Recently, the number of reports of Acanthamoeba keratitis has been increased apparently as a consequence of association with use of contact lenses, contaminated contact lens care system and high concern of ophthalmologist to Acanthamoeba keratitis. But, there were few epidemiologic studies of contamination of contact lens care system by Acanthamoeba and there was no report in Korea. We carried out a survey to demonstrate the contamination of contact lens care system by Acanthamoeba and bacteria and analysed the results according to the types of contact lenses and methods of disinfection. We examined the contact lens care system of 185 asymptomatic contact lens wearer for the contamination of Acanthamoeba and bacteria. The result showed a significant contamination of Acanthamoeba and bacteria. Twenty eight(15%) were contaminated with Acanthamoeba, eighteen(10%) were mixed with bacterial contamination and seventy four(40%) were contaminated with bacteria. There was no significant difference with sex and the result showed a lot of cocontamination with bacteria and amoeba and chemical disinfection showed a high Acanthamoeba contamination rate. Based on data from this and previous studies, the most of contact lens care system of contact lens wearer was contaminated with bacteria, amoeba and other microorganism. So, ophthalmologists should be concerned about Acanthamoeba contamination of contact lens care system.
Acanthamoeba Keratitis ; Acanthamoeba* ; Amoeba ; Bacteria ; Contact Lenses ; Disinfection ; Korea

In order to determine the contamination status of contact lens care system by Acanthamoeba, a nation-wide survey was carried out for the detection of amoeba from the storage cases and contact lenses solution of 739 asymptomatic lens wearers (238 male and 501 female). Subjects consisted of 280 residents in Youngnam, 270 in Honam, and 189 in Chungbu provinces. Acanthamoeba was demonstrated from 141 (19.1%) lens care systems. No significant difference of contamination status was observed between male (19.7%) and female (18.8). However, the contamination rate from Honam province (28.1%) were significnatly higher than those from Youngnam (16.1%) and Chungbu (10.6%) provinces. The isolation rate for Acanth-amoeba was higher in systems of daily wear soft lens (20.0%), extended wear soft lens (23.1), and hard lens (18.8%) than in system of disposable lens. The contamination rate was the higher in the sysems using chemical disinfection alone (19.8%) for disinfection. The contamination rate in systems of combined disinfection with chemicals and intermittent boiling ranged 7.0% to 8.3%, and it was different according to the boiling frequency a week. More attention should be paid to hygeneic maintenance of contact lens care system for the prevention of contact lens-related Acanthamoeba keratitis.
Acanthamoeba Keratitis ; Acanthamoeba* ; Amoeba ; Contact Lenses ; Disinfection ; Female ; Humans ; Korea* ; Male

Acanthamoeba keratitis is uncommon and rarely reported in Korea. It has been reported in world literature as a very severe, progressive necrotizing stromal keratitis due to a non-parasitic free-living amoeba. It is frequently associated with minimal corneal trauma especially from contact lens but sometimes occurs in patients without any past history. We report a case of acanthamoeba keratitis without a specific past history in a 42-year-old man. Light and electron microscopy demonstrated severe stromal keratitis with numerous thick-walled cysts, 10~15 m in diameter, scattered in the superficial and deep stroma. Because this keratitis is most often mistaken for fungal, bacterial or herpetic keratitis, early confirmatory diagnosis by direct smear, biopsy or culture is essentially required for the prevention of visual loss or devastating eyeball loss.
Acanthamoeba Keratitis* ; Acanthamoeba* ; Adult ; Amoeba ; Biopsy ; Diagnosis ; Humans ; Keratitis ; Keratitis, Herpetic ; Korea ; Microscopy, Electron

The indirect fluorescent antibody test was performed to demonstrate the antibody production in the rabbits immunized with free-living amoebas; Acanthamoeba culbertsoni and Naegleria fowleri, and antibody titer changes by immunization duration. Rabbits were immunized with Acanthamoeba culbertsoni and Naegleria fowleri which were cultured axenically in CGVS medium. For experiments, rabbits were divided into two groups; small dose group received 10(4) intravenously with live or dead free-living amoebas trophozoites as an immunizing dose three times with one week interval, and large dose group received 10(6) live or dead trophozoites respectively. The control group received physiologic saline or medium for culture of free-living amoebas intravenously. Antiserum was collected 4 times at interval of 3 days in the first 10 days, and also up to 2 months later. In the group immunized with live Acanthamoeba culbertsoni, fluorescent antibody titer was higher than in the group of dead one, and also in the large dose group than in the small dose group. Antibody titer of anti-Naegleria fowleri serum in the large dose group showed no difference by the source of amoeba antigen; live or dead. But in the small dose group, antibody titer was higher in the immunized with live Naegleria fowleri than in the group with dead one. No cross reactivity was demonstrated between the Acanthamoeba and Naegleria. And no cross reaction was observed when the free-living amoebas antigens were tested against human sera of amoebiasis, paragonimiasis and clonorchiasis.
parasitology-protozoa ; free-living amoeba ; Acanthamoeba culbertsoni ; Naegleria fowleri ; immunology ; fluorescence ; rabbit ; amoebiasis ; paragonimiasis ; clonorchiasis

Rabbits were immunized with free-living amoebas by intravenous injections. The amoebas were Acanthamoeba culbertsoni and Naegleria fowleri and obtained by axenic cultivation in CGVS medium. Each rabbit received 10(6) of Acanthamoeba culbertsoni and 10(5) of Naegleria fowleri trophozoites respectively every other day in three doses and finally one booster dose at 1 week later. Antiserum was collected from thc following day of the booster injection up to 2 months period, and stored at -30 degree C until use. The immobilization test was performed. One drop of amoeba suspension was mixed with the test serum on slide and observed the mobile state under microscope. Maximal immobilizing phenomenon observed in 30 minutes and, then gradually recovered to normal state. Inactivation of antiserum at 56 degree C for 30 minutes did not affect the immobilization phenomenon. The immobilization rates decreased by the serial dilution of antiserum. At dilution more than 1:8, the immobilization was almost the same as in the normal serum. The immobilizing antibody in anti-Acanthamoeba culbertsoni rabbit serum showed highest titre in 3rd day after booster immunization and from first to 6th week in anti-Naegleria fowleri rabbit serum. Cross matching of Acanthamoeba culbertsoni and Naegleria fowleri showed antigenic difference of the two species. It is suggested that the immobilization reaction may be of value as a supplementary test in the diagnosis of primary amoebic meningoencephalitis.
parasitology-protozoa ; free-living amoeba ; Naegleria fowleri ; Acanthamoeba culbertsoni ; rabbit ; immunology

Nowadays, inflammatory bowel disease, such as ulcerative colitis and Crohn's disease, is increasing; however, infectious colitis, such as amebic colitis, is decreasing, so many doctors are not apt to be interested in infectious colitis. In addition, recently amebic colitis has been relatively rare in Korea, and the colonoscopic and the pathologic findings of amebic colitis are very similar to those of other inflammatory bowel diseases. As a consequence, the diagnosis is very difficult if the cyst or the trophozoite of the ameba is not found in the stool examination or in the tissue pathology. The authors experienced three cases in which initial diagnoses of tuberculous colitis, ulcerative colitis, and a simple ulcer were made based on colonoscopic and X-ray findings. However a colonoscopic biopsy revealed a trophozoite form of ameba in the tissue. Hence, a diagnosis of amebic colitis could be made with confidence. Based on these results, we insist that infectious colitis should be included in the differential diagnosis when making a diagnosis of inflammatory bowel disease. In addition, it is extremely important to consider all kinds of infectious colitis, such as amebic colitis.
Amoeba ; Biopsy ; Colitis* ; Colitis, Ulcerative ; Crohn Disease ; Diagnosis ; Diagnosis, Differential ; Dysentery, Amebic* ; Inflammatory Bowel Diseases ; Korea ; Pathology ; Trophozoites ; Ulcer

Some cases have reported that amebic colitis leads to serious complications that are caused by a misdiagnosis of an inflammatory bowel disease and consequential ill-managed steroid therapy. Therefore, it should be stressed that the differential diagnosis on such a case is very important. Eosinophilic colitis may reveal its presence as diarrhea, abdominal pain, ascites, and eosinophilic deposits in tissues. Therefore, it is highly necessary to make a differential diagnosis to distinguish eosinophilic colitis from other infectious or inflammatory bowel diseases. We report a case of amebic colitis, which was mistakenly diagnosed as eosinophilic colitis and a liver eosinophilic abscess in a young male who complained of bloody diarrhea and right upper quadrant pain. However, the misdiagnosed steroid therapy did not aggravate the progress of the amebic infection.
Abdominal Pain ; Abscess ; Amoeba ; Ascites ; Colitis ; Diagnosis, Differential ; Diagnostic Errors ; Diarrhea ; Dysentery, Amebic ; Eosinophils ; Humans ; Inflammatory Bowel Diseases ; Liver ; Liver Abscess ; Male ; Steroids

The purpose of this study was to investigate the ability of Acanthamoeba to adhere to the epithelial cells of human cornea. Human corneas, obtained through the eye bank of Catholic Medical Center, were cultured in Optisol solution at 37degreesC. Trophozoites of Acanthamoeba lugdunensis cultured on non-nutrient agar plate were collected to make a suspension in concentration of 1x106/ml. 100microliter of amoeba suspension was added to the epithelial surface of cultured human corneas and each cornea was incubated for 12 hours. Each cornea was examined with scanning and transmission electron microscope. On scanning electron microscopy, trophozoites adhered to each other and to the corneal epithelium, especially to intercellular junction by their extended lobopodia at 12 hour-incubation. On transmission electron microscopy, trophozoites showed limited regions of attachment to the corneal epithelium at 12 hour-incubation, and the attached areas showed desmosome-like structure. Trophozoites adhered to each other by cytoplasmic interdigitation. In conclusion, trophozoites adhere to the corneal epithelial surface by their cytoplasmic processes and their processes appeared to have affinity to intercellular junctions of the corneal epithelium. Attachment regions between corneal epithelium and amoeba were characterized as desmosomelike junctions.
Acanthamoeba* ; Agar ; Amoeba ; Cornea* ; Cytoplasm ; Epithelial Cells ; Epithelium, Corneal* ; Eye Banks ; Humans* ; Intercellular Junctions ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission* ; Organ Culture Techniques ; Pseudopodia ; Trophozoites

The purpose of this study was to investigate the process of Acanthamoeba penetration into the organ-cultured human cornea by scanning and transmission electron microscopy. Human cornea was obtained through the eye bank of Catholic Medical Center and cultured in Optisol solution at at37degrees C. Acanthamoeba lugdunensis was cultured on non-nutrient agar plate and collected to make suspension in concentration of 1 x 106/ml.100 microliterof amoeba suspension was added to the epithelial surface of cultured cornea and each cornea was incubated for 48 and 120 hours. Each cornea was examined by scanning and transmission electron microscopy at each time point. In scanning electron microscopy, Acanthamoeba penetrated into the deep epithelial layer through the intercellular space with progressive epithelial breakdown. In transmission electron microscopically, Acanthamoebapene-trated through the intercellular space of the superficial corneal epithelium and reached to the basement membrane of basal corneal epithelium. Penetrating trophozoites had numerous electronense, mineral-like deposits in their cytoplasm and secreted enzyme-like materials. In conclusion, Acanthamoebae penetrated through the intercellular space of the corneal epithelium by their locomotion and migrated into the deep epithelial layer with secreation of enzyme-like materials and phagocytosis until they reached to the basement membrane of the basal corneal epithelium.
Acanthamoeba* ; Agar ; Amoeba ; Basement Membrane ; Cornea* ; Cytoplasm ; Epithelium, Corneal* ; Extracellular Space ; Eye Banks ; Humans* ; Locomotion ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission* ; Organ Culture Techniques ; Phagocytosis ; Trophozoites

Pathogenic Naegleria fowleri, Acanthamoeba castellanii, and Acanthamoeba polyphaga, are distributed worldwide. They are causative agents of primary amoebic meningoencephalitis or acanthamoebic keratitis in humans, respectively. Trophozoites encyst in unfavorable environments, such as exhausted food supply and desiccation. Until recently, the method of N. fowleri encystation used solid non-nutrient agar medium supplemented with heat-inactivated Escherichia coli; however, for the amoebic encystment of Acanthamoeba spp., a defined, slightly modified liquid media is used. In this study, in order to generate pure N. fowleri cysts, a liquid encystment medium (buffer 1) modified from Page’s amoeba saline was applied for encystation of N. fowleri. N. fowleri cysts were well induced after 24 hr with the above defined liquid encystment medium (buffer 1). This was confirmed by observation of a high expression of differential mRNA of nfa1 and actin genes in trophozoites. Thus, this liquid medium can replace the earlier non-nutrient agar medium for obtaining pure N. fowleri cysts. In addition, for cyst formation of Acanthamoeba spp., buffer 2 (adjusted to pH 9.0) was the more efficient medium. To summarize, these liquid encystment media may be useful for further studies which require axenic and pure amoebic cysts.
Acanthamoeba ; Acanthamoeba castellanii ; Actins ; Agar ; Amoeba* ; Desiccation ; Escherichia coli ; Food Supply ; Humans ; Hydrogen-Ion Concentration ; Keratitis ; Meningoencephalitis ; Methods ; Naegleria fowleri ; RNA, Messenger ; Trophozoites