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2018 Agenda and Abstracts | < Previous Next >

2018 OMIG Abstract

Update on the Increasing Frequency of Sheen Isolates Among Pseudomonas Aeruginosa Keratitis Isolates

Robert M.Q. Shanks1, C.V. Sundar-Raj1, Hazel Q. Shanks1, John E. Romanowski1, Michael E. Zegans2, Vishal Jhangi1, Regis P. Kowalski1
1The Charles T. Campbell Laboratory, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA.; 2Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College, Hanover, NH


Purpose: Pseudomonas aeruginosa causes vision-threatening keratitis. Approximately 20% of keratitis Pseudomonas aeruginosa isolates from the SCUT study demonstrated a colony sheen appearance, and these sheen positive isolates correlated with a worse clinical outcome. These sheen isolates were found in India between 2006 and 2010. The basis of the sheen phenotype was a build up of 4-hydroxy-2-heptylquinoline due to mutation of the lasR gene. It is not known whether North American P. aeruginosa keratitis isolates have this sheen phenotype. In this study, we examined P. aeruginosa keratitis isolates from the Charles T. Campbell Ophthalmic Microbiology Laboratory dating from 1998-2017 for a sheen phenotype.

Methods: 281 P. aeruginosa keratitis isolates from a 20 year period were streaked out on blood agar plates and analyzed for colony sheen phenotypes. Sequencing of the lasR gene for a subset of isolates was performed.

Results: Overall sheen positive isolates were found in 18% of isolates in the Campbell Laboratory collection of keratitis isolates. There is an increasing trend in the frequency of sheen positive isolates, with 11% from isolates from 1998-2002 (n=63), 15% from 2003-2007, 16% from 2008-2012, and 26% from isolates between 2013-2017 (n=101). The majority of tested sheen positive isolates had mutations in the lasR gene.

Conclusion: P. aeruginosa sheen isolates which were previously isolated from North American keratitis patients with a similar overall frequency to those observed in India. There is a trend for increasing sheen isolates that is concerning given the likely increased pathogenesis of these strains. Records for patients with sheen and non-sheen associated P. aeruginosa keratitis are currently under review for clinical outcomes.

Disclosure: N


2018 Agenda and Abstracts | < Previous Next >