Contributor: Gordon K. Klintworth
Bacterial endophthalmitis is an endophthalmitis caused by bacteria. This bacterial infection may be an endogenous endophthalmitis, but most often it follows intraocular surgery, accidental penetrating trauma, bacterial keratitis [keratitis - bacterial], scleritis, or bacterial conjunctivitis [conjunctivitis - bacterial]. Infections of the conjunctiva, cornea or sclera can also invade the eye. Bacteria that have been isolated from eyes with endophthalmitis include Neisseria meningitidis, Klebsiella pneumoniae [endophthalmitis -Klebsiella], Bacillus cereus, Escherichia sp, Pseudomonas sp., Clostridium perfringens, Staphylococcus aureus, Streptococcus viridans, Brucella [brucellosis]. Important causes of bacterial endophthalmitis are penetrating injuries of the eye and ocular surgical procedures. The potential for postoperative bacterial endophthalmitis is a major concern in many ocular operations of the eye. These infections are importanf complications of cataract extractions and filtering procedures for glaucoma. The fistula created in individuals undergoing trabeculectomy for glaucoma  produces a  potential path for microorganisms to enter the eye and infected filtering blebs spread directly and rapidly into the eye. Bacterial endophthalmitis is an uncommon complication of cataract extraction (0.09-0.5%), but the frequency of this procedure produces numerous cases. A considerable number of cases of post-surgical endophthalmitis represent nosocomial infections due to bacteria on the eyelids and conjunctiva that are inadvertently implanted during surgery. Examples include S. epidermidis, but also S. aureus, Streptococcus sp., Proteus sp. and Proprionibacterium acnes (the most frequently recovered anerobic microorganism).