Antibiotic Resistance Trends Among Ocular Pathogens in the US—Cumulative Results from the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) Surveillance Study

A ntibiotic resistance among ocular pathogens is a public health concern. The multicenter, prospective Antibiotic Resistance Monitoring in Ocular micRoorganisms (ARMOR) study is an ongoing surveillance study designed to report on antibiotic resistance rates and trends among Staphylococcus aureus, coagulase-negative staphylococci (CoNS; includes Staphylococcus epidermidis), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae isolates from ocular infections. Results for more than 4,000 isolates collected from 2009 –2015, representing 7 years of ARMOR, were recently presented. More than a third of S. aureus and almost half of all CoNS isolates were found to be resistant to methicillin. Staphylococcal isolates also showed high levels of multidrug resistance (resistance to ≥3 antibacterial drug classes) with 76.4% and 73.7% of methicillin-resistant S. aureus (MRSA) and methicillin-resistant CoNS (MRCoNS) isolates, respectively, demonstrating multidrug resistance. Resistance among S. pneumoniae was notable for azithromycin (36.8%) and for penicillin (34.0%), whereas P. aeruginosa and H. influenzae were generally susceptible to the antibiotic classes tested. Longitudinal analyses demonstrated a small decrease in methicillin resistance among S. aureus over the 7-year study period, which may be a result of improved antibiotic stewardship. Continued surveillance of antibiotic resistance among ocular pathogens is warranted.