Successful Treatment of Disseminated Fusariosis with the Combination of Voriconazole and Liposomal Amphotericin B

A 23 bp cyp51A Promoter Deletion Associated With Voriconazole Resistance in Clinical and Environmental Isolates of Neocosmospora keratoplastica

In the fungal pathogen Aspergillus fumigatus, resistance to azole antifungals is often linked to mutations in CYP51A, a gene that encodes the azole antifungal drug target lanosterol 14α-demethylase. The aim of this study was to investigate whether similar changes could be associated with azole resistance in a Malaysian Fusarium solani species complex (FSSC) isolate collection. Most (11 of 15) clinical FSSC isolates were Neocosmospora keratoplastica and the majority (6 of 10) of environmental isolates were Neocosmospora suttoniana strains. All 25 FSSC isolates had high minimum inhibitory concentrations (MICs) for itraconazole and posaconazole, low MICs for amphotericin B, and various (1 to >32 mg/l) voriconazole susceptibilities. There was a tight association between a 23 bp CYP51A promoter deletion and high (>32 mg/l) voriconazole MICs; of 19 FSSC strains sequenced, nine isolates had voriconazole MICs > 32 mg/l, and they all contained the 23 bp CYP51A promoter deletion, although it was absent in the ten remaining isolates with low (≤12 mg/l) voriconazole MICs. Surprisingly, this association between voriconazole resistance and the 23 bp CYP51A promoter deletion held true across species boundaries. It was randomly distributed within and across species boundaries and both types of FSSC isolates were found among environmental and clinical isolates. Three randomly selected N. keratoplastica isolates with low (≤8 mg/l) voriconazole MICs had significantly lower (1.3–7.5 times) CYP51A mRNA expression levels than three randomly selected N. keratoplastica isolates with high (>32 mg/l) voriconazole MICs. CYP51A expression levels, however, were equally strongly induced (~6,500-fold) by voriconazole in two representative strains reaching levels, after 80 min of induction, that were comparable to those of CYP51B. Our results suggest that FSSC isolates with high voriconazole MICs have a 23 bp CYP51A promoter deletion that provides a potentially useful marker for voriconazole resistance in FSSC isolates. Early detection of possible voriconazole resistance is critical for choosing the correct treatment option for patients with invasive fusariosis.

Fusarium species intramedullary spinal cord fungus ball: case report

The Fusarium species are one of the most common opportunistic fungal infections occurring in immunocompromised patients and are associated with high morbidity and mortality. Common sites of infection include blood, skin, nasal passages, lungs, bone, and other visceral organs. There is a paucity of literature on Fusarium infections in the brain, and the true nature and extent of central nervous system involvement is not well described. To the authors' knowledge, there have been no reported cases of Fusarium infection of the spine. The authors report the case of a man with acute myeloblastic leukemia and resultant pancytopenia who presented with fungal sinusitis, upper- and lower-extremity weakness, and cardiopulmonary arrest. Imaging studies revealed a spinal cervical intramedullary ring-enhancing lesion. Because of the progressive nature of his symptoms, neurosurgical intervention involving a C2-3 laminectomy and drainage of the lesion was performed. Intraoperative cultures and histopathology results were positive for Fusarium species and, along with intraoperative findings, were consistent with a fungus ball. The patient was placed on a regimen of intravenous and intrathecal antifungal therapy. Unfortunately, his clinical condition declined postoperatively, and he ultimately died of disseminated infection.