The role of smears, cultures, and antibiotic sensitivity testing in the management of suspected infectious keratitis

Purpose: To examine the role of routine smears, cultures, and antibiotic sensitivity testing in the treatment of suspected infectious keratitis. Methods: A retrospective chart and laboratory data review was performed for 81 consecutive patients seen in the Los Angeles County/University of Southern California Department of Ophthalmology between June 1991 and December 1993 with a primary diagnosis of community-acquired infectious keratitis. No patients were treated with antibiotics before evaluation in the authors' department, and all underwent corneal scrapings for gram-stain and bacterial, fungal, and mycobacterium cultures. Ulcers were classified as moderate or severe. All initially were treated as inpatients with a regimen including fortified cefazolin and a fortified aminoglycoside. Results: Of 81 patients, 74 ulcers were either culture- negative (n = 18) or grew bacteria (n = 56). Fungal infection was suggested in seven patients. Of the nonfungal ulcers, 33 were classified as moderate, and 41 as severe; all moderate ulcers improved without requiring a modification in antibiotic treatment, whereas 3 severe ulcers required a change in treatment. Conclusion: Most community-acquired bacterial ulcers resolve with broad spectrum empiric therapy. Alternatives to universal culture and sensitivity testing that might be considered include selectively performing cultures for more severe or suspected nonbacterial ulcers or routinely obtaining cultures in all cases, but pursuing identification and sensitivity studies only when those data are required for therapy modification.