Characterization of ocular fungal infections in Egypt

ABSTRACT

Ocular fungal infections, or oculomycosis, are being increasingly recognized as an important cause of morbidity and blindness. Keratitis is the most frequent presentation, but the orbit, lids, lacrimal apparatus, conjunctiva, sclera and intraocular structures may also be involved. The true extent of visual impairment is thought to far exceed the recognized prevalence, particularly among agricultural workers in the developing world, where a "silent epidemic" of corneal blindness has been postulated. Mycotic keratitis may account for more than 50% of all cases of culture-proven microbial keratitis, especially in tropical and subtropical areas. An overwhelming number of fungal genera and species have been implicated as causes of ophthalmic mycoses, depending on the geographical location and this number is steadily increasing. A rapid and accurate identification of the fungal species causing an ocular infection will permit the immediate institution of specific antifungal therapy. The aim of the present study was to evaluate the usefulness of polymerase chain reaction [PCR] compared with the conventional mycologic methods in the diagnosis of ocular fungal infections. Fifty subjects; in whom oculomycosis was suspected; and 20 controls were enrolled in the study. Specimens were properly collected and tested for the presence of fungi by microscopy, culture and PCR. Direct microscopy and culture were positive in 32 [64%] and 25 [50%] of the cases, respectively. Among the control group, direct microscopy and culture showed positive results in only 2 [10%] and 4 [20%] subjects, respectively. Species-specific PCR was positive for C. albicans and A. fumigatus in 6 [12%] and 7 [14%] cases, respectively, whereas it was positive for A. fumigatus in only one [5%] of the controls. The nonspecific fluorescent staining techniques and PCR are very promising methods, however, culture continues to provide many advantages