Semi-nested polymerase chain reaction over blood culture in detection of bloodstream fungal infection in leukemic children with febrile neutropenia

BACKGROUND: Children with hematologic malignancies are currently at a severe threat of developing bloodstream fungal infection (BSFI). The early detection of BSFI followed by appropriate management of these patients remains a challenge to the oncologist of today. The conventional method of detection like blood culture followed by identification is time-consuming and of low accuracy. The molecular approaches like polymerase chain reaction (PCR) and its variants like semi-nested PCR (SnPCR) can be an attractive alternative to diagnose early and accurately BSFI but need to be explored. OBJECTIVE: The aim of our study was to determine the utility of SnPCR over conventional blood culture in detecting BSFI in leukemic children with febrile neutropenia. MATERIALS AND METHODS: A total of 53 pediatric patients with febrile neutropenia due to hematological malignancy were included in this study. From each patient, blood sample was collected for conventional blood culture, while SnPCR was performed from the overnight incubated blood broth. The blood culture-positive isolates were further identified to species level using conventional techniques. The PCR products obtained were sequenced and results interpreted after nucleotide BLAST and refinement. RESULTS: Fungal DNA was detected in 13 (24.5%) febrile neutropenic patients by SnPCR, while the conventional blood culture could detect only 6 (11.3%) fungemia cases. The SnPCR had a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 93%, 100%, 100%, 98%, and 98%, respectively, versus 43%, 100%, 100%, 83%, and 85%, respectively, for blood culture. The results by SnPCR alone showed almost perfect agreement with the results of the combined method (κ = 0.95) in the detection of BSFI. CONCLUSION: The SnPCR method proved to be better compared to blood culture for the early and accurate detection of BSFI in febrile neutropenic pediatric patients.