28th July 2023

A 36 year old patient has received a heterologous bone marrow stem cell transplant for acute myeloid leukaemia.

A 36 year old patient has received a heterologous bone marrow stem cell transplant for acute myeloid leukaemia. Six weeks later, he develops a fever and becomes generally unwell. His blood tests reveal the following:

• Hb 68 g/L
• Platelets 80
• WCC 0.8
• Neutrophils 0
• Lymphocytes 0.6
• Basophils 0.1
• CRP 68

He develops shortness of breath and is intubated, with a bronchoalveolar lavage performed in the intensive care unit. After 2 days, there is growth of a branching filamentous mould.

What is the most likely causative organism?

Select the SINGLE most appropriate option from the list below. Select ONE option only.