Abstract
Purpose :
In bacterial eye infections, antibiotic resistance can impact treatment success and lead to sight-threatening complications. The ongoing Antibiotic Resistance Monitoring in Ocular micRoorganisms (ARMOR) study is the only nationwide surveillance study specific to ocular pathogens, now in its eleventh year. Here, we report preliminary susceptibility profiles from isolates collected to date in 2019.
Methods :
Ocular isolates of Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae from ocular infections were collected as part of ARMOR and subjected to in vitro antibiotic susceptibility testing at a central laboratory. Minimum inhibitory concentrations (MICs) were determined by broth microdilution methodology for up to 16 antibiotics (from 10 drug classes) according to Clinical and Laboratory Standards Institute guidelines and were interpreted as susceptible or resistant based on established systemic breakpoints.
Results :
A total of 397 isolates were collected to date in 2019, from 20 participating US sites. In vitro resistance among the staphylococci was most high for azithromycin (52-71%), oxacillin/methicillin (29-53%), and ciprofloxacin (26-32%), while CoNS isolates also exhibited substantial resistance to trimethoprim (42%). Multidrug resistance (MDR; resistance to ≥3 antibiotic classes) was observed in 26% of S. aureus and 53% of CoNS, with MDR especially prevalent among methicillin-resistant isolates (74% and 83%, respectively). S. pneumoniae isolates were resistant to azithromycin (36%), oral penicillin (23%) and tetracycline (23%) but all were susceptible to fluoroquinolones. Among P. aeruginosa, resistance was low, with <7% of isolates exhibiting resistance to polymyxin B and the fluoroquinolones. All isolates of H. influenzae were susceptible to tested drugs.
Conclusions :
Preliminary 2019 ARMOR data indicate continued high levels of antibiotic resistance among staphylococci, with many isolates demonstrating MDR. These surveillance data may inform treatment options for patients with ocular bacterial infections.
This is a 2020 ARVO Annual Meeting abstract.