Is ß-d-glucan Relevant for the Diagnosis and Follow-Up of Intensive Care Patients with Yeast-Complicated Intra-Abdominal Infection?

The usefulness of (1,3)-ß-d-glucan (BDG) detection for the diagnosis of intra-abdominal candidiasis and treatment monitoring is unknown. A prospective, single-center study of consecutive patients admitted to an ICU with complicated intra-abdominal infection (IAI) over a 2-year period was conducted. BDG was measured in the peritoneal fluid and serum between day 1 (D1) and D10. Patients with a positive peritoneal fluid yeast culture (YP) were compared to those with a negative yeast culture (YN). The evolution of serum BDG was compared in the two groups. Seventy patients were included (sixty-five analyzed): YP group (n = 19) and YN group (n = 46). Median peritoneal BDG concentration during surgery was 2890 pg.mL-1 [IQR: 942-12,326] in the YP group vs. 1202 pg.mL-1 [IQR: 317-4223] in the YN group (p = 0.13). Initial serum BDG concentration was 130 pg.mL-1 [IQR: 55-259] in the YP group vs. 88 pg.mL-1 [IQR: 44-296] in the YN group (p = 0.78). No difference in evolution of serum BDG concentrations was observed between the groups (p = 0.18). In conclusion, neither peritoneal BDG nor serum BDG appear to be good discriminating markers for the diagnosis of yeast IAI. In addition, monitoring the evolution of serum BDG in yeast IAI did not appear to be of any diagnostic value.

Determinants of amikacin first peak concentration in critically ill patients.

Amikacin antimicrobial effect has been correlated with the ratio of the peak concentration (Cmax ) to the minimum inhibitory concentration. A target Cmax ≥ 60-80 mg/L has been suggested. It has been shown that such target is not achieved in a large proportion of critically ill patients in intensive care units. A retrospective analysis was performed to examine the determinants of Cmax ≥ 80 mg/L on the first peak in 339 critically ill patients treated by amikacin. The influence of available variables on Cmax target attainment was analyzed using a classification and regression tree (CART) and logistic regression. Mean Cmax in the 339 patients was 73.0 ± 23.9 mg/L, with a target attainment rate (TAR, Cmax ≥ 80 mg/L) of 37.5%. In CART analysis, the strongest predictor of amikacin target peak attainment was dose per kilogram of lean body weight (dose/LBW). TAR was 60.1% in patients with dose/LBW ≥ 37.8 vs. 19.9% in patients with lower dose/LBW (OR = 6.0 (95% CI: 3.6-10.2)). Renal function was a secondary predictor of Cmax . Logistic regression analysis identified dose per kilogram of ideal body weight (OR = 1.13 (95% CI: 1.09-1.17)) and creatinine clearance (OR = 0.993 (95% CI: 0.988-0.998)) as predictors of target peak achievement. Based on our results, an amikacin dose ≥ 37.8 mg/kg of LBW should be used to optimize the attainment of Cmax ≥ 80 mg/L after the first dose in critically ill patients. An even higher dose may be necessary in patients with normal renal function.

Does inferior vena cava respiratory variability predict fluid responsiveness in spontaneously breathing patients?

INTRODUCTION: We have almost no information concerning the value of inferior vena cava (IVC) respiratory variations in spontaneously breathing ICU patients (SBP) to predict fluid responsiveness. METHODS: SBP with clinical fluid need were included prospectively in the study. Echocardiography and Doppler ultrasound were used to record the aortic velocity-time integral (VTI), stroke volume (SV), cardiac output (CO) and IVC collapsibility index (cIVC) ((maximum diameter (IVCmax)- minimum diameter (IVCmin))/ IVCmax) at baseline, after a passive leg-raising maneuver (PLR) and after 500 ml of saline infusion. RESULTS: Fifty-nine patients (30 males and 29 females; 57 ± 18 years-old) were included in the study. Of these, 29 (49 %) were considered to be responders (≥10 % increase in CO after fluid infusion). There were no significant differences between responders and nonresponders at baseline, except for a higher aortic VTI in nonresponders (16 cm vs. 19 cm, p = 0.03). Responders had a lower baseline IVCmin than nonresponders (11 ± 5 mm vs. 14 ± 5 mm, p = 0.04) and more marked IVC variations (cIVC: 35 ± 16 vs. 27 ± 10 %, p = 0.04). Prediction of fluid-responsiveness using cIVC and IVCmax was low (area under the curve for cIVC at baseline 0.62 ± 0.07; 95 %, CI 0.49-0.74 and for IVCmax at baseline 0.62 ± 0.07; 95 % CI 0.49-0.75). In contrast, IVC respiratory variations >42 % in SBP demonstrated a high specificity (97 %) and a positive predictive value (90 %) to predict an increase in CO after fluid infusion. CONCLUSIONS: In SBP with suspected hypovolemia, vena cava size and respiratory variability do not predict fluid responsiveness. In contrast, a cIVC >42 % may predict an increase in CO after fluid infusion.

Use of aztreonam in association with cefepime for the treatment of nosocomial infections due to multidrug-resistant strains of Pseudomonas aeruginosa to ß-lactams in ICU patients: A pilot study.

OBJECTIVES: Resistance to all ß-lactams is emerging among Pseudomonas aeruginosa (PA) clinical isolates. Aztreonam and cefepime act synergistically in vitro against AmpC overproducing PA isolates. The objective of this study was to evaluate the clinical efficacy of this treatment in ICU patients infected with multidrug-resistant PA. MATERIAL AND METHODS: Retrospective study (2 years, 2 ICUs) in a tertiary university hospital. Inclusion criteria were proven infection with evidence of a bacterial strain of PA resistant to all ß-lactams and treated with the association of at least aztreonam plus cefepime. Treatment was considered effective for pneumonia using CPIS scores at the end of treatment and for other infections, using the SOFA score and signs of infection improvement at the end of treatment. Infectious episodes were classified as cure or failure. RESULTS: Thirteen patients were included (10 nosocomial pneumonia, 3 nosocomial intra-abdominal infections). The median [25th-75th percentiles] admission SAPS2 score was 54 [51-69] and the median SOFA score at the beginning of infection was 7 [4-8]. The median CPIS scores for pneumonia at the beginning and end of treatment were 9 [7-10.5] and 2 [0.75-5.5]. The duration of treatment with the combination of aztreonam plus cefepime was 14 days [9.5-16]. Nine episodes were classified as cures and 4 as failures, indicating a clinical efficacy of 69.2%. Overall mortality was 38.5%. DISCUSSION: These data suggest that the association of cefepime plus aztreonam could be an attractive alternative in the treatment of infections with multidrug-resistant PA to all ß-lactams with a clinical efficacy rate of 69%.

Characterization of a novel AmpC ß-lactamase produced by a carbapenem-resistant Cedecea davisae clinical isolate.

A Cedecea davisae isolate, which was intermediate or resistant to third-generation cephalosporins and carbapenems, was recovered from a urine sample. Susceptibility testing, isoelectric focusing, and analysis of outer membrane proteins showed that AmpC ß-lactamase expression combined with porin deficiency accounted for the carbapenem resistance. A cloning experiment followed by phenotypic and enzymatic characterization identified a novel class C enzyme that was phylogenetically and biochemically close to the chromosome-borne ß-lactamases of the genera Enterobacter and Citrobacter.