Acanthamoeba is a free-living amoeba that can cause serious eye infection leading to blindness known as Acanthamoeba keratitis. The infection usually occurs amongst individuals wearing contact lenses. The use of contact lens disinfecting solution not effective against the Acanthamoeba cysts increases the risk for infection. There have been many studies indicating the resistance of Acanthamoeba cyst towards certain antimicrobial agents, enzymatic disinfectant and chemical disinfectant. Therefore, this study was performed to evaluate the efficacy of contact lens disinfecting solutions comprising Opti-Free® Express® & Complete™, against the cysts of Acanthamoeba. This study also investigates the effectiveness of the disinfecting solutions based on the soaking time recommended by manufacturers, 4 hours, 6 hours and 8 hours. Four clinical isolates of Acanthamoeba were tested in this study comprising HKL 11, HKL 51, HKL 32 and HKL 5. Ten microliter of cysts suspension (105 cells/ml) was tested on the disinfectant solution respectively. After an interval varying from 4 hours to 8 hours, the solutions were centrifuged and then the sediment was inoculated onto non nutrient agar lawn with E. coli. The plates were examined daily using inverted microscope for the emergence of Acanthamoeba trophozoites. The presence of Acanthamoeba trophozoites indicates that the cysts had successfully undergone excystation process denoting that the disinfecting solution is not effective. Opti-Free® Express® & Complete™ contact lens disinfecting solutions were not effective against all 4 isolates of Acanthamoeba cysts based on time recommended by manufacturers, 4 hours, 6 hours and even 8 hours soaking time. This study shows that there are more contact lens disinfecting solutions not effective against Acanthamoeba cysts compared to those that are effective.
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
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
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.
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.
Kajian ini dijalankan untuk memencilkan Acanthamoeba spp. daripada pelbagai persekitaran akuatik di Semenanjung Malaysia. Sebanyak 160 sampel diambil dengan 140 sampel menggunakan kaedah swab manakala 20 sampel lagi menggunakan kaedah pensampelan air dengan botol Schott 500 ml yang steril. Sampel swab diambil daripada kepala paip air (50), sinki (50), serta kolam renang (40) manakala sampel air diambil dari laut. Sampel swab diinokulasi secara terus ke atas agar tanpa nutrien (NNA) yang dilapisi dengan Escherichia coli matian haba secara aseptik. Sampel air dituras menggunakan membran turas bersaiz liang 0.45 µm sebelum membran turas itu dipindahkan secara aseptik ke atas piring NNA yang dilapisi dengan E. coli matian haba. Semua piring dieram pada suhu 30°C dan diperiksa setiap hari untuk kehadiran Acanthamoeba spp. sehingga hari ke-14 sebelum disahkan negatif. Secara keseluruhannya, terdapat 20% sampel yang positif untuk kehadiran Acanthamoeba. Acanthamoeba spp. paling banyak dipencilkan daripada sampel air laut dengan peratusan sebanyak 40% manakala paling sedikit dipencilkan daripada swab paip air dengan peratusan sebanyak 4% sahaja. Pencilan positif Acanthamoeba spp. daripada sinki dan kolam renang masing-masing adalah 20% dan 30%. Ketiga-tiga kumpulan genus Acanthamoeba dalam bentuk sista dapat ditemui dalam sampel yang diambil.
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.
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.
Tujuan kajian ini adalah untuk mengenal pasti punca insidens tinggi infeksi Acanthamoeba di kalangan pemakai kanta sentuh di Kuala Lumpur. Satu ratus tujuh puluh empat sampel diambil dari 66 subjek pemakai kanta sentuh lembut jenis pakaibuang dan mereka juga disoal dengan menggunakan borang kaji selidik. Kesemua pemakai kanta sentuh menggunakan pelbagai jenis larutan disinfeksi atau larutan pelbagai guna untuk membersih dan mendisinfeksi kanta sentuh. Swab diambil dari kanta sentuh yang masih dipakai, bekas kanta sentuh dan juga larutan disinfeksi yang sedang digunakan. Daripada swab ini proses pengkulturan yang lengkap dilakukan untuk pemencilan Acanthamoeba spp. Pemencilan Acanthamoeba spp. daripada 14 sampel daripada 7 subjek telah berjaya dilakukan. Hasil pemencilan yang tinggi adalah daripada bekas kanta sentuh (13.5%) dan kanta sentuh subjek (10.6%). Walau bagaimanapun tiada sebarang pemencilan didapati daripada larutan disinfeksi. Punca infeksi Acanthamoeba adalah dari bekas simpanan kanta sentuh dan kanta sentuh yang dipakai. Kaji selidik menunjukkan peratusan tidak komplain yang tinggi di kalangan pemakai kanta sentuh kerana ramai menggunakan air paip untuk mencuci kanta sentuh dan bekasnya.
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.
Acanthamoeba spp. adalah patogenik dan berpotensi menyebabkan kebutaan melalui penyakit yang dikenali sebagai keratitis Acanthamoeba (AK) khususnya dalam kalangan pemakai kanta sentuh. Kajian ini dijalankan untuk menilai kerentanan sista Acanthamoeba terhadap larutan disinfektan pelbagai guna kanta sentuh dengan menggunakan empat isolat Acanthamoeba iaitu dua isolat klinikal; HUKM 38, HKL 10 dan dua persekitaran; PBA 46 dan PBA 42. Lima jenis larutan disinfektan pelbagai guna; Complete®, Renu® fresh™, RevitaLens OcuTec®, Opti-Free® Express® dan Solo Care Aqua® telah diuji ke atas sista Acanthamoeba tersebut. Masa rendaman adalah berdasarkan masa yang disyorkan oleh pengeluar (4 jam dan 6 jam), 8 jam dan 24 jam. Setiap campuran sista dan larutan disinfektan kanta sentuh dipindahkan ke atas agar tanpa nutrien yang dilapisi Escherichia coli. Plat agar diperhatikan di bawah mikroskop songsang setiap hari sehingga hari ke-14 untuk melihat kehadiran trofozoit. Kelima-lima larutan disinfektan pelbagai guna kanta sentuh tidak efektif membunuh kesemua isolat sista Acanthamoeba yang diuji. Ini menunjukkan bahawa kebanyakan larutan disinfektan pelbagai guna kanta sentuh tidak mempunyai aktiviti anti-Acanthamoeba yang sangat diperlukan bagi mencegah jangkitan keratitis Acanthamoeba dalam kalangan pengguna kanta sentuh.
Effective disinfection of contact lenses is of paramount importance in the prevention of Acanthamoeba (AK). Therefore, this study was undertaken to evaluate the effectiveness of the multi-purpose contact lens disinfecting solutions against Acanthamoeba cysts of four isolates comprising two clinical isolates; HS 5, HTH 73, and two environmental isolates; TTA 1 and TKA 14. Five multi-purpose contact lens disinfecting solutions; Complete®, Renu® fresh™, RevitaLens OcuTec®, Opti-Free® Express® and Solo Care Aqua® were tested on cyst of the four Acanthamoeba isolates. The soaking times were based on manufactures recommendations (4 and 6 h), 8 h and 24 h. Each mixture of the cysts and disinfecting solution was transferred onto non-nutrient agar seeded with Escherichia coli. The agar plates were examined under inverted microscope daily until day 14 to detect the presence of Acanthamoeba trophozoites. All 5 multi-purpose contact lens disinfecting solutions tested were ineffective at killing all Acanthamoeba cyst isolates tested. This indicates that most multi-purpose contact lens disinfecting solutions do not have anti-Acanthamoeba activity necessary to prevent keratitis amongst the contact lens wearers.
Key words: Acanthamoeba; effectiveness; Malaysia; multi-purpose contact lens disinfecting solution
Acanthamoeba keratitis is a serious infection of the eye which can result in permanent visual impairment. Therefore this study was performed to evaluate the effectiveness of antimicrobial agents on three Acanthamoeba clinical isolates (HS 6, HKL 95 and HTH 73). Antimicrobial agents used in this study were polyhexamethylene biguanide (PHMB) and chlorhexidine and both were serially diluted. Cyst suspensions from all three strains were tested against the antimicrobial agents, respectively. After 48 h of incubation at 37°C, the suspension was filtered and the filter membrane was placed onto nonnutrient agar plate lawned with heat-killed Escherichia coli. The plates were examined daily under the inverted microscope until day 14 but were negative for Acanthamoeba trophozoites. The presence of trophozoites indicated ineffectiveness of the antimicrobial agents. Both antimicrobial agents used were found to be effective against Acanthamoeba cysts for all the strains tested. PHMB gave minimum cysticidal concentration (MCC) mean value of 4.232 µg/mL and chlorhexidine showed MCC mean value of 3.906 µg/mL. So, from this study, it can be concluded that PHMB and chlorhexidine were effective in killing the tested Acanthamoeba cysts.