Effect of low concentrations of benzalkonium chloride on acanthamoebal survival and its potential impact on empirical therapy of infectious keratitis.

Importance: The significant antiacanthamoebal effect of benzalkonium chloride, at or below concentrations used for preservation of common ophthalmic preparations, should be understood both when choosing empiric antibiotic therapy for infectious keratitis and when assessing the persistent rise in Acanthamoeba cases in the United States since 2003.

Objective: To characterize the antiacanthamoebal efficacy of low concentrations of benzalkonium chloride (BAK) for drug preservation and therapeutic effect against Acanthamoeba.

Design: Experimental study with a review of the literature.

The effect of contact lens materials on disinfection activity of polyquaternium-1 and myristamidopropyl dimethylamine multipurpose solution against Staphylococcus aureus.

Objectives: This study examined the interaction of seven different lens materials with a multipurpose solution (MPS) containing the disinfectants polyquaternium-1 (0.001%) and myristamidopropyl dimethylamine (0.0005%).

Material properties that predict preservative uptake for silicone hydrogel contact lenses.

Objectives: To assess material properties that affect preservative uptake by silicone hydrogel lenses.

Methods: We evaluated the water content (using differential scanning calorimetry), effective pore size (using probe penetration), and preservative uptake (using high-performance liquid chromatography with spectrophotometric detection) of silicone and conventional hydrogel soft contact lenses.

Results: Lenses grouped similarly based on freezable water content as they did based on total water content.

Impact of contact lens materials on multipurpose contact lens solution disinfection activity against Fusarium solani.

Objective: To investigate the effects of eight different soft contact lenses on disinfection efficacy of a multipurpose solution (MPS) containing polyhexamethylene biguanide (PHMB) against Fusarium solani.

Methods: Six silicone hydrogel lenses (galyfilcon A, senofilcon A, comfilcon A, enfilcon A, balafilcon A, and lotrifilcon B) and two conventional hydrogel lenses (polymacon and etafilcon A) were placed in polypropylene lens cases filled with MPS containing 0.0001% PHMB and soaked for 6, 12, 24, 72, and 168 hours.

The effects of contact lens materials on a multipurpose contact lens solution disinfection activity against Staphylococcus aureus.

Objectives: To determine the effect of 8 different lens materials on polyhexamethylene biguanide (PHMB) concentration in multipurpose solution (MPS) levels over time and to determine the effect of lenses on lens solution microbial efficacy over time.

Methods: Silicone hydrogel lenses and conventional hydrogel lenses were soaked in polypropylene lens cases filled with contact lens MPS containing 1 ppm PHMB for 6, 12, 24, 72, and 168 hours. Cases filled with the same solution without lenses were controls.

Strategies to optimize conditions for testing multipurpose contact lens solution efficacy against Acanthamoeba.

Objectives: To optimize the growth, culture, and life cycle conditions for testing multipurpose solutions (MPS) against Acanthamoebatrophozoites and cysts to better inform the development of an appropriate test protocol.

Methods: Two strains of Acanthamoeba castellanii were grown using 2 different methods, bacterized and axenic. Amoebae grown from both methods and from both strains were treated with 4 different MPS as trophozoites and cysts, which were generated using 4 encystment methods.

Successful treatment of chronic stromal acanthamoeba keratitis with oral voriconazole monotherapy.

Purpose: To describe the treatment of chronic stromal Acanthamoeba keratitis (AK) with oral voriconazole monotherapy.

Methods: All cases of chronic stromal AK recalcitrant to traditional therapy subsequently treated with systemic voriconazole seen at the University of Illinois Eye and Ear Infirmary between June 2003 and July 2009 were reviewed for clinical presentation, clinical course, and outcome.

Results: Three eyes of 2 patients were identified with culture-confirmed chronic stromal AK unresponsive to traditional antiacanthamoebal therapies, requiring topical corticosteroids to maintain corneal clarity.

Isolation, morphologic, serologic and molecular identification of Acanthamoeba T4 genotype from the liver of a Temminck's tragopan (Tragopan temminckii).

Members of the genus Acanthamoeba are usually free-living amoebae that are found in a variety of ecological niches including soil, fresh and brackish water, dust in the air, heating, ventilating, and air conditioning filters, swimming pools and hot tubs. Occasionally they are also known to cause central nervous system infections in humans and animals. We isolated into culture an amoeba from the liver of a Temminck's tragopan (horned pheasant) (Tragopan temminckii) that died of amoebic infection.

Polymicrobial keratitis: Acanthamoeba and infectious crystalline keratopathy.

Purpose: To report the early presentation, cause, and successful medical management of combined Acanthamoeba keratitis (AK) and infectious crystalline keratopathy (ICK).

Design: Interventional case series.

Methods: Retrospective review of 111 AK patients diagnosed and managed at the University of Illinois Eye and Ear Infirmary between June 1, 2003 and November 30, 2008 for an additional diagnosis of infectious keratitis.

The relative value of confocal microscopy and superficial corneal scrapings in the diagnosis of Acanthamoeba keratitis.

Purpose: To compare the relative diagnostic value of confocal microscopy and superficial corneal cultures in the diagnosis of Acanthamoeba keratitis by using clinical and microbiologic definitions of disease.

Methods: Results of confocal microscopy, superficial corneal smear, and superficial corneal culture were analyzed for validity against 2 different microbiologic and a clinical composite standard for Acanthamoeba keratitis.

Results: In patients with both clinical characteristics and objective evidence of Acanthamoeba keratitis, confocal microscopy exhibited a sensitivity of 90.

Efficacy of contact lens systems against recent clinical and tap water Acanthamoeba isolates.

Purpose: A recent increase in Acanthamoeba keratitis (AK) cases has been associated with Complete MoisturePlus, although many cases used other solutions. Complete MoisturePlus contains taurine and hydroxypropyl methylcellulose, unlike other multipurpose solutions (MPSs). The purpose of this study is to (1) determine contact lens solution efficacy against recent clinical and tap water Acanthamoeba isolates and (2) determine whether taurine inclusion increases Acanthamoeba survival against contact lens solutions.

Prognostic factors affecting visual outcome in Acanthamoeba keratitis.

Objective: To identify clinical and demographic factors associated with a worse visual outcome in Acanthamoeba keratitis (AK).

Design: Retrospective, case control study.

Participants: A total of 72 eyes of 65 patients with AK who were diagnosed at the University of Illinois Eye and Ear Infirmary between May of 2003 and May of 2007 with treatment complete by October of 2007.

The association of contact lens solution use and Acanthamoeba keratitis.

Purpose: To investigate Acanthamoeba keratitis (AK) risk factors. Diagnosis of AK, a rare but serious corneal infection, has recently increased significantly at the University of Illinois at Chicago (UIC) Cornea Service.

Design: Retrospective case-control study.