March 2009




Endophthalmitis cases tied to Citrobacter species

by Vanessa Caceres EyeWorld Contributing Editor


All but one case had poor visual outcomes

A 3-mm corneal laceration (arrow), exudation in anterior chamber, and traumatic cataract were identified in this patient.

During the surgery, a fundal photograph showed diffuse arterial and venous vasculitis. Source: Kuan-Jen Chen, M.D.

An unusual gram-negative bacteria with devastating ocular effects has been linked to a number of endophthalmitis cases in Asia, reports a study published in the July 2008 issue of Ocular Immunology & Inflammation.

The investigators in the study, led by Kuan-Jen Chen, M.D., Department of Ophthalmology, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine Kwei-Shan, Taoyuan, Taiwan, reported six cases of endophthalmitis linked to Citrobacter. The patients had culture-proven C. freundii (four cases) or C. koseri (two cases). Citrobacter species are associated in humans with urinary tract infections, wound infections, pneumonia, abscesses, meningitis, and other severe health problems, the investigators wrote. They are also known to cause infections in animals. Both C. freundii and C. koseri are regarded as opportunistic pathogens, Dr. Chen said.

Although a handful of case studies report endophthalmitis associated with Citrobacter, investigators wanted to take a closer look at the clinical settings, antibiotic sensitivities, and visual outcomes in their group of six patients. Of the six patients, two had undergone cataract surgery (including one with cataract surgery combined with trabeculectomy), two had ocular trauma, one had a penetrating keratoplasty, and one was presumed to have an endogenous cause.

Surgeons had to perform evisceration in three eyes because of endophthalmitis. In three eyes, an initial pars plana vitrectomy with intravitreal antibiotics was performed. “Final visual acuity was no light perception in five eyes, and one patient with traumatic C. koseri endophthalmitis achieved a final vision of 20/30,” the investigators wrote.

Here are some more details on the patients’ treatment course.

Details on the six cases

The first patient was a 63-year-old woman who had phacoemulsification in her left eye; she presented with endophthalmitis on post-op day one. She had a visual acuity of hand motions, corneal edema, a 1-mm hypopyon, and a fibrinous reaction in her anterior chamber. Surgeons treated her with a pars plana vitrectomy and intravitreal vancomycin (1 mg/0.1 mL), amikacin (0.4 mg/0.1 mL), and dexamethasone (0.4 mg/0.1 mL). She continued to receive topical vancomycin and amikacin every hour for a week. By day 14, her inflammation was reduced, and she had a visual acuity of 10/200. However, six weeks later, the patient complained of an inferior visual field defect, and a retinal tear was found. Despite treatment, her retina totally detached, and within six months she was left with a phthisical eye and a visual acuity of no light perception.

The second patient was a 30-year-old man who had experienced ocular trauma. He had a primary suture in the left eye when he was 15 years old, and he had perception of light in that eye. He was referred for endophthalmitis after he experienced eye pain for two days and intermittent chills and fever for one week. “Slitlamp examination revealed a 3-mm hypopyon and a dense fibrin plaque over the pupil,” the investigators wrote. He was treated with intravitreal vancomycin and amikacin, followed by topical vancomycin and amikacin every hour. He then also received intravenous cefazolin and gentamicin after a blood test revealed a white cell count of 23,700/microliters. “On day three post-treatment, corneal infiltration with perforation was present, and he received evisceration with [a] silicone ball implant. After system evaluation, the infection source wasn’t identified, and the cause of endophthalmitis was presumed to be endogenous,” investigators wrote.

Patient three was a 67-year-old diabetic woman who had a penetrating keratoplasty in her right eye because of pseudophakic bullous keratopathy. Gentamicin and dexamethasone were injected subconjunctivally; on post-op day two, she was found to have a fibrinous reaction over the pupil and presumed vitreous hemorrhage. The patient received topical gentamicin four times a day and prednisolone acetate every hour for a week. Thirteen days later, the patient had eye pain, a visual acuity of hand motions, an IOP of 44 mm Hg, a corneal graft that showed diffuse infiltration with melting, and diffuse dense vitreous opacity.

The patient was treated with intravitreal ceftazidime, amikacin, and topical vancomycin and amikacin every hour. Nonetheless, three days later she did not have any light perception. Surgeons performed evisceration.

The fourth patient, a 71-year-old man, complained of eye pain and decreased vision for four days after corneal perforation by an iron wire in the left eye. On examination, the patient was found to have a central corneal wound, diffuse corneal infiltration, total hypopyon, and dense vitreous opacity. The patient was treated with intravenous cefazolin and amikacin and topical amikacin.

“Panophthalmitis was diagnosed, and evisceration was performed,” the investigators wrote.

Patient five was a 43-year-old man who had a corneal perforation from an iron fragment that entered the left eye while using a lawn mower. In addition to a visual acuity of hand motions at presentation, he also complained of eye pain. Examination revealed a 3.5-mm full-thickness corneal laceration, fibrin over the papillary margin, traumatic cataract, and a high density of foreign body in the vitreous cavity. As intraocular foreign body and traumatic endophthalmitis were diagnosed, emergency surgery was performed. Surgeons performed primary suture of the corneal laceration, pars plana lensectomy with vitrectomy, and removal of the foreign body. After surgery, the patient received intravitreal injections of vancomycin and amikacin, along with intravenous vancomycin and ceftazidime and topical vancomycin and amikacin every hour. Because of persistent eye pain, the patient received intravitreal injections of amikacin and dexamethasone on day four. By day 10, inflammation had decreased, and visual acuity improved to counting fingers. At six weeks, best-corrected visual acuity (BCVA) was 20/60, and an IOL was implanted. At three months, the patient had a BCVA of 20/30.

The sixth and final patient was an 80-year-old man with cataract and primary angle-closure glaucoma who had phacoemulsification and trabeculectomy in the left eye. On post-op day 13, he complained of eye pain and blurry vision. He had no light perception in the left eye, and examination showed corneal edema, a 6-mm hypopyon, a dense fibrinous membrane in the anterior chamber, and moderate vitreous opacity.

The patient was treated immediately with pars plana vitrectomy and intravitreal injections of vancomycin and amikacin, followed by hourly doses of topical vancomycin and amikacin, along with 1% prednisolone acetate four times a day. However, within three months, the left eye was phthisical, with no perception of light.


All cases of endophthalmitis occurred within 13 days after surgery or after trauma, the study reported. Investigators found it disconcerting that visual outcomes were poor in almost all patients. “Antibiotic resistance in Citrobacter species, as in other bacteria-causing nosocomial infections, is an emerging problem,” Dr. Chen said. “Intravitreal antibiotics aminoglycoside or ceftazidime against Citrobacter species can still be applied.” The use of intravitreal antibiotics is the most important therapy component to fight infection in acute-onset bacterial endophthalmitis, the investigators wrote.

Cefuroxime and vancomycin or vancomycin with amikacin are each good combined choices to use in cases like the ones presented in this study, said J.E. “Jay” McDonald, M.D., Fayetteville, Ark.

Also, “Early pars plana vitrectomy dramatically may reduce the inflammatory debris in the vitreous cavity, provide a large specimen for diagnostic evaluation, and achieve a higher possibility of favorable visual outcome,” Dr. Chen said.

Clinicians should encourage patients to see their doctors as soon as possible after ocular trauma or penetrating injury, investigators wrote.

Patients in the United States may be more likely to seek medical attention earlier, which is why the visual outcomes reported here don’t occur as often, Dr. McDonald said. Terry Kim, M.D., associate professor of ophthalmology, Duke University School of Medicine, Durham, N.C., finds it interesting that a gram-negative organism such as Citrobacter has had such a range of cases in Taiwan but is not commonly seen in the United States. “It would be interesting if this represents a coincidental series of cases seen in Taiwan versus a growing trend either nationally or worldwide,” he said. “The issue of resistance against these gram-negative organisms is, of course, concerning as well.”

Editors’ note: Dr. Chen has no financial interests related to this study. Dr. McDonald has financial interests with AcuFocus (Irvine, Calif.), Alcon (Fort Worth, Texas), and Bausch & Lomb (Rochester, N.Y.), among other companies. Dr. Kim has financial interests with Alcon, Allergan (Irvine, Calif.), and Bausch & Lomb, among other companies.

Contact information

Kim: 919-681-3568,
McDonald: 479-521-2555,

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