[Assessment of the contribution of the immunochromatographic pneumococcal urinary antigen test to the etiological diagnosis of pneumonia in hospitalized adults]. / Bilan de la contribution de l'antigénurie pneumocoque par test immunochromatographique au diagnostic étiologique des pneumonies chez l'adulte hospitalisé.

AIM OF THE STUDY: To assess the usefulness and prescription practices of the Binax Now Streptococcus pneumoniae urinary antigen test in hospitalized adults. PATIENTS AND METHODS: The results of the pneumococcal urinary antigen tests (UAT) performed from January 2002 to September 2004 were related to that of microbiological cultures, and in positive patients to radiographic findings and C-reactive protein (CRP) levels. The evolution of the number of prescriptions and positivity rate in 2007 versus 2002-2004 was analyzed. RESULTS: The pneumococcal UAT was positive in 32 of the 278 patients included from 2002 to 2004 (11.5%). Results were concordant with that of microbiological cultures in 90% of the 247 documented cases. Pneumococcal etiology was considered to be definite in 19 patients (isolation of S. pneumoniae from blood, 17 patients; or pleural fluid, two patients), of whom 15 had a positive UAT (sensitivity: 79%); to be probable in 22 patients (positive UAT, 17 patients and/or isolation of S. pneumoniae from respiratory samples, six patients), and was retained in 39 of the 41 patients (positive predictive value: 93.7%). CRP was greater than 100mg/L in 34 of 39 documented patients and lobar alveolar radiographic opacities observed in 25 of 28 documented patients. In 2007, the dramatic increase in the number of UAT prescriptions and the diversification of prescribing units were associated to a decreased positivity rate (8.1%). CONCLUSION: Whereas the pneumococcal UAT clearly increases etiological diagnosis, pneumococcal pneumonia cannot be ruled out if negative. Indications for its use need to be refined to improve the cost-effectiveness of this test.

Influence of the rapeseed protein hydrolysis process on CHO cell growth.

Different protein hydrolysates were prepared from enzymatic hydrolyses of a rapeseed isolate (>90% protein content) using different commercial enzymes of non-animal origin. The extent of hydrolysis was controlled to produce hydrolysates corresponding to various degrees of hydrolysis (DH) from 5 to 30. These hydrolysates were characterized according to their solubility and size peptide pattern. Different growth behaviours of Chinese Hamster Ovary cells were observed when these various hydrolysates were added in serum-free medium containing transferrin, albumin and insulin. Hydrolysates from low degree of hydrolysis generally did not exhibit significant positive effect on cell growth; conversely hydrolysates from extensive hydrolysis, corresponding to a major low molecular size peptides content, usually allowed an increase of the maximal cell density. However, depending on the enzyme used, the supplementation with hydrolysates corresponding to a high degree of hydrolysis and composed of at least 70% peptides with a molecular size under 1kDa, led to different maximal cell density values, indicating the importance of enzyme specificity and consequently the nature of the released peptides. This result showed that the positive influence of the rapeseed hydrolysates on cell growth was not only due to a nutritional support tied to the addition of small peptides but may be related to the presence of peptides exhibiting growth or survival factor effects. Furthermore, total substitution of proteins (transferrin, albumin and insulin) in the cell culture medium by some rapeseed hydrolysates appeared to be a promising alternative to improve the cell growth in protein-free media.

Pharmacokinetics of ceftazidime and cefepime in burn patients: the importance of age and creatinine clearance.

AIM: The standard dosage recommendations for beta-lactam antibiotics can result in very low drug levels in intensive care (IC) patients and burn patients in the absence of renal dysfunction. We studied the pharmacokinetic parameters and serum concentrations of ceftazidime (CF) and cefepime (CE) in burn patients and analyzed the modifications according to clinical and biological parameters and in particular age and creatinine clearance. MATERIAL AND METHODS: Two pharmacokinetic studies were carried out with daily doses of 1 g x 6 for CF (n = 17) and 2 g x 3 for CE (n = 13). Creatinine clearance (CL(CR)) was both estimated and measured. Blood was sampled at steady state after an initial and a subsequent antibiotic dose. C(max) (maximal) and C(min) (minimal) concentrations were measured by HPLC. The influence of clinical and biological data was analyzed using ANOVA, ANCOVA and stepwise multiple linear regression. RESULTS: The ratio of C(min) to the low MIC break point (4 mg/l) was lower than 4 in 52% of subjects receiving CF and in 80% of subjects receiving CE. The C(min) of CF was correlated with measured CL(CR) and was higher in mechanically ventilated patients than in non-ventilated patients. The clearance of CF was correlated with age. The C(min) of CE was correlated with age and drug clearance with measured CL(CR). Therefore dosage adjustment of these drugs in burn patients needs to take into account age, measured creatinine clearance and the danger of low concentrations occurring when the creatinine clearance is greater than 120 ml x min(-1). CONCLUSION: In burn patients, the pharmacokinetic disposition of CF and CE was much more variable than in healthy subjects. Age and CL(CR) were predictors of the disposition of these antibiotics. Shortening the dosage interval or using continuous infusions will prevent low serum levels and keep trough levels above the MIC for longer periods of time. In view of the lack of a bedside measurement technique for ceftazidime and cefepime levels, we suggest a more frequent use of measured CL(CR) in order to attain efficacious clinical concentrations.

Increased amikacin dosage requirements in burn patients receiving a once-daily regimen.

Altered pharmacokinetics in burn patients may affect antibiotic plasma concentrations. Typical once-daily dosing (ODD) of 15 mg/kg amikacin (AMK) in burn patients does not always produce peak concentrations (C(max)) reaching the therapeutic objective of six to eight times the minimal inhibitory concentration (MIC). We recorded plasma concentrations following administration of 20 mg/kg AMK in burn patients and studied factors affecting pharmacokinetics. Mean C(max) was 48.3+/-10.8 mg/L and the C(max)/MIC ratio was 6+/-1.35. Statistical analysis demonstrated a relationship between C(max) and the area of the burn and Unit Burn Standard, and between AMK clearance and creatinine clearance (Cl(CR)). We conclude that ODD regimens of AMK in patients with burns >15% body surface area and/or with Cl(CR) >120 mL/min could require doses >20 mg/kg to reach adequate C(max). In all cases, patient therapeutic drug monitoring is essential to ensure the safe usage of these dosing recommendations.

Epidemiological investigation of a Serratia liquefaciens outbreak in a neurosurgery department.

Between February 2001 and March 2003, 17 patients from the neurosurgery department of the University Hospital of Rangueil (Toulouse, Southern France) developed Serratia liquefaciens infections. Due to the atypical antibiotype displayed by the clinical isolates (i.e. gentamicin resistance), an outbreak was suspected. Molecular analysis carried out by pulsed-field gel electrophoresis demonstrated a genetic link for all patients. Furthermore, the patient who introduced the epidemic Serratia strain was also identified and shown to be related to the two epidemic peaks observed during the outbreak period. Investigation failed to reveal a reservoir among the antiseptics and soaps, or among the mechanical ventilators used. However, when the colonization of patients was investigated, positive carriage was observed and could be considered as a potential risk for the spread of the epidemic strain. Due to the delay between antibiotherapy and S. liquefaciens colonization, a selection effect had to be considered. Finally, implementation of hygiene measures was accompanied by control of the outbreak.

Bacillus cereus infections in Traumatology-Orthopaedics Department: retrospective investigation and improvement of healthcare practices.

OBJECTIVE: To investigate 41 open fractures infected with Bacillus cereus in a Traumatology-Orthopaedy ward and propose a care protocol at admission. METHODS: All B. cereus strains isolated from patients hospitalized in the Traumatology-Orthopaedy ward between March 1997 and August 2001 were submitted to molecular analysis (RAPD and PFGE) in order to investigate a putative outbreak. Susceptibility to the main antibiotics and antiseptics used in this kind of surgery was also evaluated. RESULTS: The B. cereus clinical isolates were mainly isolated from patients who had initially open fractures and were not clonally related. Furthermore, analysis of the clinical data was in favour of a telluric contamination of the wound (wound contamination with terrestrial environments) before admission. Finally, betalactam antibiotics used for prophylactic chemotherapy were not effective against the strains tested as well as the antiseptics who displayed poor effect. CONCLUSION: B. cereus could be termed an emerging pathogen and people need to be aware of its potential importance in orthopaedic trauma cases. In this purpose, a systematic screening for B. cereus at admission should be necessary in front of patients with open fractures associated with telluric contamination. Furthermore, if this bacterium can be isolated, chemotherapy should be based upon ciprofloxacin that would prevent the development of B. cereus infection responsible for deleterious complications.

Cefepime in critically ill patients: continuous infusion vs. an intermittent dosing regimen.

The aim of this study was to compare the pharmacokinetic and pharmacodynamic parameters of a continuous infusion of cefepime vs. an intermittent regimen in critically ill adult patients with Gram-negative bacilli infection. The prospective randomized parallel study was carried out in 50 patients with severe pneumonia (n = 41) or bacteremia (n = 9). They received cefepime 4 g/d either as a continuous infusion or intermittent administration 2 x 2 g in combination with amikacin. Patient characteristics and the minimal inhibitory concentration (MIC) of the isolated bacteria were comparable. Clinical outcomes were assessed along with pharmacodynamic indices and compared in both groups (chi2 and Mann-Whitney U-tests). Mechanical ventilation, clinical outcome and bacteriological eradication did not significantly differ between the two groups. Also, the area under the plasma cefepime concentration curve at steady state (AUCss: 612 +/- 369 vs. 623 +/- 319 mg x 1(-1) x h), AUCss > MIC (595 +/- 364 vs. 606 +/- 316 mg x 1(-1) x h) and the area under the inhibitory concentration curve (AUICss: 4258 +/- 5819 vs. 5194 +/- 7465 mg x 1(-1) x h) were similar. If the time above MIC (t > MIC) was not significantly higher in Group 1 (100 +/- 0%) than in Group 2 (90 +/- 11%), t > five-fold MIC in Group 1 (100 +/- 0%) was significantly higher (p < 0.01) than in Group 2 (82 +/- 25%). The mean time over the French breakpoint (4 mg/l) was 100 +/- 0% and 72 +/- 27% in Group 1 and 2 (p < 0.001), respectively. In contrast to intermittent cefepime administration, continuous infusion of cefepime consistently maintained a serum concentration > 5 x the MIC of typical Gram-negative nosocomial pathogens. This results in greater bactericidal activity against organisms with a higher (2 mg/l) cefepime breakpoint even if the clinical outcome is not significantly modified.

Implication of neutral polysaccharides associated to alginate in inhibition of murine macrophage response to Pseudomonas aeruginosa.

There is evidence that exopolysaccharides (EPS) contribute to the persistence of Pseudomonas aeruginosa in cystic fibrosis lung. However, the relationship between the chemical composition of EPS and the modulation of phagocytic cells is poorly understood. In order to evaluate the role of the chemical composition of EPS in macrophage behavior changes, we pretreated macrophages with characterized EPS and assessed P. aeruginosa phagocytosis and reactive oxygen intermediate (ROI) production. The results showed that alginate and neutral polysaccharides are involved in phagocytic impairment of P. aeruginosa. Moreover, alginates were able to prime macrophages for increased P. aeruginosa-induced macrophage oxidative burst as determined by chemiluminescence. In contrast, neutral polysaccharides are responsible for the decrease of ROI by a scavenging effect evaluated by the xanthine-xanthine oxidase system. This study showed that the content of P. aeruginosa EPS in alginate, but also in neutral polysaccharides, influences the behavior of strains towards phagocytosis and macrophage oxidative burst.

Influence of nutrient media on the chemical composition of the exopolysaccharide from mucoid and non-mucoid Pseudomonas aeruginosa.

Two mucoid Pseudomonas aeruginosa strains and their non-mucoid revertants isolated from two different clinical origins (cystic fibrosis and bronchiectasis) were grown in various chemically defined media. The extracted exopolysaccharide was characterized by gas-liquid chromatography and 1H-NMR spectroscopy. The exopolysaccharide was always heterogeneous, with an alginate fraction and a neutral fraction essentially composed of glucose, galactose, rhamnose and hexosamines. The alginate composition (mannuronate/guluronate ratio and O-acetylation degree) changed according to the carbon source in nutrient media and whether the strains tested were responding differently to these environmental stimuli. In all cases, the best carbon source for the alginate production was glycerol: the two cystic fibrosis strains produced a predominantly O-acetylated alginate whereas only the mucoid bronchiectasis strain produced a polymannuronate exopolysaccharide.

Effects of characterised Pseudomonas aeruginosa exopolysaccharides on adherence to human tracheal cells.

This study evaluated, in vitro, the role of different Pseudomonas aeruginosa exopolysaccharides (EPS) in mediating adherence to human respiratory epithelial cells. Two mucoid and non-mucoid isogenic pairs of P aeruginosa strains isolated from patients with cystic fibrosis (CF) and bronchiectasis were used. Adherence was tested with human tracheal epithelial cell lines from CF and normal fetuses. The CF cells bound significantly more bacteria than the normal cells. The strain from the bronchiectasis patient was significantly more adherent than that from the CF patient and this difference was consistently most marked with the non-mucoid variant and with normal epithelial cells. The differing behaviour of mucoid CF and non-mucoid bronchiectasis strains reflected the chemical composition of their EPS: mainly alginate in the former and neutral polysaccharides in the latter. Additive inhibition experiments with chemically characterised EPS indicated that neutral polysaccharides associated with alginate may act as ligands for the adherence of P. aeruginosa to CF epithelial cells.

Effects of five antibiotics on adhesion and haemagglutinating properties of Pseudomonas aeruginosa isolated from cystic fibrosis patients.

The aim of this study was to evaluate the in vitro effect of five antibiotics at sub-inhibitory concentrations on the adhesive and haemagglutinating properties of Pseudomonas aeruginosa isolated from cystic fibrosis sputa. Eleven isolates (mucoid and non-mucoid) from cystic fibrosis, and four isolates (mucoid and non-mucoid) from other chronic respiratory infections were tested. The adhesion test was performed on human lymphoblastoid cell-lines; the haemagglutination test used human O+ and guinea-pig erythrocytes. The antibiotics were tested at six sub-inhibitory concentrations, from MIC/2 to MIC/64. Among the five antibiotics, cefsulodin and pefloxacin were the most active in decreasing the adhesive properties: this effect was statistically significant at MIC/2 and MIC/4 for cefsulodin and at all sub-inhibitory concentrations for pefloxacin. No differences appeared between mucoid and non-mucoid strains, and no correlation was noted with their clinical origins. The three other antibiotics (ceftazidime, latamoxef and imipenem) had no significant effect on the adhesion of all the strains tested, but their effect was rather strain-dependent. This fact and the heterogeneity found in adherence and haemagglutinating activity of each strain suggest that the adhesins and the haemagglutinins of P. aeruginosa are very complex structures.

[Burkholderia cepacia: dangers of a phytopathogen organism for patients with cystic fibrosis]. / Burkholderia cepacia: les dangers d'un micro-organisme phytopathogène pour les patients atteints de mucoviscidose.

Burkholderia cepacia is an environmental bacterium, capable of colonising vegetal and animal tissues, involved in human opportunist nosocomial infections, and above all, in pulmonary colonisations in patients with cystic fibrosis. In these patients, infection may be followed by a severe deterioration with bacteraemia, leading to death. Moreover, owing to the epidemic spread of some clones within cystic fibrosis communities, strict preventive guidelines have to be instituted. Early detection of Burkholderia cepacia colonisation is therefore essential, and requires the use of selective media. Identification by means of conventional procedures may be problematic, all the more as the previously named Burkholderia cepacia strains have been recently shown to constitute five genomovars (I to V), collectively designated the "cepacia complex", of which only three are classified as new species (II = Burkholderia multivorans; IV = Burkholderia stabilis; V = Burkholderia vietnamiensis). Moreover, closely related species, particularly Burkholderia gladioli, are also involved in cystic fibrosis. Many questions still need clarifications, regarding pathogenic mechanisms and propensity for the cystic fibrosis lung of these organisms. Antimicrobial therapeutic options for B. cepacia complex infections are limited by their innate and acquired antibiotic multiresistance.

[Sensitivity of Pseudomonas aeruginosa and Klebsiella spp. to ceftazidime. Current status in France]. / Sensibilité des Pseudomonas aeruginosa et des Klebsiella à la ceftazidime. Etat actuel en France.

Ceftazidime was tested against 2,224 strains of Pseudomonas aeruginosa obtained from 17 hospitals in April, May and June, 1986 and against 607 strains of Klebsiella pneumoniae and 234 strains of K. oxytoca obtained from 16 hospitals in October, 1987. The MIC's of ceftazidime against P. aeruginosa were distributed normally, with an MIC50 of 2 mg/l and an MIC90 of 4 mg/l. Depending on critical concentrations, 80 per cent of strains were sensitive, 11.4 per cent were of intermediate sensitivity and 0.54 per cent were resistant. There were few differences in results between hospitals. Ninety-two per cent of resistant strains and 45 per cent of intermediate strains (as opposed to 6 per cent of all strains) produced a high-level constitutive cephalosporinase with little variations between centres. The MIC's of ceftazidime against K. pneumoniae and K. oxytoca had a bimodal distribution: 91 per cent of strains were sensitive to 0.25 mg/l, 6 per cent of strains showed intermediate sensitivity and 3 per cent were resistant. All intermediate and resistant strains produced a very broad spectrum beta-lactamase which hydrolyzed some of the third generation cephalosporins: K. pneumoniae 36 CTX-1, 5 SHV-2, and 14 strains producing a recently identified beta-lactamase "CAZ-5/SHV-4"; K. oxytoca 3 CTX-1. These strains were isolated in 10 of the 16 hospitals which took part in the 1987 study. Comparison of these results with those of studies performed in 1984 and 1985 showed a moderate increase in the number of intermediate sensitivity strains of P. aeruginosa and the occasional occurrence, of the epidemic type, in some hospitals of Klebsiella spp. producing very broad spectrum beta-lactamases which were rare in 1985.

[Continuous administration of vancomycin in patients with severe burns]. / Vancomycine en administration continue chez le grand brûlé.

OBJECTIVES: In the severely burned patient, a marked, rapid fall in serum concentrations is often observed after intermittent infusion of vancomycin at the usual dose of 30 mg/kg. This specific "jagged" pharmokinetic course with inadequate residual concentrations raises the problem of the efficacy of this time-dependent antibiotic. Studies in patients in general resuscitation units have shown the interest of vancomycin administration in continuous infusion. METHODS: We analyzed variations in serum concentrations of vancomycin during continuous infusion in 18 patients with burns involving a mean of 40% total body surface and reported the doses necessary to maintain serum vancomycin at therapeutic levels; the possible correlations between serum vancomycin concentrations, burn parameters, age and renal function; and clinical and biological tolerance. RESULTS: Higher initial doses were required in burn patients (40 mg/kg in patients aged under 60) than in other patients. Impairment of renal function is a contra-indication of continuous infusion. CONCLUSION: This mode of administration has the advantage of ensuring greater efficacy by preventing fluctuations in serum concentrations.

[Bacterial adhesion: its consequences in antibiotherapy]. / Adhésion bactérienne: ses conséquences en termes d'antibiothérapie.

The aim of the present review is to analyze the influence of antibiotics on bacterial adhesion and to anticipate this approach as an alternative possibility of prophylactic or therapeutic interference with the infectious process. Adhesive interactions between bacteria and substratum including solid and cellular surfaces were briefly documented. Bacteria displays a very large variety of adhesins and this implies complex mechanisms in the adhesion process. Anti-adhesive therapy must take into account several factors: particularly interference with the colonization of mucosal surfaces by normal flora and phagocytic defense system in which adhesion plays a very important role as well.

Adhesion to a human cell line by Escherichia coli strains isolated during urinary tract infections.

It has been shown that some, but not all, Escherichia coli strains isolated from urine adhere, in vitro, to the surface of uroepithelial or vaginal cells. In the present study, 212 strains, isolated from urine of 212 infected patients, were tested for adhesion by using an in vitro human cell line assay. A variable degree of attachment to the cell monolayer was detected in these strains. From patients with cystitis, only 19 (9.7%) of the 195 strains examined were adherent, whereas 5 (29.4%) of the 17 pyelonephritis strains had similar properties (P less than 0.05). To investigate the incidence of adhesion in the clinical manifestations of urinary tract infection, a sample of patients was picked at random from those with cystitis. During cystitis caused by adhesive bacteria, patients suffer more often from macroscopic hematuria than from dysuria, frequency, or recurrency (P less than 0.05). This study shows that E. coli strains isolated from urine samples possess a strikingly difference in capacity to adhere to a human cell line surface as demonstrated previously with uroepithelial or vaginal cells. Moreover, according to these data, the adhesion of E. coli may be considered as a virulent factor and would play a part in the infection of the urinary tract in humans.

[Determination of factors promoting, in vitro, the expression of adhesion of Pseudomonas aeruginosa to buccal cells]. / Détermination des facteurs favorisant, in vitro, l'expression de l'adhésion de Pseudomonas aeruginosa aux cellules buccales.

The composition of the bacterial flora in the upper respiratory tract is closely correlated with the type of pathogens recovered from the respiratory tract in patients. In intensive care patients, colonization of the oral cavity with Gram-negative organisms increases the risk of Gram-negative respiratory tract infection; the ability of bacterial cells to attach to buccal cells seems to play a central role in this correlation. Similar findings have been reported in chronic respiratory tract infections, including bronchiectasis and cystic fibrosis, with Pseudomonas aeruginosa colonization. This study was undertaken to determine the conditions best suited to in vitro detection of adhesion of P. aeruginosa to buccal cells. Use of brain-heart-infusion medium, incubation at 35 degrees C for 2 hours, and a bacterial concentration of 2 x 10(9) cells/ml were the factors correlated with improved detection of adhesion to buccal cells. Furthermore, attachment of bacteria to buccal cells was not found to vary across donors or over time in a given donor. Adhesion was independent of cell viability.