Case of Keratitis Caused by an Uncommon Fusarium Species

Abstract

Fusarium polyphialidicum caused a corneal ulcer in a Spanish man. Diagnosis was established by a histopathological study and repeated cultures. The isolate was clearly resistant in vitro to the antifungal agents tested. This is the first case of human or animal mycosis by this rare fungus. CASE REPORTA 65-year-old Spanish male was referred to the Ophthalmology Service of the Lozano Blesa University Hospital in Zaragoza on 5 June 2000 because of acute keratitis in his left eye. Approximately 1 month earlier, the patient suffered a nonpenetrating foreign-body injury when he was working on his farm. Since then, he had complained of increasing disturbance in the eye. On examination, he showed a central corneal ulcer of ca. 4 mm in diameter with irregular borders, slight infiltration, and a thinned weakness but with no risk of perforation. A hypopyon 1.2 mm high was also observed. Visual acuity was 1 to 200. The right eye showed no abnormality. Results of other local and systemic examinations were negative.Deep corneal scrapings were collected with a sterile scalpel blade for fungal and bacteriological cultures. The corneal scrapings were inoculated directly onto Sabouraud glucose agar (Oxoid, Basingstoke, England) and incubated at 25 and 37°C. After 2 days, numerous small whitish colonies appeared on all cultures. All the colonies were apparently identical, and the fungus was identified as Fusarium sp. The results of routine bacteriological cultures were negative. Since the fungus was detected, treatment was initiated with 0.5% amphotericin B applied topically every hour. However, after a week, the condition of the eye worsened; the corneal infiltration and hypopyon increased. The ulcer became torpid and enlarged into a deepening corneal abscess and endophthalmitis. More corneal scrapings were collected for new cultures, which were again negative for bacteria and positive for the same fungus recovered previously. A corneal transplant was performed on 30 June. Cultures from a biopsy of the excised cornea again yielded the same Fusarium sp. Portions of the cornea were fixed in 10% formalin, embedded in paraffin, sectioned, and stained with hematoxylin and eosin. Sections of the stained tissue revealed short, contorted, hyaline, septate, hyphal fragments (Fig. 1). The transplanted eye improved considerably, and therefore the patient was discharged. In September 2000, the patient presented a visual acuity of 20 to 40 in the affected eye.The clinical strain was sent to the Faculty of Medicine of the Rovira i Virgili University in Reus, Spain, to be identified and to determine its antifungal susceptibility.Mycological study and diagnosis. For identification purposes, the fungus was subcultured on potato dextrose agar (PDA; Difco Laboratories, Detroit, Mich.) and oatmeal agar (30 g of oat flakes, 1 g of MgSO 4 ⅐ 7H 2 O, 1.5 g of KH 2 PO 4 , 15 g of agar, 1,000 ml of tap water) and incubated at 25, 37, and 40°C in darkness. After 12 days at 25°C, the colonies on PDA attained a diameter of 68 to 70 mm and those on oatmeal ag...

Phylogenetic Diversity and Microsphere Array-Based Genotyping of Human Pathogenic Fusaria, Including Isolates from the Multistate Contact Lens-Associated U.S. Keratitis Outbreaks of 2005 and 2006

“…Members of two other evolutionary lineages were identified, but they are both represented by a single known keratitis isolate, Fusarium sp. strain NRRL 43641 from a horse in Missouri and F. concolor from a human corneal ulcer in Spain (14). Although we genotyped several isolates from the FCSC, including human and equine corneal isolates from Florida (NRRL 43632) and Texas (NRRL 43636), respectively, there is only one published report of a member of this species complex causing keratitis (26).…”

Fusariumkeratitis and contact lens wear: facts and speculations

“…Although the triazoles voriconazole and posaconazole show relatively poor in-vitro activity against Fusarium sp. [76,77], therapeutic efficacy with these triazoles (notably posaconazole) has been achieved in several refractory Fusarium keratitis cases that had included unsuccessful topical and intravitreal AMB injections [72,78,79]. Of the 66 confirmed keratitis cases reported by Khor et al [25] and the 154 summarized by Chang et al [23] at least 7% and 34%, respectively, underwent keratoplasty.…”

Endophthalmitis Caused by Fusarium proliferatum

“…When this infection is caused by Fusarium, the only effective treatment is amphotericin B due to the fact that Fusarium is resistant to fluconazole (20,28). Furthermore, it is not uncommon to find Fusarium strains that are resistant to amphotericin B (12,20,37), leaving the patient untreated. In other cases, a combined therapy with oral imidazoles (fluconazole or ketoconazole) and topical natamycin was administered but was ineffective (15,31,37,39).…”