Moaz Alshaikhi, Eugene Mich?el, Stephen Guest
Purpose: To describe the microbiological isolates and antibiotic sensitivity of culture-positive endophthal- mitis in New Zealand and study their microbial pro- ftle according to the type of endophthalmitis.
Methods: Retrospective analysis of all endophthal- mitis cases presented to Waikato Hospital between 2004 and 2014. The following information was col- lected: source of infection, time to presentation, microbiological results and antibiotic sensitivity.
Results: Fifty-eight percent of endophthalmitis cases yielded positive cultures (n=45) of which 3 cases exhibited a growth of more than one organism.
Coagulase negative staphylococci (CNS) were the most prevalent organisms (40%), followed by strep- tococcus species (17%), staphylococcus aureus (11%) and bacillus species (11%). CNS were identi- fted in 30% of cataract-related endothphalmitis and in all cases occurred after intravitreal Bevacizumab injections (100%). Other Gram positive bacteria were more common in endogenous endophthalmitis (66%), post-traumatic endophthalmitis (66%) and belbitis-related endophthalmitis (80%). Gram nega- tive bacteria and fungi accounted for 9% and 4% of all isolates, respectively. The antibiotics sensitivity of gram positive bacteria was as follows: Vancomy- cin (100%), Cefuroxime (81%), Cipro?oxacin
(100%), Moxi?oxacin (90%) and Amikacin (83%). Ceftazidime, Cipro?oxacin and Amikacin were sen- sitive in all gram negative isolates.
Conclusion: Although coagulase negative staphylo- cocci remain the major cause of endophthalmitis, the prevalence of other gram positive bacteria is increas- ing. The combination of vancomycin and Ceftazi- dime offer an excellent empiric antibiotic choice for bacterial endothphalmitis. Microbial resistants to Cefuroxime is seen in about 20% of cases. Systemi- cally, cipro?oxacin was not inferior to a fourth gen- eration ?uoroquinolone agent, moxi?oxacin, in covering both gram positive and negative bacteria.