UPDATING IN DIAGNOSIS OF BLOOD STREAM INFECTION IN IMMUNOCOMPROMISED PATIENTS WITH HAEMATOLOGICAL MALIGNANCIES.

Introduction: Diagnosis of bloodstream infections using microbiological cultures suffers from low sensitivity and reporting delay. Advanced molecular techniques introduced in many laboratories provide rapid results and may show improvements in patient outcomes. This study aimed to evaluate the usefulness of a molecular technique, broad-range 16S rRNA PCR followed by Genus-specific multiplex PCR and Candida specific nested PCR for the diagnosis of bloodstream infections in immunocompromised patients with haematological malignancies, compared to automated blood culture .Methodology: Conventional broad-range PCR and candida specific nested PCR were performed , on EDTA blood and plasma samples collected from different patients with haematological malignancies complaining of febrile neutropenia; Positive cases by broad range PCR identified by genus specific multiplex PCR. results were compared with those of automated blood culture.Results: Though blood culture is regarded as the gold standard, Broad range PCR evaluation showed Sensitivity of 83.3% ,specificity of 86.8%, Positive predictive value of 66.7%, Negative predictive value of 94.3%and accuracy of 86.0% .Candida specific nested PCR evaluation showed Sensitivity of 100% ,specificity of 89.6%, Positive predictive value of 28.6% , Negative predictive value of 100%and accuracy of 90%. and the results of both techniques correlated well with those of blood culture. Conclusions: Molecular assays are promising method that can be used in the rapid diagnosis of bloodstream infections but they seem not to be sufficient to replace microbial cultures which must associate these techniques.