Impact of early antimicrobial stewardship intervention in patients with positive blood cultures: results from a randomized comparative study.

BACKGROUND: Antimicrobial stewardship intervention (ASI) appears to be necessary to realize the full benefits of rapid diagnostic technologies in clinical practice. This study aimed to compare clinical outcomes between early ASI paired with matrix-associated laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) compared with MALDI-TOF with standard of care (SOC) reporting in patients with positive blood cultures. METHODS: Adult patients with positive blood cultures and organism speciation via MALDI-TOF admitted between February 2015 and September 2015 were randomized to ASI or SOC in a 1:1 fashion. Patients admitted for at least 48 h following positive culture were included in analyses. ASI was defined as a clinical assessment by a stewardship team member with non-binding treatment recommendations offered to the primary team. The primary outcome was time to definitive therapy. Secondary outcomes included post-culture length of stay (LOS), time to first change in antibiotics, and in-hospital mortality. RESULTS: In total, 149 patients were included in the analyses (76 in the ASI group and 73 in the SOC group). ASI and SOC arms did not differ according to age, sex, comorbidities or severity of illness. Gram-positive organisms were common in both SOC and ASI arms (74.0 vs. 61.8%, P=0.11). Time to definitive therapy was reduced, on average, by 30.3 h in the ASI group (71.6 vs. 41.3 h, P=0.01). Hospital LOS following the first positive blood culture was significantly shorter in the ASI group (8.7 vs. 11.2 days, P=0.049). CONCLUSIONS: ASI combined with MALDI-TOF reduced the time to definitive therapy and time to first change in antibiotics, and was associated with a shorter post-culture LOS.

Dose, duration, and animal sex predict vancomycin-associated acute kidney injury in preclinical studies.

BACKGROUND: Although the exposure-dependent efficacy thresholds of vancomycin have been probed, less is known about acute kidney injury (AKI) thresholds for this drug. Sensitive urinary biomarkers, such as kidney injury molecule 1 (KIM-1), have shown high sensitivity and specificity for vancomycin-associated AKI. The aims of the study were to determine if there were dose-response curves with urinary KIM-1, and to evaluate the impact of therapy duration and sex on observed relationships. METHODS: A systematic review was conducted via PubMed/MEDLINE. Data were compiled from preclinical studies that reported individual subject data for urinary KIM-1 concentrations, vancomycin dose (mg/kg), duration of treatment, and sex. Sigmoidal Hill-type models were fit to the individual dose-response data. RESULTS: A total of 15 studies were identified, 6 of which reported vancomycin dose and KIM-1 data. Of these, three included individual animal-level data suitable for analysis. For all pooled rats, increasing total daily vancomycin doses displayed a dose-response curve with urinary KIM-1 concentrations (50% maximal toxic response=130.4 mg/kg/day). Dose-response curves were shifted left for females vs. males (P = 0.05) and for long (i.e. ≥7 days) vs. short (i.e. <4 days) duration of vancomycin therapy (P=0.02). CONCLUSIONS: The collective findings demonstrate a clear dose-response relationship between vancomycin dose and AKI. As these analyses focused exclusively on dose-response relationships, additional preclinical data are needed to more clearly define vancomycin exposures that predict the onset of AKI.

24-Hour Pharmacokinetic Relationships for Vancomycin and Novel Urinary Biomarkers of Acute Kidney Injury.

Vancomycin has been associated with acute kidney injury in preclinical and clinical settings; however, the precise exposure profiles associated with vancomycin-induced acute kidney injury have not been defined. We sought to determine pharmacokinetic/pharmacodynamics indices associated with the development of acute kidney injury using sensitive urinary biomarkers. Male Sprague-Dawley rats received clinical-grade vancomycin or normal saline as an intraperitoneal injection. Total daily doses between 0 and 400 mg/kg of body weight were administered as a single dose or 2 divided doses over a 24-h period. At least five rats were utilized for each dosing protocol. A maximum of 8 plasma samples per rat were obtained, and urine was collected over the 24-h period. Kidney injury molecule-1 (KIM-1), clusterin, osteopontin, cystatin C, and neutrophil gelatinase-associated lipocalin levels were determined using Milliplex multianalyte profiling rat kidney panels. Vancomycin plasma concentrations were determined via a validated high-performance liquid chromatography methodology. Pharmacokinetic analyses were conducted using the Pmetrics package for R. Bayesian maximal a posteriori concentrations were generated and utilized to calculate the 24-h area under the concentration-time curve (AUC), the maximum concentration (Cmax), and the minimum concentration. Spearman's rank correlation coefficient (rs ) was used to assess the correlations between exposure parameters, biomarkers, and histopathological damage. Forty-seven rats contributed pharmacokinetic and toxicodynamic data. KIM-1 was the only urinary biomarker that correlated with both composite histopathological damage (rs = 0.348, P = 0.017) and proximal tubule damage (rs = 0.342, P = 0.019). The vancomycin AUC and Cmax were most predictive of increases in KIM-1 levels (rs = 0.438 and P = 0.002 for AUC and rs = 0.451 and P = 0.002 for Cmax). Novel urinary biomarkers demonstrate that kidney injury can occur within 24 h of vancomycin exposure as a function of either AUC or Cmax.

Carbapenem susceptibility breakpoints, clinical implications with the moving target.

Carbapenems are primary agents used to treat a variety of Gram-negative multi-drug resistant infections. In parallel with increasing use, increasing resistance to carbapenem agents has manifested as increased minimum inhibitory concentrations (MICs). To attempt to improve clinical outcomes with carbapenems, the Clinical Laboratory Standards Institute and the Food Drug Administration decreased susceptibility breakpoints. The European equivalent expert committee, the European Committee on Antimicrobial Susceptibility Testing, also utilizes lower MIC susceptibility breakpoints. This review focuses on the rationale for recent breakpoint changes and the associated clinical outcomes for patients treated with carbapenems for infections with varying MICs proximal to the breakpoint. Supporting pharmacokinetics and pharmacodynamics that underpin the breakpoints are also reviewed.