Fatal disseminated infection by Scedosporium prolificans during induction therapy for acute leukemia: a case report and literature review

Lomentospora prolificans Disseminated Infections: A Systematic Review of Reported Cases

BACKGROUND

Lomentospora prolificans, a rare, highly virulent filamentous fungus with high rates of intrinsic resistance to antifungals, has been associated with different types of infections in immunocompromised as well as immunocompetent individuals.

OBJECTIVE

To systematically address all relevant evidence regarding L. prolificans disseminated infections in the literature.

METHODS

We searched Medline via PubMed and Scopus databases through July 2022. We performed a qualitative synthesis of published articles reporting disseminated infections from L. prolificans in humans.

RESULTS

A total of 87 studies describing 142 cases were included in our systematic review. The pathogen was most frequently reported in disseminated infections in Spain (n = 47), Australia (n = 33), the USA (n = 21), and Germany (n = 10). Among 142 reported cases, 48.5% were males. Underlying conditions identified for the majority of patients included malignancy (72.5%), hemopoietic stem cell transplantation (23.2%), solid organ transplantation (16%), and AIDS (2%). Lungs, central nervous system, skin, eyes, heart and bones/joints were the most commonly affected organs. Neutropenia was recorded in 52% of patients. The mortality rate was as high as 87.3%.

CONCLUSIONS

To the best of our knowledge, this is the first systematic review conducted on disseminated infections due to this rare microorganism. Physicians should be aware that L. prolificans can cause a diversity of infections with high mortality and primarily affects immunocompromised and neutropenic patients.

Scedosporium apiospermum infection of the urinary system with a review of treatment options and cases in the literature

Infection with Scedosporium species is associated with a significant morbidity and mortality and is becoming increasingly common, especially in immunocompromised patients. We describe the presentation and successful management of an immunocompromised patient with Scedosporium apiospermum infection of the upper urinary tract system, a rare disease manifestation. The current literature on urinary tract scedosporiosis is further reviewed with emphasis on treatment options and limitations of current antifungal therapy.

Human and animal isolates of Pseudallescheria boydii and Scedosporium species, from Melbourne, Australia, 1977-1995

From 1977 to 1995, 25 of the fungal cultures referred to the Microbiological Diagnostic Unit Public Health Laboratory at The University of Melbourne, Victoria, Australia were identified as Scedosporium apiospermum, Pseudallescheria boydii, or Scedosporium prolificans. These cultures had been isolated from 22 patients at metropolitan hospitals and three animals at Veterinary Institutes. Eight of the human isolates were identified as P. boydii, 11 as S. apiospermum and three as S. prolificans. Isolates of S. apiospermum and P. boydii were from localised infections in immunocompetent patients, after trauma in two cases; from the lungs of patients with predisposing pulmonary disorders, such as cystic fibrosis or mycobacterial infection; and from immunocompromised patients with haematological malignancies or after heart, lung or heart/lung transplantation. Scedosporium prolificans isolates were from immunocompromised patients, one of whom had received a heart transplant, another had HIV infection and the third suffered with acute myelogenous leukaemia and died with disseminated infection. An isolate from the vaginal discharge of a horse with an infected uterus was identified as S. apiospermum. Isolates from aseptically collected milk samples from a goat and a cow with histories of mastitis, were identified as P. boydii. This study records the spectrum of infections caused by these opportunistic fungal pathogens in Melbourne from 1977 to 1995.

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.

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.

Antifungal activities of posaconazole and granulocyte-macrophage colony-stimulating factor ex vivo and in mice with disseminated infection due to Scedosporium prolificans

Invasive infection due to Scedosporium prolificans is characterized by drug resistance and a high rate of mortality. The effects of posaconazole (POS), an investigational antifungal triazole, murine granulocyte-macrophage colony-stimulating factor (GM-CSF), and their combination against S. prolificans were evaluated ex vivo and in a newly developed murine model of disseminated infection due to this organism. When POS was combined with polymorphonuclear leukocytes from untreated or GM-CSF-treated mice (P < 0.01) ex vivo, it had increased activity in terms of the percentage of hyphal damage. Immunocompetent BALB/c mice were infected with 4 x 10(4) conidia of S. prolificans via the lateral tail vein. At 24 h postinfection the mice were treated with GM-CSF (5 microg/kg of body weight/day subcutaneously), POS (50 mg/kg/day by gavage), both agents, or saline only. Half of the brain, lung, liver, and kidney from each animal were cultured; and the other half of each organ was processed for histopathology. The mean survival times were 7.0 +/- 0.3 days for the controls, 7.4 +/- 0.4 days for POS-treated mice, 8.0 +/- 0.3 days for GM-CSF-treated mice (P = 0.08 compared with the results for the controls), and 7.3 +/- 0.3 days for POS-GM-CSF-treated mice. Fungal burdens (determined as the numbers of CFU per gram of tissue) were found in descending orders of magnitude in the kidneys, brains, livers, and lungs. The burdens were significantly reduced in the brains of GM-CSF-treated mice (P < 0.05) and the livers of POS-treated mice (P < 0.05). The numbers of lesions in the organs closely corresponded to the fungal burdens. GM-CSF tended to prolong survival (P = 0.08 compared with the results for the controls). While the combination of POS and GM-CSF showed enhanced activity ex vivo, it did not increase the activities of the two agents against this highly refractory filamentous fungus in mice.

A pilot study of targeted itraconazole prophylaxis in patients with graft-versus-host disease at high risk of invasive mould infections following allogeneic stem cell transplantation

Patients with severe graft-versus-host disease (GVHD) requiring intensive immunosuppression are at high risk of invasive mould infections (IMI). Prophylaxis with an active, oral antifungal agents with reliable absorption in this context is desirable. A total of 44 patients at high risk of post-engraftment IMI received itraconazole solution 2.5 mg/kg b.d. as prophylaxis. Two of the first nine patients, in whom bioavailability was compromised due to significant vomiting and/or diarrhoea, died of probable or proven invasive aspergillus. None of the subsequent 35 patients, some of whom had severe gut GVHD and who received liposomal amphotericin B prophylaxis until itraconazole was reliably tolerated and absorbed, developed IMI. The overall incidence of IMI was substantially lower than in historical controls. Itraconazole was generally well tolerated, with five patients (11%) ceasing the drug due to intolerance or disturbed liver function. Targeted prophylaxis with oral or parenteral antifungal agents in high-risk allograft recipients appears to be effective in reducing the incidence of IMI.

Invasive infections caused by Blastoschizomyces capitatus and Scedosporium spp

Blastoschizomyces capitatus, Scedosporium prolificans and S. apiospermum are emerging fungal pathogens that may cause disseminated disease in neutropenic patients. They can present as fever resistant to antibiotics and to wide-spectrum antifungal agents, although they may involve almost every organ. The proportion of recovery from blood cultures is high and they are characteristically resistant to most antifungal agents. Prognosis is poor unless patients recover from neutropenia. Voriconazole has good in-vitro activity and is currently the drug of choice for these infections.

Fatal pulmonary scedosporiosis. Letal verlaufende pulmonale Scedosporiose

We report on a case of scedosporiosis in a 72-year-old German woman. Her disease started with a purulent ulceration of unknown course at her left foot. Soon after onset of oral antibacterial therapy she needed in-hospital treatment because of an acute pneumonia. The infection progressed despite the application of different antibiotics. Microscopic examination of tracheal fluid revealed fungal hyphae and therefore treatment with itraconazole was initiated. However, the patient developed renal failure, required mechanical ventilation and finally died in treatment-resistant septic shock. Post-mortem Scedosporium apiospermum was cultured from lung tissue taken during autopsy. This is the fourth case of human infection caused by Scedosporium species diagnosed in our laboratory during the last 4 years.

Disseminated phaeohyphomycosis: review of an emerging mycosis

Disseminated phaeohyphomycosis is an uncommon infection caused by dematiaceous fungi, although the number of case reports about this infection has been increasing in recent years. A total of 72 cases are reviewed. Scedosporium prolificans is by far the most common cause. The presence of melanin in their cell walls may be a virulence factor for these fungi. The primary risk factor is decreased host immunity, although cases in apparently immunocompetent patients have been reported. Eosinophilia was seen in 11% of cases. Endocarditis is mostly reported on bioprosthetic valves, particularly those of porcine origin. The outcome of antifungal therapy remains poor, with an overall mortality rate of 79%. Special precautions taken for immunocompromised patients may help prevent exposure to fungi during the patients' period of greatest risk. The development of newer antifungal agents and combination therapy may hold promise in improving the management of these devastating infections in the future.

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 prolificans infection associated with arthritis and osteomyelitis in a horse

Scedosporium prolificans was associated with arthritis and degenerative osteomyelitis in a 6-year-old Thoroughbred racehorse. The horse was suspected to have an inflammatory lesion of the interosseous tendon, but treatment had resulted in only a minimal response. Shortly after diagnostic arthrocentesis of the left metacarpophalangeal joint was performed, the joint became severely swollen, and radiography of the area revealed lysis of the distal end of the third metacarpal bone, the proximal sesamoid bones, and the proximal end of the proximal phalanx. The horse did not respond to treatment and was euthanatized. At necropsy, severe erosive arthritis and degenerative osteomyelitis of the left metacarpophalangeal joint were seen. Swab specimens of the ulcerated lesions of the articular cartilage were submitted for microbial culture, and Scedosporium prolificans was isolated. Scedosporium prolificans is a newly recognized opportunistic fungal pathogen of humans and animals. In humans, S prolificans typically causes focal locally invasive infections that primarily involve musculoskeletal tissues; most often, infection is a result of penetrating trauma or surgical incision. In immunocompromised patients, fatal disseminated infection can occur. The fungus is resistant to almost all currently available antimycotic agents.

Disseminated infection and colonization by Scedosporium prolificans: a review of 18 cases, 1990-1999

Scedosporium prolificans infection was analyzed in 18 patients from whom the fungus was isolated during the period 1990-1999. Of these 18 patients, 12 had some predisposing factor and either unconfirmed infection or colonization, and 6 patients had confirmed disseminated infection: 4 patients with leukemia died, 1 patient with breast cancer who underwent autologous bone marrow transplantation survived, and 1 patient with advanced acquired immunodeficiency syndrome died, although the fungal infection did not seem to affect his clinical symptoms.

Fungi, mycological disease and pathogenic determinants

The rapid evolution of human fungal infections is providing a strong impetus for understanding pathogenesis and host-fungus interactions and hence new diagnostics.