Intrapulmonary concentrations of meropenem administered by continuous infusion in critically ill patients with nosocomial pneumonia: a randomized pharmacokinetic trial.

BACKGROUND: Optimal antimicrobial drug exposure in the lung is required for successful treatment outcomes for nosocomial pneumonia. Little is known about the intrapulmonary pharmacokinetics (PK) of meropenem when administered by continuous infusion (CI). The aim of this study was to evaluate the PK of two dosages of meropenem (3 g vs 6 g/day by CI) in the plasma and epithelial lining fluid (ELF) in critically ill patients with nosocomial pneumonia. METHODS: Thirty-one patients (81% male, median (IQR) age 72 (22) years) were enrolled in a prospective, randomized, clinical trial. Sixteen patients received 1 g/8 h and 15 2 g/8 h by CI (8 h infusion). Plasma and ELF meropenem concentrations were modeled using a population methodology, and Monte Carlo simulations were performed to estimate the probability of attaining (PTA) a free ELF concentration of 50% of time above MIC (50% fT>MIC), which results in logarithmic killing and the suppression of resistance in experimental models of pneumonia. RESULTS: The median (IQR) of meropenem AUC0-24 h in the plasma and ELF was 287.6 (190.2) and 84.1 (78.8) mg h/L in the 1 g/8 h group vs 448.1 (231.8) and 163.0 (201.8) mg h/L in the 2 g/8 h group, respectively. The penetration ratio was approximately 30% and was comparable between the dosage groups. In the Monte Carlo simulations, only the highest approved dose of meropenem of 2 g/8 h by CI allowed to achieve an optimal PTA for all isolates with a MIC < 4 mg/L. CONCLUSIONS: An increase in the dose of meropenem administered by CI achieved a higher exposure in the plasma and ELF. The use of the highest licensed dose of 6 g/day may be necessary to achieve an optimal coverage in ELF for all susceptible isolates (MIC ≤ 2 mg/L) in patients with conserved renal function. An alternative therapy should be considered when the presence of microorganisms with a MIC greater than 2 mg/L is suspected. TRIAL REGISTRATION: The trial was registered in the European Union Drug Regulating Authorities Clinical Trials Database (EudraCT-no. 2016-002796-10). Registered on 27 December 2016.

Systemic pharmacokinetics and safety of high doses of nebulized colistimethate sodium in critically ill patients with hospital-acquired and ventilator-associated pneumonia.

OBJECTIVES: To assess the pharmacokinetics of formed colistin in plasma and the safety of two different high doses of colistimethate sodium administered via nebulization in critically ill surgical patients with hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP). PATIENTS AND METHODS: Formed colistin plasma concentrations were measured in critically ill surgical patients with pneumonia treated with two different doses of nebulized colistimethate sodium (3 MIU/8 h versus 5 MIU/8 h). Adverse events possibly related to nebulized colistimethate sodium were recorded. RESULTS: Twenty-seven patients (15 in the 3 MIU/8 h group and 12 in the 5 MIU/8 h group) were included. Colistin plasma concentrations were unquantifiable (<0.1 mg/L) in eight (53.3%) patients in the 3 MIU/8 h group and in seven patients (58.3%) in the 5 MIU/8 h group. Median (IQR) quantifiable colistin plasma concentrations before nebulization and at 1, 4 and 8 h were 0.17 (0.12-0.33), 0.20 (0.11-0.24), 0.17 (0.12-0.23) and 0.17 (0.11-0.32) mg/L, respectively, in the 3 MIU/8 h group and 0.20 (0.11-0.35), 0.24 (0.12-0.44), 0.24 (0.10-0.49) and 0.23 (0.11-0.44) mg/L, respectively, in the 5 MIU/8 h group, with no differences between the two groups at any time. Renal impairment during nebulized treatment was observed in three patients in each group, but was unlikely to be related to colistimethate sodium treatment. Nebulized colistimethate sodium therapy was well tolerated and no bronchospasms or neurotoxicity events were observed. CONCLUSIONS: In this limited observational case series of critically ill patients with HAP or VAP treated with high doses of nebulized colistimethate sodium, systemic exposure was minimal and the treatment was well tolerated.

A practice-based observational study on the use of micafungin in Surgical Critical Care Units.

INTRODUCTION: Echinocandins are first-line therapy in critically ill patients with invasive Candida infection (ICI). This study describes our experience with micafungin at Surgical Critical Care Units (SCCUs). METHODS: A multicenter, observational, retrospective study was performed (12 SCCUs) by reviewing all adult patients receiving 100 mg/24h micafungin for ≥72h during ad-mission (April 2011-July 2013). Patients were divided by ICI category (possible, probable + proven), 24h-SOFA (<7, ≥7) and outcome. RESULTS: 72 patients were included (29 possible, 13 probable, 30 proven ICI). Forty patients (55.6%) presented SOFA ≥7. Up to 78.0% patients were admitted after urgent surgery (64.3% with SOFA <7 vs. 90.3% with SOFA ≥7, p=0.016), and 84.7% presented septic shock. In 66.7% the site of infection was intraabdominal. Forty-nine isolates were recovered (51.0% C. albicans). Treatment was empirical (59.7%), microbiologically directed (19.4%), rescue therapy (15.3%), or anticipated therapy and prophylaxis (2.8% each). Empirical treatment was more frequent (p<0.001) in possible versus probable + proven ICI (86.2% vs. 41.9%). Treatment (median) was longer (p=0.002) in probable + proven versus possible ICI (13.0 vs. 8.0 days). Favorable response was 86.1%, without differences by group. Age, blood Candida isolation, rescue therapy, final MELD value and %MELD variation were significantly higher in patients with non-favorable response. In the multivariate analysis (R2=0.246, p<0.001) non-favorable response was associated with positive %MELD variations (OR=15.445, 95%CI= 2.529-94.308, p=0.003) and blood Candida isolation (OR=11.409, 95%CI=1.843-70.634, p=0.009). CONCLUSION: High favorable response was obtained, with blood Candida isolation associated with non-favorable response, in this series with high percentage of patients with intraabdominal ICI, septic shock and microbiological criteria for ICI.

Bugs, hosts and ICU environment: countering pan-resistance in nosocomial microbiota and treating bacterial infections in the critical care setting.

ICUs are areas where resistance problems are the largest, and these constitute a major problem for the intensivist's clinical practice. Main resistance phenotypes among nosocomial microbiota are (i) vancomycin-resistance/heteroresistance and tolerance in grampositives (MRSA, enterococci) and (ii) efflux pumps/enzymatic resistance mechanisms (ESBLs, AmpC, metallo-betalactamases) in gramnegatives. These phenotypes are found at different rates in pathogens causing respiratory (nosocomial pneumonia/ventilator-associated pneumonia), bloodstream (primary bacteremia/catheter-associated bacteremia), urinary, intraabdominal and surgical wound infections and endocarditis in the ICU. New antibiotics are available to overcome non-susceptibility in grampositives; however, accumulation of resistance traits in gramnegatives has led to multidrug resistance, a worrisome problem nowadays. This article reviews microorganism/infection risk factors for multidrug resistance, suggesting adequate empirical treatments. Drugs, patient and environmental factors all play a role in the decision to prescribe/recommend antibiotic regimens in the specific ICU patient, implying that intensivists should be familiar with available drugs, environmental epidemiology and patient factors.

Bugs, hosts and ICU environment: countering pan-resistance in nosocomial microbiota and treating bacterial infections in the critical care setting.

ICUs are areas where resistance problems are the largest, and they constitutes a major problem for the intensivist's clinical practice. Main resistance phenotypes among nosocomial microbiota are: i) vancomycin-resistance/heteroresistance and tolerance in grampositives (MRSA, enterococci) and ii) efflux pumps/enzymatic resistance mechanisms (ESBLs, AmpC, metallobetalactamases) in gramnegatives. These phenotypes are found at different rates in pathogens causing respiratory (nosocomial pneumonia/ventilator-associated pneumonia), bloodstream (primary bacteremia/catheter-associated bacteremia), urinary, intraabdominal and surgical wound infections and endocarditis in the ICU. New antibiotics are available to overcome non-susceptibility in grampositives; however, accumulation of resistance traits in gramnegatives has lead to multidrug resistance, a worrisome problem nowadays. This article reviews by microorganism/infection risk factors for multidrug resistance, suggesting adequate empirical treatments. Drugs, patient and environmental factors all play a role in the decision to prescribe/recommend antibiotic regimens in the specific ICU patient, implying that intensivists should be familiar with available drugs, environmental epidemiology and patient factors.