keratomycosis caused by filamentous fungi rapidly progress deep into the stroma with edematous infiltrations , often accompanied by a severe anterior chamber inflammation . in contrast
, some species of filamentous fungi , such as alternaria , can cause mild superficial corneal infections .
unfortunately , these are frequently misdiagnosed as a bacterial corneal infection ( suzuki et al 2004 ) . here ,
we report a superficial keratomycosis caused by the filamentous fungus , beauveria bassiana ( b. bassiana ) , and its successful treatment with voriconazole ( vcz ) .
an 80-year - old woman struck her left eye with the frame of her glasses . due to continuing ocular pain and hyperemia , she was referred to our hospital 9 days after the original injury .
the patient was also suffering from recurrent diabetic iritis and continuously used topical antibiotics and corticosteroids . at the time of her first visit to our hospital , there was ulceration of the corneal epithelium at the 5 oclock region along with slight superficial infiltration , slight edema , and ciliary injection . no endothelial plaques or any immune rings
although a part of the descemet s membrane was folded , there was only slight anterior chamber inflammation ( figure 1 ) .
a corneal scraping smear indicated the presence of gram - positive fungal septate hyphae with budding ( figure 2a ) , which led to a diagnosis of keratomycosis by filamentous fungus .
positive staining by fungiflora y also supported the keratomycosis diagnosis . from the culture of the corneal scraping
, we were able to isolate a whitish yellow colony , with the fungus exhibiting zigzag rachis and oval conidia , which are characteristics of b. bassiana in slide cultures ( figure 2b ) .
two different microbiology laboratories , the department of the laboratory for clinical investigation at osaka university hospital and the chiba university research center for pathogenic fungi and microbial toxicoses , independently confirmed the presence of the organism .
the patient was managed with topical 0.1% miconazole ( mcz ) , 1% vcz once an hour , and 1% pimaricin ( pmr ) ointment administered once a day along with oral itraconazole ( itcz : 100 mg / day ) . although there was gradual amelioration of the lesion , the presence of a band - shaped calcium deposit interrupted the re - epithelization , requiring the deposit to be scraped off on two different occasions during the healing process .
the lesion healed with only mild scarring remaining after two months . in order to determine the minimum inhibitory concentration ( mic ) required for each of the antimycotic agents , asty and e - test in vitro susceptibility tests
the results for the mic tests were : amphotericin - b : 8.0 , 5-fc : 64 , fluconazole ( fcz ) : 256 , itcz : 0.25 , mcz : 0.5 , mica - fangin ( mcfg ) : 0.5 , and vcz : 0.5 ( g / ml ) .
in addition , the organism was also found to be susceptible to topically applied antimycotic agents that included , 0.5% vcz , 5% pmr , and 0.5% mcz , which were administered by the disk method ( figure 3 ) .
vcz is a powerful antimycotic agent that is used against filamentous fungi ( ozbek et al 2006 ; sponsel et al 2006 ; bunya et al 2007 ; lee et al 2007 ; thiel et al 2007 ) .
although treatments of five cases of beauveria corneal infection , four cases of b. bassiana , and one case of b. alba have been previously reported , for most of these patients , they also required an additional surgical procedure , such as penetrating keratoplasty or keratectomy , to completely manage the keratomycosis ( ishibashi et al 1984;mcdonnell et al 1984 ; sachs et al 1985 ; low et al 1997 ; kisla et al 2000 ) . in order for a successful treatment to be performed without any additional surgical procedures ,
there needs to be an effective therapeutic regimen for antimycotic agents that can be applied in cases involving filamentous fungi .
for example , in the present case , we administered vcz and our data indicated that vcz might have been the crucial factor that was responsible for the success of the treatment .
we decided to confirm the sensitivity of the antimycotic agents at their topically applied concentrations , as the sensitivity judged by the clsi standard is based upon serum concentrations , which might not always be identical to the sensitivity of the topically applied antimycotic agents .
although mcz , pmr , itcz were also effective in the treatment of our patient , the result of sensitivity test using disk method indicates that vcz was the most effective agent for b. bassiana infections .
it is also important to emphasize two characteristics of b. bassiana keratomycosis that were observed in our patient .
first , we clinically noted that the keratomycosis caused by b. bassiana was restricted to the superficial cornea .
this differs from other filamentous fungi , as the pathogenesis for b. bassiana is relatively weak and does not cause severe stromal infiltration or anterior chamber inflammation , as has been reported for the rabbit model ( ishibashi et al 1987 ) .
since the lesion caused by b. bassiana extended horizontally and not vertically within the stroma , endothelial plaque and anterior inflammation were not evoked .
on the contrary , aspergillus and fusarium , which are representative filamentous fungi of keratomycosis , will in general quickly invade deeply into the corneal stroma and induce endothelial plaque and hypopyon .
the second notable characteristic of b. bassiana in slide cultures is the presence of septate hyphae with budding and zigzag filaments at the apex .
this characteristic appearance can be used to distinguish it from the features of aspergillus and fusarium .
thus , an early smear diagnosis based on these characteristics might help to ensure a successful treatment with antimycotic agents .
however , b. bassiana is found in plants and in the soil , and because this organism is entomopathogenic , it is used as a biologic for pesticides ( posada et al 2007 ; safavi et al 2007 ) thus , the possibility exists that while the patient was working outdoors , the frame of her eyeglasses was contaminated and upon the ocular injury that was caused by the frame of her eyeglasses , the fungi were able to invade through the damaged tissue .
our patient had a long history of recurrent diabetic iritis and continuously used topical corticosteroid .
this immunocompromized situation also triggered the colonization of the fungi . in conclusion , a weak pathogenic filamentous fungus with zig - zag rachis and budding , as determined by smear , may account for b. bassiana .
vcz proved to be a powerful tool that not only was successfully used in the current case , but also in the future might be an agent that can be used therapeutically to treat similarly infected types of patients .
 clinical findings and treatment of keratomycosis caused by beauveria bassiana , an entomopathogenic filamentous fungus , are described for an 80-year - old woman , who was referred to the hospital for ocular pain and redness on the 9th day after an ocular injury caused by the frame of her glasses . 
 she had a long history of recurrent diabetic iritis and continuously used topical antibiotics and corticosteroids . at her first visit , a slit - lamp examination indicated a corneal ulcer confined within the superficial stromal layer , along with a slight infiltration and edema . 
 only a very few inflammatory cells were seen in the anterior chamber . 
 direct microscopic examination of corneal scrapings revealed septate fungal hyphae with zig - zag rachis and budding that was subsequently identified as b. bassiana by slide culture . 
 topical voriconazole with miconazole , pimaricin and oral itraconazole were effective and the lesion disappeared leaving only a mild scar at 2 months . 
 the sensitivity of b. bassiana to various antimycotic agents was confirmed by broth microdilution , agar dilution with the clinical laboratory standard institute standard , and a disk method using topically applied concentrations . 
 b. bassiana , which exhibits a characteristic appearance in smears and causes superficial keratomycosis , is sensitive to voriconazole with miconazole , pimaricin , and itraconazole . 