[Differentiation of Shigella flexneri serotype 6 from serotypes 1-5 by electrophoresis and isoelectric focusing of their elastases].

Among Shigella flexneri serotypes, serotype 6 (28 strains) was individualized from serotypes 1 to 5 (43 strains) by electrophoresis and isoelectric focusing of esterases. The taxonomic status of S. flexneri serotype 6 should be reconsidered in light of this work.

Taxonomic value of a chromogenic test for the detection of aminopeptidases in the genus Shigella.

In addition to the conventional methods for the identification of Enterobacteriaceae, enzymatic tests using chromogenic substrates have been proposed [1, 2, 5, 7, 8, 9, 10]. Many chromogenic and fluorogenic substrates are now available, and some of these have been employed for the determination of enzymatic profiles of Neisseria [3] and Enterobacteriaceae [7]. In this article, we report the activity of bacterial cultures of the genus Shigella on a new chromogenic substrate: chromozym PL.

Plasmid-mediated invasiveness of "Shigella-like" Escherichia coli.

Invasive Escherichia coli is a "Shigella-like" microorganism which causes a dysenteric syndrome through invasion of the human colonic epithelium. Representative strains of different serotypes were studied in order to determine whether plasmids are involved in their virulence. All invasive E.

[Correlation between the loss of plasmid DNA and the transition from virulent phase I to avirulent phase II in Shigella sonnei].

Transition from virulent phase I to non virulent phase II in five strains of Shigella sonnei was studied by immunofluorescence and plasmid electrophoresis. High frequency loss of phase I specific antigens was observed by use of fluorescent phase specific antibodies. Agarose gel electrophoresis of bacterial lysates showed that transition from phase I to phase II is associated with the loss of extrachromosomal DNA.

[Fermentation of galacturonate by "Shigella" (author's transl)].

The ability of 300 Shigella strains to produce acid from galacturonate (galacturonate test) was examined. With respect to this galacturonate test, all S. flexnerii serotypes (except serotype 6) were positive, and all S.

[Interest of gamma-glutamyltransferase in "Enterobacteriaceae" (author's transl)].

Gamma-Glutamyltransferase (gammaGT) could be detected in 86,6% of 3,027 strains of Enterobacteriaceae, by the use of gamma-L-glutamin-p-nitranilide acid for substrate. The following species produced gamma GT: Citrobacter freundii, Levinea malonatica, L. amalonatica, Klebsiella pneumoniae, K.

A code for reporting and comparing results in phage typing.

This code, like the others proposed, involves the definition of a characteristic reaction for each system. Each reaction must be positive or negative. As regards the interpretation of results, it is worth noting that if the bacteriophage typing system uses not less than 5 phages, there is no problem for interpreting the results of small series of 10 to 20 strains, whatever the code used.

[Phage-typing modifications induced by in vitro transfer of R plasmids. II. -- Phage-typing of Shigella sonnei (author's transl)].

Forty-two antibiotic resistance plasmids and twelve metabolic plasmids have been transferred to a strain of Shigella sonnei. The phage-typing modifications have been investigated after transfer of the different above described plasmids. Eleven of the R plasmids and five of the metabolic plasmids affect phage sensitivity.

[Phage-typing modifications induced by "in vitro" transfer of R plasmids. I.--Phage typing of Salmonella typhi (author's transl)].

The phage-typing modifications induced by transfer of antibiotic-resistance plasmids wre studied in two S. typhi Vi+ strains: n 2411 (phage-type A) and Ty2 (phage-type E1a). Forty-one R plasmids belonging to twenty-two incompatibility groups were investigated.