DNA SINGLE-STRAND CONFORMATION POLYMORPHISM IDENTIFIES 5 DEFINED STRAINS OF HEPATITIS-B VIRUS (HBV) DURING AN OUTBREAK OF HBV INFECTION IN AN ONCOLOGY UNIT

An outbreak of hepatitis B virus (HBV) infection in a children's oncol ogy unit was identified in which 61 children were shown to have been i nfected, 59 of them asymptomatically. in order to establish whether in tra-unit cross infection had occurred, we used the single strand confo rmational polymorphism (SSCP) technique to analyse viral isolates from 57 of the infected chi Id ren and 40 unrelated controls. HBV-specific primers were designed to amplify a 189 bp fragment of DNA encompassin g part of the hypervariable pre-S1 region of the HBV genome. Denatured PCR products were compared after electrophoresis through polyacrylami de gels and staining with silver. By SSCP analysis, the unrelated infe ctions each yielded a unique electrophoretic banding pattern, indicati ve of a variety of distinct virus strains. In contrast, most of the on cology patients had been infected with one of only five different stra ins. Three major groups comprising 19, 16, and 9 patients, respectivel y, and two minor groups of 5 and 3 patients were identified. Results i ndicate the occurrence of multiple episodes of cross infection, and de monstrate the sensitivity and value of SSCP as a technique to establis h common sources of infection. (C) 1996 Wiley-Liss, Inc.