamoeba Keratitis
Fulltext Ability of Acanthamoeba cyst to excyst at different temperatures

Nurul Fariza Rossle, Mohamed Kamel Abd Ghani, Anisah Nordin, Yusof Suboh, Noraina Ab Rahim

Jurnal Sains Kesihatan Malaysia, 2011;9(1):41-43.
MyJurnal

This study was carried out to observe thermotolerance ability of Acanthamoeba spp. A total of 32 Acanthamoeba spp. isolates obtained from water taps, sinks, swimming pools and sea water were used. Trophozoites of Acanthamoeba spp. were inoculated onto non-nutrient agar (NNA) seeded with heat-killed Escherichia coli using aseptic technique and incubated for 14 days at 30°C to obtain the cyst. The cysts were subcultured onto new agar plates for thermotolerance test at 37°C and 42°C. The plates were observed until 96 hours after incubation for excystation of Acanthamoeba before being declared negative. Overall, 81.25% of samples were able to excyst at 37°C while 37.5% were able to excyst at 42°C. Thermotolerant Acanthamoeba is associated with high pathogenicity potential.

Matched MeSH terms: Acanthamoeba Keratitis
Fulltext Contact lens related Elizabethkingia meningoseptica keratitis-a first Southeast ASEAN case report & literature review

Ang, Wen-Jeat, Embong Zunaina, Raja Omar Raja Norliza, Abdul Jalil Fadzillah

Journal of Biomedical and Clinical Sciences, 2017;2(1):1-4.
MyJurnal

We describe the first clinical case of contact lens related corneal ulcer caused by Elizabethkingia meningosepticaregistered in Southeast Asia. A 20-year-old female student who wasa regular soft contact lens wearer, presented with pain, photophobia and blurring of vision of the right eye for 3 days. On slit lamp examination, there was a small paracentral anterior stromal infiltrate with an overlying epithelial defect. Microbiological cultures from corneal scrapings, contact lens and its casing were positive for E.meningoseptica. Due to high likelihood of contact lens contamination causing keratitis, topical fortified gentamicin0.9% and ceftazidime 5% were administered empirically. Topical vancomycin 5% was later added tailoring to the culture and sensitivity of the organism. After 8 weeks of treatment, the keratitis subsided and corneal epithelial defect completely healed with residual corneal opacity. Even though uncommon, contact lens related E.meningosepticakeratitis can occur in healthy immunocompetent individuals with no ocular comorbidities.

Matched MeSH terms: Keratitis
Phomopsidione nanoparticles coated contact lenses reduce microbial keratitis causing pathogens

Bin Sahadan MY, Tong WY, Tan WN, Leong CR, Bin Misri MN, Chan M, et al.

Exp Eye Res, 2019 01;178:10-14.
PMID: 30243569 DOI: 10.1016/j.exer.2018.09.011

Microbial keratitis is the infection caused by pathogenic microorganisms that commonly occurs among the contact lens users. Various antimicrobial compounds were coated on contact lenses to kill keratitis causing microorganisms, however these compounds caused several adverse side effects. Hence, the aim of this study is to develop a silicone hydrogel contact lens coated with phomopsidione nanoparticle that inhibit keratitis causing clinical isolates. Phomopsidione nanoparticles were synthesized using polyvinyl alcohol as encapsulant. The nanoparticles showed an average size of 77.45 nm, with neutral surface charge. Two drug release patterns were observed in the drug release profile, which are the initial slow release phase with extended drug release (release rate 46.65 μg/h), and the burst release phase observed on Day 2 (release rate 2224.49 μg/h). This well-regulated drug delivery system enables the control of drug release to meet the therapeutic requirements. On agar diffusion assay, 3 out of 5 test microorganisms were inhibited by phomopsidione nanoparticle coated contact lenses, including two Gram negative bacteria. Besides, all test microorganisms showed at least 99% of growth reduction, with the treatment of the contact lens model. The drug loaded onto the nanoparticles is sufficient to prevent the bacterial growth. In conclusion, this study provides an effective alternative to combat keratitis-causing microorganisms among contact wearers.

Matched MeSH terms: Keratitis
Occurrence of Acanthamoeba genotypes in Central West Malaysian environments

Basher MHA, Ithoi I, Mahmud R, Abdulsalam AM, Foead AI, Dawaki S, et al.

Acta Trop, 2018 Feb;178:219-228.
PMID: 29203378 DOI: 10.1016/j.actatropica.2017.11.015

Acanthamoeba species are ubiquitous free-living protozoa that can be found worldwide. Occasionally, it can become parasitic and the causative agent of acanthamoebic keratitis (AK) and Granulomatous Amoebic Encephalitis (GAE) in man. A total of 160 environmental samples and 225 naturally-infected animal corneal swabs were collected for Acanthamoeba cultivation. Acanthamoeba was found to be high in samples collected from environments (85%, 136/160) compared to infected animal corneas (24.89%, 56/225) by microscopic examination. Analysis of nucleotide sequence of 18S rRNA gene of all the 192 cultivable Acanthamoeba isolates revealed 4 genotypes (T3, T4. T5 and T15) with T4 as the most prevalent (69.27%, 133/192) followed by T5 (20.31%), T15 (9.90%) and T3 (0.52%). Genotype T4 was from the strain of A. castellanii U07401 (44.27%), A. castellanii U07409 (20.83%) and A. polyphagaAY026243 (4.17%), but interestingly, only A. castellanii U07401 was detected in naturally infected corneal samples. In environmental samples, T4 was commonly detected in all samples including dry soil, dust, wet debris, wet soil and water. Among the T4, A. castellanii (U07409) strains were detected high occurrence in dry (45%) followed by aquatic (32.50%) and moist (22.50%) samples but however A. castellanii (U07401) strains were dominant in dry samples of soil and dust (93.10%). Subsequently, genotype T5 of A. lenticulata (U94741) strains were dominant in samples collected from aquatic environments (58.97%). In summary, A. castellanii (U07401) strains were found dominant in both environmental and corneal swab samples. Therefore, these strains are possibly the most virulent and dry soil or dusts are the most possible source of Acanthamoeba infection in cats and dogs corneas.

Matched MeSH terms: Acanthamoeba Keratitis
Fulltext Acanthamoeba-mediated cytopathic effect correlates with MBP and AhLBP mRNA expression

Ng SL, Nordin A, Abd Ghafar N, Suboh Y, Ab Rahim N, Chua KH

Parasit Vectors, 2017 12 28;10(1):625.
PMID: 29282148 DOI: 10.1186/s13071-017-2547-0

BACKGROUND: In recent years, the concern of Acanthamoeba keratitis has increased since the infection is often associated with contact lens use. Partial 18S rRNA genotypic identification of Acanthamoeba isolates is important to correlate with pathophysiological properties in order to evaluate the degree of virulence. This is the first report of genotypic identification for clinical isolates of Acanthamoeba from corneal scrapings of keratitis in Malaysia. This study is also the first to correlate the mRNA expression of MBP and AhLBP as virulent markers for axenic strains of Acanthamoeba.
RESULTS: In this study, ten clinical isolates were obtained from corneal scrapings. Rns genotype and intra-genotypic variation at the DF3 region of the isolates were identified. Results revealed that all clinical isolates belonged to the T4 genotype, with T4/6 (4 isolates), T4/2 (3 isolates), T4/16 (2 isolates) and one new genotype T4 sequence (T4/36), being determined. The axenic clinical isolates were cytopathogenic to rabbit corneal fibroblasts. MBP and AhLBP mRNA expression are directly correlated to Acanthamoeba cytopathic effect.
CONCLUSIONS: All ten Malaysian clinical isolates were identified as genotype T4 which is predominantly associated with AK. Measuring the mRNA expression of Acanthamoeba virulent markers could be useful in the understanding of the pathogenesis of Acanthamoeba keratitis.

Matched MeSH terms: Acanthamoeba Keratitis

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