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Recrudescent Acanthamoeba
Keratitis Related to Persistent
Contact Lens Wear
Elmer Y Tu1A, Charlotte E Joslin1, Megan E Shoff2, Janet A. Lee1,
Ali Djalilian1
1Department
of Ophthalmology and Visual Sciences
University of Illinois Eye and Ear Infirmary
Chicago, Illinois
2Department of Molecular Genetics
The Ohio State University
Columbus, Ohio
1A Allergan
– travel honoraria
No conflicts of interest pertaining to this presentation.
Off-label use will be discussed
Purpose: To report patients with a
second diagnosis of Acanthamoeba
keratitis after continuing contact lens
wear
Methods: Acanthamoeba keratitis
patients diagnosed between 06/2003 –
09/2007
 University of Illinois Eye and Ear Infirmary
 Cases reviewed for involvement of multiple
eyes
Results
 88 total patients identified with
Acanthamoeba keratitis
 9 patients diagnosed with multiple
infections
 7 presenting with bilateral disease
 1 patient had the contralateral eye involved
3 months later
 1 patient presented with re-involvement of
the same eye 17 months later
Case 1
Resolved
scar
 17 year old white male presented 6/1/07 with a
severe, painful recurrent keratitis OS
 Failed treatment topical antibiotics, antivirals and
corticosteroid
 Confocal microscopy c/w Acanthamoeba
 Cultures negative
 Resolution over three months with propamidine and
chlorhexidine with small residual scar (figure above)
 Patient continued contact lens wear OD, despite
warnings to discontinue
Stroma
Case 1
Acanthamoeba
Cysts
Epithelium
 Patient presented with necrotic ulcer OD
9/7/07
 Partially treated ulcer was culture negative
 Fortified cefazolin and gentamicin
 Good response clinically and symptomatically
 9/18/2007
 Reports increasing discomfort and forms an
immune ring (figure below)
 Confocal positive (see above) Partial
immune
ring
Case 2
Bright-centered
Acanthamoeba
cysts
 16 year old African-American male 2/13/06
 SCL wearer treated for 2 weeks with Viroptic and
Acyclovir
 Referred for keratitis with radial neuritis OD
 Confocal/ Diff-Quick Smear/ Culture positive
 20/20 vision after 3 months of therapy
 Propamidine and chlorhexidine
 Patient resumed contact lens wear 3 months
later
 Sports scholarship to college
Case 2
 Presented 7/26/07 with pain and
decreased vision (20/40) OD x 2 weeks
 SCL wear/ AMO Complete Moisture Plus
 Swimming in lenses 3 weeks prior in another
state where he was in school for the past 9
months
 Confocal/ Diff-Quick Smear/ Culture positive
 Genotype distinct from first isolate
Diff-Quik
Stain
(Original
magnifiction
100x oil)
Genotyping results
Sequence comparison of the two isolates obtained from Case 2 for a 135
nucleotide base region within one of the highly informative diagnostic
fragments of the Acanthamoeba 18S rRNA gene. The two isolates, 06005 and 07-072, clearly differ from each other, with 13/135 base
differences. However, as shown, each isolate separately closely
resembles different previously reported Acanthamoeba sequences found
in the DNA database GenBank.
Discussion

A common question from patients successfully treated for Acanthamoeba
keratitis (AK) is the safety of subsequent contact lens wear. Since AK is a
rare disease estimated to affect approximately 2-20 wearers per million
contact lens wearers per year, by chance alone, the likelihood of a
second infection is remote. The understanding of the risk factors and
mechanisms for the development of AK remain, however, incomplete.

While the sequential nature of bilateral AK has been previously described,
as seen in case 1, it does not distinguish the roles of environment and
individual susceptibility since these patients usually have little change in
their environment during the short time between occurrences.

Re-occurrence in the same eye 17 months apart, as illustrated in Case 2,
may still represent either a reactivation of the original infection or a
second, new infection. The interval lack of symptoms and signs of
infection and the identification of two genetically distinct pathogenic
Acanthamoeba isolates make it strongly likely that patient 2 contracted a
new infection after persisting with soft contact lens wear.
Discussion
 While uncommonly highlighted, bilateral, contemporaneous
disease may occur in up to 8-10% of patients and is congruent
with our own experience during the Chicago Acanthamoeba
outbreak. Whether this is more common to environmentally
sourced outbreaks is unclear. The odds of contracting two
separate infections without significantly common risk factors are
prohibitively unlikely, but in bilateral disease could be attributed to
a common exposure, or load, of organisms either in the
environment, as we have previously hypothesized, or overgrowth
within an individual’s contact lens care system.
 It is also unknown whether individual patients may be uniquely
susceptible to Acanthamoeba keratitis. Case 2 indicates that,
despite its rare incidence, an individual can contract a separate
rare infection in a different environment while attending college
900 miles away. Although hygiene factors may play a role, the
relative permissiveness of ocular defense mechanisms including
local and systemic immune defenses may also contribute.
Conclusion
 These cases indicate an ongoing risk for the
development of Acanthamoeba keratitis in
patients previously infected.
 Acanthamoeba keratitis may require not only the
presence of organisms, but also some measure of
individual susceptibility.
 The understanding of the mechanisms and risk
factors for human corneal infection with
Acanthamoeba remains incomplete and deserves
further study.
Selected References Acknowledgments
Joslin CE, Tu EY, Shoff ME, et al. The
Association of Contact Lens Solution Use
and Acanthamoeba Keratitis. Am J
Ophthalmol 2007.
Joslin CE, Tu EY, McMahon TT, Passaro DJ,
Stayner LT, Sugar J. Epidemiological
characteristics of a Chicago-area
Acanthamoeba keratitis outbreak. Am J
Ophthalmol 2006;142:212-7.
Wilhelmus KR, Jones DB, Matoba AY, Hamill
MB, Pflugfelder SC, Weikert MP. Bilateral
acanthamoeba keratitis. Am J Ophthalmol
2008;145:193-197.
Bernauer W, Duguid GI, Dart JK. [Early clinical
diagnosis of acanthamoeba keratitis. A study
of 70 eyes]. Klin Monatsbl Augenheilkd
1996;208:282-4.
Ficker L, Seal D, Warhurst D, Wright P.
Acanthamoeba keratitis--resistance to
medical therapy. Eye 1990;4 ( Pt 6):835-8.
Johnson AM, Fielke R, Christy PE, Robinson B,
Baverstock PR. Small subunit ribosomal
RNA evolution in the genus Acanthamoeba.
J Gen Microbiol 1990;136:1689-98.
 University of Illinois Eye
and Ear Infirmary
 Joel Sugar, MD
 Leslie T. Stayner, PhD
 Jamie Brahmbhatt, COMT
 The Ohio State University,
Dept. Molecular Genetics
 Gregory C. Booton, PhD
 Paul A. Fuerst, PhD

Support:
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
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Prevent Blindness America
Midwest Eye-Banks
NIH/NEI K23 15689
UIC Campus Research Board
Gerhard Cless Foundation