Pathogens and antibiotic sensitivities in endophthalmitis.

Background: Antibiotic prophylaxis in cataract surgery is intended to minimize endophthalmitis. We describe pathogenic organisms, antibiotic sensitivities and antibiotic prophylaxis in culture-proven endophthalmitis cases.
Design: Retrospective consecutive case series and community-based setting were used.
Participants: Two hundred fifteen cases of endophthalmitis after cataract surgery performed during 2007-2012 in Kaiser Permanente, California.
Methods and Main Outcome Measures: Descriptive analysis of isolated organisms and antibiotic sensitivities in relation to antibiotic prophylaxis in culture-proven endophthalmitis cases.
Results: The majority of culture-confirmed organisms (n = 83) were Gram positive (96%), most notably coagulase-negative Staphylococci (n = 34, 52%), of which all that underwent testing were sensitive to vancomycin (n = 32). Among 19 cases that had received only topical antibiotic prophylaxis, seven (37%) were resistant to the antibiotic given: 50% of cases (5 of 10 isolates) that had received ofloxacin were resistant to this antibiotic, 40% (2 of 5 isolates) that had received gatifloxacin were resistant. In contrast, 100% of cases (n = 4) that had received aminoglycosides were susceptible. Few culture-confirmed cases occurred in patients who received intracameral antibiotic (n = 4).
Conclusions: In cases where fluoroquinolones were administered as antibiotic prophylaxis, isolates demonstrated a degree of bacterial resistance. The majority of endophthalmitis cases isolated occured following topical antibiotic prophylaxis only and were attributed to Gram-positive organisms, while few occurred in association with intracameral antibiotic.
(© 2016 Royal Australian and New Zealand College of Ophthalmologists.)