Acanthamoeba corneal infection in a contact lens wearer

Twelve Years' Continuous Wear of the Same Therapeutic Soft Contact Lens: A Case Report

Purpose

To describe a case of a patient who had worn the same therapeutic soft contact lens (TSCL) continuously for twelve years, since he had failed to attend normal follow-up visits.

Methods

Microbiological histological and scanning electron microscopic (SEM) studies of conjunctiva, cornea and TSCL were done.

Results

Cultures were negative. Corneal histology revealed mild stromal edema and mild epithelial parakeratosis. Corneal SEM was remarkable for the preservation to some extent of normal corneal epithelial specialization with microtricae and microvillae. SEM of the TSCL showed a ruffed multi-layer surface with several cracks including different types of cells.

Conclusions

The patient showed surprising tolerance to the continuous wear of the same contact lens for 12 years.

Random amplified polymorphic DNA profiles as a tool for the characterization of Brazilian keratitis isolates of the genus Acanthamoeba

The genus Acanthamoeba comprises free-living amebae identified as opportunistic pathogens of humans and other animal species. Morphological, biochemical and molecular approaches have shown wide genetic diversity within the genus. In an attempt to determine the genetic relatedness among isolates of Acanthamoeba we analyzed randomly amplified polymorphic DNA (RAPD) profiles of 11 Brazilian isolates from cases of human keratitis and 8 American type culture collection (ATCC) reference strains. We found that ATCC strains belonging to the same species present polymorphic RAPD profiles whereas strains of different species show very similar profiles. Although most Brazilian isolates could not be assigned with certainty to any of the reference species, they could be clustered according to pattern similarities. The results show that RAPD analysis is a useful tool for the rapid characterization of new isolates and the assessment of genetic relatedness of Acanthamoeba spp. A comparison between RAPD analyses and morphological characteristics of cyst stages is also discussed.