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Biomedical subjects

J Freney

Publications and source records attributed to J Freney.

At least 55 records · Page 3Linked to original sources
PubMed1995

Evaluation of CPS ID2 medium for detection of urinary tract bacterial isolates in specimens from a rehabilitation center.

CPS ID2 medium (bioMérieux) enables the presumptive identification of Escherichia coli and enterococci as well as the detection of indologenous or nonindologenous Proteeae and bacteria belonging to the Klebsiella, Enterobacter, and Serratia group with a specificity ranging from 98 to 100%. When the cultures were polymicrobial, the sensitivity varied from 70 to 97%, and the sensitivity varied from 97 to 100% when they were monomicrobial.

Bacteriological Techniques↗
PubMed1995

[Comparison of different phenotypic methods with polymerase chain reaction (PCR) for the detection of resistance to oxacillin in coagulase negative staphylococci].

The mecA gene which confers the oxacillin resistance has been searched by PCR in 290 (124 positives, 166 negatives) coagulase-negative staphylococci (CNS) belonging to twelve species. The results were compared with the oxacillin MIC values obtained by agar dilution (4% NaCl) or by the ATB STAPH method (Api-bioMérieux; 0%, 2%, 5% NaCl) and growth inhibitory diameters obtained by agar diffusion with an oxacillin disk placed at 30 degrees C without NaCl, or at 35 degrees C in presence of 2% or 5% NaCl. Sensitivity of oxacillin resistance detection depends upon the salt concentration and the method used. The optimum concentration is 2%. With this concentration, the Api ATB test appears as the more performant (sensitivity: 89.8%). Search for the mecA gene by PCR represents a very interesting method that detects 96.9% of the oxacillin-resistant CNS strains.

Bacteriological Techniques↗
PubMed1995

The origin of the antiseptic-resistance gene ebr in Staphylococcus aureus.

The antiseptic-resistance gene ebr was detected not only in resistant strains of Staphylococcus aureus but also in sensitive strains of S. aureus, in coagulase-negative staphylococcal strains and in enterococcal strains by means of the polymerase chain reaction. The nucleotide sequence of the amplified DNA fragment of the ebr gene from a sensitive strain and that of the previously reported ebr gene were identical. It seems likely that antiseptic-resistant cells result from an increase in the copy number of a gene whose normal function is to remove toxic substances from normal sensitive cells of staphylococci and enterococci.

Anti-Infective Agents, Local↗
PubMed1994

Evaluation of a semi-automated 24-hour commercial system for identification of Enterobacteriaceae and other gram-negative bacteria.

A semi-automated commercial system (ID 32 E, bioMérieux) for 24-hour identification of Enterobacteriaceae and other gram-negative fermentative and nonfermentative bacteria encountered in diagnostic microbiology was evaluated. Overall, the system correctly identified 506 (91.5%) of the 553 strains tested, 94 (17.0%) strains requiring additional tests for complete identification. Six (1.1%) strains were misidentified and 33 (6.0%) strains were not identified. Eight (1.4%) strains were not present in the database and were misidentified or not identified. The system is a suitable alternative to existing systems for the identification of Enterobacteriaceae and other gram-negative bacteria frequently encountered in clinical samples.

Bacterial Typing Techniques↗
PubMed1994

Laboratory diagnosis of oxacillin resistance in Staphylococcus aureus by a multiplex-polymerase chain reaction assay.

A polymerase chain reaction (PCR) test was developed in which the mecA gene responsible for the intrinsic resistance to oxacillin in Staphylococcus aureus and the gyrA gene, always present in this species, were amplified in one operation. Among the 468 clinical isolates tested, the results obtained for 454 of the isolates (97%) were consistent with those of MIC determination. Discrepant results were noted for strains with low-level oxacillin resistance (MICs, 4-8 micrograms/ml) and mecA gene negative. For these strains, susceptibility to oxacillin was restored in the presence of a beta-lactamase inhibitor, which suggested a resistance by penicillinase hyperproduction. In contrast, all of the high-level resistant strains (MICs, > 8 micrograms/ml) carried the mecA gene. The presence of this gene has frequently been associated with resistance to gentamicin, tetracycline, erythromycin, lincomycin, and pefloxacin. The PCR assay described in this study can be accomplished with ease and total confidence in the clinical microbiologic laboratory for a rapid and effective establishment of antistaphylococcal chemotherapy.

Bacterial Proteins↗
PubMed1994

rRNA gene restriction patterns as possible taxonomic tools for the genus actinomyces.

Species delineation in the genus Actinomyces remains unclear, particularly regarding the two taxa, A. naeslundii and A. viscosus. The ribotyping patterns of 64 strains of Actinomyces, representing 8 species and comprising different serotypes, were studied as possible taxonomic tools, using an acetyl-aminofluorene (AAF)-labelled E. coli 16S + 23S rRNA probe. Similarities between patterns were assessed using Jaccard's coefficient and clustering achieved using the unweighted pair-group method with average linkage (UPGMA) on a Macintosh II (Apple, Cupertino, USA) computer. The dendrogram obtained from the ribotypes gave results which were in reasonable agreement with many previous reports: A. bovis, A. gerensceriae, A. israelii, A. meyerii, A. odontolyticus and A. pyogenes were found to be distinct species but the two taxa A. naeslundii and A. viscosus remained unclear. Further investigations, using a larger number of A. naeslundii and A. viscosus strains and other endonucleases, need to be carried out to provide more information concerning the relatedness of these two taxa. Nevertheless, these preliminary results suggested that the Actinomyces chromosome contains multiple rRNA operons which may be used as an epidemiological and taxonomical tool.

Actinomyces↗
PubMed1994

Molecular typing of Actinomyces pyogenes isolates.

The molecular characterization of 28 clinical Actinomyces pyogenes strains was attempted. SDS-PAGE protein profiles did not allow to distinguish isolates. Restriction endonuclease analysis of total DNA gave the finest differentiation between strains but the profiles were difficult to read. Ribotypes after DNA digestion by Bst EII or Sma I have a high discriminatory power and are more helpful epidemiological markers. No relationship could be demonstrated between molecular types and clinical sources.

Actinomyces↗
PubMed1994

Evaluation of API NH, a new 2-hour system for identification of Neisseria and Haemophilus species and Moraxella catarrhalis in a routine clinical laboratory.

API NH is a new 2-h system (bioMérieux, La Balme-les-Grottes, France) for the identification of most Neisseria and Haemophilus spp. of clinical significance and of Moraxella catarrhalis and for the detection of penicillinase production. Furthermore, this system allows the biotyping of Haemophilus influenzae and Haemophilus parainfluenzae. Three hundred eighteen strains belonging to these species, previously identified by conventional methods, were tested. Among the 305 strains belonging to species included in the data base, 225 (73.8%) were identified without additional tests, 79 (25.9%) were correctly identified after extra tests, and 1 strain (0.3%) was misidentified. For 131 (90.3%) of the 145 H. influenzae and H. parainfluenzae strains, results of biotyping were in agreement with results of standard methods. API NH is an accurate and reliable method for the routine identification of these bacteria in a clinical laboratory, for biotyping of Haemophilus spp., and for the detection of penicillinase-producing strains. The system is ready to use and time saving; inoculation of the system and reading of results are easy.

Bacterial Typing Techniques↗
PubMed1994

Method for differentiating Klebsiella planticola and Klebsiella terrigena from other Klebsiella species.

Conventional methods usually fail to identify Klebsiella planticola and Klebsiella terrigena, which represent up to 19% of clinical Klebsiella isolates. By combining four carbon substrate assimilation tests and two conventional tests, the method identified these species with a specificity and a sensitivity of 100%. Overall, sensitivity for Klebsiella identification was 94.7%.

Bacterial Typing Techniques↗
PubMed1994

[Relationship between the level of minimal inhibitory concentrations of five antiseptics and the presence of qacA gene in Staphylococcus aureus].

The Polymerase Chain Reaction (PCR) was used to detect the qacA gene which encodes antiseptic resistance in 186 clinical isolates of Staphylococcus aureus. The results were compared with those obtained by MIC determination of 4 antiseptics (benzalkonium chloride, hexamidine, chlorhexidine, acriflavine) and for ethidium bromide. The qacA gene was not detected among the 32 susceptible S. aureus strains, but was found in the 70 (85%) of the 82 S. aureus strains resistant to all 5 antiseptics. The gene was also detected in 70 (45%) of the 154 remaining strains that were resistant to at least one antiseptic.

Acriflavine↗
PubMed1993

rRNA gene restriction patterns as an epidemiological marker in nosocomial outbreaks of Staphylococcus aureus infections.

rRNA gene restriction patterns (ribotyping) were compared with phage typing, serotyping, enterotoxins and exfoliatin production in the analysis of 26 Staphylococcus aureus strains isolated from two different nosocomial outbreaks. Total DNA was cleaved by EcoRI restriction endonuclease. After agarose gel electrophoresis and Southern transfer, the hybridization of the membranes was done with radiolabelled 16S rRNA gene from Bacillus subtilis inserted into a plasmid vector. Six to 13 fragments were visualized. A core of common fragments was discerned for all strains tested. A full correlation between ribotyping and conventional markers was observed in only one of the outbreaks studied. In both outbreaks, ribotyping proved helpful in characterizing otherwise untypable strains.

Bacterial Typing Techniques↗
PubMed1993

Chemotaxonomy and molecular taxonomy of some coryneform clinical isolates.

Six reference strains of the genus Brevibacterium as well as fifteen clinical isolates tentatively assigned to the genus using conventional biochemical methods, were the subject of chemotaxonomic and DNA similarity studies. Five of these clinical isolates were assigned either to the genera Aureobacterium, Mycobacterium, Gordona or to Rhodococcus on the basis of their DNA mol% G+C, mycolic acid, amino-acid, sugar and menaquinone contents. Among the ten remaining strains, six were not brevibacteria and only four conformed to the description of the genus Brevibacterium sensu stricto. These strains showed low values of DNA relatedness with Brevibacterium epidermidis ATCC 35514T and Brevibacterium linens ATCC 9174, and could only be described as Brevibacterium spp. The results indicate that studies of chemical markers are essential for the correct identification of brevibacteria.

Bacterial Typing Techniques↗
PubMed1993

Severe human infections caused by Vibrio metschnikovii.

Vibrio metschnikovii is largely distributed in the aquatic environment; human infections are rarely observed. A fatal case of septicemia in a patient with liver cirrhosis, renal insufficiency, and diabetes is described. A second case in a 82-year-old woman with septicemia, respiratory problems, and infected leg lesions is reported; she was successfully treated.

Aged↗
PubMed1993

Identification of Staphylococcus aureus using a DNA probe: Accuprobe.

A non-isotopic nucleic probe (Accuprobe) has been presented recently by Gen-Probe for the direct specific 1-h identification of Staphylococcus aureus isolated from culture. 50 S aureus strains previously characterized by conventional methods as well as 26 atypical strains (absence of coagulase, thermonuclease and fibrinogen affinity factor) were tested. Moreover, the Accuprobe system was evaluated using 29 other staphylococcal type strains representing all the species described to date. Only the strains that belonged to the S aureus species, including the 26 atypical strains, were detected by Accuprobe, which proved to be a rapid specific mean of identifying S aureus strains, particularly those that are not readily identified by conventional methods.

DNA Probes↗
PubMed1993

Comparison of three primer sets for the detection of Mycobacterium tuberculosis in clinical samples by polymerase chain reaction.

A number of studies have underlined the interest of the polymerase chain reaction (PCR) in the detection of Mycobacterium tuberculosis in clinical samples. Among the different parameters to be carefully studied the choice of target gene and primers is essential. The amplification of nucleotidic sequences localised on three different target genes (groEL, IS6110, Pab) was examined in 196 clinical samples from patients with suspected tuberculosis or receiving antituberculous therapy. The results obtained after hybridization with non-radioactive labelled probes were compared with the culture data. None of the primer sets studied showed a satisfactory sensitivity (79% to 84%) suitable for it to be used alone. The false-negative specimens with the PCR tests usually corresponded to those that contained few mycobacteria. With the methods described in this study, the use of two or three primer sets located on different target genes allowed to improve the positivity rate compared to the culture and sensitivity of the test (90-98%), particularly for paucibacillary samples. On the other hand, the interpretation was easier when concordant results were obtained.

DNA, Bacterial↗
PubMed1993

Cell wall-active antibiotics induce specific alterations of the electrophoretic profile of membrane proteins in a Staphylococcus aureus strain.

The effect of six representative cell wall-active antibiotics upon the membrane proteins of Staphylococcus aureus CIP 65-25 was studied. The profiles of whole membrane proteins and of penicillin-binding proteins of strain CIP 65-25 grown on an antibiotic-free medium were analysed and compared with those of nine other S. aureus strains. Both profiles were found to be very similar for all strains examined. Cell wall-active antibiotics brought about definite changes dealing with a few membrane proteins of strain CIP 65-25. Some polypeptide bands of the control profiles decreased or vanished after exposure to antibiotics whereas others rose only in antibiotic-treated bacteria. None of these modified polypeptides was a penicillin-binding protein. Their possible involvement in the antibacterial effects of antibiotics or in the determinism of bacterial resistance to antibiotics is discussed.

Anti-Bacterial Agents↗
PubMed1992

Fosfomycin enhances the expression of penicillin-binding protein 2 in methicillin-sensitive and methicillin-resistant Staphylococcus aureus strains.

The effects of fosfomycin on penicillin-binding proteins (PBPs) were studied on the methicillin-resistant Staphylococcus aureus strain CIP (Collection de l'Institut Pasteur, Paris, France) 65-25 and on a methicillin-susceptible S. aureus strain CIP 65-6. The combinations of fosfomycin and oxacillin were synergistic, additive or antagonistic, depending on antibiotic concentrations. Fosfomycin induced modifications of the PBP profile of the two strains studied. In particular, it increased the expression of PBP2. This suggested that this protein is inducible; the only PBP not affected by fosfomycin was PBP3.

Bacterial Proteins↗