Fungal Blood Stream Infections (BSI) in Hematology-Oncology Patients Have Worse Outcomes Than Solid Tumour Patients
Authors: Deshani Vismay , Hemat H , Bloor Adrian , Dennis Mike , Peel Alex , Jeans Adam , Castleton Anna Z , Searle Emma , Wiseman Daniel H , Williams Mark , Chasty Richard , Abdulgawad Ahmed , Somervaille Tim , Murray John , Robertson Jane , Cavet James , Kulkarni Samar 
Published: December 2024

Introduction:
Blood stream infections (BSI) are common among patients with cancer, but incidence of fungal BSI is low and hence it is difficult to identify the risk factors for incidence and predictors of outcomes. With the availability of improved antibiotics, bacterial BSI associated mortality has significantly reduced over the last two decades. However, data on the incidence and mortality associated with fungal BSI is scarce. This analysis was undertaken to identify the incidence, yearly trends and predictors of mortality in patients with malignancies (Hematological and solid tumours) to compare these trends over a period of 22 years.
Method:
This is a retrospective evaluation of fungal BSI at tertiary cancer centres over a period from January 2002 to December 2023, with focus on the yearly incidence, disease-related factors, treatment-related factors and impact on 30-day all-cause mortality. Data was obtained from microbiology, laboratory and clinical database.
Results:
Total of 16,476 BSI occurred in 7,170 patients and 318 episodes of fungal BSI were identified in 236 patients. 44.91% were male (n=106) and 55.08% were female (n=130), with a median age of 58 years (range 16-83 years). Diagnosis was Hematology (Patients: 49; Episodes 78), Lymphoma (Patients: 22; Episodes: 28), solid tumours (Patients: 161; Episodes: 202) and 4 with no malignancy (episodes: 10). The incidence of Fungal BSI per patient was 1.6 in Hematology and 1.3 in lymphoma and solid tumours. The source of BSI was peripheral blood (n=111), Central Venous Catheter (n= 171) or was not specified (n=25). Ongoing treatment was non-intensive in 214 (67.3%), intensive in 70 (22%) and not defined in 34 (10.7%). Neutropenia was seen in 23% cases, 5.4% had renal impairment, 35% had liver impairment, 6.6% had hepatic and renal impairment, information was not available in 9% and 44.4% did not have organ impairment. 11 cases (3.5%) required admission to Intensive Care Unit (ICU). The yearly trend in the number of fungal BSI episodes have stayed stable (2002-2007: 1.9%; 2008-2013: 1.9%; 2014-2019: 2.6%; 2020-2023: 1.8%; p= 0.06). Fungal isolates were C. albicans (n=85, 26.7%), non-albicans Candida (n=180, 56.6%), yeast (n=20, 6.2%) and other organisms (n=33, 10.3%). Common non-albicans Candida were parapsilosis (n=70), glabrata (n=48) and guilliermondii (n=18). Common other fungal isolates were Rhizobium (n=12), Actinomyces (n=8) and Rhodotorulla (n=5). There was no difference in type of isolates between Hematology and other Oncology specialities. Yearly trend showed a decrease from 2002 to 2013 but increase between 2013 and 2023, especially in Hematology. Four risk factors identified for all-cause 30 day mortality were Hematology cancers (58%, 95% CI: 37-79, vs. 27.5%, 95% CI:20-35; p=0.01 ), C.albicans isolate (54%, 95% CI: 35-73 vs. 27%, 95% CI: 19-35; p=0.01), ICU admission (99%, 95% CI: 18-100 vs. 25%, 95% CI: 32-40; p=0.0007) and hepatic impairment (45%, CI:32-59 vs. Rest:25%, 95% CI:16-35; p=0.001 ). Risk factor (RF) score stratification defined three groups with increasing mortality (RF 0-1: 12%; RF 2: 40%: RF 3-4: 75%, p&lt;0.0001).
Conclusions:
Incidence of fungal BSI has not changed over the two decades. The risk of mortality is higher in Hematology-Oncology patients, associated hepatic with/without renal dysfunction, C.albicans isolates and need for intensive care unit support. Higher mortality with C.albicans raises the question if current prophylaxis with azoles may be inadequate and hence explore the need for alternative agents, especially in Hematology-Oncology patients.