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J C Lefèvre

Publications and source records attributed to J C Lefèvre.

At least 19 recordsLinked to original sources
PubMed2000

Chlamydia pneumoniae induces interleukin-10 production that down-regulates major histocompatibility complex class I expression.

Recently, it was demonstrated that CD8(+) T cells are important for the response against Chlamydia pneumoniae. By use of the human monocytic cell line U937 and human monocytes taken from peripheral blood, we investigated the effect of infection on various molecules critical for CD8(+) T cell function. A strong secretion of interleukin (IL)-10 by infected cells was observed, together with an inhibited expression of major histocompatibility complex (MHC) class I antigens, but without significant alteration of tumor growth factor-beta secretion or MHC class II expression. Recombinant IL-10 added to uninfected U937 cells decreased the expression of MHC class I, whereas blocking antibodies to IL-10 and its receptor abolished the C. pneumoniae-induced inhibition of MHC class I expression. Analysis of our data provides evidence that IL-10 secretion induced by C. pneumoniae infection of monocytic cells down-regulates the expression of MHC class I molecules and thereby might reduce the presentation of bacterial epitopes by MHC. This would decrease the ability of CD8(+) T cells to eliminate infected cells.

CD18 Antigens↗
PubMed1998

Comparative in vitro susceptibility of a tetracycline-resistant Chlamydia trachomatis strain isolated in Toulouse (France).

BACKGROUND AND OBJECTIVES: We recently reported the first isolation of a tetracycline-resistant Chlamydia trachomatis strain in Toulouse from a woman treated with tetracycline. To characterize this isolate, its in vitro susceptibility was compared with those of 34 other C. trachomatis isolates recovered in Toulouse. STUDY DESIGN: The susceptibilities of C. trachomatis strains were determined in terms of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) using McCoy cells in 96-well microdilution plates, with an inoculum of 5.10(3) to 1.10(4) inclusion-forming units/ml. The antimicrobial agents tested were tetracycline, azithromycin, erythromycin, ofloxacin, and pristinamycin. RESULTS: No difference was observed between the MICs and MBCs except for the tetracycline. Tetracycline-resistant strain MIC and MBC were > 64 micrograms/ml, although < 1% of the bacterial population showed resistance. For the other isolates, the MIC of tetracycline was < or = 0.25 microgram/ml. The antibiotics other than tetracycline were active in vitro against all strains. CONCLUSIONS: These results show that the tetracycline resistance observed in Toulouse differs from the "heterotypic resistance" described previously in the United States in multiresistant C. trachomatis isolates. They confirm that the resistance we observed may be a new phenomenon.

Chlamydia trachomatis↗
PubMed1995

Molecular analysis by pulsed-field gel electrophoresis of penicillin-resistant Streptococcus pneumoniae from Toulouse, France.

A sample of 28 penicillin-resistant Streptococcus pneumoniae strains isolated between 1991 and 1993 in a large hospital in Toulouse, France, was characterized by pulsed-field gel electrophoresis of genomic DNA. Also included were 6 penicillin-susceptible clinical isolates from Toulouse and 12 penicillin-resistant strains from different parts of the world. The restriction endonucleases ApaI and SmaI were used to digest intact chromosomes, and the fragments were resolved by field-inversion gel electrophoresis. Seven major pattern types could be recognized among the penicillin-resistant isolates from Toulouse. Nine of these isolates could be assigned to two clones that were also found in Spain and were associated with serotypes 6B and 9V. A third clone was isolated in South Africa and in Spain and contained serotype 23F isolates. The profiles obtained by field-inversion gel electrophoresis suggested that 15 of the 16 penicillin-resistant serogroup 23 isolates from Toulouse belonged to the same Spanish 23F clone. The molecular test profiles of penicillin-susceptible strains differed from those of resistant strains of the same serotype except those of 9V strains. These data underline the importance of the geographic spread of resistant clones from Spain in the emergence of penicillin-resistant pneumococci in France.

DNA, Bacterial↗
PubMed1994

Rheologic effects of plasma substitutes used for preoperative hemodilution.

This study was designed to compare the influence of various plasma substitutes, administered for preoperative hemodilution, on blood rheology. We studied 40 patients, ASA grade I, who underwent elective facial reconstructive surgery and received 4% albumin (n = 10), 3.5% dextran 40 (n = 10), gelatin (n = 10), or hydroxyethyl starch (HES) (n = 10). Ten patients, undergoing the same surgical procedure without hemodilution, were chosen as controls. After hemodilution, hematocrit was decreased approximately 30%. Fibrinogen decreased in all tested groups except in the gelatin group. Plasma viscosity decreased with albumin (1.13 +/- 0.05 to 1.06 +/- 0.03 mPa.s; P < 0.01) and increased with HES (1.15 +/- 0.04 to 1.22 +/- 0.05 mPa.s; P < 0.01). At a high shear rate, the blood viscosity decreased in all groups. In contrast, at a low shear rate and at 40% corrected hematocrit, the blood viscosity decreased in the albumin (15.9 +/- 1.9 to 13.1 +/- 2.1 mPa.s; P < 0.01) and the dextran 40 (16.9 +/- 2.9 to 12.8 +/- 2.5 mPa.s; P < 0.01) groups and was unchanged in the gelatin and the HES groups. Erythrocyte aggregation (measured with primary aggregation time) was markedly decreased in the albumin (3.27 +/- 1.74 to 7.03 +/- 2.95 s; P < 0.01) and in the dextran 40 (2.72 +/- 0.58 to 6.24 +/- 2.55 s; P < 0.001) groups, unchanged with HES, and increased with gelatin (2.41 +/- 0.90 to 1.55 +/- 0.33 s). These findings suggest that albumin and dextran 40 may be the plasma substitutes of choice for preoperative hemodilution when this technique aims to improve rheologic conditions.

Adolescent↗
PubMed1994

Pulsed field gel electrophoresis for molecular epidemiology of penicillin resistant Streptococcus pneumoniae strains.

The emergence of strains of Streptococcus pneumoniae resistant to penicillin and other antibiotics has become a major concern for antimicrobial therapy of pneumococcal infections. The spread of that resistance over the world increases the need for their epidemiological surveillance: specific epidemiological markers are required. In this study, pulsed field gel electrophoresis of genomic DNA was carried out on sixteen resistant isolates of S. pneumoniae from different parts of the world and fifteen resistant isolates from Toulouse. The restriction endonucleases ApaI and SmaI were used to digest intact chromosomes and the fragments were resolved by field inversion gel electrophoresis (FIGE). Each digest produced 10 to 19 fragments for comparison between strains. The polymorphism obtained with FIGE was greater than that obtained with serotyping which appeared to be not a good criterion for genetic relatedness. Three common clones could be recognized among the penicillin-resistant isolates. Two clones were found in Spain and in Toulouse and were associated with serotypes 6B and 9V, respectively. The third clone was isolated in South Africa and in Spain and contained serotype 23F isolates and one serotype 19F strain. The FIGE profiles observed in this study also demonstrated that serogroup 23 multiresistant strains isolated in Toulouse are genetically closely related and might have originated from the same Spanish 23F clone. These results underline the importance of the geographic spread of resistant clones in the increase in the incidence of penicillin-resistant pneumococci. They indicate that pulsed field gel electrophoresis should be an effective tool for the typing of resistant S. pneumoniae strains capable of tracing their origin.

DNA, Bacterial↗
PubMed1993

[Multicenter study of the in vitro sensitivity of genital mycoplasmas to antibiotics].

The in vitro susceptibility of Ureaplasma urealyticum (Uu) and Mycoplasma hominis (Mh) was evaluated in a multicentric study performed in seven hospitals from different geographic areas in France. During a three month period, 324 Uu and 72 Mh clinical isolates were tested using a system ready for use, SIR Mycoplasma (Sanofi Diagnostics Pasteur). For Uu, the percentage of strains intermediate (I) or resistant (R) was as follows: doxycycline (3), minocycline (2.5), lymecycline (6.7), erythromycin (72, most I), josamycin (0.9), clindamycin (88), pristinamycin (0.3), ofloxacin (34, most I). For Mh, the percentage of strains I or R was respectively: doxycycline (2.7), minocycline (5.5), lymecycline (15.2), erythromycin (100), clindamycin (1.4), ofloxacin (2.7), josamycin (0) and pristinamycin (0). Comparable results were observed in the different geographic areas. The frequency of acquired resistances does not justify modifications in the usual treatment of genital mycoplasma infections but leads to monitor their susceptibility to antibiotics.

Clindamycin↗
PubMed1993

In vitro evaluation of activities of azithromycin, clarithromycin and sparfloxacin against Chlamydia trachomatis.

The in vitro activities of azithromycin, clarithromycin and sparfloxacin were evaluated by studying inhibition of in vitro Chlamydia trachomatis propagation in McCoy cells, comparatively with erythromycin, ofloxacin and tetracycline. Fifteen clinical isolates of C. trachomatis were tested with an inoculum of 5.10(3) inclusion--forming units in a 96--well microtiter plate. Minimal inhibitory concentration (MIC) ranges were as follows: azithromycin, 0.06 to 0.125 microgram/ml; clarithromycin, 0.008 microgram/ml; erythromycin, 0.06 to 0.125 microgram/ml; ofloxacin 0.5 to 1 microgram/mg; sparfloxacin, 0.03 to 0.06 microgram/ml; and tetracycline 0.125 to 0.25 microgram/ml. Minimal bactericidal concentration (MBC) ranges, calculated from passage into antibiotic--free medium, were as follows: azithromycin 0.25 to 0.5 microgram/ml; clarithromycin, 0.03 to 0.125 microgram/ml; erythromycin, 0.25 to 2 micrograms/ml; ofloxacin, 0.5 to 1 microgram ml; sparfloxacin, 0.03-0.06 microgram/ml; and tetracycline, 1 to 4 micrograms/ml. Clarithromycin and sparfloxacin showed the greatest activity and clinical studies of these agents in C. trachomatis infections are therefore indicated.

Anti-Bacterial Agents↗
PubMed1993

[Recent bacteriologic data: from physiopathology to treatment].

Bacterial vaginosis is characterized by a change in the vaginal ecosystem in which Lactobacillus spp, the dominant members of the normal flora, are replaced by an association of various bacterial species including Gardnerella vaginalis, anaerobes (Bacteroides spp, Prevotella spp, Porphyromonas spp, Peptostreptococcus spp and Mobiluncus spp) and Mycoplasma hominis. The reasons for this imbalance are unknown, although the loss of lactobacilli that produce hydrogen peroxide (which is toxic for G. vaginalis and numerous anaerobes) may be an essential element. The introduction of one or several of these species into the vagina (they can occasionally be isolated in small numbers even in the absence of vaginosis) following intercourse or from the intestinal tract may also play a role. G. vaginalis itself is not considered to cause vaginosis, but is almost always present and multiplies rapidly; in addition, it has a high capacity for adherence to epithelial cells both in vivo and in vitro. It is now agreed that the concomitant growth of one or several anaerobic species is required for bacterial vaginosis to develop. Our knowledge of the bacteriology of bacterial vaginosis has implications for diagnosis and treatment. It is now possible to obtain a precise bacteriologic diagnosis, not by culturing G. vaginalis (a costly and low-yield procedure), but by direct examination of the vaginal flora after Gram staining, which shows the replacement of lactobacilli by a characteristic polymorphic flora. Therapy is based on the use of antibiotics such as the imidazoles, which are active against G. vaginalis and anaerobes, but not against the commensal lactobacilli.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteria, Anaerobic↗
PubMed1992

In vitro activity of sparfloxacin and other antimicrobial agents against genital pathogens.

The in vitro activity of sparfloxacin was determined for 60 strains of Neisseria gonorrhoeae, 15 strains of Chlamydia trachomatis and 40 strains each of Gardnerella vaginalis, Mycoplasma hominis, and Ureaplasma urealyticum and compared with those of ampicillin, azithromycin, clarithromycin, erythromycin, ofloxacin, temafloxacin and tetracycline. Sparfloxacin was active against all the strains studied and appeared to be the most potent quinolone tested. Sparfloxacin had the lowest MICs against N. gonorrhoeae (MICs 0.002-0.06 micrograms/ml). Its MICs against C. trachomatis (0.03-0.06 micrograms/ml) were higher than those of clarithromycin but lower than those of the other antimicrobial agents. Sparfloxacin was particularly active against tetracycline-susceptible as well as resistant strains of M. hominis (MICs, 0.06 micrograms/ml) and U. urealyticum (MICs 0.125-1 micrograms/ml). Because of this in vitro activity and its tissue distribution, sparfloxacin might be a valuable therapeutic agent for treating major bacterial sexually transmitted diseases.

Ampicillin↗
PubMed1992

[In vitro sensitivity to antibiotics of genital mycoplasmas isolated in Toulouse. Study of new molecules (macrolides and quinolones)].

The minimal metabolism-inhibiting concentrations (MMC) of 11 antibiotics were determined for 40 strains each of M. hominis and U. urealyticum using a terminal color change broth method. All strains were recovered in 1990. Resistance to tetracycline (MMC greater than 8 mg/l) was found for 12.5% of strains of M. hominis and U. urealyticum, as compared with 5% in 1985. Rokitamycin was the most active macrolide against M. hominis (MMC 90: 0.06 mg/l). U. urealyticum strains were susceptible to all the macrolides tested, with the greatest activities being seen for rokitamycin and clarithromycin (MMC 90: 0.06 mg/l and 0.12 mg/l respectively). Sparfloxacin was the most active quinolone against both species. Human clinical trials designed to evaluate these new molecules for the treatment of mycoplasmal and ureaplasmal genital infections are warranted.

4-Quinolones↗
PubMed1991

Conversion of large heterologies in Streptococcus pneumoniae.

In genetic transformation, long deletions dramatically increase the frequency of wild-type recombinants in 2-point crosses. In 3-point crosses in which the deletion was localized between 2 point mutations we demonstrated that this hyper-recombination was the result of genetic conversion extending over several scores of bases outside the deletion. As this conversion did not require an active DNA polymerase A gene, it was proposed that the mechanism of conversion involves breakage and ligation between DNA molecules. A similar hyper-recombination was observed when donor DNA carried an insertion. These results suggest that long heterologies participated in recombination so that surrounding homologous regions are almost completely paired and that these long heterologies are converted. It appears that it is a process that evolved to correct errors of replication which lead to long deletions and which are not eliminated by other systems.

Chromosome Deletion↗
PubMed1991

[First isolation in France of a penicillinase-non producing Neisseria gonorrhoeae with high level tetracycline resistance].

We report the first isolation in France of a penicillinase-non producing Neisseria gonorrhoeae with high level tetracycline resistance. The minimal inhibitory concentrations (MICs) of nine antibiotics were determined by agar dilution for the tetracycline resistant strain and 39 other penicillinase-non producing N. gonorrhoeae strains which were isolated during the same year (1989), in Toulouse. No difference was observed between the MICs except for the tetracycline (tetracycline-resistant strain MIC = 32 mg/l). The commonly used antibiotics other than tetracycline were active in vitro against all the strains. The plasmid content of the tetracycline-resistant strain was analysed by agarose gel electrophoresis and revealed the presence of two plasmids: the 2.6-megadalton in cryptic plasmid and the 25.2-megadalton Tet M conjugative plasmid.

Anti-Bacterial Agents↗
PubMed1989

Conversion of deletions during recombination in pneumococcal transformation.

Genetic analysis of 16 deletions obtained in the amiA locus of pneumococcus is described. When present on donor DNA, all deletions increased drastically the frequency of wild-type recombinants in two-point crosses. This effect was maximal for deletions longer than 200 bases. It was reduced for heterologies shorter than 76 bases and did not exist for very short deletions. In three-point crosses in which the deletion was localized between two point mutations, we demonstrated that this excess of wild-type recombinants was the result of a genetic conversion. This conversion extended over several scores of bases outside the deletion. Conversion takes place during the heteroduplex stage of recombination. Therefore, in pneumococcal transformation, long heterologies participated in this heteroduplex configuration. As this conversion did not require an active DNA polymerase A gene it is proposed that the mechanism of conversion is not a DNA repair synthesis but involves breakage and ligation between DNA molecules. Conversion of deletions did not require the Hex system of correction of mismatched bases. It differs also from localized conversion. It appears that it is a process that evolved to correct errors of replication which lead to long heterologies and which are not eliminated by other systems.

Chromosome Deletion↗
PubMed1988

[Calculation of the blood volume to be removed for intentional normovolemic hemodilution].

Intentional haemodilution is more and more frequently used. Although it is a simple technique, it can only be carried out with a maximum of safety if the operator has an idea of the amount of blood that needs to be removed to obtain the required haematocrit value. Several methods have been suggested, using more or less complex calculations, or nomogrammes. A new simple rule is presented here which gives an estimation of the amount of blood to be removed in three steps: 1) the theoretical total blood volume (VS), according to weight, height and sex of the patient, 2) the ratio (R) between the initial and required final haematocrit, and 3) the volume of blood to be removed (Vp) according to VS and R. A mono-compartment model with identical inflow and outflow was used. A multicentre trial with 229 haemodilutions showed that the volume removed (mean = 1,325 ml; SD = 642 ml) was 15% less than the calculated volume (mean = 1,526 ml; SD = 561 ml). No one factor was found to explain this difference. The haematocrit values obtained by microcentrifuge were compared with those obtained by a laboratory automatic counter. The mean of the differences was 0.002 (SD = 0.029). Because of the possible errors involved in estimating the total blood volume and the haematocrit before dilution, it is essential that the haematocrit be checked at least once during the haemodilution.

Blood Volume↗
PubMed1988

In vitro activity of six quinolone derivatives against Neisseria gonorrhoeae.

The in vitro activities of six quinolone derivatives, rosoxacin, pefloxacin, ofloxacin, ciprofloxacin, A-56619 and A-56620, were compared with those of penicillin, cefotaxime, spectinomycin, chloramphenicol, tetracycline and erythromycin against 50 nonpenicillinase-producing and 15 penicillinase-producing Neisseria gonorrhoeae strains. Ciprofloxacin was the most active compound in vitro (MIC50, 0.004 mg/l) followed by ofloxacin and A-56620 (MIC50, 0.008 mg/l), A-56619 and cefotaxime (MIC50, 0.016 mg/l). The six quinolones are highly active against all the strains tested but 2, with decreased sensitivity.

Anti-Bacterial Agents↗
PubMed1985

[Management of Pierre-Robin syndrome].

Pierre Robin syndrome continuously raises problems of intensive care that are difficult to surmount. A peak has to be overcome, the date of which varies as a function of the severity of the affection, following which the infant remains a neonate at high risk. Intensive care of these infants during the neonatal period involves avoidance of the sequence of disturbances provoked by the disorders of ventilation and deglutition. Surveillance of biological variables, feeding and the fight against glossoptosis are mainly the concern of medical procedures: from orthostatic nipples to continuous gastric feeding, from procubitus to intubation with assisted ventilation, and including pharyngeal catheters and physiotherapy. Surgery is required only exceptionally at this stage, mainly in the form of hyomandibulopexy.

Abnormalities, Multiple↗
PubMed1985

[Etiology of bacterial vaginosis (non-specific vaginitis)].

56 women who were diagnosed bioclinically as having a bacterial vaginal infection were studied, as were 35 women as a control group. The study was a semi-quantitative analysis of the vaginal bacterial flora, both aerobic and anaerobic. It shows that Gardnerella vaginalis and anaerobic bacteria such as Peptococcus, Peptostreptococcus, Bacteroïdes, Veillonella and Mobiluncus were associated in a statistically significant way with bacterial vaginitis. On the other hand Lactobacilli were less frequently found (p less than 0.001) than in the control group of women. The way in which the microbial flora is changed has been observed during attacks of vaginitis and is discussed, as is the importance of making the diagnosis and of treating this syndrome.

Bacterial Infections↗