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H Monteil

Publications and source records attributed to H Monteil.

At least 109 records · Page 6Linked to original sources
PubMed1994

Genomic diversity among Corynebacterium jeikeium strains and comparison with biochemical characteristics and antimicrobial susceptibilities.

Levels of DNA relatedness were determined by performing DNA-DNA hybridization experiments (S1 nuclease procedure) with 13 human isolates exhibiting various antimicrobial susceptibility patterns which had been identified as Corynebacterium jeikeium by classical tests and the API Coryne system and with reference strains of C. jeikeium and related taxa. Twelve of 13 isolates which formed three genomic groups showed between 22 and 75% relatedness with the type strain of C. jeikeium. One of these genomic groups included all the strains resistant to penicillin and gentamicin and is genomically related to the C. jeikeium type strain at the species level. In addition, the reference strain of "Corynebacterium genitalium" biotype II was found to belong to this genospecies and therefore can be considered as a synonym of C. jeikeium. In contrast, one isolate and the reference strains of "Corynebacterium pseudogenitalium" biotypes C-3 and C-4 which were assigned to C. jeikeium by the API Coryne system were less than 10% related to the C. jeikeium type strain. These nongenomically related strains can be differentiated from the jeikeium-related strains on the basis of positive acidification from fructose and growth under anaerobic conditions. Furthermore, these strains exhibited full susceptibility to penicillin whereas the strains related to the C. jeikeium type strain are resistant to or only moderately susceptible to penicillin. No genomic relationship was found between C. jeikeium-related strains and other lipophilic coryneforms, identified as Corynebacterium accolens or Corynebacterium group G or F. Our study demonstrates the necessity to perform the fructose fermentation test or respiratory-type test for the correct identification of lipophilic coryneforms as C. jeikeium. Although these strains show genomic diversity at the species level, in a practical aspect, biochemical properties as well as antimicrobial susceptibility may allow the classification of such isolates in this single taxon.

Bacterial Typing Techniques↗
PubMed1993

Effect of okadaic acid on the cytotoxic activity of Clostridium difficile toxin B and Clostridium sordellii toxin L.

Clostridium difficile toxin B and Clostridium sordellii toxin L, which are immunologically related toxins, possess a cytotoxic activity inducing depolymerization of microfilaments and cellular retraction of cell bodies that are different for toxin B- and toxin-L-treated cells. The biological mechanisms responsible for these effects are unknown, but a previous study revealed that both toxins induce modification of phosphorylation of cellular proteins extracted from toxin B- and toxin L-treated cells without changes in protein kinase C activity or cAMP concentration. In the present study, we have investigated the effect of okadaic acid, an inhibitor of protein phosphatases, on the cytotoxic activity of toxins B and L in MacCoy cells. Firstly, we reveal by cytotoxic assay and staining of F-actin that okadaic acid (1 microM or higher) induces depolymerization of microfilaments and cellular morphological modifications which are similar to that of cells treated with toxin L. Secondly, we show that 1 microM okadaic acid potentials the cytotoxic activity of toxin L but not of toxin B. These observations suggest that the cytotoxic mechanisms induced by okadaic acid and toxin treatment are partly common, indicating that an increase in phosphorylation favors the cytotoxicity of toxin L. Since okadaic acid had no influence on the cytotoxicity of toxin B, we suggest that toxin B and L, alter the cells by different cellular biological mechanisms.

Actins↗
PubMed1993

Toxin content, phallotoxin and amatoxin composition of Amanita phalloides tissues.

The toxin content and composition of Amanita phalloides tissues were determined in three specimens at two carpophore development stages. The carpophore was subdivided into six parts, namely, the cap, gills, ring, stipe, volva and bulb. To our knowledge, this is the first report of such an investigation on the ring and the bulb. Substantial differences in the tissue toxin content were revealed. The ring displayed a very high amount of toxins, whereas the bulb had the lowest toxin content. Compositional differences in relation to the nature of the tissue were also noted. The highest amatoxin content was found in the ring, gills and cap, whereas the bulb and volva were the richest in phallotoxins. Furthermore, variability in the toxin composition was observed. The differences in the distribution of individual toxins in the tissues might be related to the carpophore developmental stage.

Amanita↗
PubMed1993

Taxonomic study of Corynebacterium Group ANF-1 strains: Proposal of Corynebacterium afermentans sp. nov. containing the subspecies C. afermentans subsp. afermentans subsp. nov. and C. afermentans subsp. lipophilum subsp. nov.

We have determined the cell wall composition, guanine-plus-cytosine (G+C) contents of the DNA, rRNA gene restriction patterns, and the levels of DNA-DNA relatedness of 11 strains identified biochemically as Centers for Disease Control (CDC) Corynebacterium group absolute nonfermenter 1 (Corynebacterium group ANF-1). For seven of these strains, growth is abundant on 5% sheep blood agar, which differentiates them from the four other strains, whose growth requires a lipid supplement such as Tween 80. Two of the lipid-requiring strains produced mucoid colonies on 1% Tween 80-supplemented sheep blood agar. All strains possess cell wall component type IV, short-chain mycolic acids, and G+C contents of DNA of 66 to 68 mol% as determined by reverse-phase high-performance liquid chromatography. DNA-relatedness experiments by an S1 nuclease procedure showed that nine of these strains, including two of the lipid-requiring strains, constitute a new genomic species less than 40% related to Corynebacterium species and other coryneform groups. The lipid-requiring strain T18502 exhibited 98% DNA relatedness with another lipid-requiring strain, T88593 (difference in thermal denaturation midpoint [delta Tm] = 2 degrees C) and 71 to 77% similarity with the nonlipophilic strains (delta Tm range of from to 5 degrees C). Conversely, the DNA relatedness between strain LCDC 88199 and the six other nonlipophilic strains ranged from 86 to 100% (delta Tm range of from 1 to 3 degrees C) and was only 73 and 76% with the lipophilic strains T18502 and T88593, respectively (delta Tm, 3 and 4 degrees C). These results indicated that these two cultural types of bacteria constitute two subspecies within the new genomic species.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Typing Techniques↗
PubMed1993

Pharmacokinetics of intravenous fusidic acid in patients with cholestasis.

The pharmacokinetics of fusidic acid and 3-ketofusidic acid were investigated in cholestatic and noncholestatic patients after intravenous administration of single and multiple doses of 500 mg of sodium fusidate. The patients, all with low serum albumin levels, were divided into three groups. Group I consisted of six noncholestatic patients; group II consisted of nine mildly cholestatic patients with mild hepatic impairment (conjugated bilirubin, 47 mumol liter-1; alkaline phosphatase, 280 IU liter-1; gamma-glutamyltranspeptidase, 190 IU liter-1); group III consisted of six benign intrahepatic cholestatic patients with high isolated conjugated hyperbilirubinemia (98.1 mumol liter-1). Assays were performed by high-pressure liquid chromatography. At steady state, the mean peak concentrations in serum were 63.7, 44.9, and 92.2 micrograms ml-1 in groups I, II, and III, respectively; over a dosage interval, areas under the concentration-time curve were 411.1, 238.7, and 603.4 micrograms.h ml-1 and the mean body clearances were 0.34, 0.53, and 0.25 ml min kg-1 in groups I, II, and III, respectively. The accumulation ratio of fusidic acid increased from 2.8 and 2.4 in groups I and II to 4.2 in group III. At steady state, the ratios of the areas under the concentration-time curve from 0 to 8 h for 3-ketofusidic acid/fusidic acid were 0.11, 0.09, and 0.10 in the three groups, respectively. Only very small amounts of fusidic acid and 3-ketofusidic acid were found in urine. These results substantiate the following hypotheses. In group I and II patients the clearance is higher than that in healthy volunteers because of the increased free, unbound fraction of fusidic acid, a consequence of lower serum albumin concentrations, resulting in increased distribution in tissue and hepatic metabolism. In group III patients, the higher bilirubinemia results in competition with fusidic acid for the limited glucuronidation, thus compensating for the increased elimination with fusidic acid because of the low serum albumin concentration. These results suggest that fusidic acid can be administered normally even to patients with high bilirubinemia because the postoperative serum albumin concentration is usually low.

Adult↗
PubMed1993

Biliary excretion of cefixime: assessment in patients provided with T-tube drainage.

The biliary excretion profile of cefixime was studied in 10 patients provided with T-tube drainage of the common bile duct after cholecystectomy. Following a single 200-mg oral dose, the peak concentration of cefixime in bile reached 56.9 +/- 70 mg/liter, approximately 20 times as high as the peak concentration in serum, 2.3 +/- 0.85 mg/liter. Cefixime levels in bile proved relatively sustained, since a concentration of 4.3 +/- 3.7 mg/liter was still found 20 h after dosing. The cumulative amount of cefixime recovered in the 24-h bile drainage averaged 10.0 +/- 12.3 mg, which is 5% of the administered dose and positions this beta-lactam antibiotic among the most highly bile-excreted cephalosporins. The presented results show that a single 200-mg oral dose of cefixime provided drug levels in bile consistently higher than the MICs for the most frequently recovered members of the family Enterobacteriaceae in biliary tract infections and maintained these levels for over 20 h after dosing. Accordingly, this cephalosporin deserves further clinical trials to assess its usefulness in both prophylaxis and treatment of biliary tract infections.

Administration, Oral↗
PubMed1993

Effects of Clostridium difficile toxin B on human monocytes and macrophages: possible relationship with cytoskeletal rearrangement.

Toxin B from Clostridium difficile is cytopathic in vitro for various types of cells, including polymorphonuclear cells, lymphocytes, and monocytes. Since intestine lamina propria is rich in macrophages, we studied the effect of toxin B on human monocytes and on human macrophages generated in vitro by long-term culture of purified circulating blood monocytes. Upon addition of toxin B, human monocytes exhibited few modifications whereas macrophages adopted a stellate morphology, with rounding up of the perikaryon. Toxin B made microfilaments of actin disappear and induced an important reorganization of vimentin and a redistribution of tubulin. Membrane area increased by approximately 16%. Toxin B did not affect the viability of human mononuclear phagocytes and did not exert any significant lytic effect. It profoundly altered the phagocytic function of macrophages. When activated by gamma interferon in the presence of toxin B, monocytes were more cytotoxic for U-937 target cells than control monocytes activated in absence of toxin. Finally, the combined treatment of monocytes with gamma interferon and toxin B increased significantly the secretion of tumor necrosis factor alpha, whereas toxin B alone was unable to induce tumor necrosis factor production. These results suggest that morphological and functional alterations induced in human mononuclear phagocytes by toxin B from C. difficile are due to the disorganization of the cytoskeleton and the resulting impairment of the membrane traffic equilibrium.

Bacterial Proteins↗
PubMed1993

Pharmacokinetic profile of vinorelbine, a new semi-synthetic vinca alkaloid, determined by high-performance liquid chromatography.

1. Vinorelbine (NVB), a new semi-synthetic vinca alkaloid, is currently used in the treatment of advanced non-small-cell lung cancer (NSCLC) and advanced breast cancer. The pharmacokinetic profile of NVB has been redefined with a specific h.p.l.c. method which measures NVB and desacetyl-NVB. 2. In man, the pharmacokinetics of NVB are best characterized by a three-compartment model with a terminal half-life of 42 h and a large volume of distribution (75 l/kg). The total clearance was 1.26 lh-1 kg-1 and about 11% of the dose was eliminated by the kidneys. Desacetyl-NVB was a minor urinary metabolite. 3. Human pulmonary distribution study showed higher levels of NVB in lung tissue than in serum during the first 3 h after NVB injection; the tumour concentrations were lower than those determined in healthy parenchyma. 4. In the micropig, the 0-48 h biliary excretion of unchanged drug accounted for 25% dose with 21.5% being eliminated during the first 8 h. Desacetyl-NVB concentrations were low and inconsistent. 5. Preliminary results show a better response rate with the combination of cisplatin and NVB than that obtained with NVB alone in the treatment of advanced NSCLC. This increased activity is not the result of a pharmacokinetic interaction since it was shown that cisplatin did not alter the kinetic profile of NVB. 6. This is the first pharmacokinetic investigation of unlabelled vinca alkaloids by a h.p.l.c. procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Mobile species of the genus Aeromonas: difficulties of identification and pathogenicity].

Sixty-two Aeromonas strains (39 of clinical and 23 of environmental origin) were identified. The suicide phenomenon and autoagglutination were studied. Identification is based on esculin hydrolysis; fermentation of arabinose salicin, sucrose and mannitol; gas production from glucose, indole and beta hemolysis; Voges-Proskauer and decarboxylation reactions; and finally resistance to cephalothin (30 micrograms) and colistin (4 micrograms/ml). Thirty-four per cent of A hydrophila, 33% A caviae, 28% A veronii subspecies sobria, 3% A jandaei, 2% A veronii subspecies veronii were accurately identified. Also, several new species were identified such as A trota, A enteropelogenes, A schubertii, A ichthiosmia, according to the more recently proposed taxa. This identification scheme could enhance our knowledge concerning virulence factors, pathogenicity and environmental distribution.

Aeromonas↗
PubMed1992

Simultaneous assay for amatoxins and phallotoxins in Amanita phalloides Fr. by high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic method is described that allows the simultaneous determination of up to eight amatoxins and phallotoxins. The method identifies both neutral toxins (alpha- and gamma-amanitin, phalloidin, phallisin and phalloin) and acidic toxins (beta-amanitin, phallacidin and phallisacin). Toxins were separated, identified and determined by gradient elution with 0.02 M aqueous ammonium acetate-acetonitrile and simultaneous monitoring of the absorbances at 214 and 295 nm. The assay was successfully applied to the analysis of the toxins in a crude extract of Amanita phalloides. The limit of detection for each toxin was 10 ng/ml of extraction medium. The assay was further validated by analysing the toxin content in Galerina marginata, a species containing only amatoxins. This relatively simple method should be suitable for the detection of amatoxins and phallotoxins in almost any species of mushrooms.

Amanita↗
PubMed1992

Comparative study of immunological properties and cytotoxic effects of Clostridium difficile toxin B and Clostridium sordellii toxin L.

We compared the immunological properties and cytotoxic effects of Clostridium difficile toxin B and Clostridium sordellii toxin L. These two cytotoxins are immunologically related in that the cytotoxic effect of either toxin can be neutralized by the polyclonal antiserum prepared against either cytotoxin. On the other hand, polyclonal antiserum prepared against Clostridium difficile enterotoxin A did not cross-react with the cytotoxins B and L when tested by cytotoxic neutralization test nor by double immunodiffusion assay. However, despite this immunological relationship between toxins B and L, the morphological modifications observed in MacCoy cells induced by treatment with these cytotoxins are clearly distinct. We describe the first quantitative analysis of specific cellular parameters which illustrates the morphological differences induced by these cytotoxins. Moreover, immunocytochemical experiments show that, whereas disruption of microfilaments is observed with toxin B- and L-treatments, alterations of F-actin network are different in the cells treated with toxin B or L. The observation that the cellular modifications induced by toxin B- and toxin L-treatment differ suggests that the molecular mechanisms involved in the respective cytotoxicities are also likely to be different.

Actin Cytoskeleton↗
PubMed1992

Identification of toxigenic Clostridium difficile strains using a toxin B gene-specific oligonucleotide probe.

We describe the use of a new specific synthetic oligonucleotide probe, deduced from the sequence of the gene for Clostridium difficile toxin B, to identify toxigenic strains of C. difficile. This probe does not hybridize to the DNA of non-toxigenic strains of C. difficile nor to DNA isolated from different Clostridium species, including C. sordellii. None of the enteric pathogenic bacteria tested were seen to hybridize with the probe. A preliminary study of direct probing of faecal specimens indicates a potential for the use of this DNA probe in the clinical laboratory for the rapid identification of toxigenic strains of C. difficile.

Bacterial Proteins↗
PubMed1992

Penetration of ofloxacin into heart valves, myocardium, mediastinal fat, and sternal bone marrow in humans.

Ofloxacin penetration into heart tissue (valve and myocardium), mediastinal fat, and sternal bone marrow was the object of a prospective nonrandomized study. Thirty-six patients undergoing mitral and/or aortic valve replacement were included. Patients were divided into two groups of 18 patients each. Group 1 patients were administered a single 400-mg intravenous dose of ofloxacin over a 30-min period upon anesthesia (n = 6) or at 1 h (n = 6) or 6 h (n = 6) prior to surgery. Group 2 patients received a 200-mg oral dose of ofloxacin every 12 h during the 48 h preceding surgery. In this group, the final dose of ofloxacin was administered 3 h (n = 9) or 8 h (n = 9) before anesthesia. Plasma and tissue ofloxacin concentrations were assayed by high-pressure liquid chromatography. In group 1 patients, the peak level in plasma was 15.9 +/- 2.5 micrograms/ml. Peak ofloxacin levels in tissue were reached by hour 1 and were 8.89 +/- 2.16 micrograms/g in myocardium and 5 +/- 0.75 micrograms/g in heart valves. A significant decrease in ofloxacin levels in heart valve tissue and sternal bone marrow was observed after hour 3. Nevertheless, ofloxacin myocardial, heart valve, and sternal bone marrow levels remained higher than the MICs for the usually susceptible pathogens for at least 3 h. In group 2 patients, myocardial levels were long lasting (6.46 +/- 1.92 micrograms/g [4 to 8 h] and 5.92 +/- 0.95 micrograms/g [8 to 12 h]) and remained higher than those observed in the other tissues over the entire study period. A progressive but insignificant decrease in ofloxacin heart valve levels was observed (from 2.46 +/- 0.40 micrograms/g [4 to 8 h] to 1.57 +/- 0.22 micrograms/g [8 to 12 h]). In both groups, concentration in mediastinal fat were lower and tended to decrease with time. These were 1.83 +/- 0.61 micrograms/g with the first hour and 0.85 +/- 0.43 micrograms/g between hours 8 and 12 in group 1 and 1.74 +/- 0.52 micrograms/g between hours 4 and 8 and 0.67 +/- 0.11 micrograms/g between hours 8 and 12 in group 2. In conclusion, satisfactory diffusion of ofloxacin into heart tissue seems to favor use of the drug in the treatment of bacterial endocarditis due to susceptible pathogens. Furthermore, the progressively decreasing concentrations observed in heart valve and sternal bone marrow and the poor levels achieved in mediastinal fat suggest the need for renewing injection 3 h following initial infusion if the drug is used as an antibiotic prophylactic agent during cardiovascular surgery.

Adipose Tissue↗
PubMed1992

Detection of Legionella spp. in bronchoalveolar lavage fluids by DNA amplification.

By using Taq polymerase, DNA amplification of a specific fragment of the macrophage infectivity potentiator (mip) gene from Legionella pneumophila was used to detect Legionella spp. in bronchoalveolar lavage (BAL) fluid specimens. We were able to detect DNAs from all 30 L. pneumophila strains tested (serogroups 1 to 14), L. micdadei, and L. bozemanii serogroup 1. DNA from bacteria of other species tested and DNA from human leukocytes were not amplified by this procedure. After optimization of the conditions for DNA extraction from BAL fluid, a 2-ml sample of BAL fluid seeded with 25 CFU/ml tested positive after DNA amplification. A total of 68 frozen BAL fluid specimens sent to the laboratory because of suspected legionellosis were tested in a retrospective study. The eight culture-positive samples were all positive after specific DNA amplification. Among 60 culture-negative samples, 7 were positive after amplification. Of these seven samples, four were from patients who had presented a typical clinical history of legionellosis; the samples had antibody titer increases of 2 dilutions. For the three remaining samples, serological diagnosis of legionellosis in the patients from whom the samples were obtained could not be documented, and although the causative agent of these pulmonary infections was not determined, the clinical features of the patients were in accordance with legionellosis.

Bacteriological Techniques↗
PubMed1992

Evaluation of cefixime biliary disposition in the isolated perfused rabbit liver model and in humans.

Cefixime is a new orally effective third-generation cephalosporin. It inhibits a wide variety of Gram-positive and Gram-negative bacteria, especially most of the Enterobacteriaceae. Since extrarenal excretion processes have been reported to account for 60% of cefixime systemic clearance we have endeavoured to determine the place taken up by biliary excretion of unchanged cefixime in this pattern. We initially used the isolated perfused rabbit liver technique. Six perfusions were performed. Cefixime concentrations were measured by HPLC chromatography. After addition of a single 10-mg dose of cefixime to the circulating blood, biliary elimination of the drug proved to be very low, since only 0.28 +/- 0.15% of the dose was recovered during the 3-h perfusion period. The rate of cefixime biotransformation in the liver was found to be 16.2%. In contrast, the data obtained in humans highlight substantial biliary excretion of the drug. In six healthy volunteers submitted to duodenal aspiration and receiving a single 200-mg i.v. dose of cefixime, drug levels in duodenal fluid were at least fivefold greater than the simultaneous concentrations in serum. Biliary excretion of cefixime was further investigated in ten cholecystectomized patients provided with T-tube drainage: following a single 200 mg oral dose of cefixime, Cmax in bile reached 56.9 +/- 70 mg/l, that is about 25 times as high as Cmax in serum, 2.3 +/- 0.85 mg/l. Drug levels in choledochal bile proved to be sustained, since a concentration of 4.3 +/- 3.7 mg/ml was still observed 20 h after dosing.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Antibiotic-impregnated plaster of Paris beads. Trials with teicoplanin.

Teicoplanin-impregnated plaster of Paris beads were made and in vitro release properties were studied. Teicoplanin was released in an initial massive dose, with a rapid decline during the first three days, followed by a slowly declining prolonged release up to 30 days. The release tested by diffusion in gelose and high-performance liquid chromatography was found to be 21.4% and 28.2%, respectively, of the amount theoretically present in the beads. Plaster of Paris is a resorbable, nontoxic biomaterial that has already been used to fill dead spaces in bone and deliver antibiotics in the treatment of chronic osteomyelitis. The addition of teicoplanin, a new antistaphylococcal agent with low known bacterial resistance, is a promising alternative. Follow-up tests in vivo, simulating local conditions of the osteomyelitic bone, are necessary to prove efficacy.

Anti-Bacterial Agents↗
PubMed1992

[Biliary excretion and hepatic disposal of cefixime: experimental and clinical study].

Cefixime is a new oral cephalosporin with in vitro activity similar to that of third-generation cephalosporins. Renal excretion accounts for only 40% of systemic clearance of cefixime, suggesting that biliary excretion of the drug may be significant. This study was designed to determine to what extent nonrenal clearance of cefixime is due to biliary excretion of the parent compound. In an isolated perfused rabbit liver model, biliary excretion of cefixime was very low, with only 0.28 +/- 0.15% of a single 10 mg dose injected in the system being recovered in the bile after three hours perfusion. The liver biotransformation rate for cefixime was found to be 16.2%. These results are in striking contrast with those obtained in human studies. Cefixime levels in duodenal juice aspirates collected over four hours following an intravenous injection of 200 mg cefixime in six healthy volunteers were at least fivefold concomitant serum levels. Studies of bile collected by external biliary drainage during 24 hours following an oral dose of 200 mg cefixime in ten cholecystectomized patients showed that the Cmax was 56.9 +/- 70 mg/l, i.e., 25-fold the serum Cmax (2.3 +/- 0.85 mg/l). The bile AUC/serum AUC ratio was 20.4 +/- 20.3. Mean bile level of cefixime was still as high as 4.3 +/- 3.7 mg/l 20 hours after dosing. The amount of cefixime excreted in the bile over 24 hours was 10.0 +/- 12.3 mg i.e., 5% of the dose administered. Twenty-four hour renal excretion of cefixime was 53.3 +/- 26.2 mg.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗