Efficacy of Vitrectomy in Improving the Outcome of Bacillus Cereus Endophthalmitis

Abstract

Purpose To evaluate the efficacy of vitrectomy with vancomycin for the treatment of experimental Bacillus cereus endophthalmitis. Methods Endophthalmitis was initiated in rabbits via intravitreal injection of 100 CFU B. cereus. Treatment groups included included 25-gauge transconjunctival sutureless vitrectomy with intravitreal vancomycin (1 mg) or vancomycin alone. Groups were treated at 4 h, 5 h, or 6 h postinfection. At 48 h (for 4 h and 5 h groups) or 36 h (for the 6 h group) postinfection, eyes were analyzed by electroretinography, histology, and inflammatory cell counts. Results Treatment with vitrectomy/vancomycin at 4 h resulted in significantly greater retinal function compared to that of vancomycin alone. Intraocular inflammation following treatment at 4 h was minimal for both treatment groups. Treatment with vitrectomy/vancomycin or vancomycin alone at 5 h or 6 h postinfection resulted in similar levels of retinal function loss (i.e. >90%) and significant intraocular inflammation. Conclusions These results demonstrate that vitrectomy may be of therapeutic benefit in the treatment of B. cereus endophthalmitis, but only during the early stages of infection.

Infectious endophthalmitis: review of 420 cases

“…This surgical procedure can serve as a therapeutic incision for drainage; removing the bulk of infectious organisms and associated inflammatory debris from the eye, providing a large quantity of vitreous for diagnostic smear and culture, and permitting better antibiotics distribution 23. In a rabbit model of endophthalmitis caused by intravitreal injection of Bacillus cereus , Callegan et al demonstrated that eyes treated by combined vitrectomy and intraocular vancomycin during the early stage of infection resulted in significantly greater retinal function compared with that of intraocular antibiotics alone 24. In the current study, 189 eyes with endophthalmitis were treated with a combination of vitrectomy and intraocular antibiotics.…”

Modeling intraocular bacterial infections

“…Vancomycin provides good coverage against Gram-positive bacteria such as Staphylococcus , Streptococcus, Enterococcus , and Bacillus species, and has been shown in the rabbit model to be safe and effective with a single dose (Callegan et al, 2011; Forster, 1992; Park et al, 1999; Smith et al, 1997; Wiskur et al, 2008b; Wiskur et al, 2009). However, vancomycin is still considered a last line of defense against Gram-positive bacteria, because it is often one of the few antibiotics to which multidrug-resistant pathogens are susceptible (Benz et al, 2004).…”

“…Talley et al (1987) reported that vitrectomy with cefazolin and gentamicin resulted in significant vitreal clarity compared to use of antibiotics alone in the S. aureus endophthalmitis model. Forster (1992) tested vitrectomy with infused vancomycin in rabbit models of E. faecalis, S. aureus, S. epidermidis, and B. cereus endophthalmitis and reported that “…vancomycin with or without vitrectomy did not significantly alter the overall inflammatory response to these four endophthalmitis isolates.” Callegan et al (2011) tested the efficacy of vitrectomy and vancomycin in the rabbit model of B. cereus endophthalmitis and reported a therapeutic benefit only if the vitrectomy was performed at four hours post-infection, during the earliest stages of infection when inflammation was minimal. For experimental B. cereus endophthalmitis, vitrectomy with infused vancomycin performed at five or six hours post-infection had no better visual outcomes than treatment with intravitreal vancomycin alone.…”

A Preliminary Study to Treat Severe Endophthalmitis via a Foldable Capsular Vitreous Body with Sustained Levofloxacin Release in Rabbits

“…[14][15][16] Vitrectomy is an appealing adjunct to management, which often is used to debride and remove the nidus of infection, as well as provide much more space for antibiotics, especially in those cases involving intraocular foreign bodies. 17 Meanwhile, retinal detachment is one of the most serious complications of endophthalmitis and occurs with a 21% incidence 18 after vitrectomy procedures due to inadequate support to the retina. In response to these problems, artificial vitreous substitutes should be implanted to refill the vitreous cavity, improve anatomic stabilization, and reduce the risk of retinal detachment.…”