Application of biosafety principles in blood establishments

Derivation of a biologically contained replication system for human immunodeficiency virus type 1

Human immunodeficiency virus type 1 (HIV-1) proviral mutants that lack viral regulatory genes are unable to replicate unless rescued by complementation in trans. Structurally intact virus can be produced by infecting recombinant cell lines expressing the deficient genes. A HIV-1 mutant functionally defective in tat and rev (vIIIB delta Tat/Rev), which replicates only in a recombinant T-cell line expressing tat and rev (CEMTART), is described in this report. Infection of the CEMTART cell line with vIIIB delta Tat/Rev permits the complete HIV-1 life cycle, including cytopathology, decreased expression of CD4, and production of viral structural proteins, to be biologically contained. Culture supernatants from infected CEMTART contain virus that is able to replicate only in uninfected CEMTART. No reversion of vIIIB delta Tat/Rev to wild-type HIV-1 was observed as measured either by sequencing proviral vIIIB delta Tat/Rev or by detecting the ability of vIIIB delta Tat/Rev to replicate in CEM or activated CD4-bearing T lymphocytes. Defective HIV-1 mutants produced by trans complementation of essential genes permit infection and analysis of defined genotypes on cellular function and phenotype. Authentic HIV-1 structural proteins and infected cells can be prepared in mass, and agents that interfere with the HIV-1 life cycle can be studied on a large scale with minimum risk of exposing workers to virulent HIV-1.

Determinants of blood and body fluid exposure in a large teaching hospital: hazards of the intermittent intravenous procedure

Determinants of staff exposure to blood and body fluids in a 1100-bed hospital were examined over a 2-year period. Eighty-two percent of the 799 reported accidental exposures were needlestick injuries, and 18% were cutaneous or mucous membrane splashes. Nurses and nursing students incurred 78.8% of the exposures; respiratory technologists and laboratory personnel, 9.2%; medical personnel, 7.5%; and support staff, 4.2%. Rate of exposure per 100,000 hours worked showed nursing students to be at particularly high risk, highlighting the need for specific instruction. Analysis of events leading to needlestick-related exposures revealed that the heparin lock intermittent intravenous procedure was involved in 26%; recapping accounted for 17%; improper disposal, 15%; manipulating equipment, 14%; phlebotomy, 12%; and other needlestick events, 16%. Ocular splashes and spills onto nonintact skin each accounted for 50% of the total number of non-needlestick-related exposures. This study revealed the hazardous nature of the intermittent intravenous procedure, prompting specific revisions in this procedure as well as promoting point-of-use sharps disposal and other preventive measures.

Decreasing the risk of human immunodeficiency virus or hepatitis B virus infection during endoscopic surgery

The risk of transmission of human immunodeficiency virus and hepatitis B virus infection is small but finite. Urological surgeons are exposed through needle punctures in open surgery and splashes during endoscopic surgery. Safety glasses are difficult to use during endoscopic surgery and they do not offer complete protection. The Steri-Shield, a facial shield designed to be fixed to the endoscope, is described.