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Shareef Ahmed, Himanshu Aggarwal, Oscar Kuruvilla, David Chin Yee, Yue Li, Paul Edwards, Xiaoxi Qiao, Hua Gao; Intraocular Penetration of Systemic Antibiotics Following Scleral or Corneal Penetrating Injury. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1107.
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© ARVO (1962-2015); The Authors (2016-present)
To determine if penetrating injury can enhance intraocular penetration of systemic moxifloxacin, vancomycin, and ceftazidime.
Thirty New Zealand rabbits were divided into 3 groups, 10 rabbits for each of 3 antibiotics. In each group, 5 rabbits were used for scleral injury and 5 for corneal injury. Right eyes were used for injury while left eyes served as controls. For scleral injury, a 4 mm laceration was made 5 mm posterior to the temporal limbus, and for corneal injury, a 3 mm laceration was made in the central cornea. Moxifloxacin 20 mg/kg, vancomycin 15 mg/kg, or ceftazidime 50 mg/kg was administered intravenously 10 minutes after injury. Eyes were enucleated 20 minutes later, frozen, and the vitreous harvested. Intra-cardiac blood was collected before animals were sacrificed. HPLC was performed to determine vitreous and plasma concentration of antibiotics.
Intravitreal moxifloxacin concentration was unchanged by injury (3.34 and 3.28 ug/ml in scleral and corneal injury eyes, respectively) when compared to control eyes (3.48 and 3.26 ug/ml). It reached 47% to 51% of plasma concentration. MIC90 (minimum inhibitory concentration) was achieved in the vitreous against the most common endophthalmitis-causing organisms. Intravitreal vancomycin levels were not significantly enhanced by injury (0.4 and 0.22 ug/ml in scleral and corneal injury eyes, respectively) compared to control eyes (0.28 ug/ml to non-detectable). It reached only 1-2% of plasma level and did not reach the MIC90 for organisms commonly causing intraocular infection. Intravitreal ceftazidime was increased in the injured eyes, 1.78 ug/ml (67% higher) and 1.50 ug/ml (73% higher) in scleral and corneal injury eyes, respectively compared to 1.065 and 0.74 ug/ml in control eyes. It reached 0.98% to 1.36% of plasma concentration and reaches MIC90 of many gram-negative bacteria.
Intravitreal antibiotic penetration of systemic antibiotics with or without penetrating injury varies depending on the antibiotic. For prevention or treatment of gram-positive bacteria-causing endophthalmitis from penetrating ocular injury, intravitreal injection is required when vancomycin is considered, whereas systemic administration can be used for moxifloxacin. Systemic ceftazidime can be used for many gram-negative bacteria, but intravitreal injection is recommended for better coverage, especially for more potent organisms.
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