Acanthamoebae are free-living amoebae found in the environment, including soil, freshwater, brackish water, seawater, hot tubs, and Jacuzzis. Acanthamoeba species can cause keratitis, a painful vision-threatening infection of the cornea, and fatal granulomatous encephalitis in humans. More than 20 species of Acanthamoeba belonging to morphological groups I, II, and III distributed in 15 genotyp...

Cultures of 10 different bacteria were used to serve as food sources for axenically grown Acanthamoeba castellanii, Acanthamoeba polyphaga, and Hartmannella vermiformis. The nonpigmented enterobacteriaceae Escherichia coli K-12 and Klebsiella aerogenes appeared to be excellent feed to all three amoebae. Hardly any growth or ammonium production was observed in tests with Chromatium vinosum and S...

PURPOSE To identify host-tissue amoeba interactions that may be important in the pathogenesis of Acanthamoeba keratitis, the ability of the opportunistic pathogen Acanthamoeba polyphaga to bind various components of the extracellular matrix (collagen type IV, laminin, or fibronectin) was examined in vitro. METHODS A polyphaga, isolated from a case of human amoebic keratitis, was used in the s...

Drinking water (DW) biofilm communities influence the survival of opportunistic pathogens, yet knowledge about the microbial composition of DW biofilms developed on common in-premise plumbing material is limited. Utilizing 16S and 18S rRNA gene pyrosequencing, this study characterized the microbial community structure within DW biofilms established on unplasticized polyvinyl chloride (uPVC) and...

Introduction Definition Free-living amebae of the genera Naegleria, Acanthamoeba, and Balamuthia cause fatal diseases of the central nervous system (CNS) of humans.1-33 Naegleria fowleri causes an acute and fulminant primary amebic meningoencephalitis (PAM) in children and young adults with a history of exposure to fresh water leading to death within 5 to 10 days after the onset of symptoms.4-6...

Abstract With some 3,700 described species, Dryopoidea are a moderately diverse superfamily of beetles whose position within basal Polyphaga has been historically difficult to elucidate. Members most extant dryopoid families set apart from the majority other polyphagans by their association with aquatic habitats, but little is known about origin these derived life habits and phylogeny superfami...

The incidence of Acanthamoeba keratitis, a disease associated with contact lens wear, has been in apparent decline with the advent of multipurpose contact lens solutions. The concentrations of the biguanides chlorhexidine digluconate (CHX) and particularly polyhexamethylene biguanide (PHMB) included in multipurpose solutions (MPSs) are sublethal for amoebae. We evaluated by flow cytometry the e...

Viral infection had not been observed for amoebae, until the Acanthamoeba polyphaga mimivirus (APMV) was discovered in 2003. APMV belongs to the nucleocytoplasmatic large DNA virus (NCLDV) family and infects not only A. polyphaga, but also other professional phagocytes. Here, we review the Megavirales to give an overview of the current members of the Mimi- and Marseilleviridae families and thei...

PURPOSE To characterize better the ameba-host interactions that may be involved with the pathogenesis of Acanthamoeba keratitis, the role of calcium (Ca2+) on the binding of Acanthamoeba polyphaga to extracellular matrix proteins was examined in vitro. METHODS The binding of a metabolically labeled A. polyphaga (CDC:0187:1) isolate from a case of human keratitis to collagen type IV, laminin, ...

We recently described a giant double stranded DNA virus called Mimivirus, isolated from amoebae, which might represent a new pneumonia-associated human pathogen. Its unique morphological and genomic characteristics allowed us to propose Mimivirus as a member of a new distinct Nucleocytoplasmic Large DNA viruses family, the Mimiviridae. Mimivirus-specific features, namely its size and its genomi...