To diagnose invasive fungal infections, the detection of (1 → 3)-β-
d
-glucan in serum has shown variable specificity, depending on the targeted population. Several circumstances for false-positive ...results of beta-glucan tests have been identified, among which are severe bacterial infections. In this study, we measured (1 → 3)-β-
d
-glucan by the Fungitell test in the serum of 62 patients (one serum sample tested per patient) for whom invasive fungal infection was not suspected: 19 control subjects and 43 patients with bacteraemia. The test was interpretable for 58 sera: all 19 control subjects had negative beta-glucan test; among the 39 bacteraemic patients, we report 16 false-positive results. For the 22 patients undergoing bacteraemia due to Gram-negative bacilli, we observed 13 false-positive results (59%). Among the 17 patients with bloodstream infection involving Gram-positive cocci, three false-positive tests were recorded, but none in the eight cases of
Streptococcus pneumoniae
bacteraemia. Statistical analysis showed that beta-glucan levels were significantly higher in patients with Gram-negative bacilli bloodstream infection in comparison to those with bacteraemia due to Gram-positive cocci. These results were independent from other previously described causes for false-positive beta-glucan tests. These data might help physicians to interpret positive beta-glucan detection when an invasive fungal infection is suspected, especially for patients with bacterial infections.
But de l'étude. –
La ceftazidime présente une activité bactéricide temps-dépendant qui nécessite des concentrations plasmatiques optimales et constantes dans les infections sévères. Le but de notre ...étude est de comparer deux modalités d'administration de la ceftazidime (perfusion continue vs administration intermittente) chez des patients de réanimation présentant une pneumonie hypoxémiante sous ventilation mécanique.
Patients et méthodes. –
Il s'agit d'une étude randomisée, prospective, réalisée sur 16 patients répartis en deux groupes après tirage au sort : le BRAS A recevait 60 mg/kg par jour à débit continu de ceftazidime après une dose de charge de 20 mg/kg ; le BRAS B recevait 20 mg/kg de ceftazidime en 30 minutes trois fois par 24 heures. Pour chaque patient, 12 prélèvements (BRAS A) et 18 prélèvements (BRAS B) sanguins sont effectués sur 48 heures. La détermination des concentrations de ceftazidime est réalisée par chromatographie liquide à haute performance couplée à une détection ultraviolette. Du fait de notre écologie locale, le seuil de concentration sérique minimal retenu est de 20 mg/l de ceftazidime.
Résultats. –
Dans le BRAS A, le temps pendant lequel les concentrations sériques de ceftazidime sont supérieures au seuil fixé (
T
>
20 mg/l) est de 100 % (
exprimé en pourcentage du temps sur 48 heures). Dans le BRAS B, ce temps n'atteint en moyenne que 56
±
33 %.
Conclusion. –
Notre étude montre qu'une administration continue de ceftazidime présente un avantage pharmacodynamique dans les pneumonies hypoxémiantes, comparativement à l'administration intermittente.
Goal of the study. –
It is well known today that the main determinant of beta-lactam antibiotics efficacy is the duration of the time that concentrations remain in excess of the minimum inhibitory concentration (MIC) of susceptible organism over the course of therapy. This prospective study aimed to evaluate the efficacy, in term of pharmacodynamic profile, of continuous infusion versus intermittent administration of ceftazidime in intensive care unit patients with severe nosocomial pneumonia.
Patients and methods. –
16 patients under mechanical ventilation with nosocomial pneumonia were randomised to receive either 60 mg/kg/day ceftazidime by constant rate infusion following a 20 mg/kg loading dose (Group A) or 20 mg/kg every 8 hour by intravenous bolus injection (Group B). In both groups, serial blood samples were collected during 48 hours (12 and 18 samples in Group A and B, respectively) after the start of drug administration. Plasma concentrations of ceftazidime were measured by high performance liquid chromatography. Based on our local bacteriological conditions, the pharmacodynamic profile of ceftazidime was assessed as the duration of time the plasma concentration remained above a desired target concentration of 20 mg/l for each regimen.
Results. –
The mean time (expressed as a percentage) for which plasma ceftazidime concentrations were above 20 mg/l was 100% for the continous infusion group (Group A) and 56
±
33% for the intermittent administration group (Group B).
Conclusion. –
These findings show that ceftazidime administered by continuous infusion in critically ill patients under mechanical ventilation with nosocomial pneumonia appears to substantially improve the pharmacodynamic profile of this beta-lactam compared to the intermittent regimen.
To diagnose invasive fungal infections, the detection of (1arrow right3)-β-d-glucan in serum has shown variable specificity, depending on the targeted population. Several circumstances for ...false-positive results of beta-glucan tests have been identified, among which are severe bacterial infections. In this study, we measured (1arrow right3)-β-d-glucan by the Fungitell test in the serum of 62 patients (one serum sample tested per patient) for whom invasive fungal infection was not suspected: 19 control subjects and 43 patients with bacteraemia. The test was interpretable for 58 sera: all 19 control subjects had negative beta-glucan test; among the 39 bacteraemic patients, we report 16 false-positive results. For the 22 patients undergoing bacteraemia due to Gram-negative bacilli, we observed 13 false-positive results (59%). Among the 17 patients with bloodstream infection involving Gram-positive cocci, three false-positive tests were recorded, but none in the eight cases of Streptococcus pneumoniae bacteraemia. Statistical analysis showed that beta-glucan levels were significantly higher in patients with Gram-negative bacilli bloodstream infection in comparison to those with bacteraemia due to Gram-positive cocci. These results were independent from other previously described causes for false-positive beta-glucan tests. These data might help physicians to interpret positive beta-glucan detection when an invasive fungal infection is suspected, especially for patients with bacterial infections.PUBLICATION ABSTRACT
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