Recently, concern has been expressed regarding the choice of amikacin sulfate as the companion drug to vancomycin hydrochloride for intravitreal injection in the initial treatment of patients with postoperative endophthalmitis.1 The concern arises because of reports suggesting that amikacin may cause macular infarction. It has been recommended that ceftazidime be used in its place. Because of these reports, investigators and consultants of the Endophthalmitis Vitrectomy Study (EVS), sponsored by the National Eye Institute, reviewed their choice of antibiotics for intravitreous injection in the treatment of postoperative endophthalmitis.
In vitro, both amikacin and ceftazidime are highly active against gram-negative bacilli, and few strains are resistant. Data from a retrospective series of cases of endophthalmitis caused by gram-negative bacilli showed one of 35 strains resistant to amikacin and none to ceftazidime.2 So far, in the EVS, three of 21 isolates were resistant to ceftazidime and two to amikacin. Based on
Doft BH, Barza M. Ceftazidime or Amikacin: Choice of Intravitreal Antimicrobials in the Treatment of Postoperative Endophthalmitis. Arch Ophthalmol. 1994;112(1):17-18. doi:10.1001/archopht.1994.01090130027002