Invasive Aspergillosis in the Intensive Care Unit

Question: A 32-year-old woman developed a fever 12 days after a bone marrow transplant. Broad-spectrum antimicrobial therapy was initiated, but the fever persisted. On day 17, the patient developed skin lesions across her body and lower extremities; a biopsy was obtained. Microscopic evaluation of the tissue revealed hyphal elements. That same day, after 5 days of incubation, the patient's blood cultures were positive with a yeast-like colony. Although antifungal therapy was initiated, the patient died on day 22. Which fungi are most likely to be implicated in this patient's infection? Answer: Aspergillus species is most like likely to be implicated in the infection of the patient. The reason is that Aspergillusinfections are occurring with an increasing frequency in transplant recipients and the patient in the case study had undergone a bone marrow transplant. Even though new antifungal treatment strategies, invasive aspergillosis (IA) is one of the main causes of infectious mortality after bone marrow transplantation (BMT). Tissue biopsy can be performed to definitively identify the causing organism (Meersseman, 2014). Aspergillus can reproduce sexually or asexually. In most cases they reproduce asexually. Spores are released in the air and then carried by the wind as the main agent. When they reach a place where there are suitable conditions, they germinate producing foot cells. More branching occurs and elongation of hyphae creating a mass of hyphae or mycelium. Soon conidiophores grow from the foot cells and then the head made of spores (conidial head). Sexual reproductiontakes place in two different ways in fungi. The first type is outcrossing (inheterothallicfungi) in which two different individuals contribute nuclei, and the other type is self-fertilization or selfing (inhomothallicfungi) in which both nuclei are derived from the same individual. References Meersseman, W. (2014). 10 Invasive Aspergillosis in the Intensive Care Unit. InHuman Fungal Pathogens(pp. 179-189). Springer Berlin Heidelberg.