Investigating the presence of fungal agents in febrile neutropenic patients using different microbiological, serological, and molecular methods

Abstract

This study aimed to investigate fungal agents in febrile neutropenic patients with hematological malignancies. Direct microscopy and cultures were performed on clinical samples collected from febrile neutropenic episodes. The galactomannan (GM) antigen was tested using enzyme-linked immunosorbent assays, and Aspergillus fumigatus and Candida albicans deoxyribonucleic acid (DNA) assessed using real-time polymerase chain reaction (PCR) in consecutive serum samples. Of the 199 episodes investigated, 1.5% were classified as definite invasive aspergillosis (IA), 4.0% as IA with high probability, and 4.0% as IA with low probability. Additionally, candidaemia was detected in eight episodes (4.1%). The GM antigen was found negative for 86.4% of episodes, as one positive for 7.0% of episodes, as two or more consecutive positives for 5.5% of episodes, and as positive in any two serum samples in 1.0% of episodes. While no C. albicans DNA was detected in 98.5% of 199 episodes, one positive result was obtained in 1.0% of episodes, and two or more consecutive positives in 0.5% of episodes. A. fumigatus PCR results were found negative in 81.9% of episodes, as one positive in 16.1% of episodes, as positive in any two serum samples in 1.0% of episodes, and consecutively positive in 1.0% of episodes. GM antigen tests were found consecutively positive in all three patients diagnosed as having definite IA. These findings indicate that conventional, serological, and molecular methods should be used in combination to detect fungal agents in febrile neutropenic patients.

Current Sites of Infections and Types of Microorganisms in Patient with Febrile Neutropenia in Hematological Wards – Single Center Study

“…Gram-positive cocci were isolated in 34.61% while Gram-negative bacilli were identified in 61.53% in a study by Mandal et al [51]. Fungal infections in form of aspergillosis accounted for 6% of febrile neutropenic patients in this study, similar result found in a study by Sönmez et al [52] in which aspergillosis accounted for 5.9%. Among Gram-negative bacteria, E. coli was found to be the most common culprit pathogen (46.6%) Gaytán-Martínez et al found that E. coli was the pathogen isolated mostly during episodes of primary bacteremia among patients with cancer and febrile neutropenia [53].…”

Candida Antigen Titer Elevation and Mortality in Burn Patients

“…18 , 19 An invasive candidosis might lead to a life threatening candidemia, especially in immune-compromised patients. 7 Here, a CAG titer of 1:8 and higher might be a valuable predictor to an increased risk for mortality in burn patients. However, an increasing CAG titer by itself has also been reported a Dumping–phenomenon in a previous study.…”

“…6 Additionally, in clinical settings, where diagnosis of candidemia leans heavily on the use of real-time PCR or PCR while these tests are not available, clinical importance of CAG titer should not be underestimated. 7…”

“…Furthermore, it can be used to quantify the amount of template DNA and has been used to measure fungal loads. 6 , 7 However, in none of the scores nowadays used fungal blood stream infection is being considered in calculating morbidity and mortality for the burn patient population. This is where measuring CAG titer might become a useful tool to predict increased mortality.…”

Evaluation of Febrile Neutropenia in Hospitalized Patients with Neoplasia Undergoing Chemotherapy

“…The risk of invasive fungal infection is estimated to be 15-25% in high-risk patient groups, with over 90% of fungal infections attributed to Candida and Aspergillus species. Mortality rates are high, reaching 50% for Candida infections and 100% for Aspergillus infections [47]. The use of prophylactic fluconazole has led to an increase in non-albicans Candida strains.…”