Abstract
Purpose: :
To identify organisms and evaluate antibiotic sensitivities in cases of endophthalmitis associated with microbial keratitis.
Methods: :
Microbiology department records were reviewed on all patients with concurrent positive corneal and vitreous cultures at the Bascom Palmer Eye Institute between January 1, 1995 and September 31, 2009. Responsible organisms were identified and antibiotic sensitivities were recorded. Viral keratitis cases were excluded.
Results: :
In the current study, 33 patients were found to have concurrent positive corneal and vitreous cultures. A single organism was identified in 27 cases, and multiple organisms were identified in 6 cases. Of the primary responsible organisms, gram positive bacteria accounted for 17 cases, gram negative bacteria accounted for 9 cases, and fungi accounted for 7 cases. Three different species of staphylococci were identified: S. aureus (n=5), S. epidermidis (n=3) and S. salivarius (n=1). 100% of Staphylococcus isolates were sensitive to vancomycin, 57% were sensitive to gentamicin, and 29% were sensitive to ciprofloxacin and trimethoprim/sulfa. Four different species of streptococci were identified: S. pneumoniae (n=5), S. agalactiae (n=1), S. pyogenes (n=1) and S. anginosus (n=1). 100% of Streptococcus isolates were sensitive to vancomycin, 71% were sensitive to gentamicin and 17% were sensitive to trimethoprim/sulfa. Additionally, two gram negative organisms were identified: Pseudomonas aeruginosa (n=7) and Serratia marcescens (n=3). 100% of gram negative bacteria were sensitive to amikacin, ceftazidime, tobramycin, gentamicin, ciprofloxacin and trimethoprim/sulfa. All gram negative bacteria were found to be resistant to cefazolin. Finally, five species of fungi were identified, the most common being Paecilomyces (n=2) and Fusarium (n=2), followed by Colletotrichum (n=1), Candida (n=1), and Aspergillus (n=1).
Conclusions: :
Gram positive bacteria were the most common isolates identified in our case series, all of which were sensitive to vancomycin. P. aeruginosa and S. marcescens were the only gram negative bacteria identified in our case series, and these bacteria were sensitive to a wide range of antibiotics, including ceftazidime and amikacin. Antibiotic sensitivity results reinforce the standard use of intravitreal vancomycin and ceftazidime in the management of endophthalmitis associated with bacterial keratitis. Additionally, fungi represented over one-fifth of the cases in our series, and should be considered in the differential diagnosis of concomitant bacterial keratitis and endophthalmitis.
Keywords: endophthalmitis • keratitis • antibiotics/antifungals/antiparasitics