Evaluation of (1,3)--d-glucan assay in diagnosis of invasive fungal infections with Aspergillus

Abstract

Invasive fungal infections caused by Aspergillus are a significant problem in immunocompromised and critically ill patients and associated with increased morbidity and mortality. Early diagnosis of invasive aspergillosis is still a big clinical and diagnostic challenge. Conventional methods are not sensitive enough, and therefore, there is a need for rapid, more sensitive methods for early diagnosis of invasive fungal infections with Aspergillus. The aim of this study was to evaluate the diagnostic performance, sensitivity and specificity of serological panfungal (1,3)-b-D-glucan marker compared to conventional method for diagnosis of invasive fungal infections with Aspergillus. Material and methods: Specimens of 125 patients divided into 4 groups (group I - immune deficiency, group II - prolonged ICU stay, group III - chronic aspergillosis, group IV - cystic fibrosis), classified according to clinical diagnosis and EORTC/MSG criteria, were analyzed at the Institute of Microbiology and Parasitology, with conventional and serological methods, during a period of two years. Results: A total of 71 isolates of Aspergillus were confirmed in this study. Four isolates were recovered from bloodculture of patients with primary immune deficiency. With BAL culture, Aspergillus was detected in the group of chronic aspergillosis (63.33%), followed by the groups of cystic fibrosis (56.67%), primary immune deficiency (51.43%), and the group with prolonged ICU stay (43.33%). Sensitivity and specificity of BAL culture were: 64.29% and 100%, 59.09% and 100%, 54.55% and 12.5%, 100% and 54.17%, in I, II, III and IV group, respectively. In 79.1% (53/67) from positive BAL cultures in all groups, A. fumigatus was confirmed, of which, 32.1% (17/53) in group III, followed by group I – 26.42% (14/53) and group IV – 26.42% (14/53), and 15.1% (8/53) in group II. Other species confirmed in BAL were A. flavus 16.42% (11/67) and A.terreus 4.48% (3/67). Sensitivity and specificity of the serological panfungal (1,3)-b-D-glucan (BDG) marker were: 64.71% and 85.71%, 50% and 87.5%, 36.36% and 50%, in groups I, II and III, respectively. No positive findings of the panfungal (1,3)-b-D-glucan (BDG) marker were found in the group with cystic fibrosis. Conclusion: The results obtained in this study have demonstrated that a positive (1,3)-b-D-glucan assay highlights the value of this test as a diagnostic adjunct in the serodiagnosis of invasive fungal infections with Aspergillus, and along with the results from conventional mycological investigation, helped in reaching a timely antifungal treatment with a favorable clinical outcome.