PubMed Health⌕ Search

Biomedical subjects

M Meyran

Publications and source records attributed to M Meyran.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Bactericidal activity of imipenem].

The bactericidal activity of imipenem against Pseudomonas aeruginosa, Enterobacteriaceae and Staphylococcus aureus was compared with that of other antibiotics, using the time-related kill rate curve method. The activity of imipenem was found to be less rapid and less intense than that of aminoglycosides, similar to that of fluoroquinolones and more rapid than that of beta-lactam antibiotics, notably ticarcillin and ceftazidime against P. aeruginosa and cefotaxime against Enterobacteriaceae. As with aminoglycosides, this bactericidal activity was concentration-dependent against Enterobacteriaceae and S. aureus but not against P. aeruginosa. Unlike the beta-lactam antibiotics, but like aminoglycosides and fluoroquinolones, imipenem remained active against "quiescent" P. aeruginosa, though not against Enterobacteriaceae. Successive transfers into liquid media rapidly produced resistant variants among P. aeruginosa strains and methicillin-resistant S. aureus strains, but not among Enterobacteriaceae. This shows that the bactericidal activity of imipenem is markedly different from that of other beta-lactam antibiotics.

Acinetobacter↗
PubMed1990

Nosocomial outbreaks due to amikacin-resistant tobramycin-sensitive Acinetobacter species: correlation with amikacin usage.

Fifty-seven patients in the Val-de-Grâce hospital were infected or colonized with amikacin-resistant, tobramycin-sensitive Acinetobacter spp. between January 1985 and December 1987. This resistance phenotype was attributed to the recently described 3'-O-aminoglycoside phosphotransferase (APH(3')-VI), on the basis of substrate profile and DNA-DNA hybridization, and was mainly encountered in various biotypes of A. baumannii isolated from patients. It was also encountered in saprophytic A. johnsonii isolates from the hands of 11 healthy workers among the medical staff, which provided evidence for the dissemination of an epidemic gene among different biotypes and species of Acinetobacter. A retrospective epidemiological survey showed a significant correlation between amikacin consumption and case incidence in the wards where cross-infection had occurred.

Acinetobacter Infections↗
PubMed1990

[Comparative antibacterial activity of ceftibuten (SH 39 720) against 150 K. pneumoniae strains producing different beta-lactamases].

Comparative antibacterial activity of ceftibuten (SH 39 720) on 150 K. pneumoniae strains producing different beta-lactamases. MICs of ceftibuten, cefotaxime + clavulanic acid (10 mg/l), ceftazidime and azthreonam were determined for 150 clinical isolates of K. pneumoniae: 15 "wild" type producing only the SHV-1 type beta-lactamase, 15 TEM-1 and 120 producing new "extended spectrum" beta-lactamases (48 CTX-1, 9 SHV-2, 4 SHV-3, 35 SHV-4, 24 SHV-5). Against SHV-1 and TEM-1 strains the bacteriostatic activity of ceftibuten was close to that of the other beta-lactams tested. This activity was preserved against strains producing CTX-1, SHV-2, SHV-3 beta-lactamases and MICs were comparable to those of cefotaxime + clavulanic acid. The MICs of ceftibuten against strains producing SHV-4 and SHV-5 beta-lactamases were higher (1 to 8 mg/l) but this level of antibacterial activity was superior to that of the other beta-lactam antibiotics. The bactericidal activity of ceftibuten was evaluated by kill kinetic studies: this activity was preserved against the CTX-A and SHV-2 strains--with concentrations equal to 2 or 4 x CMI a 4 log10 reduction of the bacterial inoculum was obtained at 24 h. A such reduction was not obtained with cefotaxime. This preserved antibacterial activity of ceftibuten against K. pneumoniae producing some new "extended spectrum" beta-lactamases need further studies to state the structure-activity relation-ships of this antibiotic.

Anti-Bacterial Agents↗
PubMed1990

[In vitro antibacterial activity of rokitamycin, a new macrolide antibiotic. Results of a multicenter study].

Minimal inhibitory concentrations (MIC) of rokitamycin (R) were evaluated by agar dilution for 914 bacterial strain isolated in 4 hospitals and classed as a function of susceptibility and resistance to Macrolides-Lincosamides-Streptogramines group (MLS). MICs of R ranged from 0.06 to 1 microgram/ml (mode MIC 0.25-0.5) on Staphylococci susceptible to MLS and on MLSB inducible strains; R was inactive on MLSB constitutive strains. MICs of R ranged from 0.008 to 0.5 microgram/ml (mode MIC 0.06 to 0.25) for Streptococci and Pneumococci susceptible to erythromycin (E) and from 0.06 to greater than 128 for strains resistant to E. Enterococci susceptible to E were inhibited by 0.06 to 0.5 microgram/ml (mode MIC 0.5) and strains resistant to E by 0.25 to greater than 128. Haemophilus were inhibited by 0.5 to 0.65 microgram/ml (mode MICs of R ranged generally from 0.016 to 0.5 microgram/ml (mode MIC 0.12) for C. perfringens and from 0.016 to 1 (mode MIC 0.06) for B. fragilis. Thus, R was shown to be among macrolide antibiotics of resistance strains. Its activity was superior to that of other products of this group spiramycin, josamycin, miokamycin, particularly on Gram positive cocci. R had a good activity on Neisseria, Branhamella, anaerobes and, as others macrolides, was poorly active on Haemophilus.

Anti-Bacterial Agents↗
PubMed1989

[Antibacterial effect of cefixime].

Cefixime (CFM) is a new hemi-synthetic orally active cephalosporin which exhibits a particular affinity for PBPs 3, 1a, 1bs. Its penetration through the Gram negative bacilli outer membrane is similar to that of third generation cephalosporins. The MICs were assessed by the agar dilution method against 2,489 bacterial strains collected in 10 hospitals. Against Enterobacteriaceae, MICs50 and 90 are respectively (mg/l): naturally non beta-lactamase-producing species: E. coli and Shigella: 0.25-0.5, Salmonella: 0.06 - 0.25, P. mirabilis: 0.008 - 0.0.32; chromosomal penicillinase producing species: Klebsiella: 0.06 - 2; chromosomal cephalosporinase producing species: E. cloacae and C. freundii: 1 - greater than 128, S. marcescens: 0.25 - 16, Proteus indole: + 0.06 - 4, P. stuartii: 0.032 - 0.5. CFM activity is not altered in strains producing an acquired penicillinase. On the other hand, CFM appears to be inactive against cephalosporinase hyperproducing mutants and its activity is variably decreased against expanded spectrum beta-lactamase producing strains. CFM is inactive against P. aeruginosa (MIC50 and 90: 64 - 128) and against A. baumannii (16 - 128). Haemophilus and gonococci, beta-lactamase producing or not, as well as meningococci, are highly susceptible to CFM (MIC 0.008 - 0.12). B. catarrhalis is usually inhibited by 0.03 to 0.5. CFM is moderately active against meticillin-sensitive staphylococci (MIC50 and 90: 1-64), and inactive against meticillin-resistant strains. Enterococci are usually resistant, whereas streptococci and pneumococci are inhibited by low concentrations: 0.08 to 1. CFM is a bactericidal antibiotic, as shown by MBC and killing curves determination. These antibacterial properties relate CFM to the third generation cephalosporins and position the compound in an excellent place among the orally active cephalosporins.

Cefixime↗
PubMed1989

Comparative study of five plasmid-mediated ceftazidimases isolated in Klebsiella pneumoniae.

Five plasmid-mediated beta-lactamases conferring a high level of resistance to ceftazidime were isolated from Klebsiella pneumoniae strains. These ceftazidimases (CAZ) differed in their isoelectric point (from 5.3 to 8.2) and were encoded by large self-transferable plasmids of 85 kb (CAZ-2, CAZ-3) or greater than or equal to 150 kb (CAZ-1, CAZ-4, CAZ-5). The 85 kb plasmids seemed closely related to pCFF04 encoding CTX-1 enzyme and belonged to the same incompatibility group 7 or M. These beta-lactamases hydrolysed all beta-lactams with the exception of cephamycins and carbapenems. For CAZ-1, CAZ-2 and CAZ-3 producers, MICs of ceftazidime (32-256 mg/l) were higher than MICs of cefotaxime (0.12-2 mg/l) and aztreonam (1-16 mg/l). For the strains producing the beta-lactamases CAZ-4 and CAZ-5, MICs of aztreonam were the highest (greater than or equal to 256 mg/l). The impaired activities of cephalosporins and monobactams were restored equally well by 2 mg/l of clavulanate, sulbactam and CL-298741 for CAZ-2 producing strains (wild type and transconjugant). Sulbactam (2 mg/l) had a lower protective effect than other inhibitors on ceftazidime for CAZ-1 and CAZ-3 producing K. pneumoniae. The protective effect of sulbactam (2 mg/l) was lower than that of the other inhibitors on all beta-lactams for CAZ-4 and CAZ-5 producers. The enzymes CAZ-1, CAZ-2 and CAZ-3 derived from TEM beta-lactamase whereas CAZ-4 and CAZ-5 derived from SHV-1 enzyme.

Autoradiography↗
PubMed1989

[In vitro effects of combinations of teicoplanin and ceftriaxone against Staphylococcus aureus and Enterococcus].

The in vitro activity of antibiotic combinations of teicoplanin (T) and ceftriaxone (C) was evaluated on 10 methicillin sensitive S. aureus (MSSA), 10 methicillin resistant S. aureus (MRSA), 4 Enterococcus and 2 E. coli. By the checkerboard method the combination T + C showed synergism against 9 MRSA, 2 MSSA, 4 Enterococcus, indifferent effect against the other strains. By the time-kill-curves method synergism was found for the combinations T + C at 1/2 CMI against MRSA, MSSA and Enterococcus, and indifference with the combinations at 1 X CMI, 2 X CMI, 4 X CMI against all the strains. Antagonistic effect was never found. These results suggest that teicoplanin in combination with ceftriaxone can be tested in in vivo study to demonstrate the possible benefits of the synergism particularly in the therapy of the nosocomial infections.

Ceftriaxone↗
PubMed1989

[Meleney's postoperative gangrene].

The authors report the case of a 40 years old man undergoing MOPP chemotherapy for stage III Bb type 2 Hodgkin's disease with immune depression. Six years later he developed two episodes of unilateral transient loss of vision and severe stenosis of the left common carotid artery was found leading to surgical reimplantation of the left subclavian artery. Quickly spreading cutaneous necrosis was observed 5 days after surgery on the scar and the irradiated area: Meleney's postoperative gangrene, an unusual and frequently fatal complication of unknown cause. The patient recovered in two months after wide excision of the necrosed tissues and a skin autograft.

Adult↗
PubMed1989

[Advanced cancer of the ovary and pregnancy. Apropos of 2 cases].

Cancer of the ovary together with pregnancy is rare. The authors report two new case histories which are of particular interest because of advanced cancer of the ovary and a continuing pregnancy, and also because of the anatomophathological type of the malignant tumour, which was an immature (malignant) teratoma of the ovary. Looking at these cases carefully makes it possible to describe the characteristics of this very serious combination and to describe the principles for deciding on the method of treatment.

Adult↗
PubMed1989

[Comparative bactericidal activity of fourteen antibiotics against Staphylococcus aureus].

The bactericidal activity of LY 146032 (LY), Oxacillin (OXA), Cefamandole (CEF), Rifampin (RIF), Gentamicin (GEN) or Tobramycin (TOB), Pefloxacin (PEF), Vancomycin (VAN), Teicoplanin (TEI), Pristinamycin (PRI) was compared against 8 strains of S. aureus (4 Meth. sensitive, 4 Meth. resistant). Kill Kinetics studies were done: bacteria were incubated with antibiotics at their MICs, 2 X MIC, 4 X MIC and at concentrations obtained in vivo with usual therapeutic doses. With 4 X MIC, a 3 Log reduction of the initial inoculum was observed only at 24 h with OXA, CEF (MSSA), RIF, PEF, VAN, at 30 h with TEI and PRI. With LY, GEN or TOB at 2 X MIC the 3 Log reduction was observed at 3 h or 4 h, a greater than or equal to 5 Log reduction at 24 h: LY and Aminoglycosides are the most bactericidal antibiotics against S. aureus.

Anti-Bacterial Agents↗
PubMed1988

[In vitro bactericidal effect of cefotetan-aminoside combinations].

Bactericidal activity of cefotetan-gentamicin combinations was studied on 6 bacterial strains: S. aureus, K. pneumoniae, E. cloacae, S. marcescens, P. vulgaris, P. stuarti. Time kille curves technic was performed with final concentrations of cefotetan: 4 at 32 mg/l, and of gentamicin: 0.25; 0.5; 1; 2; 8 mg/l and with an 10(6) CFU/ml inoculum. Cefotetan at 4 mg/l was not able to obtain a 0.01% (percentage of survivors) bactericidal activity before 24 h. The combination cefotetan-gentamicin (0.25 to 2 mg/l according to the strains) were bactericidal (0.01% of survivors) before 24 h: 1 to 6 h according to the strains, more rapidly than with gentamicin alone at the same concentration. This more rapid bactericidal activity obtained by cefotetan-gentamicin combination seems to indicate this combination in the treatment of severe infections in immunocompromised patients.

Bacteria↗
PubMed1988

[The frequency of isolating urinary infection germs at a community practice and their sensitivity to various antibiotics].

Nine hundred and thirty one urine's specimens of patients affected by urinary infection have been studied by pathology practising in different towns in France. The most frequently germs retrieved are: Escherichia coli 76%, Proteus mirabilis 12%, Klebsiella 5%, Staphylococcus epidermidis 2%. Were studied Gram negative rods sensibility to ampicillin (A), cephalosporin 1st generation (C), nalidixic acid (Nal), gentamicin (G), norfloxacin (Norf); Gram positive cocci resistance to oxacillin (Oxa), erythromycin (E), pristinamycin (P), gentamicin (G), norfloxacin (Norf). For E. coli: the resistance was 24% A, 2% C1, 0.1% G, 4% Nal, 0.1% Norf. For Klebsiella: the resistance was respectively 96% A, 12% C1, 10% Nal, 18% G., 4% Norf. For P. mirabilis: 11% A, 3% C1, 0% Nal, 9% G, 0% Norf. E. coli strains cephalo R; Gram negative rods Genta R or quinolone R; staphylocoque oxa R or pristina R have been checked by HIA Begin microbiology laboratory. Discrepancies in results have been analysed. This study enabled the participants to improve their bacteriological technic, antibiogramm's reading, results' interpretation.

Adult↗
PubMed1988

[Comparative bactericidal activity of imipenem and other antibiotics against Pseudomonas aeruginosa].

The bactericidal activity of imipenem (IM), ticarcillin (TIC), ceftazidime (CEZ), amikacin (AMK) or tobramycin (TOB), ciprofloxacin (CIP), was compared on 6 P. aeruginosa: 1 ticarcillin, susceptible strain (TICs), 5 constitutive beta-lactamases producing strains (PSE, TEM, OXA1, OXA2, cephalosporinase (CEP). The time-kill-curves method was performed. Bacteria were incubated with antibiotics at M.I.C. X2 and at concentrations obtained in vivo with usual therapeutic doses: IM 4-8 mg/l, TIC 64-128, CEZ 4-32, TOB 2-8, AMK 4-16, CIP 1-4. The bactericidal activity of IM was independent of the concentration. A 5 Log10 reduction in viability was observed at 3 h for strains TICs, TEM and PSE, 3 Log10 for strains OXA and CEP. This bactericidal activity was also observed in a non growing system. The bactericidal activity of TIC (strain TICs) and CEZ was slower and weaker: 1-2 Log10 at 6 h, 2-3 Log10 at 24 h. It is not observed in a non growing system. On the other hand, the bactericidal activity of aminoglycosides and ciprofloxacin was rapid: 3-4 Log10 at 3 h, 5 Log10 at 6 h for all strains in growing and non growing systems. IM is the only beta-lactam antibiotic bactericidal on growing and non growing cells of P. aeruginosa like aminoglycosides and new quinolones.

Amikacin↗
PubMed1987

[Methods for in vitro studies of antibiotic combinations. Indications and limits].

Several methods are available in the bacteriology laboratory to study the antibacterial effect of antibiotic combinations. With "end point" methods, results are read and interpreted after 18 or 24 hours of incubation. Amongst these methods, gel diffusion is technically easy but gives only qualitative results. Respective concentrations in the interaction zone cannot be evaluated and are unrelated to concentrations obtained in vivo. In liquid medium, the "checker board" method offers the possibility of combining a large number of concentrations. Interpretation may be graphic or mathematical. It is often arbitrary. But above all these methods fail to recognize events which occur during the 18 or 24 hours of incubation. Kinetic methods can be used to evaluate the kinetics of bactericidal action in relation to time and hence to compare the rapidity and degree of the bactericidal action of antibiotics used alone or in combination. However, only a limited number of concentrations can be studied. During the evaluation of a new antibiotic all methods must be tried to determine the possible synergistic or antagonistic effects of combinations regarding bacteria with known different resistance mechanisms. The broad outline thus obtained serves as a prescribing base for combinations. Bactericidal effect should be confirmed by a kinetic method where the concentrations in contact with the bacterial inoculum are selected in relation to presumed concentrations obtained at the site of infection.

Anti-Bacterial Agents↗
PubMed1987

[Beta-lactam combinations with new quinolones].

The combination of new quinolones with beta-lactam antibiotics can be an alternative to the classical use of aminoglycoside-beta-lactam antibiotic combinations. In vitro studies, in particular using cefotaxime-pefloxacin or ofloxacin combinations against Enterobacteria and cefsulodin or ceftazidime with pefloxacin or ofloxacin against P. aeruginosa rarely show evidence of synergistic antibacterial activity when the "static" checker board method is used. In contrast, kinetic bactericidal studies very often show a notable increase in the rapidity of bactericidal activity as well as the disappearance of the frequent secondary regrowth seen after 6 hours with the antibiotics used alone. Techniques studying the development of resistance in vitro show that the combination of pefloxacin-cefotaxime against enterobacteria and pefloxacin-cefsulodin against P. aeruginosa are capable of inhibiting the emergence of resistant variants. These promising results require confirmation by studies using animal models and, above all, by the clinico-microbiological analysis of the results of clinical trials.

Anti-Bacterial Agents↗
PubMed1987

[Characteristics of penicillinase-producing strains of Neisseria gonorrhoeae isolated in France, 1979-1986].

Penicillinase producing Neisseria gonorrhoeae PPNG, had been first isolated in France in 1979. Since, they regularly increased if we considered France on the whole. From 1979 to 1986, 284 strains had been collected by a multicentric group. The frequency of isolation was strongly different in France, unknown in some region they rose 12% in specific areas in Paris. The PPNG strains were more frequently isolated from male than female (sex ratio was higher with PPNG than for non producing strain). They were more often responsible of complicated infections in female than male at the same rate than the non producing strains. Auxotype distribution was different between producing and non producing strains. Plasmidic content from african type (Af) was almost the same than from asian type (As). Strains with Af type associated with the conjugative plasmid were increasing.

Adult↗