Antimicrobial agents and chemotherapy
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Antimicrob. Agents Chemother. · Jun 2011
Vancomycin dosing in critically ill patients: robust methods for improved continuous-infusion regimens.
Despite the development of novel antibiotics active against Gram-positive bacteria, vancomycin generally remains the first treatment, although rapidly achieving concentrations associated with maximal efficacy provides an unresolved challenge. The objective of this study was to conduct a population pharmacokinetic analysis of vancomycin in a large population of critically ill patients. This was a retrospective data collection of 206 adult septic critically ill patients who were administered vancomycin as a loading dose followed by continuous infusion. ⋯ Simulation data showed that a 35-mg/kg loading dose was necessary to rapidly achieve vancomycin concentrations of 20 mg/liter. Daily vancomycin requirements were dependent on CrCl, such that a patient with a CrCl of 100 ml/min/1.73 m² would require at least 35 mg/kg per day by continuous infusion to maintain target concentrations. In conclusion, we have found that higher-than-recommended loading and daily doses of vancomycin seem to be necessary to rapidly achieve therapeutic serum concentrations in these patients.
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Antimicrob. Agents Chemother. · May 2011
Molecular detection of mutations associated with first- and second-line drug resistance compared with conventional drug susceptibility testing of Mycobacterium tuberculosis.
The emergence of multi- and extensively drug-resistant tuberculosis is a significant impediment to the control of this disease because treatment becomes more complex and costly. Reliable and timely drug susceptibility testing is critical to ensure that patients receive effective treatment and become noninfectious. Molecular methods can provide accurate and rapid drug susceptibility results. ⋯ The values for the second-line drugs were also calculated. The size and scope of this study, in numbers of loci and isolates examined, and the phenotypic diversity of those isolates support the use of DNA sequencing to detect drug resistance in the M. tuberculosis complex. Further, the results can be used to design diagnostic tests utilizing other mutation detection technologies.
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Antimicrob. Agents Chemother. · Apr 2011
Multicenter Study Clinical TrialPenetration of meropenem into epithelial lining fluid of patients with ventilator-associated pneumonia.
Antibiotic penetration to the infection site is critical for obtaining a good clinical outcome in patients with ventilator-associated pneumonia (VAP). Surprisingly few studies have quantified the penetration of β-lactam agents into the lung, as measured by the ratio of area under the concentration-time curve (AUC) in epithelial lining fluid (ELF) to AUC in plasma (AUC(ELF)/AUC(plasma) ratio). These have typically involved noninfected patients. ⋯ The range of AUC(ELF)/AUC(plasma) penetration ratios predicted by the Monte Carlo simulation was large. The 10th percentile of lung penetration was 3.7%, while the 90th percentile of penetration was 178%. The variability of ELF penetration is such that if relatively high ELF exposure targets are required to attain multilog kill or resistance suppression for bacteria like Pseudomonas aeruginosa, then even receiving the largest licensed dose of meropenem with an optimal prolonged infusion may not result in target attainment for a substantial fraction of the population.
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Antimicrob. Agents Chemother. · Mar 2011
Randomized Controlled TrialInfluence of continuous venovenous hemofiltration and continuous venovenous hemodiafiltration on the disposition of doripenem.
The pharmacokinetics, safety, and tolerability of a single 1-hour, 500-mg intravenous infusion of doripenem were assessed in dialysis-dependent subjects with stage 5 chronic kidney disease undergoing continuous renal replacement therapy (CRRT) via 12-hour continuous venovenous hemofiltration (CVVH) (n = 6) or continuous venovenous hemodiafiltration (CVVHDF) (n = 5). Healthy volunteers were also assessed (n = 12). Concentrations of doripenem and the primary metabolite doripenem-M-1 were measured in plasma and ultrafiltrate or ultrafiltrate/dialysate by a validated liquid chromatography-tandem mass spectrometry method. ⋯ Despite significant removal of drug by CVVH and CVVHDF, a single 1-hour, 500-mg doripenem infusion produced significantly higher plasma concentrations of doripenem, higher systemic exposure (area under the plasma concentration-time curve from time zero to 12 h after the start of infusion [AUC(0-12)]), and longer half-life (t(1/2)) in subjects receiving CVVH or CVVHDF than in healthy volunteers. The recovery of drug in ultrafiltrate and ultrafiltrate/dialysate and the enhanced rate of reduction of plasma concentrations indicate that CVVH and CVVHDF significantly augmented residual total body clearance of doripenem in subjects receiving CRRT. Doripenem dosage regimens for patients receiving CRRT thus need to be adjusted.
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Antimicrob. Agents Chemother. · Feb 2011
Randomized Controlled TrialPhase 2, randomized, double-blind, dose-ranging study evaluating the safety, tolerability, population pharmacokinetics, and efficacy of oral torezolid phosphate in patients with complicated skin and skin structure infections.
Torezolid (TR-700) is the active moiety of the prodrug torezolid phosphate ([TP] TR-701), a second-generation oxazolidinone with 4- to 16-fold greater potency than linezolid against Gram-positive species including methicillin-resistant Staphylococcus aureus (MRSA). A double-blind phase 2 study evaluated three levels (200, 300, or 400 mg) of oral, once-daily TP over 5 to 7 days for complicated skin and skin structure infections (cSSSI). Patients 18 to 75 years old with cSSSI caused by suspected or confirmed Gram-positive pathogens were randomized 1:1:1. ⋯ No patients discontinued treatment due to an adverse event. Three-stage hierarchical population pharmacokinetic modeling yielded a geometric mean clearance of 8.28 liters/h (between-patient variability, 32.3%), a volume of the central compartment of 71.4 liters (24.0%), and a volume of the peripheral compartment of 27.9 liters (35.7%). Results of this study show a high degree of efficacy at all three dose levels without significant differences in the safety profile and support the continued evaluation of TP for the treatment of cSSSI in phase 3 trials.