Study of Pathogens of Fungal Keratitis and the Sensitivity of Pathogenic Fungi to Therapeutic Agents with the Disk Diffusion Method.
OBJECTIVE
To identify the causative fungi of fungal keratitis, test their susceptibility to antifungal agents with the disk diffusion method and study the relationship between the organisms, the inhibition zones and the clinical outcomes.


METHODS
535 patients with fungal keratitis in one eye were included in this study. Pathogenic fungi were isolated by corneal scraping, identified by fungal cultivation and subjected to drug sensitivity tests conducted with the disk diffusion method. The patients were treated initially with voriconazole, terbinafine and natamycin eye drops for one week. Further treatment continued using the most effective drug according to the drug sensitivity results. The patients were followed up every week until three months after cured. The inhibition zones of fungi cultured with voriconazole, terbinafine and natamycin were compared. The relationship between inhibition zones and organism, organism and treatment results measure, and each treatment results measure and inhibition zones were evaluated.


RESULTS
Of 535 patients, 53.84%, 19.25% and 26.91% were infected with Aspergillus, Fusarium and other fungi, respectively. Keratitis patients infected with Aspergillus keratitis had the worst outcome. The size of the inhibition zones of Aspergillus spp., Fusarium spp. and other fungal genera differed significantly in response to voriconazole, terbinafine and natamycin. The inhibition zone associated with natamycin correlated significantly with the clinical outcome of fungal keratitis (OR = 0.925), but no other such correlations were found for the other drugs tested.


CONCLUSIONS
Aspergillus and Fusarium were the predominant pathogenic genera causing fungal keratitis in our patients. Among the causative fungi, infections due to Aspergillus spp. were associated with the worst outcomes. The inhibition zones of fungal isolates in response to natamycin significantly correlated with the treatment outcomes of keratitis. Specifically, the smaller the natamycin inhibition zone, the lower the probability that the fungal keratitis had been eliminated.
a Department of Ophthalmology , Zhengzhou University People's Hospital , Zhengzhou , P.R. China.
Lulu
L
Wang
a Department of Ophthalmology , Zhengzhou University People's Hospital , Zhengzhou , P.R. China.
Liya
L
Wang
a Department of Ophthalmology , Zhengzhou University People's Hospital , Zhengzhou , P.R. China.
Lei
L
Han
a Department of Ophthalmology , Zhengzhou University People's Hospital , Zhengzhou , P.R. China.
Weijing
W
Yin
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000935:Antifungal Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001228:Aspergillosis / Q000188:drug therapy / Q000382:microbiology*; D001230:Aspergillus / Q000187:drug effects / Q000302:isolation & purification; D002648:Child; D003320:Corneal Ulcer / Q000188:drug therapy / Q000382:microbiology*; D052978:Disk Diffusion Antimicrobial Tests; D015821:Eye Infections, Fungal / Q000188:drug therapy / Q000382:microbiology*; D005260:Female; D005658:Fungi / Q000187:drug effects / Q000302:isolation & purification*; D060585:Fusariosis / Q000188:drug therapy / Q000382:microbiology*; D005670:Fusarium / Q000187:drug effects / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009883:Ophthalmic Solutions
D000935:Antifungal Agents; D009883:Ophthalmic Solutions
Disc diffusion method; drug sensitivity; fungal pathogens; inhibition zone; keratitis; treatment results