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2019 OMIG Abstract

Antibiotic Resistance Among Bacterial Pathogens Collected from the Ocular Surface in the ARMOR Surveillance Study

Penny A. Asbell, MD1, Christine M. Sanfilippo, PhD2, Heleen H. DeCory, PhD2
1Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN;
Medical Affairs, Bausch + Lomb, Rochester, NY

Purpose: Bacterial ocular surface infections can potentially be sight-threatening, and antibiotic resistance may complicate treatment success. The Antibiotic Resistance in Ocular MicRoorganisms (ARMOR) study is a nationwide surveillance program which evaluates in vitro antibacterial resistance among ocular pathogens. Here, we report resistance rates among conjunctiva- and cornea-sourced isolates collected from 2009 through 2018.

Methods: Clinically relevant ocular surface isolates of Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae were obtained from clinical centers across the US as part of ARMOR. Minimum inhibitory concentrations were determined at an independent central laboratory for up to 16 antibiotics (10 classes), and isolates were classified as susceptible or resistant per Clinical and Laboratory Standards Institute methodology and interpretive criteria, where available. Oxacillin was used to classify staphylococci as methicillin-resistant (MR) or methicillin-susceptible (MS).

Results: A total of 2897 isolates (1026 S. aureus, 838 CoNS, 269 S. pneumoniae, 447 P. aeruginosa, and 317 H. influenzae) were collected from conjunctival swabs (n=1609) or corneal scrapings (n=1288) of patients with ocular surface infections at 65 sites. Staphylococci exhibited significant levels of resistance to oxacillin (31-47%), azithromycin (54-61%), and ciprofloxacin (30-32%). Among S. pneumoniae, substantial resistance was detected only for azithromycin and oral penicillin (32% and 30%, respectively). Little resistance to polymyxin B (9%) and ciprofloxacin (6%) was seen among P. aeruginosa, while nearly all H. influenzae were susceptible to tested drugs. Multidrug resistance (=3 antibiotic classes) was found in 29% of S. aureus and 41% of CoNS isolates, with rates approximately doubled among MR staphylococci (MR S. aureus [MRSA], 78%; MRCoNS, 77%).

Conclusion: In this cumulative analysis of conjunctival and corneal isolates collected over 10 years in ARMOR, in vitro antibiotic resistance was high among staphylococci and pneumococci, but low among P. aeruginosa and H. influenzae. These findings may inform treatment options for patients with ocular surface infections.

Disclosure: C: (PAB); E: (CMS, HHD)


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