Antibiotics resistance in culture-positive endophthalmitis

Abstract

Purpose : To assess antibiotic resistance among patients with acute Bacterial endophthalmitis and positive cultures. To assess the clinical characteristics of antibiotic-resistant endophthalmitis and to establish if the current empirical treatment with vancomycin and ceftazidime is still advisable as first line treatment

Methods : Retrospective study. We review the clinical record of all cases of acute bacterial endophthalmitis from 2009 to 2015. From each record we note the visual acuity at presentation and at discharge, the time needed for a positive culture result, the time needed for case resolution, relevant medical history, all treatment needed and suspected etiology. Antibiotic sensitivity was assessed for each isolated bacteria by disk diffusion method for 30 different antibiotics. The population was further divided in groups: Group 1: cases with bacterial strains sensitive to both vancomycin and ceftazidime. Group 2: cases with bacterial strains resistant to either vancomycin or ceftazidime; and group 3: cases with bacterial strains resistant to vancomycin and ceftazidime. Statistical analysis was done with a two sample t-test and a one way ANOVA test. Risk for surgical intervention was assessed by Odds ratio.

Results : We included 81cases from 78 medical records. Coagulase-negative staphylococcus was the most prevalent isolated pathogen. Gram positive bacteria showed a statistically significant increase in the resistance toward dicloxacillin (p=0.01), gentamicin (p=0.04) and tobramycin (p=0.01). Other drugs like vancomycin and clindamycin also showed an important trend toward increased resistance but only reached marginal significance (p=0.07). Fourth-generation fluoroquinolones resistance remains low and provides a good coverage for gram positive and negative bacteria. There were no difference between group 1, 2 and 3 in visual acuity. Patients in group 2 and 3 had a higher risk for needing surgery. All patient in group 3 received oral o intravitreal moxifloxacin as part of their treatment.

Conclusions : Although vancomycin/ceftazidime combination is still the gold standard for the empirical treatment of endophthalmitis the evidence found in this study points to a possible change in the regional bacterial susceptibility profile. There was no clinical difference between cases with resistant strains of endophthalmitis. Nevertheless all patients in group 2 and 3 received moxifloxacin as part of their treatment.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.