Bacterial keratitis. Therapeutic regimens based an microbiological analysis

Purpose: The study presented differentiates between the aetiological agents of bacterial keratitis in patients with and without a history of contact l ens wear. Based on these results, recommendations are given for optimal ant ibiotic primary therapy. Patients and methods: Swabs and corneal scrapings were taken from 218 patie nts referred to the University Eye Hospital in Munich with a diagnosis of b acterial keratitis from 1989 to 1997. Ninety-two of these patients had a hi story of contact lens wear; 126 had none. The germs were isolated and ident ified by staining and microscopy. Observing polymicrobial growth in 51 pati ents, a total of 275 germs was isolated. Results: The most frequent pathogens were Staphylococcus epidermidis (44%), S. aureus (18%), Streptococcus spp. (10%), Propionibacterium acnes (7%) an d Pseudomonas aeruginosa (6%). Gram-negative germs were nearly exclusively isolated from contact lens wearers, gram-positive germs were predominant in non-contact lens wearers. Conclusion: Keratitis in patients with a history of contact lens wear is of ten caused by aggressive gram-negative germs. Those cases should immediatel y be treated with quinolones and erythromycin. In keratitis caused by gram- positive pathogens, a combination with aminoglycosides and erythromycin is sufficient.