COMPARISON OF 3 METHODS FOR EXTRACTION OF VIRAL NUCLEIC-ACIDS FROM BLOOD CULTURES

Reliable nucleic acid extraction techniques for blood specimens are re quired for the sensitive detection of viral DNA. Standardized procedur es for processing blood specimens for the molecular detection of herpe sviruses (cytomegalovirus [CMV], herpes simplex virus, varicella-zoste r virus, and Epstein-Barr virus [EBV]) have not been established, Thre e methods were used to extract DNA from blood specimens from healthy d onors and asymptomatic immunocompromised patients: (i) IsoQuick treatm ent of whole blood, (ii) extraction of the peripheral blood leukocytes by lysis (lysis buffer and proteinase K), and (iii) extraction of per ipheral blood leukocytes with phenol-chloroform (sodium docecyl sulfat e solution and proteinase K), All blood specimens from 25 healthy bloo d donors were negative for CMV, herpes simplex virus and varicella-zos ter virus nucleic acid sequences, regardless of the extraction method, while three samples (12%) extracted by the lysis technique were posit ive for EBV DNA. Of 25 blood samples from asymptomatic immunocompromis ed patients, CMV and EBV each were detected in nine specimens by lysis extraction, four each by IsoQuick and four (CMV) and six (EBV) by the phenol-chloroform method, Our results indicate that the lysis method is optimal for the detection of CMV and EBV DNA sequences by PCR from the leukocytic fraction of blood specimens. DNA of these viruses is fr equently present in blood specimens from asymptomatic immunocompromise d patients and occasionally from healthy donors.