Abstract
Purpose :
Antibiotic resistance among ocular bacterial pathogens can impact the success of antibacterial treatments. The Antibiotic Resistance Monitoring in Ocular micRoorganisms (ARMOR) study, now in its 9th year, is the only nationwide antibiotic resistance surveillance program specific to ocular pathogens. We report susceptibility profiles of ocular isolates collected to date in 2017.
Methods :
Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae isolates were collected from ocular sources and subjected to antibiotic susceptibility testing. Minimum inhibitory concentrations were determined by broth microdilution for up to 16 antibiotics (10 classes) according to the Clinical and Laboratory Standards Institute guidelines. Isolates were categorized as susceptible or resistant (intermediate plus full resistance) based on systemic breakpoints, where available.
Results :
385 isolates were collected from 19 participating US sites across 14 states. Among staphylococci, resistance rates generally remained similar to 2016 rates, with considerable resistance against azithromycin (54-66%), oxacillin/methicillin (14-56%), and ciprofloxacin (16-22%). CoNS isolates also exhibited resistance to tobramycin (18%) and trimethoprim (26%). Isolates of S. pneumoniae were resistant to azithromycin (32%) and penicillin (36%) with no resistance to fluoroquinolones and chloramphenicol. Multidrug resistance (MDR; resistance to ≥3 antibiotic classes) was observed in 11% of S. aureus and 29% of CoNS, with MDR remaining prevalent among methicillin-resistant (MR) isolates (59-65%). All isolates of P. aeruginosa were susceptible to fluoroquinolones, with 8% exhibiting intermediate resistance to polymyxin B. No resistance to tested drugs was observed among H. influenzae isolates.
Conclusions :
Preliminary data for 2017 indicate continued high levels of antibiotic resistance among staphylococci, with considerable multidrug resistance. These findings should help inform anti-infective treatment choices.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.