Fungal panophthalmitis secondary to Scedosporium apiospermum (Pseudallescheria boydii) keratitis

Pseudallescheria boydii keratitis

A case of Pseudallescheria boydii keratitis is presented. The patient was successfully treated with topical natamycin and systemic itraconazole in conjunction with penetrating keratoplasty, leading to visual acuity of 20/40.

[A case of Scedosporium apiospermum keratitis confirmed by a molecular genetic method]

A 54-yr-old male, who was treated by chemotherapy for gastric cancer 15 months ago, presented to Yongdong Severance Hospital, Seoul, with complaints of pain in his right eye caused by a foreign body from the ground in the previous week. He had been treated with topical and oral antibacterial in addition to antifungal agents, but did not show significant clinical improvement. After a positive corneal culture with mold, topical amphotericin B was added to the initial regimen. The mold was identified as Scedosporium apiospermum by macroscopic and microscopic morphologies and the nucleotide sequences of a fungal PCR product showing 99% homology with those of S. apiospermum (EF151349). He recovered with good results at 25 days after corneal epithelial debridement. The early diagnosis of S. apiospermum keratitis is very important for proper treatment. It is recommended that molecular diagnostic methods such as fungal PCR and sequencing be done with conventional cultures whenever a fungal infection is suspected.

Infections caused by Scedosporium spp

Scedosporium spp. are increasingly recognized as causes of resistant life-threatening infections in immunocompromised patients. Scedosporium spp. also cause a wide spectrum of conditions, including mycetoma, saprobic involvement and colonization of the airways, sinopulmonary infections, extrapulmonary localized infections, and disseminated infections. Invasive scedosporium infections are also associated with central nervous infection following near-drowning accidents. The most common sites of infection are the lungs, sinuses, bones, joints, eyes, and brain. Scedosporium apiospermum and Scedosporium prolificans are the two principal medically important species of this genus. Pseudallescheria boydii, the teleomorph of S. apiospermum, is recognized by the presence of cleistothecia. Recent advances in molecular taxonomy have advanced the understanding of the genus Scedosporium and have demonstrated a wider range of species than heretofore recognized. Studies of the pathogenesis of and immune response to Scedosporium spp. underscore the importance of innate host defenses in protection against these organisms. Microbiological diagnosis of Scedosporium spp. currently depends upon culture and morphological characterization. Molecular tools for clinical microbiological detection of Scedosporium spp. are currently investigational. Infections caused by S. apiospermum and P. boydii in patients and animals may respond to antifungal triazoles. By comparison, infections caused by S. prolificans seldom respond to medical therapy alone. Surgery and reversal of immunosuppression may be the only effective therapeutic options for infections caused by S. prolificans.

[Fungal keratitis caused by Scedosporium apiospermum]

INTRODUCTION

We report a case of posttraumatic keratomycosis caused by Scedosporium apiospermum that was treated with oral and topical voriconazole and penetrating keratoplasty.

CASE REPORT

A patient was admitted to the hospital with a corneal abscess of his right eye due to trauma while gardening. No improvement was noted with topical fortified antibiotics (vancomycin, gentamicin, and cefazolin) and antimycotic (amphotericin B 1%) and oral itraconazole (200 mg/day). Fungal cultures of corneal scrapings revealed growth of Scedosporium apiospermum, a strain for which the main antifungals showed high minimal inhibitory concentrations (MICs), whereas the MIC of voriconazole was 0.125 microg/mL. Despite some improvement with topical 1% voriconazole and oral voriconazole (200 mg/day) treatment, a therapeutic penetrating keratoplasty was performed because of the high risk of corneal perforation. The graft remained clear without fungal recurrence with topical 2% cyclosporine A, dexamethasone, and voriconazole treatment.

CONCLUSION

Scedosporium apiospermum is an uncommon cause of mycotic keratitis in humans. Prognosis is generally poor because of delayed diagnosis and resistance to conventional antifungals. Voriconazole is a triazole broad-spectrum antifungal agent. In conjunction with its oral administration, topical application of voriconazole extends the current armamentarium of antifungal agents for keratomycosis.

Infections Due to Scedosporium apiospermum and Scedosporium prolificans in Transplant Recipients: Clinical Characteristics and Impact of Antifungal Agent Therapy on Outcome

BACKGROUND

Unique characteristics, impact of therapy with antifungal agents, and outcome of infections with Scedosporium species were assessed in transplant recipients.

METHODS

The patients comprised a total of 80 transplant recipients with Scedosporium infections, including 13 patients from our institutions (University of Pittsburgh Medical Center [Pittsburgh, PA], University of Maryland [Baltimore], Duke University Medical Center [Durham, NC], Emory University [Atlanta, GA], and Hospital Gregorio Maranon [Madrid, Spain]) and 67 reported in the literature. The transplant recipients were compared with 190 non-transplant recipients with scedosporiosis who were described in the literature.

RESULTS

Overall, 69% of the infections in hematopoietic stem cell transplant (HSCT) recipients and 53% of the infections in organ transplant recipients were disseminated. HSCT recipients, compared with organ transplant recipients, were more likely to have infections caused by Scedosporium prolificans (P=.045), to have an earlier onset of infection (P=.007), to be neutropenic (P<.0001), and to have fungemia (P=.04). Time elapsed from transplantation to Scedosporium infection in transplant recipients has increased in recent years (P=.002). The mortality rate among transplant recipients with scedosporiosis was 58%. In a logistic regression model using amphotericin B as comparison treatment, voriconazole was associated with a trend towards better survival (odds ratio [OR], 10.40; P=.08). Presence of disseminated infection (OR, 0.20; P=.03) predicted lower survival, and receipt of adjunctive surgery as treatment (OR, 5.52; P=.02) independently predicted a better survival in this model.

CONCLUSIONS

Scedosporium infections in transplant recipients were associated with a high rate of dissemination and a poor outcome overall. The use of newer triazole agents warrants consideration as a therapeutic modality for these infections.

Voriconazole in Fungal Keratitis Caused by Scedosporium apiospermum

OBJECTIVE

To describe the first case, to the best of our knowledge, of posttraumatic Scedosporium apiospermum (ScA) keratitis successfully treated with systemic and topical voriconazole.

CASE SUMMARY

A 19-year-old man was admitted to the hospital with an incisive wound of his left eye and the cornea totally sectioned after trauma with a cutter used in gardening. Initial empirical treatment was followed by systemic and topical voriconazole, and the eye did not have to be enucleated. Five months after the trauma, a penetrating keratoplasty and chamber intraocular lens implantation was performed with a favorable visual outcome.

DISCUSSION

ScA keratitis is rare, but it must be suspected if a history of ocular injury with contaminated objects exists. Among the antifungals available to treat ScA keratitis, voriconazole has shown advantages such as the lowest minimum inhibitory concentration and the availability of an oral formulation.

CONCLUSION

Voriconazole shows promise as an effective alternative to conventional antifungals in the treatment of ScA keratitis. It is available both as oral and intravenous preparations, which is a great advantage in these lengthy infections.

Scedosporium apiospermum keratitis treated with itraconazole

Mycotic keratitis usually occurs in conjunction with trauma to the cornea. Scedosporium apiospermum, a dematiaceous fungus linked to the teleomorph Pseudallescheria boydii is not a common agent of mycotic keratitis. A 22-year old male patient with mycotic keratitis due to S. apiospermum is presented. In in vitro susceptibility testing, the isolate showed resistance against amphotericin B (minimum inhibitory concentration [MIC] 16 microg ml(-1)) but was susceptible to itraconazole (ITC) and fluconazole with MICs of 0.125 microg ml(-1) and 4 microg ml(-1), respectively. The patient was cured clinically after ITC treatment and surgical intervention. Azoles may be superior for eliminating S. apiospermum from infected ocular sites.

Activity of voriconazole against corneal isolates of Scedosporium apiospermum

PURPOSE

To determine the in vitro antifungal activity of voriconazole, a new triazole, compared with other polyene and imidazole antifungal agents against corneal isolates of Scedosporium apiospermum.

METHODS

Macro-broth dilution susceptibility testing was performed on five isolates of S. apiospermum obtained from patients with keratomycosis to determine the minimal inhibitory concentrations (MICs) for amphotericin B, natamycin, ketoconazole, itraconazole, and voriconazole. The use of oral voriconazole in the management of a patient with posttraumatic S. apiospermum keratitis is described.

RESULTS

S. apiospermum is generally resistant to commonly used topical ophthalmic antifungal agents. The MIC of voriconazole was 0.5 microg/mL, a concentration lower than that of other imidazoles.

CONCLUSION

Voriconazole has promising activity against and may prove useful in the management of fungal keratitis.

Fungal keratitis caused by Scedosporium apiospermum: report of two cases and review of treatment

PURPOSE

We report our experience in treating two cases of Scedosporium apiospermum keratitis and provide a review of basic scientific and clinical data regarding the treatment of this visually devastating disease.

METHOD

We present a case report and literature review.

RESULTS

A 35-year-old woman and a 73-year-old man both reported pain, redness, and a foreign body sensation in the eye after trauma. They were initially treated with antibacterials. When cultures were positive for S. apiospermum, the first patient was treated with fluconazole and amphotericin with good results. The second was treated with fluconazole and natamycin, but the infection persisted and the eye was eventually enucleated. Review of the literature showed variable responsiveness of S. apiospermum to antifungal treatment.

CONCLUSIONS

It is difficult to predict how S. apiospermum keratitis will respond to treatment, but miconazole appears to be useful in conjunction with other antifungals. Voriconazole shows promise as an effective alternative.

Severe keratomycosis secondary to Scedosporium apiospermum

PURPOSE

To report an unusual case of severe keratomycosis caused by Scedosporium apiospermum without any known previous ocular injury, that resulted in a corneal perforation, which was treated with an emergency penetrating tectonic keratoplasty and later with phacoemulsification and astigmatic keratotomy to restore good visual function.

METHODS

A 45-year-old woman with a history of multiple sclerosis presented with a severe and refractory corneal abscess in her right eye without any known prior injury. Corneal scrapings were obtained and stained for microscopic evaluation. The samples were sent for aerobic and anaerobic bacterial and fungal cultures.

RESULTS

Microbiologic examination of the corneal scraping showed Scedosporium apiospermum micelle. The fungal culture was sensitive to miconazole, itraconazole and voriconazole. Partial clinical improvement was achieved with hourly topical natamycin, amphotericin B, and systemic itraconazole application, although in vitro sensitivity tests showed resistance to the topical antifungal agents used. A corneal paracentral perforation occurred despite aggressive treatment. An emergency eccentric penetrating keratoplasty was performed with satisfactory results. Subsequent phacoemulsification and astigmatic keratotomy restored a good visual function.

CONCLUSION

A fungal etiology should be suspected in a progressive and refractory corneal abscess. This report highlights the utility of microbiologic investigation to perform an early and accurate diagnosis. Aggressive medical treatment and even therapeutic penetrating keratoplasty to remove infected tissue could result in the maintenance of useful visual function. In view of the poor prognosis of this specific fungus, a closer observation and early keratoplasty might be required to preserve the ocular globe.

Scedosporium endophthalmitis: two fatal disseminated cases of Scedosporium infection presenting with endophthalmitis

The incidence of disseminated infection with Scedosporium species is increasing in patients with haematological malignancy. Two fatal cases are reported of patients with acute myeloid leukaemia and neutropenia who presented with Scedosporium endophthalmitis. Diagnosis of fungal infection was delayed as blood and vitreous cultures were positive only after 3 days in patient 1 and blood culture was positive at 7 days in patient 2. Despite antifungal therapy with amphotericin B and additional fluconazole in patient 2, both patients died of overwhelming fungal septicaemia. Post-mortem examination of the right globe in patient 1 showed haemorrhagic necrotizing chorioretinitis with numerous fungal hyphae in choroidal vessels, choroid, retina and vitreous. Scedosporium species are often resistant to conventional antifungal therapy including amphotericin B. Diagnosis is difficult and mortality in disseminated infection is high.

Scedosporium apiospermum chorioretinitis

PURPOSE

A case of a 24-year-old immunocompetent woman who developed unilateral Scedosporium apiospermum chorioretinitis and diffuse cervical lymphadenitis 10 years after facial steroid injection is described.

METHODS

The patient was initially treated for the misdiagnosis of tuberculous lymphadenitis. Contemporaneous to the enlargement of her lymph nodes, she experienced gradual loss of vision in her left eye. She subsequently underwent lymph node biopsy.

RESULTS

Histopathologic sections stained with Grocott's methenamine silver showed branched septate hyphae and cultures on Sabouraud's agar yielded Scedosporium apiospermum. The patient received oral itraconazole 200 mg twice daily. Lymphadenitis regressed within a year and chorioretinitis scarred within two years.

CONCLUSION

Scedosporium apiospermum may cause isolated chorioretinitis in an immunocompetent individual years after local surgery or trauma and result in significant visual morbidity. Treatment may require prolonged use of systemic itraconazole.

Corneal co-infection with Scedosporium apiospermum and Acanthamoeba after sewage-contaminated ocular injury

PURPOSE

To describe a corneal co-infection with the fungus Scedosporium apiospermum and Acanthamoeba that result in spontaneous corneal perforation.

METHODS

A 27-year-old man presented due to severe ocular pain in his left eye caused by a corneal ulcer. The patient was injured 7 days before presentation by metallic thread contaminated by sewage. Corneal scrapping and deep stromal biopsy were obtained and stained for microscopic evaluation with periodic acid-Schiff, Giemsa, and Gomori's methenamine silver stains. Samples were sent for aerobic and anaerobic bacterial and fungal cultures.

RESULTS

Corneal biopsy and corneal scrapping showed viable Acanthamoeba cysts in the corneal stroma and S. apiospermum micelle, respectively. The fungal culture was sensitive to ketoconazole, miconazole, econasole, and traconazole. Devastating corneal perforation occurred despite aggressive antifungal and antiamoebic topical and systemic treatment initiated after diagnosis. The corneal button showed a necrotic tissue devoid of inflammatory cells and microorganisms.

CONCLUSION

S. apiospermum and Acanthamoeba may co-infect immune privilege sites, such as the cornea, in immunocompetent hosts. Compromised corneal surface, e.g., after trauma by sewage-contaminated objects, may increase the susceptibility for such devastating coinfection. Prevention may be possible by use of protective eyewear by high-risk individuals. Treatment should be initiated promptly with broad-spectrum antimicrobial agents after ocular injury by sewage-contaminated objects. Repeated corneal cultures and biopsies, if the cultures are negative, are warranted. Corticosteroids should be withheld until the causative agents are identified and targeted treatment is initiated.

Pathology of hyalohyphomycosis caused by Scedosporium apiospermum (Pseudallescheria boydii): an emerging mycosis

The genus Scedosporium contains two medically significant species of emerging mycotic agents, S. apiospermum and S. prolificans, which have received scant attention. Scedosporium apiospermum is the anamorph, or asexual state, of the cosmopolitan fungus Pseudallescheria boydii, with both sharing the same risk factors for infection, clinical spectrum, and histopathologic features. Scedosporium prolificans is a recently recognized agent of bone, soft tissue, and joint infections that occurs with highest frequency in children and young adults. S. prolificans may also cause potentially fatal disseminated infections in immunocompromised persons. The drug sensitivities of both Scedosporium species are significantly different from those of most other fungi, and thus identification of these organisms is important. Unfortunately, the pathological features of Scedosporium infections may be easily confused with other mycotic agents, resulting in delayed or inappropriate medical therapy. Because many pathologists and clinicians are unfamiliar with the significance of Scedosporium spp. infection, this communication describes three persons with differing clinical and pathological presentations of S. apiospermum infection. In one patient with sickle cell disease and chronic mycotic sinusitis, fungal colonies of S. apiospermum removed from the sinuses showed a pattern of alternating zones of mycelial hypercellularity and hypocellularity associated with conidiation, similar to a previous report of P. boydii infection. The clinicopathologic features of an immunocompetent person with S. apiospermum osteomyelitis, and a patient with S. apiospermum infection of the brain after bone marrow transplantation, are also described.