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EW NEWS & OPINION 26 September 2014 ed intravitreal injections prompted retina specialists to discontinue their use in favor of antiseptics, a practice Dr. O'Brien thinks anterior segment specialists should adopt. "I think for prevention, we realize that antibiotics may not be the most rational choice, so the use of antiseptics is probably preferred," he said. The challenge is how to pre- vent and eliminate the serious peril posed by microbial contamination around ophthalmic procedures. Because antibiotic development has been relatively stagnant and most new drugs are molecular vari- ants of existing drugs, these results highlight the need for new, innova- tive antimicrobial agents with novel mechanisms, said Dr. O'Brien. Anti- microbial peptides are one option, as are analogs to N-chlorotaurine, an endogenous oxidant that has been shown to have antimicrobial activity and to neutralize some bac- terial toxins. Pharmaceutical devel- opment should also include efforts to develop agents that inhibit and/ or break down biofi lms, he said. Dr. O'Brien stressed the need to stay vigilant when it comes to antibiotic resistance, a problem that he sees as a serious global threat to public health. "Surveillance is critical to heighten awareness of the threat that is before us," he said. "We in eyecare need to pay attention to this. We in ophthalmology are not insulated or isolated from this problem. It's our problem, and our patients' problem, just like it is for the rest of the medical world." EW Editors' note: Dr. O'Brien serves as ad hoc consultant for Alcon (Fort Worth, Texas), Allergan (Irvine, Calif.), Bausch + Lomb, Santen Pharmaceutical (Osaka, Japan), and Senju Pharmaceutical (Osaka, Japan), but he has no fi nancial interests in the agents or companies mentioned. Contact information O'Brien: tobrien@med.miami.edu by Lauren Lipuma EyeWorld Staff Writer How to use the data Microbiologic surveillance is key to staying ahead of resistant pathogens, he said, and clinicians should use the data provided by this and other studies to inform decisions regarding management of ocular infections. The high rates of multidrug resistance among staphylococcal strains, as shown in the ARMOR study, should be taken into account when choosing the appropriate ini- tial empirical antibiotic treatment, Dr. O'Brien said. "If you have or suspect a meth-resistant staph, you should choose an agent other than a fl uoro- quinolone for treatment," he said. Ophthalmologists should con- sider use of older agents with low resistance profi les, like bacitracin and trimethoprim-polymyxin B, to their advantage. "These may be agents that have selective value even though they're not the traditional broad-spectrum super drugs," Dr. O'Brien said. He cautioned, however, that ophthalmologists must continue to closely monitor the effectiveness of these drugs, as the ability of organisms to evolve resistance mechanisms is so great. When it comes to prophylax- is, Dr. O'Brien thinks alternatives to antibiotics are a more rational choice. Development of resistance to topical antibiotics given after repeat- tested isolates of gram-positive Streptococcus pneumoniae, Staphy- lococcus aureus, and Staphylococcus epidermidis, as well as gram-negative Pseudomonas aeruginosa and Haemophilus infl uenzae. Results indicated that resis- tance to several different classes of antibiotics increased from 2012 to 2013 among strains of Staphylococci and P. aeruginosa, species well known for rapidly developing resistance in systemic infections. Strains of both S. aureus and S. epidermidis showed increased resistance to penicillins, macrolides, and fl uoroquinolones. Additionally, multidrug resistance was common in the 2 species, reach- ing levels as high as 81% in strains already resistant to methicillin. Resistance to ciprofl oxacin and imipenem more than doubled to 14% and 21%, respectively, among Pseudomonas aeruginosa strains. Encouragingly, resistance to drugs not used in systemic medicine was minimal. Isolates showed sus- ceptibility to the fourth-generation fl uoroquinolone besifl oxacin as well as the older antibiotics bacitracin and polymyxin B. "What was encouraging and a pleasant surprise was that for besi- fl oxacin, which doesn't have other systemic medical, animal husbandry, or agricultural use, the susceptibility profi le remains very similar to what we've observed in the last several years," Dr. O'Brien said. Resistant organisms constitute a serious threat to treatment of eye infections D ata presented at the 2014 Association for Research in Vision and Ophthal- mology (ARVO) meeting showed that bacteria fre- quently implicated in eye infections in the U.S. are becoming increasing- ly resistant to available antibiotics. Paralleling what has happened in systemic medicine, strains of resistant bacteria are becoming more common and the evolution of multidrug resistance is on the rise. Researchers from Bausch + Lomb (Bridgewater, N.J.) reported the results from the 2013 Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) study. Started in 2009, the study is a col- laborative effort to track antibiotic resistance among ocular pathogens to both well-established antibiotics and new therapeutic agents. The ability to deliver antibiotics topically and achieve high concen- trations in target tissues has buffeted ophthalmic infections against the increasing resistance patterns seen elsewhere in medicine, but resis- tant populations have nonetheless emerged and constitute a growing problem. "There was this false per- ception that we didn't have to worry as much about resistance because we had this advantage of topically administered antibiotics," said Terrence P. O'Brien, MD, professor of ophthalmology, Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami. "And it certainly is an advantage of drug delivery. But the fact that resis- tant organisms are communicating and resistant populations emerge is something to which eyecare practi- tioners need to pay attention." The study Participants in the ARMOR study collected more than 200 isolates of bacterial species common in eye in- fections and tested them for suscep- tibility to 16 antibiotics. Researchers Antibiotic resistance continues to rise among ocular pathogens Methicillin-resistant Staphylococcus aureus bacteria Source: SCIENCE SOURCE/Getty Images

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