352. Evaluation of Serial Serum (1-- >3)-b-D-glucan Assay in Patients with Invasive candidiasis, Pneumocystis Jiroveci Pneumonia and Aspergillosis

Abstract

Background Serum (1-- >3)-b-D-glucan (BDG) assay is a noninvasive serological marker that can be used as an adjunct to the diagnosis of invasive candida infections, Pneumocystis jiroveci pneumonia (PJP) as well as aspergillosis. There is limited data in serial monitoring of serum BDG in those fungal infections after treatment was initiated. Figure 1:Serial serum BDG levels of each subject after treatment initiation Methods This is a cross-sectional study of subjects with proven fungal infection (invasive candidiasis, aspergillosis or PJP) and with increased serum BDG >500 pg/ml who were admitted to University of Kentucky (UK) hospitals or clinics from 01/2012 to 01/2021. It was approved by institutional IRB. We compared at least two measures of the serum β-D-glucan levels obtained within two to eight weeks after initial diagnosis to evaluate the levels of β-D-glucan during and post-treatment. A decrease in BDG level is defined as any value below 500 pg/ml; normal serum BDG level as < 80 pg/ml. Results Of 26 subjects included in this cohort, 14 (51.8%) subjects had invasive candidiasis, six (22.2%) subjects had PJP, and six (22.2%) subjects had invasive aspergillosis. Twelve patients did not have a repeat BDG level after at least two separate levels with >500 pg/ml. Ten (38.5%) subjects had a decline in BDG level 2-3 weeks after starting treatment. Serum BDG level did not return to within normal limits at week 4 of treatment except one patient. A repeat serum BDG level was seen decline at three weeks of treatment in four of six (66.6%) subjects with PJP, six weeks of treatment in three of six (50.0%) subjects with invasive aspergillosis and 8 weeks of treatment in six of 14 (42.8%) patients with invasive candidiasis. Two subjects had persistent elevation of BDG 8 weeks after treatment. (Figure 1) Conclusion Serial serum BDG level was not routinely done for monitoring the treatment response in this cohort. There was no linear decline in serum BDG level even after appropriate treatment in invasive fungal infections. A decline in serum BDG level was best observed among subjects with PJP pneumonia. It appears that the duration of a decline in serum BDG level was shorter in patients with PJP and longer in patients with invasive candidiasis. Disclosures All Authors: No reported disclosures.