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Molecular epidemiology and resistance profiles among healthcare- and community-associated Staphylococcus aureus keratitis isolates

Authors Peterson JC, Durkee H, Miller D, Maestre-Mesa J, Arboleda A, Aguilar MC, Relhan N, Flynn Jr HW, Amescua G, Parel JM, Alfonso E

Received 9 October 2018

Accepted for publication 18 January 2019

Published 11 April 2019 Volume 2019:12 Pages 831—843


Checked for plagiarism Yes

Review by Single-blind

Peer reviewer comments 2

Editor who approved publication: Dr Eric Nulens

Jeffrey C Peterson,1,2 Heather Durkee,1,2 Darlene Miller,3,4 Jorge Maestre-Mesa,3,4 Alejandro Arboleda,1 Mariela C Aguilar,1 Nidhi Relhan,1 Harry W Flynn Jr,3 Guillermo Amescua,3 Jean-Marie Parel,1–3 Eduardo Alfonso3

1Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA; 2Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA; 3Anne Bates Leach Eye Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA; 4Ocular Microbiology Laboratory, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA

Purpose: To characterize the molecular, epidemiological, and resistance profiles of methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) keratitis isolates.
Patients and methods: We used a combination of standard microbiological techniques and DNA microarray analysis to characterize the molecular and antibiotic resistance profiles of 75 Staphylococcus aureus keratitis isolates collected over an 11-year period (2006–2016).
Results: Two major USA clonal complexes (CC), CC5 (n=30, 40%) and CC8 (n=28, 37.3%), accounted for 77.3% of the collected S. aureus isolates. USA100, traditionally healthcare associated (n=18/47, 38.3%), and USA300, traditionally community associated (n=12/47, 25.5%), were the dominant MRSA strains. Four (22.2%) of the USA100 MRSA isolates were recovered from patients with no prior healthcare exposure. Eleven (91.7%) of the USA300 isolates were recovered from patients with documented healthcare risk factors. MSSA isolates were polyclonal (n=13). Ninety-three percent of MSSA infections were of healthcare origin. Thirty-seven of 61 (60.6%) healthcare- and 11 of 14 (78.6%) community-associated strains were resistant to three or more antibiotic classes. Sixty-eight percent (n=51) of isolates harbored three of more resistance determinants (genes). The Panton-Valentine Leucocidin gene was detected in 11 (14.7%) of the study isolates. The majority (72.7%) of the strains were members of the USA300 MRSA clone.
Conclusion: Clonal complexes CC5 and CC8 were the most frequent clones detected among both the MSSA and the MRSA keratitis isolates. USA100 and USA300 clones were the dominant MRSA genotypes. The USA300 MRSA clone has become a leading cause of healthcare-associated keratitis in South Florida. The USA100 MRSA clone has emerged as an increasing cause of community-associated corneal infections in our outpatient population. This shifting epidemiology coupled with the increasing prevalence of multidrug resistance among both MSSA and MRSA keratitis is a cause of concern.

Keywords: MRSA, MSSA, DNA microarray, USA100, USA300, clones

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