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J C Lefevre

Publications and source records attributed to J C Lefevre.

At least 19 recordsLinked to original sources
PubMed1990

Evaluation of the Captia enzyme immunoassays for detection of immunoglobulins G and M to Treponema pallidum in syphilis.

Two new enzyme-linked immunosorbent assays (ELISA), one for the measurement of immunoglobulin G (IgG) (Captia Syphilis-G) and one for the measurement of IgM (Captia Syphilis-M), were evaluated for detecting antibodies to Treponema pallidum. Serum samples from 169 patients, 96 with various stages of untreated syphilis, 63 with treated syphilis, and 10 who were noninfected, were investigated. All sera were also examined by traditional treponemal and cardiolipin tests and by the fluorescent treponemal antibody absorption (FTA-ABS) test for 19S(IgM). The overall sensitivity of Captia Syphilis-G was 98.3%. The IgG ELISA was very sensitive (100%) in all stages of untreated syphilis, except in primary syphilis (82%). In all diagnostic groups of syphilis, the reactivity of Captia Syphilis-M was similar to that of the 19S(IgM) FTA-ABS test, except in reinfections, in which the IgM capture ELISA was less sensitive. False-positive IgM capture ELISA results were not found in the 10 neonates born to mothers adequately treated for syphilis. However, of six serum samples containing rheumatoid factor, two were reactive in the Captia Syphilis-M test but not in the 19S(IgM) FTA-ABS test. This indicated that the specificity of the IgM capture ELISA was not absolute. All serum samples from treated patients were reactive in the IgG ELISA, but only 15 samples were reactive in the IgM capture ELISA, which appeared to be as effective as the 19S(IgM) FTA-ABS test in monitoring the effect of treatment. Simultaneous measurement of IgG and IgM antibodies for T. pallidum by the Captia immunoassays appears to be an efficient and simple method for confirming the diagnosis of syphilis as well as for indicating whether active disease is present.

Antibodies, Bacterial↗
PubMed1989

[In vitro activity of 5 new quinolones against Gardnerella vaginalis].

The minimal inhibitory concentrations (MICs) of five new quinolones were determined by agar dilution, for 50 clinical isolates of Gardnerella vaginalis. They are compared with those of metronidazole, ampicillin, erythromycin and tetracycline which are widely used for the treatment of lower genital tract infections in women. The MICs of rosoxacin and pefloxacin are high, but those of ofloxacin (MIC 50, 2 mg/l), fleroxacin (MIC 50, 2 mg/l) and ciprofloxacin (MIC 50, 1 mg/l) are lower. They can explain the effectiveness observed with this latter antibiotic in vivo, and allow their clinical experiment.

Ampicillin↗
PubMed1988

[Surveillance of Neisseria gonorrhoeae strains isolated in Toulouse. In vitro antibiotic sensitivity and plasmid content].

The minimal inhibitory concentration (MIC) of twelve antibiotics was determined by the method of dilution in agar for 50 non penicillinase-producing and 15 penicillinase-producing Neisseria gonorrhoeae (PPNG) strains. The commonly used antibiotics are active in vitro against all the strains. For the non PPNG stains, no difference was observed between the MICs with a previous investigation, in 1980. New quinolones are highly active against all the strains tested but two, with decreased sensitivity. Since 1980, 16 PPNG strains were isolated (2.2%) and analysed for plasmid content. Asian type plasmid (7.4 kb) was present in 9 strains and african type (5.3 kb) in 7 strains. The conjugative plasmid (39 kb) was present in 5 strains and the cryptic plasmid (4.4 kb) in all the strains.

Anti-Bacterial Agents↗
PubMed1985

Localized conversion in Streptococcus pneumoniae recombination: heteroduplex preference.

In pneumococcal transformation the frequency of recombinants between point mutations is generally proportional to distance. We have recently described an aberrant marker in the amiA locus that appeared to enhance recombination frequency when crossed with any other allele of this gene. The hyperrecombination that we have observed in two-point crosses could be explained by two hypotheses: the aberrant marker induces frequent crossovers in its vicinity or the mutant is converted to wild type. In this report we present evidence showing that, in suitable three-point crosses, this hyperrecombination does not modify the recombination frequency between outside markers, suggesting that a conversion occurs at the site of this mutation. To estimate the length over which this event occurs, we isolated very closely linked markers and used them in two-point crosses. It appears that the conversion system removes only a few base pairs (from three to 27) around the aberrant marker. This conversion process is quite different from the mismatch-repair system controlled by hex genes in pneumococcus, which involves several thousand base pairs. Moreover, we have constructed artificial heteroduplexes using separated DNA strands. It appears that only one of the two heteroduplexes is specifically converted. The conversion system acts upon 5'..ATTAAT..3'/3'.. TAAGTA..5'. A possible role of the palindrome resulting from the mutation is discussed.

Base Sequence↗
PubMed1983

[Sensitivity of Gardnerella vaginalis to antibiotics. Study of 40 strains isolated at the Purpan University Hospital Center of Toulouse].

40 strains of Gardnerella vaginalis were tested for their in vitro susceptibility to 10 antibiotics, by an agar dilution method. All strains were inhibited by 0,5 microgram or less of penicillin and ampicillin. Erythromycin was the most active of the antibiotics tested; for all strains the minimal inhibitory concentrations were less than or equal to 0.06 microgram/ml. All strains were inhibited by 8 micrograms of streptomycin per ml and 4 micrograms of chloramphenicol per ml. 50% of the strains were inhibited by less of 2 micrograms of tetracyclin and all strains tested exhibited MIC greater than or equal to 64 micrograms when tested against colistin, nalidixic acid and sulfafurazole. At least, 85% of strains were inhibited by 2 to 16 micrograms of metronidazole.

Anti-Bacterial Agents↗
PubMed1981

[Limitations of passive treponema haemagglutination test (TPHA) in the detection of early syphilis (author's transl)].

The sera from 80 patients with clinical signs of primary syphilis were subjected to fluorescent treponemal antibody absorption test (FTA-abs), TPHA test and cardiolipin reactions (Kline, VDRL, Kolmer). The superiority of the FTA-abs test in screening for early primary syphilis was confirmed, but the TPHA test was less sensitive: the sera of 14 patients were reactive in the FTA-abs test and cardiolipins reactions but not in the TPHA test. The TPHA test alone cannot be relied upon to detect early syphilis; when the FTA-abs test is not performed, it must always be combined with one of the cardiolipin reactions.

Cardiolipins↗
PubMed1980

Transformation of Streptococcus pneumoniae with S. pneumoniae-lambda phage hybrid DNA: induction of deletions.

The genetic fate of a fragment of Streptococcus pneumoniae DNA cloned into a derivative of the Escherichia coli bacteriphage lambda has been studied in pneumococcal transformation. Transforming activity of this hybrid DNA is 8 times higher than standard S. pneumoniae DNA. Hybrid DNA is mutagenic for the recipient bacteria. Mutations are induced at a rate of 2 per 1000 transformation events. Most of these mutations are deletions adjacent to the cloned pneumococcal fragment, starting at or near its extremities and extending outside. The length of these deletions, estimated by genetic analysis or by gel electrophoresis of DNA fragments generated by restriction endonucleases, is quite variable, ranging from 150 base pairs to more than 1800 base pairs. Insertion of lambda DNA bas been detected in two large deletions by using DNAxDNA hybridization as a probe. This suggests that nonhomologous regions adjacent to the cloned fragment may be illegitimately integrated by the tranformation process. During the genetic analysis of these induced mutations we have observed that not only these deletions but also spontaneous deletions drastically increase recombination rates when present on donor DNA in transformation of neighboring markers. Such an effect is interpreted as partial exclusion of deletions from synapsis between donor and recipient DNA.

Aminopterin↗
PubMed1979

Donor deoxyribonucleic acid length and marker effect in pneumococcal transformation.

The efficiency of transformation of point mutations depends upon base pair mismatches during the recombination process. For low-efficiency markers, the genetic information carried on the donor deoxyribonucleic acid is preferentially lost. To understand this elimination process, we investigated the effect of the size of donor deoxyribonucleic acid on the relative efficiency of low-efficiency point mutations. The deoxyribonucleic acid was shortened either by mechanical shearing or by restriction enzyme treatments. The results indicate that transformation by low-efficiency markers was not affected by shortening the distance between them and the end of the molecule any more than was transformation by the other markers. Moreover, no lethal event could be detected for either cell or chromosomal marker survival. These data do not exclude the double-strand-break hypothesis that was proposed to explain the loss of genetic information for low-efficiency markers, but they offer no support for it.

DNA Restriction Enzymes↗
PubMed1977

Formation of HfrH-type donor cells as a result of integrative suppression by R-F recombinant plasmids.

Three recombinant plasmids, resulting from recombination between an R plasmid of the FI incompatibility group and the F of HfrH, were introduced in a temperature-sensitive dnaA mutant to isolate Hfr-type-donors. All of the temperature-insensitive clones isolated from two of the three recombinant plasmids had the same origin and transfer pattern as the parental HfrH strain.

Chromosomes, Bacterial↗
PubMedDate not supplied

Postmeningococcal urethritis caused by Chlamydia trachomatis: a case report.

The authors describe a case of meningococcal urethritis that was followed, after treatment with spectinomycin, by development of urethritis due to Chlamydia trachomatis. This case report emphasizes the need for thorough differentiation of species of Neisseria and of direct microbiologic diagnosis of chlamydial infection in laboratories.

Adult↗