Transcript A Case of Beauveria Bassiana Keratitis Confirmed by Gene

A Case of Beauveria Bassiana Keratitis
Confirmed by Gene Sequencing
Sung-Dong Chang, M.D., Jong-Hwa Jun, M.D.
Department of Ophthalmology, School of Medicine,
Dongsan Medical Center,
Keimyung University, Daegu, Korea
INTRODUCTION
Beauveria genus is composed by the insect pathogens, soil fungus, and Beauveria
bassiana is distributes worldwide. 8 cases of human infection, and 4 cases of ocular
infection have been reported. Ocular infection induces very severe keratitis, and
surgical removal such as deep lamellar dissection or penetrating keratoplasty of
infected tissues is required. As the diagnosis, in most cases, early diagnosis is difficult
resulting in the administration of antifungal agents under the condition that
keratomycosis is progressed substantially, and thus early appropriate treatment is
delayed and poor prognosis is shown. Among cases reported until now, none of cases
was definitely diagnosed by gene sequencing for more early diagnosis, and it is
considered that for cases suspicious to be fungal keratomycosis, by performing gene
sequencing, it could be definitely diagnosed early and aggressive treatments could be
administered, hence, the prognosis of patient could be improved
CASE
•
A 70 years old male patient visited our clinic for
the chief complaint of the progressive deterioration
of the visual acuity after injury with a splint in the
left eye 1 week ago. In the past history, he had a
history of chemotherapy due to nasopharyngeal and
gastric cancer, and the past history of ocular surgery
was not shown. The visual acuity of the left eye was
A
0.06, and the intraocular pressure of the left eye was
8 mmHg. In the slit lamp examination, severe
conjunctival injection and follicular hypertrophy were
shown, and after fluorescein staining, in the slightly
nasal side of the corneal center of the left eye, linear
epithelial
defect
0.7*1.0
mm
in
size
was
detected(Figure A,B)
B
CASE
•
In the vicinity, infiltration of immune cells, Desmets’
membrane folds, and edema findings in the stroma were
detected, and in the border of the epithelial defect, a
pattern of the slight elevation of the healed epithelium
was shown. In the anterior chamber, weak inflammation
findings and flare were detected. Smear and culture test
were performed by corneal scraping, and in the smear
A
test, special findings were not detected (Figure A)
•
During
the
follow
up
observation
while
administering antibiotic eye drops, approximately after 2
weeks, the size of epithelial defect was increased to
3.7*2.7 mm, and the pattern of the augmentation of
inflammation findings in the anterior area was shown
(Figure B)
B
CASE
•
At the 5 weeks of the treatment, smear and culture were
repeated, and several hyphae were detected, and thus the sample
was cultured in Sabouraud dextrose agar, it was suspected to be
Beauveria spp, and gene sequencing was performed by the use of
the MicroSeq D2 LSU r DNA fungal sequencing kit, and it was
identified to be Beauveria bassiana. Natamycin eye drops were
administered every hour, and at the 7 weeks of treatment, the
A
epithelial defect showed a pattern to be slightly decreased, however,
due to the thinning of the stroma caused by ongoing destruction,
Desmatocele was developed and thus amniotic membrane
transplantation was performed (Figure A)
•
After amniotic membrane transplantation, amphotericin B eye
drops were administered additionally, and at the 1 week of treatment,
the epithelial defect was healed completely, and noticeable reduction
of inflammation in the anterior chamber could be observed (Figure B)
B
DICUSSION
Recently, the incidence of keratomycosis shows a trend to be increased continuously due to
the expanded use of antibiotics, steroid, and immunosuppressant, and consequently,
interests on it are on the rise. Among them, regarding Beuaveria bassiana, prior to the
infection in the cornea in 1985 by Sachs et al. for the first time, it has been known to be a
fungus with weak pathogenicity that could not induce keratomycosis. After the report in
1985 by Sachs et al. infection cases such as keratomycosis, deep tissue infection, fungal
empyema, disseminated infection, etc. have been reported, and particularly, it has been
reported that upon the development of keratomycosis, it is detected to be negative in
fungus culture by corneal scraping in many cases, and early appropriate fungus treatment is
delayed in many cases, hence, even in cases definitely diagnosed to be fungus
keratomycosis, surgical treatments such as penetrating keratoplasty are required in most
cases
DICUSSION
In keratomycosis cases, 4 cases have been reported, and for 3 cases required surgical
treatments, penetrating keratoplasty was performed in 2 cases, and 1 case was treated by
deep lamellar dissection, and regarding cases treated with medical management, Kisla et al.
have reported 1 case, and thus for cases developed keratomycosis, surgical treatments were
required in most cases. In our case, in the second corneal scraping test, several hyphae were
detected, and thus medical agents were switched to natamycin eye drop, and afterward, it
showed a pattern to be improved, nonetheless, because of the progressive destruction of
the stroma, permanent amniotic membrane transplantation was required. Afterward,
amphotericin B eye drops were administered additionally, and the epithelial defect and cell
infiltration findings in the vicinity were improved rapidly, and without penetrating
keratoplasty, his ocular intergrity could be maintained.
Conclusion
Different from previously reported 8 cases of human infection, in our case, by fungal
culture, Beauveria spp. was suspected, and thus for its definite diagnosis, gene sequencing
was performed, and it could be ultimately diagnosed as Beauveria bassiana, and with the
aggressive use of antifungal agents, the rapid improvement pattern of keratitis could be
observed. In our case also, the initial diagnosis by corneal scraping and culture failed, the
disease course was prolonged, the level of corneal destruction was severe, and amnion
membrane transplantation was required, and it is considered that from now, for cases
suspected to be fungal keratomycosis, by the application of aggressive diagnosis methods
such as gene sequencing, and by the administration of of appropriate antifungal agents,
conservation of the eye could be achieved.