Prevalence and seasonal variation of Acanthamoeba in domestic tap water in greater Sydney, Australia.

Background: This study examined the prevalence of free-living Acanthamoeba in domestic tap water in the greater Sydney region, Australia, and determined any seasonal variation in prevalence.

Methods: Fifty-four participants were included in this study following approval from an institutional human research ethics committee. Each participant self-collected two samples (one in summer and another in winter) from the surface of the drain of the bathroom sink using an instructional kit.

The relationship between environmental sources and the susceptibility of Acanthamoeba keratitis in the United Kingdom.

Purpose: To determine whether Acanthamoeba keratitis (AK) patients have higher rates of Acanthamoeba and free-living amoeba (FLA) colonising domestic sinks than control contact lens (CL) wearers, and whether these isolates are genetically similar to the corneal isolates from their CL associated AK.

Methods: 129 AK patients from Moorefield Eye Hospital, London and 64 control CL wearers from the Institute of Optometry were included in this study. The participants self-collected home kitchen and bathroom samples from tap-spouts, overflows and drains using an instructional kit.

Antimicrobial efficacy of a novel povidone iodine contact lens disinfection system.

Purpose: Contact lens (CL) wear is a risk factor for the acquisition of microbial keratitis. Accordingly, compliance to manufacturers' recommended hygiene and disinfection procedures are vital to safe (CL) use. In this study we evaluated a novel povidone-iodine (PI) (CL) disinfection system (cleadew, Ophtecs Corporation, Japan) against a range of bacterial, fungal and Acanthamoeba.

Fibrous Catalyst-Enhanced Acanthamoeba Disinfection by Hydrogen Peroxide.

Significance: Hydrogen peroxide (H2O2) disinfection systems are contact-lens-patient problem solvers. The current one-step, criterion-standard version has been widely used since the mid-1980s, without any significant improvement. This work identifies a potential next-generation, one-step H2O2, not based on the solution formulation but rather on a case-based peroxide catalyst.

The Characterization of an Adrenergic Signalling System Involved in the Encystment of the Ocular Pathogen Acanthamoeba spp.

The aim of this study was to identify and characterize the receptor system involved in controlling encystment in Acanthamoeba using specific agonists and antagonists and to examine whether endogenous stores of catecholamines are produced by the organism. Acanthamoeba trophozoites suspended in axenic growth medium were exposed to adrenoceptor agonists and antagonists to determine which compounds promoted or prevented encystment. Second, trophozoites were cultured in medium containing a catecholamine synthesis inhibitor to investigate the effect this had on natural encystment.

Autofluorescence Signatures of Seven Pathogens: Preliminary in Vitro Investigations of a Potential Diagnostic for Acanthamoeba Keratitis.

Purpose: Acanthamoeba keratitis can cause devastating damage to the human cornea and is often difficult to diagnose by routine clinical methods. In this preliminary study, we investigated whether Acanthamoeba may be distinguished from other common corneal pathogens through its autofluorescence response. Although only a small number of pathogens were studied, the identification of a unique Acanthamoeba signature would indicate that autofluorescence spectroscopy as a diagnostic method merits further investigation.

The in vitro efficacy of antimicrobial agents against the pathogenic free-living amoeba Balamuthia mandrillaris.

The free-living amoeba Balamuthia mandrillaris causes usually fatal encephalitis in humans and animals. Only limited studies have investigated the efficacy of antimicrobial agents against the organism. Assay methods were developed to assess antimicrobial efficacy against both the trophozoite and cyst stage of B.

Development of standardized methods for assessing biocidal efficacy of contact lens care solutions against Acanthamoeba trophozoites and cysts.

Purpose: To investigate experimental variables in the development of standardized methods to assess the efficacy of contact lens disinfection systems against the trophozoite and cysts of Acanthamoeba spp.

Methods: A. castellanii (ATCC 50370), A.

Resistance and growth of Fusarium species in contact lens disinfectant solutions.

Purpose: To compare the biocidal efficacy of contact lens care solutions against clinical isolates and the American Type Culture Collection (ATCC) 36031 reference strain of Fusarium species and to determine the ability of the organism to survive and grow in such systems.

Methods: The ISO 14729 reference method to assess biocidal efficacy was applied to the purified conidial form of 10 strains of Fusarium species. Six multipurpose disinfectant solutions (MPDSs), a one-step hydrogen peroxide (Per-1) system, a hydrogen peroxide-sodium chlorite (Per-2) system, and a one-step povidone iodine (PI) system were compared.

Identification and susceptibility to multipurpose disinfectant solutions of bacteria isolated from contact lens storage cases of patients with corneal infiltrative events.

Corneal infiltrative events (CIEs) are being reported with increasing frequency in lens wearers and may be related to specific multipurpose disinfecting solution (MPDS), contact lens type or bacterial bio-burden. Here, the efficacy of MPDS's against bacteria from contact lens storage cases (CLSC) of patients with CIEs was investigated. Eighteen CLSC from patients with CIEs were cultured.

The efficacy of simulated solar disinfection (SODIS) against coxsackievirus, poliovirus and hepatitis A virus.

The antimicrobial activity of simulated solar disinfection (SODIS) against enteric waterborne viruses including coxsackievirus-B5, poliovirus-2 and hepatitis A virus was investigated in this study. Assays were conducted in transparent 12-well polystyrene microtitre plates containing the appropriate viral test suspension. Plates were exposed to simulated sunlight at an optical irradiance of 550 Wm(-2) (watts per square metre) delivered from a SUNTEST™ CPS+ solar simulator for 6 hours.

Development of a rapid DNA extraction method and one-step nested PCR for the detection of Naegleria fowleri from the environment.

Naegleria fowleri is a small free-living amoebo-flagellate found in natural and manmade thermal aquatic habitats worldwide. The organism is pathogenic to man causing fatal primary amoebic meningoencephalitis (PAM). Infection typically results from bathing in contaminated water and is usually fatal.

The efficacy of simulated solar disinfection (SODIS) against Ascaris, Giardia, Acanthamoeba, Naegleria, Entamoeba and Cryptosporidium.

The antimicrobial activity of simulated solar disinfection (SODIS) in the presence and absence of riboflavin against various protozoa and helminth organisms was investigated in this study. Assays were conducted in transparent 12 well microtitre plates containing a suspension of test organisms in the presence or absence of 250 μM riboflavin. Plates were exposed to simulated sunlight at an optical irradiance of 550 Wm(-2) (watts per square metre) delivered from a SUNTEST™ CPS+ solar simulator.

Development of a nested PCR for environmental detection of the pathogenic free-living amoeba Balamuthia mandrillaris.

A DNA extraction and nested PCR method for detecting the pathogenic amoeba Balamuthia mandrillaris from the environment was developed. Sixteen of 17 Californian soil samples were positive compared with 0/44 from the United Kingdom. This approach will enable a greater understanding of B.

Antimicrobial efficacy of multi-purpose contact lens disinfectant solutions following evaporation.

Purpose: Non-compliance is a significant factor in contact lens related microbial keratitis and includes solution reuse and failure to recap the lens storage case resulting in evaporation effects. To address this, impact of partial evaporation on the antimicrobial efficacy of multipurpose contact lens care solutions was investigated.

Methods: Solutions were evaporated under a stream of air to 2× and 4× concentration and challenged with Fusarium solani (ATCC 36031), Candida albicans (ATCC 10231) and Acanthamoeba castellanii (ATCC 50370).

Antimicrobial activity of simulated solar disinfection against bacterial, fungal, and protozoan pathogens and its enhancement by riboflavin.

Riboflavin significantly enhanced the efficacy of simulated solar disinfection (SODIS) at 150 watts per square meter (W m(-2)) against a variety of microorganisms, including Escherichia coli, Fusarium solani, Candida albicans, and Acanthamoeba polyphaga trophozoites (>3 to 4 log(10) after 2 to 6 h; P < 0.001). With A.

Acidified nitrite enhances hydrogen peroxide disinfection of Acanthamoeba, bacteria and fungi.

Objectives: In the human innate immune system, stimulated phagocytes release reactive nitrogen intermediates that can react with superoxide to form the powerful oxidant peroxynitrite and other less abundant species. In this study, the efficacy of hydrogen peroxide (H2O2) and acidified nitrite (NaNO2) alone and in combination was compared against a variety of bacteria, fungi and protozoa.

Methods: Challenge test assays based on the international standard (ISO 14729) were used to determine the antimicrobial activity of H2O2 and acidified NaNO2 at pH 5 alone and in combination against Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, Mycobacterium aurum, Bacillus subtilis spores, Candida albicans, Fusarium solani conidia and Acanthamoeba polyphaga trophozoites and cysts.

The disinfection efficacy of MeniCare soft multipurpose solution against Acanthamoeba and viruses using stand-alone biocidal and regimen testing.

Purpose: To assess the disinfection efficacy of MeniCare Soft contact lens multipurpose solution against Acanthamoeba and viruses in suspension and when inoculated on to contact lenses and subjected to rub-and-rinse or no-rub-and-rinse care regimes.

Methods: MeniCare Soft was challenged with Acanthamoeba spp trophozoites or cysts, herpes simplex virus (type 1), adenovirus (type 8), and poliovirus (type 2) and the log reduction in Acanthamoeba viability and viral infectivity determined over time. In addition, contact lenses were incubated with Acanthamoeba and viruses and the number of viable organisms determined after the lenses were processed using rub-and-rinse or no-rub-and-rinse care regimes followed by a 4 hr soaking time.

Acanthamoeba keratitis: diagnosis and treatment update 2009.

Purpose: To describe the current management of Acanthamoeba keratitis (AK).

Design: A perspective based on the literature and author experience.

Results: Early diagnosis and appropriate therapy are key to a good prognosis.

A comparison of regimen methods for the removal and inactivation of bacteria, fungi and Acanthamoeba from two types of silicone hydrogel lenses.

Purpose: To compare the antimicrobial efficacy of commercial contact lens solutions when used according to the manufacturers' recommended regimens with two types of silicone hydrogel lenses.

Methods: Four multipurpose contact lens care solutions were examined, representing manufacturer recommended regimens of "rub & rinse", "no rub, rinse" or "no rub, no rinse". Test organisms were Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, Fusarium solani, Candida albicans and Acanthamoeba castellanii (trophozoites and cysts).

Encystment of Acanthamoeba during incubation in multipurpose contact lens disinfectant solutions and experimental formulations.

Objectives: Acanthamoeba keratitis (AK) is most commonly found in contact lens wearers with poor lens care hygiene. Recent reports have indicated an increase in cases of AK in the United States associated with the use of Complete MoisturePlus multipurpose solution. This association may not appear explainable by differences in Acanthamoeba kill rates among multipurpose solutions.

Solar disinfection of poliovirus and Acanthamoeba polyphaga cysts in water - a laboratory study using simulated sunlight.

Aims: To determine the efficacy of solar disinfection (SODIS) in disinfecting water contaminated with poliovirus and Acanthamoeba polyphaga cysts.

Methods And Results: Organisms were subjected to a simulated global solar irradiance of 850 Wm(-2) in water temperatures between 25 and 55 degrees C. SODIS at 25 degrees C totally inactivated poliovirus after 6-h exposure (reduction of 4.

Efficacy of multipurpose solutions against Acanthamoeba species.

Aim: The disinfection efficacy of contact lens multipurpose solutions (MPSs) against Acanthamoeba polyphaga (Ros) and Acanthamoeba castellanii (ATCC30868) cysts and trophozoites was determined by both biocidal and manufacturer-recommended no-rub/rinse regimen testing.

Methods: A biocidal assay using four MPSs (ReNu with MoistureLoc, Opti-free Express, Solo-care Plus, and Complete MoisturePlus) was conducted with or without the presence of organic soil. A second test procedure compared the ability of five MPSs (ReNu with MoistureLoc MPS, ReNu MultiPlus, Opti-free Express, Solo-care Aqua, and Complete MoisturePlus) to remove and kill Acanthamoeba species cysts and trophozoites from SofLens 38 and Surevue conventional hydrogel lenses, and Focus Night & Day silicone hydrogel lenses using the manufacturer-recommended regimen.

Solar and photocatalytic disinfection of protozoan, fungal and bacterial microbes in drinking water.

The ability of solar disinfection (SODIS) and solar photocatalytic (TiO(2)) disinfection (SPC-DIS) batch-process reactors to inactivate waterborne protozoan, fungal and bacterial microbes was evaluated. After 8 h simulated solar exposure (870 W/m(2) in the 300 nm-10 microm range, 200 W/m(2) in the 300-400 nm UV range), both SPC-DIS and SODIS achieved at least a 4 log unit reduction in viability against protozoa (the trophozoite stage of Acanthamoeba polyphaga), fungi (Candida albicans, Fusarium solani) and bacteria (Pseudomonas aeruginosa, Escherichia coli). A reduction of only 1.