Abstract
Purpose:
Antibiotic resistance is a serious concern in the treatment of bacterial infections of the eye. The ARMOR (Antibiotic Resistance Monitoring in Ocular MicRoorganisms) surveillance study was initiated in 2009 to monitor resistance trends among bacterial pathogens of ocular significance. Here we report the study results to date for 2013 and compare the results to those from 2012.
Methods:
To date, 239 isolates of Streptococcus pneumoniae, Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Pseudomonas aeruginosa, and Haemophilus influenzae from 27 sites were subjected to antibiotic susceptibility testing. Minimum inhibitory concentrations were determined by broth microdilution for up to 16 representative antibiotics per Clinical and Laboratory Standards Institute methods. Systemic breakpoints (where available) were used to categorized isolates as susceptible or non-susceptible (intermediate and resistant).
Results:
Compared to 2012, ciprofloxacin and imipenem non-susceptibility rates for P. aeruginosa more than doubled to 14% and 21%, respectively, while again no resistance was detected in H. influenzae isolates. Non-susceptibility to penicillin remained steady at 6% among S. pneumoniae, although azithromycin and imipenem non-susceptibility rates decreased to 29% and 6%, respectively. Isolates of S. aureus and CoNS were non-susceptible to oxacillin/methicillin (43-59%), ciprofloxacin (33-43%), clindamycin (21%), and azithromycin (60-63%), showing slight increases over the previous year. In addition, multi-drug resistance remained prevalent in S. aureus and CoNS isolates (38-39%) from 2013, especially among methicillin-resistant staphylococci (60-81%).
Conclusions:
To date, the 2013 ARMOR surveillance data show increased levels of drug resistance among the already problematic staphylococci as well as among P. aeruginosa isolates. Continued monitoring of antibiotic susceptibility is necessary in order to determine whether changes among ocular pathogens reflect annual fluctuations, sampling variations, or true trends in resistance patterns. Nonetheless, these results indicate the need for judicious use of antibiotic therapy in the treatment of ocular infections and the importance of ongoing, prospective, multi-center surveillance studies of ocular pathogens.
Keywords: 433 bacterial disease •
422 antibiotics/antifungals/antiparasitics •
463 clinical (human) or epidemiologic studies: prevalence/incidence