Preparation of conductive PDDA/(PEDOT:PSS) multilayer thin film: influence of polyelectrolyte solution composition.

Self-assembled multilayer films made of PEDOT:PSS poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) and PDDA poly(diallyldimethylammonium chloride) were prepared using layer-by-layer method. In order to modify the growth regime of the multilayer, to fabricate an electrical conductive film and to control its thickness, the effects of pH, type of electrolyte, ionic strength and polyelectrolyte concentration were investigated. Optical reflectometry measurements show that the pH of the solutions has no effect on the film growth while the adsorbed amount increases more rapidly when BaCl2 is used instead of NaCl as electrolyte. An increase in the ionic strength (with NaCl) induces a change in the growth regime from a linear to an exponential one at low polyelectrolyte concentration. As UV-vis measurements indicate, no decomplexation of PEDOT was recorded after film preparation. With polyelectrolyte concentration below 1 g L(-1), no conductive films were obtained even if 50 bilayers were deposited. A conductive film was prepared with a polyelectrolyte concentration of 1 g L(-1) and the measured conductivity was 0.3 S m(-1). A slight increase in conductivity was recorded when BaCl2 was used probably due to a modification of the film structure.

[Activity of tigecycline against pathogen bacteria isolated in respiratory infectious disease in Europe. TEST study 2004-2007]. / Activité in vitro de la tigécycline vis-à-vis des germes pathogènes isolés d'infections respiratoires en Europe. Le Programme TEST 2004-2007.

Tigecycline (TGC), a semisynthetic glycylcycline, has a documented activity on Gram+ and Gram- pathogens including oxacillin-resistant (MRSA) and an extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae. Tigecycline Evaluation and Surveillance Trial (TEST) is an international surveillance study designed to assess the in vitro activity of TGC and 11 comparators against a range of important clinical pathogens from both the community and the hospital. The aim of this study was to assess efficacy of TGC, using this database, against pathogens implicated in community or hospital pneumonia and sinusitis. A total of 4163 isolates were consecutively collected in 21 European countries during three years (2004-2007). In all center, minimum inhibitory concentration (MIC) were determinated with the same Microscan panel (Dade-Behring). Tigecycline exhibited a good activity against respiratory pathogens, with the exception of Pseudomonas aeruginosa. Hundred percent of cocci Gram+ (Streptococcus pneumoniae, Staphylococcus aureus, Enterococcus sp.) and 100% of Haemophilus sp. are inhibited with 0.5 mg/L, without effect of an associated beta-lactam resistance mechanism. TGC is active in vitro on 89% of Enterobacteriaceae, with MIC 90 less or equal to 2mg/L. Eighty-nine percent of Enterobacter sp. and 77% of Serratia sp. are susceptible with range of MIC 90 from 2 to 4 mg/L. These interesting results obtained in vitro are to be strengthened by clinical studies.

[Susceptibility of Pseudomonas aeruginosa to antibiotics isolated from patients of intensive care units in France in 1998. Resistant phenotypes to beta-lactams]. / Sensibilité de Pseudomonas aeruginosa aux antibiotiques, isolés chez des malades de soins intensifs français en 1998. Phénotypes de résistance aux beta-lactamines. Etude ESCRIME.

Pseudomonas aeruginosa is responsible for nosocomial infections and demonstrates many types of resistance mechanisms to antibiotics. Thus, in vitro susceptibility survey are frequently required. In this study, susceptibility has been assessed on 105 non redundant consecutive strains isolated from ICU's in 18 general hospitals, from 01.02.98 to 30.06.98. Only clinically significant samples have been considered. MICs have been measured for nine beta-lactams, three aminoglycosides, one fluoroquinolone and colistine. For ticarcilline resistant strains, phenotype has been assessed on Mueller-Hinton medium supplemented with beta-lactamases inhibitor. Transferable beta-lactamases has been identified using pl and PCR. MIC 50 and MIC 90 (mg/L) for beta-lactams are the following (MIC 50-->90): ticarcilline (16-->512), ticarcilline + clavulanic acid (16-->512), piperacilline (4-->512), pipéracilline + tazobactam (4-->64), aztreonam (4-->16), cefsulodine (4-->32), ceftazidime (2-->16), cefepime (4-->16), imipeneme (1-->8). For aminoglycosides: gentamicine (2-->32), tobramycine (1-->32), amikacine (4-->16). For ciprofloxacine (0.25-->32) and colistine (0.5-->2). According to CA-SFM break points recommendations, 50% of isolated strains are resistant to gentamicine, one out of three for ticarcilline + clavulanic acid (29%), one out of four for tobramycine (25%) and ciprofloxacine (25%), one out of ten for amikacine (9%), tazocilline (8%) and imipeneme (9%). Resistance to ceftazidime and aztreonam is uncommon (respectively 2%-1%) and never observed for cefepim. For ticarcilline resistant strains, (38% of total isolates) the following phenotypes have been detected: 6.7% non enzymatic resistance, 15.2% transferable beta-lactamase (TEM 4.8%, CARB 4.8%, TEM + CARB 4.8% and OXA-10 and derivated 0.9%) and 16.2% high level cephalosporinase. Extended-spectrum beta-lactamase has never been detected. TEM beta-lactamase is associated with resistance to amikacine and ciprofloxacine.

[Diffusion of ceftriaxone in healthy and infected peritoneal tissue]. / Etude de la diffusion de la ceftriaxone dans le tissu péritonéal sain et infecté.

The authors studied the peritoneal diffusion of ceftriaxone in the four quadrants of the abdomen (right and left inguinal and right and left hypochondrium) in 50 adult patients divided into 4 groups: pre-operative IVD administration of ceftriaxone in patients with healthy peritoneum, 1 g (group I), 2 g (group II): pre-operative IVD administration of ceftriaxone in patients presenting peritonitis 1 g (group III), 2 g (group IV). After laparotomy, a fragment of peritoneal membrane was resected from each of the four quadrants, the product was extracted from the peritoneum by a crushing technique and the assayed by HPLC with concomitant blood level assay. The mean assayed concentrations in situ are respectively in groups I to IV: 27.2, 31.2, 31.36 and 43.65 micrograms/g, with a rapid time of appearance (30 minutes) and a homogeneous topographic distribution for all peritoneal sample sites. In cases of peritonitis, the concentrations are higher by a factor of 1.15 and 1.39 for the dosages of 1 and 2 g as compared to healthy peritoneum. Beyond the third hour after injection, peritoneal concentrations remained high at 9.8 micrograms/g in patients having received 1 g of ceftriaxone and very high at 22.6 micrograms/g in patients having received 2 g. These levels are therefore effective whatever the posology in antibioprophylaxis, taking into account the MIC of the product on Gram- bacilli.

[Treatment of septicemias and skin infections in burn patient by teicoplanin. Study of its skin diffusion]. / Traitement des septicémies et infections cutanées chez le brûlé par la téicoplanine. Etude de sa diffusion cutanée.

In this study, teicoplanin was administered to burnt patients by IV and IM route in monotherapy or in association with other antibiotics. 12 cases of septicaemia and 8 severe cutaneous cocci Gram + infections were treated. Dosage varied from 5 mg/kg to 14 mg/kg. Clinical cure was observed in 89% of cases, and eradication of cocci Gram + in 83%. The MICs of Staphylococcus were between 0.25 micrograms/ml and 4 micrograms/ml, with a majority of methicillin-resistant Staphylococcus at 1. Average through serum concentrations were 7.4 micrograms/ml, and peak serum concentrations were 26 micrograms/ml (1 hour after injection). Tolerance was good in 19 of the 20 cases (95%). Skin levels of teicoplanin were found to be 1.6 times the through serum level. It was noted that in burnt patients whose UBS is superior to 100, the dose should be increased by about 50%.