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Acanthamoeba is free living amoeba consisting of many species that are naturally pathogenic and have been isolated from different environmental sources. The purpose of this study was to determine the prevalence and relative abundance of Acanthamoeba species in soil and water samples within the University of Jos environment and to create public health awareness on the dangers of this parasitic protozoan. The study was conducted in the eleven (11) Faculties of the University of Jos. Soil and water samples were collected from each of the faculties, cultured and morphologically identified for positive samples. In addition, quantitative data on occurrence were examined to help better understand the potential risk to the university community. The prevalence of Acanthamoeba based on the chi-square analysis indicates that there is a significant difference between the number of Acanthamoeba species in the soil and water samples collected (P Acanthamoeba based on the Man-Whitney test indicates that there was no significant difference in the distribution of Acanthamoeba species in the water and soil samples between different faculties (P > 0.05). Morphological identification indicates the presence of probably Acanthamoeba castellani. The demonstration of the presence of Acanthamoeba species in soil and water sources calls for awareness among the clinical community, as cases of keratitis and granulomatous amoebic encephalitis might have never been recorded due to lack of expertise or unawareness amongst the clinical community. An improved treatment of water supply and strict adherence to water act needs to be strictly encouraged.

This study aimed to determine the anti-parasitic activity of the water extract obtained from Thymbra spicata (L.). The plant material was extracted with methanol in a Soxhlet apparatus. The extract was then fractionated with water and chloroform. The water phase was frozen and freeze-dried. Afterward, this extract was applied on A. castellani trophozoites and cysts at various concentrations, and the viability rates were determined by counting under the microscope. At the end of the experimental process, it was determined that there was a strong correlation between the increasing extract concentration and the anti-parasitic effect. T. spicata extract was not effective enough to neutralize all cysts at any of the concentrations examined. T. spicata extract, at concentrations of 16.0 and 32.0 mg/ml, removed all trophozoites in the medium from the 24th h of the experiment. Based on this result, it was determined that the plant species evaluated here could be used to treat A. castellani infections. It will be possible to achieve a good effect on the cyst forms of the parasite species by testing higher extract concentrations, which cannot be evaluated during the experimental process. In addition, with advanced analyzes, it will be possible to reveal the chemical substance responsible for the activity in the plant species in question and to perform further analyzes on this substance.

This study investigated the efficacy of a novel povidone-iodine based disinfection solution for rigid gas permeable (RGP) lenses compared to three other currently available multipurpose and hydrogen peroxide solutions. Bactericidal and fungicidal activities were assessed using ISO 14729 reference methods, whilst amoebicidal properties were evaluated using an automated viability counter. All solutions were also assessed for long term storage stability over a 3-month period. The FDA guidelines were adequately achieved by all solutions tested and 3-month storage did not affect their activity against bacterial and fungal agents. Activity against Acanthamoeba castellani trophozoites reached 1-log reduction for the povidone-iodine solution and approached this level for the remaining solutions. Activity against cysts was somewhat reduced and ranged from 78 to 86% reduction in viability. A povidone-iodine based solution, which may offer advantages as resistance to this agent has not been demonstrated and it lacks toxicity, provided equivalent antimicrobial activity to other RGP solutions.

International audience; We report a case of Acanthamoeba castellani keratitis in a person who wore contact lenses. The amebae hosted an ameba-resistant bacterial symbiont, provisionally named ``Attilina massiliensis,'' a yet undescribed alpha-Proteobacterium.

WOS: 000255728800007, PubMed ID: 18255065, In this study, disinfection of water containing Giardia intestinalis and Acanthamoeba castellani cysts with TiO2 and modified catalyst silver loaded TiO2 (Ag-TiO2) was investigated. Destruction of the parasites was evaluated after UV illumination of the suspension consisting 5 x 10(8)-13.5 x 10(8) cysts/mL in the presence of 2 g/L neat or modified TiO2 at neutral pH. In the initial stage, the solid photocatalyst particles penetrated the cyst wall and then oxidant species produced by TiO2/UV destroyed both cell wall and intracellular structure. In the case of G. intestinalis inactivation (disinfection) performance of TiO2/UV system reached 52.5% only after 25 min illumination and total parasite disinfection was achieved after 30 min illumination. However, silver loaded TiO2 seemed to be more effective as this loading provided better catalytic action as well as additional antimicrobial properties. Cell viability tests showed that parasite cysts, their walls in particular, were irreversibly damaged and cysts did not re-grow. Nevertheless the studied system seemed to be ineffective for the inactivation of A. castellani. Inactivation percentages of TiO2/UV and Ag-TiO2/UV systems were far lower than that of UV alone, being 50.1% and 46.1%, respectively. (C) 2008 Elsevier Inc. All rights reserved.

TEZ12170 Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 2016. Kaynakça (s. 37-40) var. xi, 41 s. :_res. (bzs. rnk.), tablo ;_29 cm. Acanthamoeba türlerinin doğal çevrede serbest halde bulunmasından dolayı, insanların bu parazitle enfekte olma riski büyüktür. Acanthamoeba türleri granülomatöz amibik ensefalit (GAE), kutanöz acanthamoebiasis, Acanthamoeba keratiti oluştururken, AIDS’li hastalarda enfeksiyonun çeşitli organlara yayılmasına bağlı olarak kronik sinüzit, otit, kutanöz lezyonlar, sinüs lezyonları, deri ülserleri gibi hastalıklar meydana getirirler. Bu çalışmada Türkiye’nin Doğu ve Güneydoğu bölgelerinde bulunan Diyarbakır, Batman, Mardin, Siirt, Bitlis ve Van illerindeki yüzme havuzlarından, kaplıca sularından, hamamlardan, sulama kanalından, park ve bahçelerden alınan toplam 65 su ve toprak örneğinin 6 tanesi mikroskobik inceleme yöntemi ile, 11 tanesi kültür yöntemi ile ve 15 tanesi konvansiyonel PCR ve real time PCR yöntemi ile Acanthamoeba spp. pozitif bulundu. Çalışmada Acanthamoeba spp. laboratuvar tanı yöntemlerinden kültür metodu; mikroskobi, konvansiyonel PCR ve real time PCR yöntemleri ile karşılaştırıldı. Kültür yönteminin mikroskobi, konvansiyonel PCR ve real time PCR yöntemlerine göre duyarlılığı sırası ile %100, %73,33, %73,33 ve özgüllüğü sırası ile%91,53,%100, %100 olarak saptandı. İncelenmesi yapılan ve Acanthamoeba spp. tanısı alan 15 örneğin kist yapılarını ve moleküler analizlerini değerlendirdiğimizde 4 (%26,67) Acanthamoeba castellanii, 3 (%20) Acanthamoeba polyphaga ve 8 tanesinin (%53,33) Acanthamoeba palestinensis olduğu belirlendi. Çalışmamız Güneydoğu Anadolu bölgesinde yapılan Acanthamoeba spp. ile ilgili ilk saha çalışması olup Acanthamoeba keratiti için doğal çevrede risk oluşturan türler tanımlandı. Due to the presence of Acanthamoeba species in the natural environment, people at risk of becoming infected with this parasite. Acanthamoeba species occur such as granulomatous amoebic encephalitis (GAE), cutaneous acanthamoebiasis, Acanthamoeba keratitis, AIDS, chronic sinusitis due to spread to various organs of the infection in patients with otitis, cutaneous lesions, sinus lesions,and skin ulcers. In this study, It was collected 65 water and soil samples from the environment in East and South East Anatolia regions located in Diyarbakir, Batman, Mardin, Siirt, Bitlis and Van provinces in Turkey of the swimming pool in the thermal springs, the baths, the irrigation canals, parks and the gardens. Six, 11 and 15 Acanthamoeba species found by microscopic examination, culture and conventional PCR and real time PCR methods, respectively. The sensitivity and specificity of culture methods were compared with microscopy, conventional PCR and real time PCR method for Acanthamoeba spp.; The sensitivity was found as 100%, 73,33%, 73,33% and specificity was found as 91,53%, 100% and 100%, respectively. When the investigation made and positively found by culture and molecular analysis 15 samples were evaluated in 4 (%26,67) Acanthamoeba castellanii, in 3 (%20) with Acanthamoeba polyphaga and in 8 (%53,33) with Acanthamoeba palestinensis. This is the first field study was conducted in South-East Anatolia on Acanthamoeba spp. at the molecular level and the positive samples were genotyped from the natural environment that pose a risk for Acanthamoeba keratitis.

Legionele su fakultativni unutarstanični patogeni koji parazitiraju unutar slobodno-živućih ameba i zbog povoljnih uvjeta, razmnožavaju u velikom broju. Prilagođene su na život u vodenom okolišu, no sposobne su živjeti i u tlu (Legionella longbeachae). Upravo sposobnost unutarstaničnog razmnožavanja u alveolarnim makrofazima, ključna je za pojavu legionarske bolesti najčešće uzrokovane vrstom Legionella pneumophila. Uz amebe i alveolarne makrofage, spomenuti unutarstanični patogeni se razmnožavaju i unutar različitih staničnih linija kao što su alveolarne epitelne (A549) stanice. Cilj ovog istraživanja bio je ispitati utjecaj sušenja na kultivabilnost, vijabilnost i patogenost dviju vrsta bakterija roda Legionella. Kultivabilnost je praćena nasađivanjem na BCYE podlozi, vijabilnost LIVE/DEAD tehnikom fluorescentnog bojenja, a patogenost kokultivacijom VBNC oblika bakterija s Achantamoeba castellanii i infekcijom A549 stanica. U ovom istraživanju, bakterije su pripremljene u sterilnoj vodi. Po 20 μl bakterijske suspenzije (~10(8) CFU/ml) nakapano je na mikrotitar pločicu u 5 rupica te izloženo laminarnom strujanju zraka u sterilnoj komori kroz 1 sat. Sušene bakterije, kao i kontrolna bakterijska suspenzija u vlažnim uvjetima, čuvane su na sobnoj temperaturi. U različitim vremenskim intervalima, bakterije su rehidrirane i kultivirane na BCYE agaru. Bakterijske stanice izložene sušenju dodane su A. castellanii i inkubirane 48 sati u PAGE mediju. Inkubacija A549 stanica inficiranih bakterijskim stanicama izloženima sušenju trajala je 2 sata nakon čega su razarane i nasađivane u deseterostrukim razrijeđenjima na BCYE podlogama. 3, 7 i 10 dan sušenja bakterijske suspenzije ispitivana je vijabilnost LIVE/DEAD tehnikom fluorescentnog bojenja. Nakon rehidracije obje vrste moguće je kultivirati na BCYE agaru samo nakon 1 dana izlaganja sušenju. Nakon 15 dana sušenja legionele su sposobne inficirati amebe i razmnožavati se unutar njih, dok u kulturi alveolarnih epitelnih stanica (A549) i L. pneumophila i L. longbeachae adheriraju i internaliziraju do 4 dana nakon izlaganja suhim uvjetima. LIVE/DEAD postupkom dokazano je kako obje vrste legionela i deseti dan nakon što su bile izložene sušenju, zadržavaju svojstvo vijabilnosti. Izlaganjem suhim uvjetima, L. pneumophila i L. longbeachae brzo gube kultivabilnost, ali svojstvo vijabilnosti i patogenosti zadržavaju 15 dana nakon podvrgavanja sušenju zbog čega mogu predstavljati opasnost za ljude.

WOS: 000302814700023, PubMed ID: 22037826, Amoebic keratitis is difficult to treat without total efficacy in some patients because of cysts, which are less susceptible than trophozoites to the usual treatments. The aim of this study is to evaluate the in vitro amoebicidal activity of the methanolic extracts of Teucrium polium and Teucrium chamaedrys. In the presence of methanolic extracts (ranging from 1.0 to 32.0 mg/ml), numbers of the viable Acanthamoeba castellani trophozoites and cysts were decreased during the experimental process. Both extracts showed time- and dose-dependent amoebicidal action on the trophozoites and cysts. Among the extracts tested, T. chamaedrys showed the strongest amoebicidal effect on the trophozoites. In the presence of 16 mg/ml or above extract concentrations, no viable trophozoites were observed within 48 h. In the case of T. polium, no viable trophozoites were observed within 48 h at 32 mg/ml concentration. As expected, cysts were found more resistant to the extracts than the trophozoites., Research Council of Cumhuriyet University (CUBAP), Sivas-TURKEY [F-346], This study is financially supported by the Research Council of Cumhuriyet University (CUBAP), Sivas-TURKEY with the project number of F-346.

Limited evidence exists to suggest that the ability to invade and escape protozoan host cell bactericidal activity extends to members of the Chlamydiaceae, intracellular pathogens of humans and animals and evolutionary descendants of amoeba-resisting Chlamydia-like organisms. PCR and microscopic analyses of Chlamydophila abortus infections of Acanthamoeba castellani revealed uptake of this chlamydial pathogen but, unlike the well-described inhabitant of A. castellani, Parachlamydia acanthamoebae, Cp. abortus did not appear to propagate and is likely digested by its amoebal host. These data raise doubts about the ability of free-living amoebae to serve as hosts and vectors of pathogenic members of the Chlamydiaceae but reveal opportunities, via comparative genomics, to understand virulence mechanisms used by Chlamydia-like organisms to avoid amoebal digestion.

Attachment of Acanthamoeba species to hydrogel contact lenses is a possible route of infection in Acanthamoeba keratitis. In this study, Acanthamoeba adsorption was compared with extent of lens deposition in worn lenses of different hydrogel polymers. After wear, lenses (80 lenses of 5 different types) were analyzed for total protein, surface area of deposition, and Acanthamoeba castellani trophozoite and cyst adsorption. Adsorption of Acanthamoeba trophozoites to worn lenses was greater than adsorption to unworn lenses for four of the five lens polymers (p0.01). Adsorption of cysts was greater for one of the five lens polymers (p0.001); all other adsorption assays showed no change with wear (p0.05). Adsorption was affected by both the water content and ionicity of the lens polymer. These results show that adsorption of Acanthamoeba to worn hydrogel contact lenses is greater than or equal to adsorption to unworn lenses.

MICROBIOLOGY The soil fungus Cryptococcus neoformans can enter and persist within human macrophages, causing virulent infections if the person becomes immunocompromised. This fungus need not infect a vertebrate in order to complete its life cycle, so its pathogenicity is puzzling. A clue to its virulence may come from its life in soil, where predatory microorganisms, such as amoebas, are present. Steenbergen et al. have discovered remarkable parallels between the defensive strategies used by C. neoformans when eaten by Acanthamoeba castellani and when surviving in human cells. Amoebas ingest the fungal cells, but the cells remain within vacuoles and produce a toxic polysaccharide, as they do when residing within macrophage vacuoles. The engulfed fungus possesses other unfriendly characteristics also exhibited during macrophage infection, and it ultimately kills its host amoeba, whose death releases vital nutrients. Other soil fungi, such as Histoplasma capsulatum , that cause potentially fatal human infections are probably similarly armed because they, too, must run the gauntlet of voracious amoebas. — CA Proc. Natl. Acad. Sci. U.S.A. 98 , 15245 (2001).

Along general lines, the fine structure of the Acanthamoeba castellani Sn cell corresponds to the aspects described by other authors in the free forms. Of particular interest was the presence in the amoeba cytoplasm of some free formations, with a cell envelop and internal bacteria-like structure. The presence of these bacterial bodies free in the amoeba cytoplasm and without a surrounding host cell membrane as well as the aspects suggestive of cell division, led the authors to consider them as integrated in the Acanthamoeba Sn economy, correlating them with bacterial endosymbionts. Similar endosymbionts have not yet been described in Acanthamoeba and might be implicated in the pathogenic potential of the Sn strain.

• An irritated left eye followed by a geographic epithelial corneal defect developed in a 42-year-old man. Disciform edema developed in the cornea, and the lesion progressed to a ring-shaped abscess. The lesion failed to respond to medical therapy. After two penetrating keratoplasties, histopathologic examination and electron microscopic studies established the diagnosis of Acanthamoeba keratitis. Subsequent cultures and immunofluorescent studies identified the organism as Acanthamoeba castellani . Following treatment with antibiotics and corneal cryotherapy, there has been no evidence of recurrence. Morphologically and immunologically identical amebae were also cultured from the patient's hot tub and surrounding garden.

Nero , L. C. (Illinois Institute of Technology, Chicago), Mae G. Tarver, and L. R. Hedrick . Growth of Acanthamoeba castellani with the yeast Torulopsis famata . J. Bacteriol. 87: 220–225. 1964.— Acanthamoeba castellani and Torulopsis famata cells were cultured together for 10 days at three different temperatures: 18, 25, and 32 C. In the 18- and 25-C series, the yeast population reached a peak within 3 to 5 days and then declined for the next 5 days. This decrease in yeast population corresponded with an increase in the development of amoebae, which first appeared as vegetative cells and later transformed themselves into cysts. The changes in population were determined by counts in a hemocytometer. The vegetative amoeba population seldom exceeded 4 × 10 7 cells per bottle culture, but the encysted population approached 16 × 10 7 cysts per bottle culture within 10 days of incubation. The amoebae actively ingested the yeasts and used these cells as their principal source of energy. At 18 C each amoeba consumed 70 yeast cells per day; at 25 C each amoeba ingested 35 yeast cells per day. In the 32-C series, both the yeast and the amoebae had slow growth rates. The development of cysts corresponded with the growth of the yeast population without the rapid increase in yeast population prior to the growth of the amoebic cells.

• Trophozoites and cysts of amebas were found within the necrotic cornea of an enucleated eye. The organism was identified, by indirect immunofluorescent staining using specific antiserum, to beAcanthamoeba castellani. This case report illustrates the difficulty of clinical diagnosis and typical inefficacy of medical therapy shown in other reports of this rare keratitis.

A low molecular weight RNA has been identified as a constituent of the large rRNA (26 s rRNA) in the free-living amoeba, Acanthamoeba castellani, by using treatments designed to disrupt complementary base pairing (e.g. brief heating, dimethylsulfoxide, low salt or low pH, etc.). The molecular size of the low molecular weight RNA, estimated from its mobility on polyacrylamide gels, is 4.3 × 104 daltons. Additionally, exposure of 26 s rRNA to the above treatments led to the observation that the remainder of the molecule is discontinuous and composed of two sharply defined RNA species with mobilities on polyacrylamide gels corresponding to molecular weights of 0.88 × 106 and 0.60 × 106 daltons. The larger rRNA derived from the dissociation of the 26 s rRNA (i.e. 0.88 × 106 daltons) is identical in size to the rRNA characteristic of the small ribosomal subunit. The demonstration of low molecular weight RNA in the large rRNA of a single-celled eukaryote supports the suggestion that low molecular weight RNA may represent a distinct evolutionary difference between prokaryotes and eukaryotes. Moreover, the discontinuity of the remainder of the 26 s rRNA in A. castellani indicates that further modification of the large rRNA may have occurred during evolution of eukaryotic organisms.

• The effects of cryotherapy and antibiotics (paromomycin, neomycin, or propamidine isethionate) on the viability of Acanthamoeba polyphaga and Acanthamoeba castellani cysts were studied in vitro. Either cryotherapy or exposure to antibiotic led to a decrease in the number of viable A castellani detected; A polyphaga showed variable response to the antibiotics tested. The combination of cryotherapy and antibiotic therapy was more cysticidal than either modality alone and eliminated detectable viable organisms in five of six experiments. Of the antibiotic solutions tested, paromomycin (15 mg/mL) was the most effective.

Axenic Acanthamoeba castellani (Douglas) were grown both on nutritionally adequate, and on inadequate media to test effects of starvation on form and movement. No significant effects on shape of or function of pseudopods, other than decrease in size, were noted, nor on the mechanics of locomotion, unless the amebas were moribund. Wellfed amebas when starved decreased in mass, but not in length, implying there is a nonshrinking pellicular covering present which is important in locomotive function and pseudopodal formation. The pellicle is proven to be present. Some observations on burrowing forms, and encystment and excystment are included. During development of techniques to acquire bacteria-free clones of Acanthamoeba castellani (Douglas), we2 saw apparent changes in the size and peripheral proportions of that ameba in starving cultures. Some morphological changes in body proportions and contours of amebas have been misconstrued, and confused with the specific differences more properly related to formation and deployment of the organelles of locomotion (i.e., the pseudopodal complexes) (Kudo, 1954; Verworn, 1893). Therefore I experimented further with this ameba, determining what, if any, real as well as seeming changes developed in its morphology when well-fed, poorly-fed and starved. MATERIALS AND METHODS I collected the original specimens of my clones of Acanthamoeba castellani from Hogtown Creek at Northwest 22nd Street in suburban Gainesville, Florida. It grew well nonclonally on nutrient agars (Bovee. 1960a; Neff, 1957), in petri dishes with "wild" bacteria as food. A clone was later grown from a single cyst with Aerobacter aerogenes as food. Ultimately the clone was established bacteria-free by Harrison's (1957) antibiotic disc technique, and was grown in Neff's (loc. cit.) solution. Daughter clones were partially starved by planting them on lownutrient agars which limited growth of the bacterial food. Others were intensely starved on low nutrient agars with added antibiotics 1 Supported by NIH Research Grant E-1 158. 2 I wish to express my appreciation to Dr. Jacqueline A. Hynes, now at the University of California, Los Angeles, whose invaluable assistance in growing these cultures of amebas, and others, contributed much to the progress of the