Evaluating the optimal time for amikacin administration with respect to haemodialysis using an in vitro pharmacodynamic simulation against epidemic nosocomial OXA-48 producing Klebsiella pneumoniae ST405 strains

In vitro killing of drug susceptible and multidrug resistant bacteria by amikacin considering pulmonary drug concentrations based on an inhaled formulation

Nosocomial infections with drug resistant bacteria impact morbidity and mortality, length of therapy and stay and the overall cost of treatment. Key pathogens with ventilator associated pneumonia may be drug-susceptible or multi-drug resistant and inhaled amikacin has been investigated as an adjunctive therapy option. High pulmonary drug concentrations (epithelial lining fluid [ELF]) along with minimal systemic toxicity is seen as an advantage to inhaled formulations. In vitro killing of bacteria using clinically relevant drug concentrations provide insight on bug-drug interactions. The aim of this study was to measure killing of clinical isolates of Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and methicillin-susceptible S. aureus using the minimum inhibitory concentration (MIC), mutant prevention concentration (MPC) and median (976 µg/ml) ELF drug concentration for amikacin. Overall killing took longer at the MIC drug concentration and was inconsistent amongst the pathogens tested with the percentage of bacteria killed following 180 min of drug exposure ranging from growth in the presence of the drug to 95% kill. At the MPC drug concentrations, killing ranged from 55-88% for all pathogens following 30 min of drug exposure and increased to 99-100% following 180 min of drug exposure. At the ELF amikacin tested, killing was 81-100% following 20 min and 94-100% by 30 min of drug exposure. Rapid killing against MDR respiratory pathogens by amikacin ELF drug concentrations is encouraging.

Antimicrobial Pharmacokinetics and Pharmacodynamics in Critical Care: Adjusting the Dose in Extracorporeal Circulation and to Prevent the Genesis of Multiresistant Bacteria

Critically ill patients suffering from severe infections are prone to pathophysiological pharmacokinetic changes that are frequently associated with inadequate antibiotic serum concentrations. Minimum inhibitory concentrations (MICs) of the causative pathogens tend to be higher in intensive care units. Both pharmacokinetic changes and high antibiotic resistance likely jeopardize the efficacy of treatment. The use of extracorporeal circulation devices to support hemodynamic, respiratory, or renal failure enables pharmacokinetic changes and makes it even more difficult to achieve an adequate antibiotic dose. Besides a clinical response, antibiotic pharmacokinetic optimization is important to reduce the selection of strains resistant to common antibiotics. In this review, we summarize the present knowledge regarding pharmacokinetic changes in critically ill patients and we discuss the effects of extra-corporeal devices on antibiotic treatment together with potential solutions.

Aminoglycosides in Critically Ill Septic Patients With Acute Kidney Injury Receiving Intermittent Hemodialysis: A Multicenter, Observational Study

PURPOSE

Data on aminoglycoside stewardship in critically ill septic patients with acute kidney injury (AKI) needing intermittent hemodialysis (IH) are scarce. The first objective of the study was to evaluate whether aminoglycoside administration occurs before vs after IH in the real-life management of critically ill septic patients with AKI needing IH. The second objective was to assess the delay in achieving a potential reinjection window for a second dose of aminoglycoside, which should be obtained with a postdialysis vs predialysis regimen.

METHODS

A post hoc observational analysis of a multicenter randomized trial of critically ill patients with AKI needing renal replacement therapy was conducted. Inclusion criteria consisted of any patients receiving IH for AKI during an antimicrobial therapy for a septic episode.

FINDINGS

Among 206 of 341 septic patients (60%) receiving aminoglycosides, 90 underwent IH (46 with previous continuous renal replacement therapy and 44 without). Amikacin and gentamicin were administered for a mean (SD) of 2.2 (1.5) and 2.5 (2.1) days with mean (SD) doses of 20.6 (6.6) and 5.4 (2.5) mg/kg, respectively. In the 44 patients undergoing exclusive IH, aminoglycosides were administered in a predialysis in 53% of episodes versus 35% in a postdialysis schedule. The first C_min target was obtained earlier with a predialysis vs postdialysis schedule (33.9 [14.2] hours vs 50.9 [12.2] hours, P = 0.009).

IMPLICATIONS

Despite being less frequently used than a predialysis schedule, the postdialysis administration of aminoglycosides remains a regular practice in the intensive care unit. A predialysis schedule of administration in IH reduces the interval time to tolerable aminoglycoside redosing.