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Y A Chabbert

Publications and source records attributed to Y A Chabbert.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

[Genetic map and structure in "Escherichia coli" K12 of a resistance plasmid isolated from "Salmonella ordonez" (author's transl)].

A resistance plasmid called R IP173 has been transferred into E. coli K12 from a multiresistant strain of S. ordonez isolated during an epidemic in Dakar. This plasmid mediates for colicine Ib production and resistance to ampicillin, streptomycin, spectinomycin, kanamycin, chloramphenicol, tetracycline and sulfonamides. It is transducible "en bloc" by the phage P1-kc between strains of E. coli K12. Compatibility studies have shown that R IP173 belongs to the fi- class, I1 group. It is transferred "en bloc" in conjugation experiments between E. coli K12 strains. But during transfers from S. ordonez into E. coli, incomplete variants are obtained, lacking different markers. A deletion map was obtained after analysis of 19 different variants, and it is suggested that the loss of markers results from the loss of genetic material during transfer. In this particular case, the deletions observed in transduction or conjugation experiments lead to identical genetic maps.

Ampicillin↗
PubMedDate not supplied

Plasmid DNA content of multiresistant Staphylococcus aureus strains.

Multiresistant S. aureus strains (also called methicillin-resistant in clinical laboratories) share many common properties. In addition to the commonly used epidemiological markers (pattern of resistance to antibiotics and metal ions, serotype and lysotype), we considered using the molecular and genetical properties of the plasmid DNA harboured by these strains. In this paper we report an epidemiological study of two groups of S. aureus strains sampled since 1975 and carrying new resistance characters which appeared with increasing frequency in France. The Tm-SgR strains (5 strains) carry, in addition to 13 resistance characters commonly observed, two new characters: the resistance to gramin components A and B (Sg). The two new characters were shown to be encoded by a single plasmid. Amongst the 5 strains studied, two harbour a similar plasmid DNA content while the three others were clearly distinct. Because of the variability of the plasmid DNA content observed in these strains, the similarity of this content observed between two of them suggest a close phylogenic relationship. These two strains are probably derivatives from a single clone. The spread of the two new characters amongst the distinct strains might be related to the spread of ancestrally related Tm-Sg plasmids. The Tob-GenR strains (16 strains) carry, in addition to 12 wide-spread resistance markers, the newly observed resistance to many aminoglycosides, mainly the resistance to tobramycin (Tob) and gentamicin (Gen). They all harbour a 22-kb plasmid DNA generating similar restriction cleavage patterns and conferring the resistance to penicillin G, arsenate, arsenite and cadmium. Some of them harbour one or two extra small plasmids (3.4 and 2.3 kb); the presence of these two plasmids was not associated with a modification of the resistance pattern of the strains. Most of the resistance characters--including the new ones--are probably encoded by chromosomal genes. In this epidemiological situation, the spread of the new aminoglycoside resistance characters carried by the 16 strains having the same phenotype and harbouring the same 22-kb plasmid is attributed to the spread of derivatives from a single clone.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Characteristics of "Streptococcus mutans" from endocarditis and susceptibility to antimicrobial agents (author's transl)].

Strains of Streptococcus mutans were isolated from blood cultures of ten patients with endocarditis. Nine of these patients had a typical clinical picture of subacute bacterial endocarditis, with fever, weakness, heart murmur and multiple positive blood cultures. All the patients had previous valvular heart diseases; only in three cases the initiating event involved some type of dental manipulations which where supposed as the source of infection. The major criteria for recognizing S. mutans were colony morphology on blood agar, characteristic extracellular polysaccharide production in 5% sucrose broth, acid formation in mannitol and sorbitol broth, and the failure of antigenic extracts of S. mutans to react with streptococcal group antisera. The susceptibility to antimicrobial agents was tested by the diffusimetric method with susceptibility disks. All the strains were susceptible to penicillin G, erythromycin, pristinamycin, lincomycin and tetracycline, and resistant to streptomycin and gentamicine.

Endocarditis, Subacute Bacterial↗