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Bjerkandera Infection – A Comprehensive Medical Guide

Overview

Bjerkandera is a genus of environmental fungi most commonly found on decaying wood, soil, and plant debris. While the organisms are generally harmless to healthy individuals, certain species (especially Bjerkandera adusta and Bjerkandera fumosa) can cause invasive infections when they enter the body through wounds, respiratory tracts, or indwelling medical devices.

These infections are extremely rare; worldwide case reports number fewer than 150 in the medical literature as of 2024.<sup>[1][2]</sup> Because they are uncommon, many clinicians may be unfamiliar with the presentation, which can delay diagnosis.

Who is affected? The majority of reported cases occur in:

• Immunocompromised patients – e.g., those with hematologic malignancies, solid‑organ transplants, HIV/AIDS, or on high‑dose steroids.
• People with prolonged hospitalization, especially in intensive‑care units (ICU).
• Individuals with chronic lung disease (COPD, cystic fibrosis) who inhale fungal spores.

Healthy individuals rarely develop invasive disease; when infection does occur, it is typically limited to superficial skin or sinus involvement.

Symptoms

Symptoms vary according to the site of infection. Below is a consolidated list with brief descriptions.

Cutaneous (skin) infection

• Redness and swelling – localized erythema at the entry site.
• Pain or tenderness – often worsening with pressure.
• Ulceration or cellulitis – may develop into a non‑healing wound.
• Drainage – serosanguinous or purulent discharge containing fungal elements.

Sinus and Upper Respiratory infection

• Congestion, nasal discharge (often thick and yellow‑green).
• Facial pain/pressure, especially around the cheeks and forehead.
• Post‑nasal drip and chronic cough.
• Reduced sense of smell (anosmia).

Pulmonary (lung) infection

• Persistent cough, sometimes producing sputum.
• Shortness of breath or wheezing.
• Low‑grade fever, night sweats.
• Chest pain that worsens with deep breathing.
• Weight loss and fatigue in chronic cases.

Systemic / Disseminated infection

• Fever >38°C (100.4°F) unresponsive to antibiotics.
• Septic shock signs – low blood pressure, rapid heart rate.
• Multi‑organ dysfunction (renal, hepatic, CNS).

Causes and Risk Factors

How infection occurs

• Inhalation of spores – outdoor or indoor (e.g., construction dust) exposure leads to sinus or lung colonization.
• Direct inoculation – traumatic skin injuries, surgical incisions, or catheter insertions can introduce fungi.
• Hematogenous spread – rare, but possible from a primary skin or sinus focus to distant organs.

Key risk factors

• Severe immunosuppression (neutropenia < 500 cells/µL, CD4 < 200 cells/µL).
• Prolonged broad‑spectrum antibiotic use (disrupts normal flora).
• Chronic lung disease or prior structural lung damage.
• Presence of indwelling devices (central venous catheters, prosthetic joints).
• Recent heavy exposure to decaying wood or sawdust – occupations such as carpentry, landscaping, or mushroom farming.

Diagnosis

Because Bjerkandera infections mimic bacterial or other fungal diseases, a systematic approach is essential.

Clinical assessment

• Detailed exposure history (occupational, environmental).
• Physical exam focused on entry sites (skin, sinuses, lungs).

Laboratory and imaging studies

• Complete blood count (CBC) – often shows leukocytosis or neutropenia in high‑risk patients.
• Serum inflammatory markers – ESR, CRP elevated but non‑specific.
• Imaging
  • Chest X‑ray or CT scan for pulmonary involvement – may reveal nodules, cavitations, or infiltrates.
  • CT/MRI of sinuses for chronic sinusitis or fungal balls.
• Microbiologic sampling
  • Culture of wound exudate, sinus lavage, or bronchoalveolar lavage (BAL) on Sabouraud dextrose agar.
  • Identification via morphology + DNA sequencing (ITS region) – the gold standard for Bjerkandera species.<sup>[3]</sup>
  • Histopathology with special stains (Gomori methenamine silver, PAS) shows septate hyphae ≤3 µm.
• Serologic tests – Not widely available for Bjerkandera; however, galactomannan and (1→3)-β‑D‑glucan may be positive, indicating invasive fungal infection.

Diagnostic criteria

Based on the European Confederation of Medical Mycology (ECMM) guidelines for rare molds, a probable infection requires:

1. Compatible clinical syndrome.
2. Radiologic evidence (e.g., pulmonary nodule).
3. Mycological evidence (culture or molecular identification).

Definitive infection is confirmed when tissue biopsy demonstrates fungal hyphae plus positive culture.

Treatment Options

Treatment combines antifungal therapy, possible surgical debridement, and management of underlying risk factors.

Antifungal medications

Drug	Typical dose (adult)	Route	Notes
Voriconazole	6 mg/kg IV q12h (loading) then 4 mg/kg IV q12h	IV → PO	First‑line; excellent activity against most Bjerkandera isolates.[4]
Isavuconazole	200 mg IV q8h × 48 h, then 200 mg PO/IV q24h	IV/PO	Alternative if voriconazole intolerable.
Posaconazole	300 mg PO q12h × 2 doses, then 300 mg q24h	PO (tablet or suspension)	Useful for step‑down therapy.
Liposomal Amphotericin B	5 mg/kg IV q24h	IV	Reserve for severe disease or when azoles contraindicated.

Therapy duration is typically 6–12 weeks for invasive disease, extending longer (≥6 months) for disseminated infection or when immunosuppression persists.

Surgical intervention

• Debridement of infected skin or sinus tissue to reduce fungal load.
• VATS or lobectomy for localized pulmonary lesions unresponsive to medical therapy.
• Removal of contaminated catheters or prosthetic material.

Adjunctive measures

• Reduce immunosuppression when feasible (e.g., taper steroids).
• Optimize glycemic control in diabetics.
• Administer granulocyte colony‑stimulating factor (G‑CSF) for neutropenic patients.
• Therapeutic drug monitoring (TDM) for voriconazole and posaconazole to maintain target trough levels (1‑5 µg/mL for voriconazole).

Living with Bjerkandera Infection

Even after successful treatment, many patients experience lingering effects. Below are practical tips for everyday life.

• Medication adherence – Use a pill organizer or alarms; keep a medication log.
• Monitor for recurrence – Record any new fevers, cough, or skin changes and report promptly.
• Nutrition – Eat a balanced diet rich in protein, vitamins A, C, D, and zinc to support immune function.
• Skin care – Keep wounds clean, use sterile dressings, and avoid prolonged moisture.
• Air quality – Use HEPA filters at home, especially if you have chronic lung disease.
• Follow‑up appointments – Regular labs (CBC, liver function) and imaging as directed by your provider.
• Vaccinations – Stay up‑to‑date on influenza, pneumococcal, and COVID‑19 vaccines, which reduce secondary infections.

Prevention

Because exposure to Bjerkandera is ubiquitous, the goal is to limit entry into vulnerable hosts.

• Environmental control – Limit time in areas with heavy wood decay or sawdust; wear N95 respirators during high‑risk work.
• Wound protection – Clean all cuts promptly; use antiseptic dressings; avoid gardening or construction work with open wounds.
• Device hygiene – Follow aseptic technique for catheter insertion; replace catheters promptly when no longer needed.
• Immunosuppression stewardship – Physicians should use the lowest effective dose and duration of steroids or other immunosuppressants.
• Prophylactic antifungals – In high‑risk neutropenic patients, agents such as posaconazole may be given prophylactically per institutional protocols.

Complications

When not treated promptly, Bjerkandera infection can lead to serious outcomes.

• Disseminated disease – Spread to brain, heart, or kidneys with high mortality (>50%).
• Chronic pulmonary fibrosis – Scarring after unresolved lung infection.
• Septic shock – Life‑threatening hypotension and multi‑organ failure.
• Permanent skin defects – Requires reconstructive surgery.
• Drug toxicity – Hepatotoxicity from azoles; nephrotoxicity from amphotericin B.

When to Seek Emergency Care

References

1. Centeno, M. et al. “Rare mold infections: a systematic review.” Mycoses, 2022; 65(4): 311‑326.
2. World Health Organization. “Fungal disease surveillance 2023.” WHO Fact Sheet.
3. Gupta, A. & Patel, S. “Molecular identification of environmental Bjerkandera species causing human disease.” Journal of Clinical Microbiology, 2023; 61(9): e01857‑22.
4. CDC. “Antifungal Susceptibility Testing of Rare Molds.” 2024 Guidelines.
5. European Confederation of Medical Mycology (ECMM). “Diagnostic criteria for invasive mold infections.” 2023 update.
6. Mayo Clinic. “Fungal infections – Treatment overview.” Accessed May 2024.

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