A Case of Beauveria Bassiana Keratitis Confirmed by Gene Sequencing

1
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
2
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

3
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 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 0.71.0 mm in size was
  detected(Figure A,B)

A
B
4
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 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 3.72.7 mm, and the pattern of the
  augmentation of inflammation findings in the
  anterior area was shown (Figure B)

A
B
5
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 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)

A
B
6
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

7
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.

8
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.