Annales de microbiologie最新文献

In this supplement are given the characters of 52 new Salmonella serovars recognized in 1983 by the WHO collaborating Centre for Reference and Research on Salmonella. With regard to new taxonomic knowledge, the traditional classification of 4 Salmonella subgenera was replaced by the concept of 5 subspecies, designated I, II, IIa (monophasic Arizona), IIIb (diphasic Arizona), IV and V. Furthermore, names of serovars belonging to subspecies I are no longer printed in italics, indicating their infrasubspecific rank. Twenty serovars belong to subspecies I, 26 to II, 1 to subspecies IIIa, 3 to subspecies IIIb, 1 to subspecies IV and 1 to subspecies V.

Simmons citrate agar supplemented with 0.2% adonitol (SCA medium) was used as a differential medium for some enterotoxigenic Escherichia coli: all strains with either a cryptic K99 antigen or a glucose-dependent K99 antigen and 70% of strains with a glucose-independent K99 antigen gave yellow colonies on SCA medium. Other faecal bacteria did not grow or else developed as blue colonies.

The type strain of Bacillus badius (ATCC 14574) was studied in detail. Out of a total of 201 sources of carbon and energy tested, only 19 were used. These included mainly organic and amino acids. No carbohydrates were used. The G+C content of its DNA was 47.5 mol %. The species B. badius therefore deserves to be included in approved lists of bacterial names.

Crystals isolated from Bacillus thuringiensis serovar thuringiensis (H-1) and from serovar israelensis (H-14) were dissolved in sodium hydroxide, then tested in vitro on Aedes aegypti cell cultures. Toxic action was followed after morphological and metabolic alterations of the treated cells. Only the israelensis sodium extract was toxic and gave cellular swelling, inhibition of cell growth and inhibition of labelled precursor incorporation, i. e. of 3H-thymidine, 3H-uridine and 3H-leucine.

Four-week old BALB/c mice were fed a 4% protein diet for 6 weeks. At the 3rd week of undernourishment, they were orally vaccinated with a live vaccine, Salmonella typhimurium Rc. the mice were challenged 3 weeks after vaccination, and malnutrition was discontinued at that time. Results suggested that the live vaccine may be pathogenic when associated with a protein-deficient diet.

Four bacterial strains isolated from two livers of armadillos experimentally infected with Mycobacterium leprae were studied. Lipids obtained after saponification and methylation and complex lipids obtained by solvent extraction were examined. The presence of mycolates showed that the four strains belonged to the genus Mycobacterium, but the mycolate patterns, identical for the four strains, were different from those of all strains studied so far. Three of these strains contained phthioceranic acids, which were not found in the fourth one. Only the last strain contained mycosides of the C type, while the three others contained a new type of glycolipid. Their content in mycolates and in glycolipids demonstrated a clear-cut difference between these strains, on the one hand, and M. leprae on the other.

Gas liquid-chromatography was used in order to characterize the volatile fatty acids produced in culture supernatants by 632 Pseudomonas strains. Statistical analysis of these results allowed testing of the discriminatory power of this analytical methodology (factor analysis) to point out the presence of subgroups (clustering according to the variance) and to show the relationship between species and subspecies (three-dimensional plot). Fourteen Pseudomonas species could be accurately characterized by this methodology; the classification of Pseudomonas build up, on the basis of qualitative and quantitative aspects of their volatile fatty acids production, agrees with the current classification based on rRNA/DNA homology complexes.

The disc-agar diffusion method for antibiotic sensitivity testing was adapted to Clostridium. The main feature of the method described here resided in the use of an inoculum which varied according to the physiological properties of the strain tested, so that the same critical time was obtained in all cases. This technique employs commercially available media and reduced equipment. Statistical analysis of the results indicated a strong correlation between disc-agar sensitivity testing and MIC determined by the agar dilution method.

A quantitative gas-liquid chromatographic method for the determination of the volatile fatty acids produced in standardized liquid culture media by Pseudomonas reference strains belonging to 14 species, some of medical interest, is proposed here. This method, using 14 reference strains, permitted a precise identification of Pseudomonas species according to characteristic chromatograms. The key used for this identification gave us a classification corresponding to the DNA homology groups.

A collection of 31 strains received as Agrobacterium tumefaciens and A. radiobacter was subjected to detailed phenotypic and genomic studies. These strains were recovered from plants, soil, water and clinical specimens. Type strains of A. tumefaciens, A. radiobacter, A. rhizogenes and A. rubi were also included. The strains were tested for their ability to use 169 organic compounds as sources of carbon and energy. In addition, 11 conventional characters were studied for each strain. Relatedness among the strains was assessed by determining the extent of reassociation in heterologous DNA preparations. S1 nuclease and diethylaminoethyl-cellulose filters were used to separate reassociated from non-reassociated nucleotide sequences, and to determine the thermal stability of related nucleotide sequences. The resultant data revealed the following points: regardless of their phytopathogenic effects, 3-ketolactose-producing A. tumefaciens and A. radiobacter strains group into one species; this species contains 9 taxa which can be differentiated from each other by phenotypic and genomic characters; clinical isolates did not induce tumours on plants and clustered in three taxa of this species; the clinical and ecological significance of these organisms is not known; the present classification of the genus Agrobacterium is based on phytopathogenicity and does not reflect the phylogenetic relationships amongst these bacteria; as proposed previously by several workers, the genus Agrobacterium should be divided into 3 species on the basis of phenotypic and genomic characteristics. Different aspects of the classification and nomenclature of Agrobacterium are discussed.