[Non-viral infectious keratitis: predisposing factors, etiologic agents and laboratory diagnosis]

Infectious keratitis cause significant morbidity and, if it is not promptly and appropriately treated, can lead to severe ocular disability. Almost all cases of keratitis are associated to predisposing conditions. In occident, the main risk factor is contact lens wear, but previous ocular surgery or trauma are also important, as well as various ocular surface diseases. An enormous diversity of etiologic agents for infectious keratitis exist, including virus, bacteria, mycobacteria, fungi and parasites. This review provides literature and personal based information about main predisposing factors, etiologic agents and pathophysiology of infectious keratitis, excluding those of viral origin. Focus is made on microbiologic procedures, describing stains and media that should be used, and highlighting their utility. A special mention on particular situations is made, including laboratory diagnosis of Acanthamoeba keratitis, utility of lens cases analysis, keratitis in patients with previous treatment, as well as molecular biology techniques described in ophthalmology.