Eyeworld

67 EW RESIDENTS September 2017 after cataract surgery and should pro- mote a reevaluation of the country's predominant practice pattern. EW References 1. Matsuura K, et al. Survey of Japanese ophthalmic surgeons regarding perioperative disinfection and antibiotic prophylaxis in cata- ract surgery. Clin Ophthalmol. 2014;8:2013–8. 2. Miyanaga M, et al. Changes in drug suscep- tibility and the quinolone-resistance determin- ing region of Staphylococcus epidermidis after administration of fluoroquinolones. J Cataract Refract Surg. 2009;35:1970–8. 3. Nejima R, et al. Effect of the administration period of perioperative topical levofloxacin on normal conjunctival bacterial flora. J Cataract Refract Surg. 2017;43:42–48. 4. Results of the Endophthalmitis Vitrectomy Study. A randomized trial of immediate vit- rectomy and of intravenous antibiotics for the treatment of postoperative bacterial endoph- thalmitis. Endophthalmitis Vitrectomy Study Group. Arch Ophthalmol. 1995;113:1479–96. 5. Chang DF, et al. Antibiotic prophylaxis of postoperative endophthalmitis after cata- ract surgery: Results of the 2014 ASCRS member survey. J Cataract Refract Surg. 2015;41:1300–5. Contact information Patel: Vivek.Patel@med.usc.edu coagulase negative species were the most common bacteria isolated in post-cataract endophthalmitis, and 61% of patients presented in the first week following cataract surgery. 4 In the U.S. and Europe, the common practice after cataract surgery is to use postoperative topical antibiotics for 1 week or less, usually a fluoro- quinolone that has broad Gram-pos- itive and Gram-negative coverage. 5 This study strengthens our knowledge about the long-term effects of topical levofloxacin on the normal ocular flora and its poten- tial effect on the development of antibiotic resistant bacteria; specif- ically, there is an alteration in the normal flora for 6 months with a demonstrable increase in the MIC for S. epidermidis after long-term postoperative antibiotic use. These alterations and risk of antimicro- bial resistance are not seen after short-term postoperative antibiotic regimens as commonly used in other countries. The potential adverse microbial consequences without any current evidence to establish benefit may have important implications on the value, effectiveness, and risk of long-term antibiotic use in Japan patients specifically with S. epider- midis or P. acnes isolates would be interesting, especially to see what other isolates were noted in these patients and if those isolates had de- veloped any indication of bacterial resistance. One notable confounding factor in this study that the authors acknowledge is the use of the oral cefcapene after surgery in conjunc- tion with topical levofloxacin; this makes it difficult to ascertain the true effect of the topical levofloxacin on the perioperative surgical bacteri- al environment. Although endophthalmitis is a rare complication after cataract surgery, the threat of infection and questions as to how to prevent such infections persist. Moreover, the risk of development of antibiotic resis- tant microbes is an ongoing concern that must also be simultaneously addressed. While newer approaches for endophthalmitis prophylaxis such as intracameral antibiotics have been more recently advocated, topical antibiotics have consistently been used to prevent infection with varying treatment durations. The Endophthalmitis Vitrectomy Study (EVS) showed that Gram-positive, epidermidis after 1 week of postop- erative levofloxacin compared to 1 month of postoperative levofloxa- cin; they found that at the 3-month follow-up the MIC of the 1-month group was twice that of the 1-week group, and there were 20% less susceptible strains in the 1-month group. 3 The results of that study and this present one suggest that using postoperative antibiotics for a short- er period of time prevents the devel- opment of antibiotic resistant strains and prevents significant alteration to the normal ocular flora. While the authors sensibly focus on the development of levofloxacin resistant strains after levofloxacin use in their study, the effects of pro- longed antibiotic use may still have effects on the normal flora beyond development of resistance to one an- tibiotic alone. For example, it is in- teresting to note the sharp increase in methicillin resistant S. epidermidis species 3 and 6 months after antibi- otics use, which is not emphasized by the authors. The ocular bacterial milieu is complex and antibiotic use may have other, unforeseen, or as of yet unidentified consequences on the ocular flora. A sub-analysis of surgery with topical Vivek Patel, MD, Brandon Wong, MD, and J. Bradley Randleman, MD Source: USC Roski Eye Institute

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