Biomedical subjects

E Derlot

Publications and source records attributed to E Derlot.

22 records · Page 2Linked to original sources

PubMed1986

[A study by the National Reference Center for Antibiotics on inocula for antibiotic sensitivity testing].

We compared the diameters of inhibition zones obtained during antibiotic sensitivity testing using two different techniques for preparing and seeding the inoculum, i.e. photometric adjustment followed by flooding, and turbidity adjustment followed by swab streaking. There was no significant difference between the results recorded following photometry-flooding of a light inoculum (2 to 3 X 10(6) CFU/ml) and following swab seeding of a bacterial suspension with a turbidity equal to 0.5 Mac Farland unit. These results indicate that both methods tested answer the NCCLS performance standards for disc antibiotic sensitivity testing and the critical values of the S.F.M. Antibiotic Sensitivity Testing Committee.

Escherichia coli↗

PubMed1985

[Effect of ceftazidime on enterobacteria and Pseudomonas producers of beta-lactamases].

The activity of cephalotin, cefoxitin, cefamandole, cefoperazone, cefotaxime, latamoxef, thienamycin, azthreonam, cefsulodine and ceftazidime against beta-lactamase producing strains of Enterobacteriaceae and Pseudomonas was compared by determination of 99% inhibitory concentrations. The isogenic strains studied differed by a single genetic event: mutation, gene amplification, acquisition of a high or low copy-number plasmid or of a transposon and were representative of the major known mechanisms of resistance toward beta-lactams. The results obtained indicate an overall excellent activity of ceftazidime, in particular against Pseudomonas.

Ceftazidime↗

PubMed1983

Comparative activity of cefotetan on Escherichia coli K12 possessing plasmid-mediated beta-lactamases.

The antibacterial activity of cefotetan, a new cephamycin, was compared with that of cephalothin, cefoxitin, cefamandole, cefoperazone and cefotaxime on 12 substrains of Escherichia coli K12 BM13 harbouring single and multi-copy plasmids coding for plasmid-mediated beta-lactamases TEM, SHVI, OXA-I and OXA-III. The 99% inhibitory concentrations (IC99) for the recipient strain were increased in proportion to the enzyme activity in the case of cefamandole and cefoperazone. In contrast, the activity of cefoxitin, cefotaxime and cefotetan was not significantly modified. Since these enzymes are responsible for the resistance of Enterobacteriaceae in the great majority of clinical isolates, cefotetan can be expected to be fully active against strains producing them. Cefotetan was not hydrolysed by chromosomal cephalosporinase and it was active against Enterobacter, Citrobacter and Morganella strains producing a low level of enzyme but hyperproducing variants were highly resistant to cefotetan.

Anti-Bacterial Agents↗

PubMed1983

Selection and characterization of beta-lactam-resistant Escherichia coli K-12 mutants.

beta-Lactam-resistant mutants of Escherichia coli K-12 were selected by using 12 different beta-lactam derivatives. The mutants fell into three categories showing (i) altered permeation through reduction or loss of outer membrane porin proteins (including ompF, ompR, and envZ alleles); (ii) increase in the rate of synthesis of chromosomally mediated beta-lactamase; or (iii) defective synthesis or action of cyclic adenosine 3',5'-phosphate (cya and crp alleles).

Anti-Bacterial Agents↗