Schematic drawing of the vaa locus of isolate 132. A: Restriction map of the vaa locus showing the cleavage sites for Bgl II (B), Eco RI (E) and Hin dIII (H). Fragments amplified by inverse PCR are shown as thick lines above the restriction map. B: Open reading frames of the vaa locus. The vaa gene is shown as a red arrow and show opposite transcriptional direction compared to the other ORFs. C: The PCR products amplified from isolate 132 are shown in cyan (upstream fragment) and purple (downstream fragment).