Bacterial Virulence Predicts Visual Prognosis in Post-Op Bacterial Endophthalmitis

August 01, 2013

By Will Boggs, MD

NEW YORK (Reuters Health) Aug 01 - Bacterial virulence level is the main predictor of visual prognosis in patients who develop acute bacterial endophthalmitis after cataract surgery, researchers from France report.

Although postoperative endophthalmitis occurs in less than 0.1% of cataract procedures, the consequences can include anatomical or functional loss of the eye, the team writes in JAMA Ophthalmology online July 25. Identifying baseline prognostic factors may help find patients who need aggressive therapy as early as possible.

"The (new) report does give impetus to surgeons to obtain sufficient samples (vitreous is best but not always possible, aqueous if vitreous is not available) for PCR analysis so that virulent organisms can be identified if present," said Dr. Neal Shorstein from Kaiser Permanente in Walnut Creek, California, who was not involved in the research but has studied endophthalmitis.

"In addition, arrangements with laboratories can be made so that rapid PCR analysis can be obtained in the event of suspected endophthalmitis," he told Reuters Health by email.

Dr. Christophe Chiquet from University Hospital in Grenoble, France, and colleagues studied visual outcomes prospectively at six months in 99 patients with acute postoperative endophthalmitis occurring within six weeks (median, five days) of cataract surgery. They defined the outcome as good when visual acuity was 20/40 or better and as poor when it was worse than 20/100.

In univariate analysis, winter season, absence of complications during cataract surgery, initial visual acuity, detection of coagulase-negative Staphylococcus species, absence of microorganism detection, fundus visibility, shorter duration of surgery, younger age, and less hypopyon all predicted good visual outcomes.

Factors associated with poor visual outcomes included infection of the right eye, initial poor visual acuity, corneal edema, and detection of a bacterial species other than coagulase-negative Staphylococcus species.

Most of these factors lost significance in multiple logistic regression analysis, which showed high bacterial virulence to be the only independent predictor for poor visual outcome (odds ratio, 14.0; p=0.001). Low bacterial virulence (OR, 0.2; p=0.01) and absence of complications during cataract surgery independently predicted good visual acuity (OR, 0.1; p=0.003).

"Although most patients currently undergo binary treatment, the use of pars plana vitrectomy (PPV) or intravitreal injections and rapid bacterial identification and characterization (especially for virulence and antibiotic resistance) could guide clinicians in adapting the therapy regimen to each patient," the researchers conclude.

"Their conclusion was that more aggressive treatment should be instituted if a virulent organism is identified in a patient," Dr. Shorstein said. "Makes sense. Problem is, depending on the report, 1/3 or more of patients with infection do not yield an identifiable organism with non-PCR bacterial culture. Not every facility has PCR testing available for organism identification, and as the report indicates, if they do, the turnaround may be several days when significant damage might have already occurred."

Dr. Chiquet did not respond to a request for comments.


JAMA Ophthalmol 2013.


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