This nosocomial outbreak of infection due to a highly vancomycin-resistant strain of Enterococcus is the first epidemic in which an electronic thermometer has been implicated as the vehicle of transmission for an infectious agent.

The nucleotide sequences of the envelope genes of an African and a North American acquired immunodeficiency syndrome (AIDS) viral isolate have been determined. When their deduced amino acid sequences were aligned with the-envelopes of the lymphoadenopathy and AIDS-associated retrovirus isolates, conserved and divergent regions were readily identified. (4,10,11). For example, sequence analysis of the env region of the lymphoadenopathy virus (LAV) and AIDSassociated retrovirus (ARV) isolates revealed the presence of numerous nucleotide substitutions and several reciprocal insertions and-deletions resulting in 9% polynucleotide sequence heterology and a 15% difference in the deduced amino acid sequence (10).The AIDS retrovirus interacts with the immune system in a puzzling way. Virtually everyone infected with the virus synthesizes an antibody directed against a portion of the viral envelope (11-14). However, unlike antibodies reactive with other viral envelopes, the one detected in the sera of individuals exposed to the AIDS retrovirus has little if any protective value (15). Since several therapeutic and preventative strategies of viral intervention currently focus on envelope proteins, a definitive evaluation of the structurally diverse env gene and its polypeptide products is urgently needed. In this report we present the nucleotide and deduced amino acid sequences ofthe env genes of one African and one North American AIDS retrovirus isolate. Their alignment with the analogous segment of the LAV and ARV isolates indicates the location of highly conserved and profoundly divergent domains of the env gene. MATERIALS AND METHODSVirus holates and Molecular Cloning. The African (Z3) and North American (NY5) AIDS retroviruses used in this study were isolated in 1983 and 1984, respectively, and have been previously described (5). Molecular clones of proviral DNAs were obtained from cellular DNA preparations isolated from infected, phytohemagglutinin-stimulated, normal peripheral blood lymphocytes (16). On the basis of previous restriction mapping (5), integrated proviral DNA of NY5 was cloned as two separate EcoRI restriction fragments. Infected cellular DNA was prepared as previously described (17), digested with EcoRI, ligated to EcoRI-digested X Charon 4A (18) arms with T4 DNA ligase, packaged in vitro, and plated on Escherichia coli DP50 supF as previously described (19). The Z3 clone was obtained from a library prepared from a size-selected partial Mbo I digest of infected cellular DNA, inserted into BamHI-cleaved EMBEL-3 (20) phage DNA, packaged in vitro, and plated on E. coli NM539 cells (Promega Biotec, Madison, WI). Approximately 2 x 106 phage plaques from each library were screened (21), using the 2P-labeled pBENN-6 (16) DNA clone of the LAV provirus.Restriction maps of the proviral DNA clones were constructed by using Southern blot hybridization (22) and several contiguous 32P-labeled LAV probes as previously outlined (5). Presumptive full-length proviral DNAs were inserted into pBR322 (NY5 as two s...