Oral polio vaccine: fact versus fiction.

The author of this article has now become the principal target of the accusation that HIV-1 was introduced into man through the wildcat production of an oral polio vaccine in chimpanzee cell culture more than 40 years ago in the Belgian Congo. The putative evidence presented in support of this accusation rests essentially on testimonials by local witnesses. Such an accusation is strongly rejected on basis of a factual review of the author's career and his publications, as well as his total incapability to have managed such a feat at the supposed time.

Vaccine could not have been prepared in Stanleyville.

In Stanleyville, at the time of vaccination campaigns, tissue cultures were primitive, experimental and used solely for diagnostic purposes. Production of vaccine was impossible to carry out. A few chimpanzee kidneys were minced and sent to Philadelphia as part of the hepatitis experiments of Dr Deinhardt.

Typing of nosocomial strains of Serratia marcescens: comparison of pulsed-field gel electrophoresis of macrorestriction fragments with biotyping, esterase typing and ribotyping.

Fifty nosocomial isolates of Serratia marcescens, collected in six Belgian hospitals between 1986 and 1990, were characterized by using pulsed-field gel electrophoresis (PFGE) with XbaI. The results were compared with those previously obtained by three other methods: biotyping, esterase electrophoresis typing and ribotyping with EcoRI and HindIII. Macrorestriction analysis (42 PFGE groups) and esterase typing (42 zymotypes) proved to be the most discriminating, followed by ribotyping (28 ribotypes) and biotyping (10 biochemical profiles).

Ribotyping for use in studying molecular epidemiology of Serratia marcescens: comparison with biotyping.

Ribotyping carried out with a nonradioactive probe (acetylaminofluorene ribosomal RNA kit I from Eurogentec, Seraing, Belgium) was performed for the characterization of 139 hospital strains of Serratia marcescens. These strains, which belonged to 11 biotypes and 1 nontypeable group, were isolated in seven hospitals in Belgium between 1986 and 1992. EcoRI and HindIII were used to obtain cleavage patterns.

Combination of biotyping and electrophoretic patterns of esterases for differentiation of nosocomial Serratia marcescens strains.

A total of 292 Serratia marcescens strains isolated in seven Belgian hospitals between 1986 and 1992 were submitted to both biotyping by carbon source utilization and esterase electrophoresis typing. The strains were assigned to 11 biotypes (290 isolates) or were auxotrophic (2 isolates), whereas the various electrophoretic patterns of their esterases produced 54 zymotypes. The two typing methods correlate well, since biotypes embraced more than one zymotype, while each zymotype was restricted to a single biotype.