Prophylaxis of experimental Pseudomonas aeruginosa endophthalmitis after vitrectomy using ceftazidime in the irrigating solution

Abstract

Purpose: To test the efficacy of ceftazidime in irrigating solution during vitrectomy to prevent experimental Pseudomonas aeruginosa endophthalmitis.

Methods: Thirty-two rabbit eyes were divided into 6 groups. Vitrectomy using one of two different irrigating solutions was followed by intravitreal injection of P. aeruginosa: Group 1, balanced salt solution (BSS) followed by 100 colony-forming units (CFU) P. aeruginosa; Group 2, BSS fortified with ceftazidime 175 microg/mL (CBSS) followed by intravitreal injection of 100 CFU P. aeruginosa; Group 3, BSS followed by 500 CFU P. aeruginosa; Group 4, CBSS followed by 500 CFU P. aeruginosa; Group 5, BSS followed by 5000 CFU P. aeruginosa; and Group 6, CBSS followed by 5000 CFU P. aeruginosa. The eyes were examined clinically. Vitreous samples were cultured and histology was performed.

Results: Group 1: Three of 5 eyes showed mild to moderate vitreous opacities. Group 2: No vitreous opacities developed. Group 3: All eyes demonstrated endophthalmitis. Group 4: All 6 eyes had clear vitreous with visible fundus. Group 5: Severe endophthalmitis occurred in all 6 eyes. Group 6: Four eyes had clearly visible fundus, 2 eyes had hazy vitreous with red reflex of the fundus. Bacterial growth in groups 3, 4, 5, and 6 was seen in 4/4, 1/6, 6/6, and 0/6 eyes, respectively.

Conclusion: When 100-5000 CFU P. aeruginosa were injected after vitrectomy, ceftazidime in the irrigating solution inhibited the signs of intraocular inflammation, and the rate of positive bacterial culture.