Biomedical subjects

Catherine Cailliez-Grimal

Publications and source records attributed to Catherine Cailliez-Grimal.

4 recordsLinked to original sources

PubMed2006

A selective enumeration medium for Carnobacterium maltaromaticum.

A selective medium was proposed for isolating the species Carnobacterium maltaromaticum from cheeses. This medium, named CM, was elaborated using combinations of three antibiotics (gentamicin, nalidixic acid, vancomycin) and alkaline pH value (8.8). An experimental design (Doehlert matrix) was drawn up to optimize the experimental conditions of the preparation of the medium. Based on the TS-YE agar medium, it contained 3.5 mg L(-1) of vancomycin, 5.0 mg L(-1) of gentamicin, and 20 mg L(-1) of nalidixic acid. The incubation time was 36 to 48 h at 25 degrees C. The selectivity of this medium was tested against bacterial strains present in the dairy industry and controlled by the PCR method. Thanks to this medium, it was easy to detect C. maltaromaticum and to follow this species in the cheese-making process.

Anti-Bacterial Agents↗

PubMed2005

Quantitative polymerase chain reaction used for the rapid detection of Carnobacterium species from French soft cheeses.

An identification method by PCR, specific to the Carnobacterium genus, was optimised by testing it on 28 bacterial strains. Primers from the literature were tested to differentiate Carnobacterium strains present among various bacterial species. The DNA of Carnobacterium species (C. alterfunditum, C. divergens, C. funditum, C. gallinarum, C. inhibens, C. maltaromaticum, C. mobile, C. viridans), specifically amplified by the Cb1-Cb2R primer couple at a hybridization temperature of 69 degrees C, gave only one band of 340 bp. The validation of this technique was carried out on a French soft cheese made with pasteurised milk inoculated with C. maltaromaticum LMA 28. Using classical PCR, detection was not possible for decimal dilutions of the cheese above 1 g L(-1). With Sybr Green I real time PCR, the specificity of the reaction was confirmed by the T(m) value. The standard curve constructed using the main threshold cycle and various concentrations of C. maltaromaticum LMA 28 (ranging from 10(0) to 10(8) cfu mL(-1)) showed good linearity and a sensitivity limit of > or = 10(4) cfu g(-1) of cheese. This technique was applied on commercially available cheeses made from raw cow's milk. The Sybr Green I real time PCR method constitutes an effective and easy-to-perform method to quantify Carnobacterium sp. in cheese.

Animals↗

PubMed2004

Cell envelope analysis of insensitive, susceptible or resistant strains of Leuconostoc and Weissella genus to Leuconostoc mesenteroides FR 52 bacteriocins.

Mesenterocins 52A and 52B belong to class II of lactic acid bacteria bacteriocins. To study susceptibility, insensitivity and resistance to these mesenterocins, four wild-type bacterial strains and four resistant strains, all from Leuconostoc or Weissella genus, were compared. Several cell envelope features were investigated: susceptibilities to antibiotics and to lysozyme, cell morphology and membrane phospholipids contents. The strain insensitive to the two mesenterocins appeared to be resistant to lysozyme and exhibited the highest resistance to antibiotics. Resistant strains displayed cell morphology modifications, several increases in antibiotic resistance and modifications in lysozyme susceptibility. Moreover, mesenterocin 52A-resistant strains displayed modifications in their membrane phospholipids, leading to a more cationic membrane. Insensitivity and resistance of Leuconostoc or Weissella strains seem to be due to various minor modifications of the membrane and/or of the cell wall.

Anti-Bacterial Agents↗

PubMed2004

Synergistic mode of action of mesenterocins 52A and 52B produced by Leuconostoc mesenteroides subsp. mesenteroides FR 52.

Few studies have been published on the effects of two bacteriocins combinations and particularly on combinations of two bacteriocins with different structures produced by the same strain. In this work, the actions of mesenterocin 52A (class IIa) and mesenterocin 52B (class II), produced by Leuconostoc mesenteroides subsp. mesenteroides FR 52, were studied on strains susceptible to only one bacteriocin or to both. In broth, combination of mesenterocins enhanced the adaptation time of the strain susceptible to the both mesenterocins (48 h vs 17 h with only one bacteriocin). In agar medium, mesenterocins displayed, as expected, a synergistic effect on this strain (FIC(index) < 1), but also on the two strains susceptible to only one mesenterocin. This original result was probably due to membrane composition modifications induced by the mesenterocin that enhanced bacteriocin action. Thus, this hurdle technique seems to be interesting in food preservation in terms of minimizing bacteriocin concentrations.

Bacterial Proteins↗