Eyeworld

EW RESIDENTS 66 January 2017 by Monica Ertel, MD, PhD, Charles Cole, MD, Grace Sun, MD, and the residents of the Weill Cornell Department of Ophthalmology the form of perioperative topical antibiotics. In a 2014 ASCRS survey of 1,147 ophthalmologists across the U.S., 85% reported using preoper- ative antibiotics initiated up to 3 days preoperatively. Almost 100% of responding ophthalmologists reported using prophylactic antibiot- ics postoperatively. Of these physi- cians, 72% reported using 1 week of postoperative antibiotics, 21% used antibiotics for several weeks postop- eratively, and 7% tapered antibiotics over the course of several weeks. 7 While evidence exists demon- strating the benefits of prophylactic antibiotic use, there is also concern about emerging antibiotic resistance secondary to antibiotic exposure. Kim and Toma demonstrated increas- ing antibiotic resistance in eyes after repeat exposure to topical ophthal- mic antibiotics. 8 The presence of drug-resistant CNS strains may be a risk factor for the development of en- dophthalmitis. Miller found that as the rate of endophthalmitis increas- es, CNS isolates from these patients demonstrate an increased frequency of fluoroquinolone resistance. 9 The presence of multidrug resistant bac- teria in the normal conjunctival flora is also common, with one in four patients demonstrating colonization with multidrug resistant bacteria. 10 Recent literature, such as the article discussed in this review, has focused on understanding antibiotic resis- tance patterns and the factors influ- encing development. "An investigation of the effect of the administration period with perioperative topical levofloxacin on normal conjunctival bacterial flora" investigates the impact of periop- erative antibiotics on conjunctival flora. Specifically, it compares the resistance patterns of conjunctival flora in patients who received levo- floxacin therapy for 1 week postop- eratively to patients who received a 1-month course of antibiotic thera- py. The authors noted that while 72% of U.S. respondents of the 2014 ASCRS survey used postoperative an- tibiotics for 1 week or less, in Japan, 93% of their facilities reported using antibiotics for 2 weeks to more than a month postoperatively. Participants in this study were patients undergoing cataract surgery at Miyata Ophthalmic Hospital in Japan over a several month period in 2015. Eligible patients were equal to or older than 20 years. Exclusion criteria included the use of topical ophthalmic antibiotics within 3 months before surgery, the use of topically administered medication for glaucoma, and the use of long- term topical steroids or immune suppressing therapy. Subjects were divided into two groups receiving levofloxacin 1.5% three times a day; the first group received antibiotic therapy for 1 week postoperatively, and the second group received anti- biotic therapy for 1 month postop- eratively. All participants received 3 days of preoperative topical levoflox- acin 1.5% three times a day, topical polyvinyl alcohol iodine intraopera- tively, and a standard postoperative treatment regimen of topical steroid therapy (betamethasone) for 1 week and topical nonsteroidal anti-inflam- matory therapy (bromfenac) for 2 months. Conjunctival cultures were collected at: (1) pre-administration of antibiotics, (2) the completion of antibiotic drug therapy (1 week or 1 month), (3) 1 month, 3 months, and 6 months after completion of thera- py, and (4) in patients in the arm of the study receiving antibiotics for a month, cultures were also obtained at 1 week postoperatively. Specimens were obtained using a sterile swab in the inferior fornix after administration of topical anes- thesia. The samples were then plated Review of "An investigation of the effect of the administration period with perioperative topical levofloxacin on normal conjunctival bacterial flora" Grace Sun, MD, director, ophthalmology residency program, Weill Cornell Medical College, New York C ataract surgery is the most commonly performed intraocular surgery, and al- though rare, postoperative endophthalmitis is a po- tentially devastating complication. Despite appropriate therapy, visual outcomes are usually poor, and half of patients are unable to recover vision better than 20/40. 1,2 In cases where a causative organism is iden- tified, the most commonly isolated are endogenous conjunctival and adnexal bacteria. Specifically, coagu- lase negative staphylococcus (CNS), which is the most common bacteria isolated in studies of normal con- junctival flora, has been implicated in between 70 and 80% of cases. 1,3,4 Other commonly associated bacteria include Staphylococcus aureus and Streptococcus species. 2,5 In cases of sub-acute endophthalmitis occur- ring weeks to years after surgery, the most commonly associated bacteria is Propionibacterium acnes. 2 Studies have shown that using perioperative antibiotics decreases the presence of conjunctival bac- teria and also is associated with a decreased risk of endophthalmitis. 1,6 As a result, surgeons take prophy- lactic measures to reduce the risk of endophthalmitis, typically in Weill Cornell ophthalmology residents, from left: Ru-Ik Chee, MD, Alex Port, MD, Monica Ertel, MD, Abdallah Mahrous, MD, Matthew Nguyen, MD, Elizabeth Marlow, MD, Paul Petrakos, MD, Christina Grassi, MD, and Thomas Dohlman, MD Source: Weill Cornell Medical College continued on page 68 How long should topical anti- biotic prophylaxis be continued following cataract surgery? The Weill Cornell residents reviewed this excellent study on microbial antibiotic resistance that appears in the January issue of JCRS. –David F. Chang, MD, EyeWorld journal club editor

• Cover