Purpose:
To study the microbial spectrum and sensitivity in endophthalmitis at a tertiary referral center in Northeast United States. Such knowledge may help physicians make more informed decisions about empiric treatments for endophthalmitis.
Methods:
All vitreous samples sent to the microbiology laboratory from 1987 to 2009 were reviewed. Isolate sensitivity from 1987-1998 and 1999-2009 were compared. The identity and antimicrobial sensitivity of all isolates were analyzed using Microsoft Excel and Mathworks Matlab software.
Results:
A total of 165 isolates were yielded from 147 positive cultures sent to the microbiology laboratory. The most common organisms grown were coagulase-negative Staphylococcus (38%), Viridans Streptococcus (10%) and Streptococcus pneumoniae (7%). The organisms were 81% gram-positive, 12% gram-negative and 7% fungal. Staphylococcus and Streptococcus formed 42% and 24% of all organisms, respectively. Overall, organisms were most sensitive to vancomycin, TMP/SMX, tetracycline, clindamycin, ceftriaxone and chloramphenicol. Gram-positive bacteria had > 80% sensitivity to vancomycin, tetracycline, rifampin, gentamicin, clindamycin, ceftriaxone and chloramphenicol. Staphylococcus strains had > 80% sensitivity to vancomycin, TMP/SMX, tetracycline, rifampin, gentamicin, clindamycin and chloramphenicol, while Streptococcus had > 80% sensitivity to ceftriaxone, clindamycin, penicillin and vancomycin. Comparing the 90 isolates collected in 1987-1998 with the 75 collected in 1999-2009, a trend in decreased sensitivity was seen in cefazolin, erythromycin, penicillin, tetracycline and TMP/SMX, and a trend in increased sensitivity was seen in chloramphenicol and gentamicin.
Conclusions:
The most common organisms were coagulase-negative Staphylococcus, Viridans Streptococcus and Streptococcus pneumoniae. Most organisms were gram-positive followed by gram-negative and then fungal. Staphylococcus formed the largest genus followed by Streptococcus. The decrease in sensitivity for cefazolin, erythromycin, penicillin, tetracycline and TMP/SMX is important in light of increasing drug resistance.
Keywords: endophthalmitis • antibiotics/antifungals/antiparasitics • vitreous