Rare mould infections caused by Mucorales, Lomentospora prolificans and Fusarium, in San Diego, CA: the role of antifungal combination therapy

Non-Aspergillus invasive mould infections (IMIs) are associated with devastating morbidity and mortality rates and are increasingly diagnosed in immunocompromised hosts. The aim of this study was to describe the epidemiology and outcomes of non-Aspergillus IMIs at a university hospital in San Diego, California, USA. A retrospective chart review of the medical records of all patients with cultures growing non-Aspergillus moulds at the microbiology laboratory in the Center for Academic Laboratory Medicine, Department of Pathology, University of California, San Diego (UCSD) Health between mid-2014 and mid-2017 (3-year period) was performed. A total of 23 cases of non-Aspergillus IMI were identified, including 10 cases of mucormycosis, 8 cases of lomentosporiosis and 5 cases of fusariosis. Antifungal susceptibility testing was performed for 14 isolates, and 10/11 Fusarium and Lomentospora isolates had minimum inhibitory concentrations (MICs) of >16 µg/mL for voriconazole and/or posaconazole. Overall 180-day mortality was significantly lower among those who received combination antifungal therapy than among those who received single-agent therapy [3/13 (23%) vs. 9/10 (90%); P = 0.003]. In conclusion, Lomentospora prolificans (35% of non-Aspergillus IMIs) and Fusarium spp. (22%) accounted for high proportions of non-Aspergillus IMIs during the study period. Non-Aspergillus IMIs were detected in patients with various underlying diseases and were associated with high mortality rates, which was significantly lower in those who received antifungal combination therapy.