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Fusarium and Lomentospora coinfection in a pediatric patient with acute myelogenous leukemia: Always Occam's razor may not apply

  • Jordan Mah
    Affiliations
    Division of Pathology, Stanford University School of Medicine, Stanford, California

    Clinical Microbiology Laboratory, Stanford Health Care, Stanford, California
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  • Ruzan Orkusyan
    Affiliations
    Division of Infectious Diseases, Department of Pediatrics, Stanford University School of Medicine, Stanford, California
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  • Torsten Joerger
    Affiliations
    Division of Infectious Diseases, Department of Pediatrics, Stanford University School of Medicine, Stanford, California
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  • Niaz Banaei
    Correspondence
    Corresponding author: Niaz Banaei., Department of Pathology, Stanford University, California, 3375 Hillview Ave, Palo Alto, CA, 94304.
    Affiliations
    Division of Pathology, Stanford University School of Medicine, Stanford, California

    Clinical Microbiology Laboratory, Stanford Health Care, Stanford, California

    Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California
    Search for articles by this author
Open AccessPublished:November 17, 2022DOI:https://doi.org/10.1016/j.ijid.2022.11.019

      Highlights

      • Coinfection with two invasive molds, Fusarium and Lomentospora, is a rare phenomenon.
      • Invasive fungal infections are difficult to treat; high mortality is associated with host immune status.
      • Anchoring bias based on the initial diagnosis can delay the diagnosis of a coinfection.

      Keywords

      Case

      A 14-year-old female with acute myelogenous leukemia presented with 1 day of fever, myalgias, and a single necrotic lesion on her left foot. She was undergoing intensification chemotherapy, was severely neutropenic for 2 weeks, and was taking prophylactic voriconazole. Biopsy of the necrotic lesion revealed angioinvasive fungal elements, with Fusarium growing from culture (Figure 1). Whole-body imaging revealed lung nodules with halo sign (Figure 2).
      Figure 1
      Figure 1Histopathologic and microbiologic findings from the skin biopsy. (a) Single necrotic skin lesion of the left leg. (b) Tissue sections stained with hematoxylin and eosin, showing hyphae (arrow) with angioinvasion (arrowheads) at 20X magnification. (c) Fungal culture on potato dextrose agar incubated at 30°C, showing white, woolly, spreading colonies. (d) Lactophenol cotton blue stain of the culture at 40X magnification, showing thick-walled, smooth, and sickle-shaped macroconidia consistent with Fusarium spp.
      Figure 2
      Figure 2Images from chest computed tomogaphy with contrast, showing multiple irregular, solid nodules with surrounding ground-glass opacity (halo sign, red arrow) throughout both lungs, without central cavitation. Dominant nodules noted in the right lung are shown. (a) Right lower lobe lesion measuring 1.1 × 1.1 cm. (b) Right lower lobe medial superior segment lesion measuring 0.9 × 0.8 cm. (c) Right upper lobe apical lesion measuring 1.6 × 1.2 cm.
      On day 2 of hospitalization, the results of in-house polymerase chain reaction testing of plasma cell-free DNA were positive for Scedosporium spp. Blood cultures that were drawn at admission grew mold with septate hyphae at 56 hours. The mold was presumed to be Fusarium; however, it was identified as Lomentospora prolificans (Figure 3).
      Figure 3
      Figure 3Microbiologic findings from the blood culture. (a) Positive results of BD BACTEC Plus Aerobic/F culture vial at 56 hours stained with Gram stain, showing septate hyphae (arrow). (b) Subculture to potato dextrose agar incubated at 30°C, showing small black colonies. (c) Lactophenol cotton blue stain of the culture at 40X magnification, showing septate hyphae with short, swollen, smooth, flask-shaped conidiophores (arrow) giving rise to single or small clusters of conidia from elongated necks, consistent with Lomeontospora prolificans (formerly Scedosporum prolificans); species was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
      Treatment with liposomal amphotericin B and granulocyte colony-stimulating factor was initiated. Voriconazole was replaced with intravenous posaconazole on day 4. Terbinafine was added on day 7 but was discontinued after 24 hours due to transaminitis. Despite aggressive therapy, the patient remained persistently fungemic, developed multiorgan failure, and died on day 9 of hospitalization.
      Coinfection with invasive molds is rare; few cases have been described (
      • Amirrajab N
      • Aliyali M
      • Mayahi S
      • Najafi N
      • Abdi R
      • Nourbakhsh O
      • et al.
      Co-infection of invasive pulmonary aspergillosis and cutaneous Fusarium infection in a patient with pyoderma gangrenosum.
      ;
      • Seidel D
      • Hassler A
      • Salmanton-García J
      • Koehler P
      • Mellinghoff SC
      • Carlesse F
      • et al.
      Invasive Scedosporium spp. and Lomentospora prolificans infections in pediatric patients: analysis of 55 cases from FungiScope® and the literature.
      ). This is the first reported coinfection with Fusarium and Lomentospora. These infections are associated with high mortality, which is related to the host's immune status and inherent antifungal resistance (
      • Nucci M
      • Anaissie E.
      Fusarium infections in immunocompromised patients.
      ;
      • Seidel D
      • Hassler A
      • Salmanton-García J
      • Koehler P
      • Mellinghoff SC
      • Carlesse F
      • et al.
      Invasive Scedosporium spp. and Lomentospora prolificans infections in pediatric patients: analysis of 55 cases from FungiScope® and the literature.
      ). Premature closure and anchoring bias based on microbiologic diagnosis of the initial fungus can delay diagnosis and administration of appropriate antifungal therapy; this reinforces the importance of maintaining a broad differential. Although Occam's razor is the general rule, Hickam's dictum may prevail in immunocompromised hosts.

      Declarations of competing interest

      The authors have no competing interests to declare.

      Funding

      This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

      Ethical approval

      Ethical approval was not sought in the writing of the case report. Consent from the patient's parents was obtained in writing this clinical image.

      Author contributions

      JM and NB conceived the case report. JM and RO drafted the manuscript. All authors provided critical appraisal of manuscript drafts, critically revised the manuscript for important intellectual content, gave final approval of the version to be published, and agreed to be accountable for all aspects of the work.

      References

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        • et al.
        Co-infection of invasive pulmonary aspergillosis and cutaneous Fusarium infection in a patient with pyoderma gangrenosum.
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        Invasive Scedosporium spp. and Lomentospora prolificans infections in pediatric patients: analysis of 55 cases from FungiScope® and the literature.
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