Pulmonary mucormycosis and Achromobacter xylosoxidans co-infection in an immunocompromised host: a case report

Pulmonary mucormycosis (PM) is a severe fungal infection threatening immunocompromised individuals, especially with uncontrolled diabetes. Co-infection with bacteria like Achromobacter xylosoxidans complicates management. We report a rare and fatal case of PM co-infected with A. xylosoxidans, which was further complicated by a subsequent SARS-CoV-2 superinfection.

A 55-year-old female with poorly controlled type 2 diabetes mellitus and multiple comorbidities presented with worsening dyspnea. Investigations revealed severe hyperglycemia (927 mg/dL), hyponatremia, and imaging showed a large right upper lobe cavitary lesion. Bronchoscopy confirmed acute necrotizing pneumonia with Zygomycetes (Mucor) elements and grew >100 000 CFU/mL A. xylosoxidans/denitrificans. Computed tomography also revealed extensive nasopharyngeal mucormycosis. Her hospital course was complicated by a hyperosmolar hyperglycemic state, pulseless electrical activity cardiac arrest secondary to hemoptysis, and a subsequent SARS-CoV-2 superinfection, ultimately resulting in death.

This case exemplifies the diagnostic difficulties of PM, often mimicking other pulmonary conditions and requiring invasive testing for confirmation. Uncontrolled diabetes was a critical predisposing factor. The presence of A. xylosoxidans, an intrinsically resistant bacterium, alongside PM created significant therapeutic hurdles. The subsequent SARS-CoV-2 superinfection likely further compromised the patient's critical status. The subsequent SARS-CoV-2 infection likely further compromised the patient's status. The case underscores the lethal synergy of these sequential opportunistic infections, and the poor prognosis associated with PM, especially when compounded by critical illness and co-infections.

High suspicion for invasive fungal infections is crucial in high-risk patients with refractory pneumonia. Prompt invasive diagnostics and awareness of bacterial co-pathogens are essential, as outcomes remain poor despite aggressive therapy.