The FINANCIAL — Bausch + Lomb announced on October 26 the five-year results from the ARMOR (Antibiotic Resistance Monitoring in Ocular MicRoorganisms) surveillance study, published online first in JAMA Ophthalmology.
Consistent with resistance trends reported for nonocular staphylococcal isolates, the study found prevalent methicillin resistance among staphylococcal isolates from ocular infections, with many strains demonstrating multidrug resistance. While the results indicate that overall resistance among the ocular isolates collected did not increase during the five-year study period, the authors stressed the critical role of continued surveillance of ocular isolates, according to Bausch + Lomb.
“Physicians often treat ocular infections empirically, as current clinical laboratory methods can take several days to grow bacteria in culture and determine an isolate’s antibiotic resistance profile,2” said Penny Asbell, MD, lead ARMOR study author, professor of Ophthalmology at Icahn School of Medicine at Mount Sinai, and director of the Cornea Service and Refractive Surgery Center at Mount Sinai Hospital. “Collecting and reporting long-term data through a surveillance study like ARMOR can identify risk groups and susceptibility trends to help physicians in the selection of empirical treatment.”
Researchers reported the antibiotic resistance profiles of 3,237 ocular isolates submitted from 72 centers in the United States from January 1, 2009 through December 31, 2013. The study collected ocular strains of Streptococcus pneumoniae, Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Pseudomonas aeruginosa, and Haemophilus influenzae, organisms frequently implicated in bacterial eye infections, some with potentially serious consequences.
Methicillin resistance was found among 493 S. aureus isolates (42.2%) and 493 CoNS isolates (49.7%) and methicillin-resistant (MR) isolates had a high probability of concurrent resistance to fluoroquinolones, aminoglycosides, or macrolides (P<0.001). Multidrug resistance to 3 or more additional antibiotic classes continues to be a challenge and was found in 428 MR S. aureus isolates (86.8%) and 381 MRCoNS isolates (77.3%). All staphylococcal isolates were susceptible to vancomycin. Resistance among S. pneumoniae isolates was highest for azithromycin (113 isolates [34.2%]) whereas resistance among P. aeruginosa and H. influenzae was low against the antibiotics tested. Staphylococcal isolates from elderly patients were more likely to be MR, as were S. aureus isolates obtained from the southern United States (P<0.001). Methicillin resistance among staphylococci did not increase during the 5-year study period (P≤0.22), and small decreases in resistance to ciprofloxacin among CoNS and MRCoNS and to tobramycin among CoNS (P≤0.03) were found.
Initiated in 2009, the ARMOR study is the only ongoing nationwide antibiotic resistance surveillance program specific to ocular pathogens, and represents the most robust evaluation of nationwide antibacterial susceptibility of common ocular pathogens to date. The study is sponsored by Bausch + Lomb.
“Although many national and even global agencies monitor antibiotic resistance trends among bacteria that cause systemic diseases, only the ARMOR study evaluates only ocular pathogens,” said Cal Roberts, M.D., chief medical officer, Bausch + Lomb. “We are proud to provide this service to the ophthalmology community, and intend to continue supporting this study as part of our commitment to serving eye care professionals.”