Assessing antimicrobial stewardship initiatives: Clinical evaluation of cefepime or piperacillin/tazobactam in patients with bloodstream infections secondary to AmpC-producing organisms

Management of micro-organisms harbouring AmpC β-lactamases remains challenging. Carbapenems are often considered first-line agents. Due to growing concern regarding carbapenem-resistant Enterobacteriaceae, integrating non-carbapenem treatment strategies is being explored for these pathogens. The primary objective of this study was to evaluate clinical outcomes in patients with bacteraemia secondary to AmpC-producing organisms treated with cefepime or piperacillin/tazobactam (TZP). A retrospective study of adult patients receiving cefepime or TZP for the treatment of AmpC -producing organisms with positive cefoxitin screen (i.e. Citrobacter, Enterobacter or Serratia spp. along with cefoxitin resistance) isolated from blood cultures was conducted. The primary endpoint was clinical cure at end of therapy (EOT). Secondary endpoints included microbiological eradication, frequency of susceptibility changes following treatment, and 7- and 30-day all-cause mortality. Clinical cure at EOT was 87.1%, with 93.2% of patients achieving microbiological eradication. The 7- and 30-day mortality rates were 3.8% and 10.6%, respectively. Organism susceptibility was exceptionally high, with minimum inhibitory concentrations (MICs) of ≤2 μg/mL in 90% of patients treated with cefepime (n = 108). Selection for resistance to third-generation cephalosporins or primary antimicrobial therapy was infrequent at 6.1% (8/132). In conclusion, use of cefepime or TZP for management of AmpC bloodstream infections was associated with clinical and microbiological cure with infrequent selection for resistance.

Impact of an Extended Infusion Β-lactam Strategy on Outcomes in Critically Ill Patients with Pseudomonas Infections

Background

Pseudomonas aeruginosa (PSA) is frequently associated with nosocomial infections resulting in significant morbidity and mortality. High MICs in MDR strains highlights the need to maximize antibiotic exposure with the goal of improving patient outcomes. For β-lactams, optimal efficacy is achieved when free drug concentrations are above the MIC for ~ 40–60% of the dosing interval. Unfortunately, due to significant pharmacokinetic variability in the critically ill, achieving this target with standard intermittent infusions (II) is challenging, resulting in preference for extended (EI) or continuous infusion strategies. Additional data in patients with PSA infections are needed to understand the association between infusion strategy and clinical outcome.

Methods

A single-center, retrospective chart review. Adult patients with positive respiratory or blood cultures for PSA treated with cefepime or piperacillin/tazobactam managed in an ICU from January 2012 to May 2016 were included. Primary endpoint was clinical cure (CC) at end of therapy (EOT) between patients receiving EI or II. Secondary endpoints included microbiologic eradication (ME), 28-day mortality, length of ICU and hospital stay, and effect of baseline kidney function on clinical cure.

Results

Eighty-three patients were included in the analysis. Patient characteristics were well matched except for a higher frequency of malignancy in the EI arm (P = 0.02). CC was achieved in an overwhelming majority of EI patients compared with II (89.2% vs. 69.6%, P = 0.031). Further, patients with normal renal function (CrCL ≥ 60; P = 0.02) or APACHE II ≥ 17 (P = 0.04) receiving II experienced higher failure rates. In multivariate analysis, use of II associated with 4-fold higher incidence of clinical failure (OR 4.5 [1.3–16.3]). For other secondary endpoints, ME was observed in 73% of EI vs. 65% of II (P = 0.44) and 28-day mortality was observed in 13% of patients in both arms (P = 0.94). No significant differences were observed with other secondary variables.

Conclusion

Use of an EI strategy in critically ill patients with PSA infections improves CC. Further, EI benefitted those patients with normal to augmented renal clearance suggesting that improved exposure may play a role in clinical outcomes.

Disclosures

K. Klinker, The Medicines Company: Scientific Advisor, Consulting fee.

Pharmacologic Interventions for the Management of Critical Bleeding

Hospital pharmacists are often consulted for their knowledge about coagulation and therapeutic interventions for the management of critical bleeding. Many pharmacotherapies are available for this purpose, both systemic and topical, and others are in development. These agents and their mechanisms of action are reviewed, and perspectives are provided regarding their use in various clinical settings. Also provided are associated precautions to promote safe use. Current controversies surrounding pharmacotherapeutic agents used to control serious bleeding (e.g., in various types of surgery, trauma, obstetrics, and intracranial hemorrhage) are also discussed.