Purchase this article with an account.
Penny A Asbell, Christine M Sanfilippo, Megan E Cavet, Heleen DeCory; Antibiotic Resistance Trends Among Staphylococci in the ARMOR Study: 2009-2017. Invest. Ophthalmol. Vis. Sci. 2018;59(9):3676.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Staphylococci are known common causative pathogens in ophthalmic infections, with numerous studies demonstrating significant antibiotic resistance among these bacteria. The Antibiotic Resistance in Ocular MicRoorganisms (ARMOR) study is a nationwide surveillance study on antibacterial resistance levels among ocular pathogens now in its 9th year. Previous ARMOR data suggested that methicillin resistance (MR) among staphylococci, while high, may have plateaued and could be decreasing. Here, we examined antibiotic resistance trends over time among staphylococci isolates collected in ARMOR through the time of abstract submission to determine if this trend continued in 2017.
From Jan 2009 through Oct 2017, 1854 Staphylococcus aureus and 1591 coagulase-negative staphylococci (CoNS) were collected in ARMOR. Minimum inhibitory concentrations (MICs) were determined by broth microdilution according to Clinical and Laboratory Standards Institute guidelines, and MICs were interpreted as susceptible, intermediate, or resistant based on established systemic breakpoints. Longitudinal trends were evaluated using a Cochran-Armitage test for linear trends in a proportion.
Nine-year trend analysis confirmed the previously noted decrease in MR among S aureus (from 39% to 14%; P<0.001) but not among CoNS (P=0.455), with more than half of CoNS demonstrating continued persistence in MR. Further analysis showed decreased resistance among S aureus to azithromycin (62% to 52%), ciprofloxacin (39% to 16%), tobramycin (24% to 6%), and chloramphenicol (6.6% to 4.4%), and among CoNS to ciprofloxacin (46% to 22%; P≤0.005 for all). As in previous years, a high proportion of methicillin resistant staphylococci demonstrated multidrug resistance (≥3 antibiotic classes), although none were vancomycin resistant. 2017 MIC90s (in µg/mL) for besifloxacin, moxifloxacin, gatifloxacin, ciprofloxacin, and levofloxacin, were 0.25, 2, 2, 8, and 4, respectively, for S aureus, and 0.5, 4, 2, 32, and 16, respectively, for CoNS.
Nine-year trend analyses confirm that among S aureus, MR and resistance to macrolides, fluoroquinolones, aminoglycosides, and phenicols is decreasing. In contrast MR remains high among CoNS, with a decrease observed in fluoroquinolone resistance.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
This PDF is available to Subscribers Only