Combating bacterial resistance to Meropenem by infusion strategy applied to septic burn patients with vasopressor requirements or acute kidney injury to achieve the target

Abstract

Introduction: Faced with the growing challenge to the use of antimicrobials for the adequate and effective therapy of nosocomial infections, international health agencies have reinforced that combating bacterial resistance and preventing the development of multidrug-resistant (MDR) strains are urgent, since a significant increase based on minimum inhibitory concentration (MIC) for therapeutic agents were reported by the committee of hospitals infection. Meropenem, a carbapenem agent, is widely prescribed for therapy of septic shock caused by susceptible Gram-negative bacteria. In general, the prolonged 3-hrs-infusion has been widely applied in these patients over the past 10 years providing coverage only against susceptible Gram-negative pathogens (MIC 2 mg/L), extended also to intermediate susceptible strains up to MIC 4 mg/L, according to Clinical Laboratory Standard Institute (CLSI database). However, new strategies have been recommended to combat the development of resistance to pathogens isolated from cultures to increase the coverage of this carbapenem agent up to MIC 8 mg/L, to avoid mutant selection with death in ICU. Subject: Clinical protocol was carried out to investigate the efficacy & safety of meropenem at the dose regimen recommended 1g q8h by prolonged infusion, based on serum levels and on cultures monitoring of isolates. Aim of protocol was to assess pharmacodynamics (PD) based on changes of pharmacokinetics (PK), which could affect the coverage of meropenem in septic burns patients with increased or decreased renal function. Pharmacokinetic-pharmacodynamics (PK/PD) tools were applied to investigate efficacy & safety. Methods-clinical protocol: Forty-eight major septic burn patients with high variability on renal function in ICU were included. Cultures were collected before meropenem therapy starts; all of them had nosocomial infection caused by Gram-negative pathogens isolated. Patients undergoing meropenem therapy at the initial stage of septic shock from day-0 to day-8 (D0-D8) and at the late stage of septic shock from day 8 to day 14 (D-8 to D-14) were investigated according to dose requirements based on creatinine clearance, drug serum levels (TDM), and coverage up to MIC 8 mg/L, dose dependent on renal function. Results: Coverage occurred for all patients of both groups after the extended infusion against susceptible Gram-negative strains up to MIC 2 mg/L (minimum inhibitory concentration), and up to MIC 4 mg/L, strains of intermediate susceptibility, according to Clinical Laboratory Standards Institute (CLSI, database) of our hospital. It was demonstrated in patients with renal function augmented by vasopressors, the superiority on coverage by trice that occurred in 24/27 patients (89%) after 4 hrs.-infusion at TDM3 against strains MIC 8 mg/L by comparison with coverage registered in 12/39 patients (30%) after 3 hrs.-infusion at TDM2. On the other hand, meropenem dose regimen must be adjusted to 1g q24h in patients with AKI to guarantee effectiveness & safety in those patients. In addition, after continuous venovenous haemodialysis-filtration (CVVHDF) installed in those patients, meropenem PK/PD target was attained up to MIC 8 mg/L in patients with the empirical dose regimen recommended of 1g q8h, 3hrs.-infusion. Conclusion: Precision medicine guarantees meropenem serum levels combined with cultures monitoring; consequently, must be applied routinely to guarantee coverage against Gram-negative nosocomial pathogens susceptible including strains of intermediate susceptibility (MIC 4-8 mg/L) to avoid mutant selection. Therefore, effective, and safe antimicrobial therapy for patients in septic shock, combined with a continuous monitoring of inflammatory biomarkers, should guide clinical management to ensure cure with early ICU discharge.