Efficacy Of Intravitreal Moxifloxacin Versus Intravitreal Vancomycin Plus Ceftazidime In The Treatment Of Acute Bacterial Endophthalmitis In An Animal Model

Abstract

Purpose: : To compare the efficacy of intravitreal moxifloxacin(MXF) versus intravitreal vancomycin plus ceftazidime[V+C] in an animal model of bacterial endophthalmitis

Methods: : Prospective,experimental and comparative study using New Zealand adult rabbits complying with the ARVO statement for the use of animals in ophthalmic and visual research.Four groups of 6 rabbits each were formed and divided according to bacterial strain and treatment.The strains used were Pseudomonas aeruginosa and Staphylococcus epidermidis,using for each strain 490 000 and 180 000 colony-forming units (CFU) respectively;and the treatment was either intravitreal MXF at a dose of 0.5mg/0.1mL obtained from a commercially available ophthalmic presentation (Vigamoxi,Alcon) or vancomycin 1 mg/0.1ml plus ceftazidime 2.25 mg/0.1ml.The group distribution was:Group 1 S. epidermidis and MXF;Group 2 S. epidermidis and V+C; Group 3 P.aeruginosa and MXF and Group 4 P.aeruginosa and V+C.We inoculated one eye of each rabbit with the bacterial strain and at the first clinical sign of endophthalmitis a vitreous sample was obtained and treatment was delivered.Finally the eye was enucleated at either 24 or 48 hours postinjection.Clinical response to treatment,number of CFU in the vitreous humour and histopathological changes were analyzed

Results: : Groups 1 and 2 showed the first sign of endophthalmitis 48 hours posterior to inoculation with moderate inflammation and 48 hours posttreament great clinical improvement was observed.Mean number of pretreatment CFU were 106,000 and 10,300 and posttreament were 19 and 0,respectively (p:0.043 and 0.109).Histopathologically only a mild inflammatory infiltrate was observed in 100% in both groups.Groups 3 and 4 presented severe inflammation 24 hours postinoculation with mild improvement 24 hours postreatment.Regarding CFU the mean number pretreatment was 44,800,000 and 50,000,000 and postreatment 0 and 18.6 respectively (p:0.027 and 0.028),observing severe inflammation by histopathology in 100% of both groups.Comparing group 1 and 2 a statistically significant difference was observed (p 0.012) and also between groups 3 and 4 (p 0.002),in favor of MXF

Conclusions: : Intravitreal MXF at a dose of 0.5mg/0.1ml is more efficient than [V+C] for the treatment of acute bacterial endophthalmitis secondary to P.aeruginosa and S.epidermidis in an animal model

Keywords: endophthalmitis • drug toxicity/drug effects • retina