Association of vancomycin trough concentration on the treatment outcome of patients with bacteremia caused by Enterococcus species

Is It Still Beneficial to Monitor the Trough Concentration of Vancomycin? A Quantitative Meta-Analysis of Nephrotoxicity and Efficacy

This study conducted a quantitative meta-analysis to investigate the association of vancomycin indicators, particularly area under the curve over 24 h (AUC24) and trough concentrations (Ctrough), and their relationship with both nephrotoxicity and efficacy. Literature research was performed in PubMed and Web of Science on vancomycin nephrotoxicity and efficacy in adult inpatients. Vancomycin Ctrough, AUC24, AUC24/minimum inhibitory concentration (MIC), nephrotoxicity evaluation and treatment outcomes were extracted. Logistic regression and Emax models were conducted, stratified by evaluation criterion for nephrotoxicity and primary outcomes for efficacy. Among 100 publications on nephrotoxicity, 29 focused on AUC24 and 97 on Ctrough, while of 74 publications on efficacy, 27 reported AUC24/MIC and 68 reported Ctrough. The logistic regression analysis indicated a significant association between nephrotoxicity and vancomycin Ctrough (odds ratio = 2.193; 95% CI 1.582-3.442, p < 0.001). The receiver operating characteristic curve had an area of 0.90, with a cut-off point of 14.55 mg/L. Additionally, 92.3% of the groups with a mean AUC24 within 400-600 mg·h/L showed a mean Ctrough of 10-20 mg/L. However, a subtle, non-statistically significant association was observed between the AUC24 and nephrotoxicity, as well as between AUC24/MIC and Ctrough concerning treatment outcomes. Our findings suggest that monitoring vancomycin Ctrough remains a beneficial and valuable approach to proactively identifying patients at risk of nephrotoxicity, particularly when Ctrough exceeds 15 mg/L. Ctrough can serve as a surrogate for AUC24 to some extent. However, no definitive cut-off values were identified for AUC24 concerning nephrotoxicity or for Ctrough and AUC24/MIC regarding efficacy.

Association between ratio of area under the concentration-time curve to minimum inhibitory concentration of vancomycin and clinical outcomes in Enterococcus faecium bacteremia

The purpose of this study was to evaluate the relationship between the treatment resolution of Enterococcus faecium bacteremia and the pharmacodynamic targets of vancomycin. This is a retrospective single-center cohort study involving patients with E. faecium bacteremia on vancomycin therapy hospitalized between January 2010 and December 2021. The average vancomycin area under the concentration-time curve (AUC)0 -24 was computed using the Bayesian approach. The minimum inhibitory concentration (MIC) was determined using the broth microdilution method, and The AUC24/MIC value over the initial 24-48 h of therapy was calculated. We assessed 30-day mortality, as the primary outcome. Classification and regression tree analysis (CART) was used to identify the vancomycin AUC24/MIC target associated with 30-day mortality. Eighty-seven patients with E. faecium bacteremia were included in this study, with 14 (16.1%) being non-survivors. In the CART analysis, vancomycin AUC/MIC ≥414.3 was associated with a higher treatment success. In multivariate analysis, an AUC/MIC ≥414.3 was a significant factor for treatment success (adjusted odds ratio = 17.5, 95% confidence interval, 3.7-83.9). Our findings suggest that a target vancomycin AUC/MIC ≥414.3 is a good prognostic indicator and could be useful for treatment monitoring of E. faecium bacteremia.

Effect of the Minimum Inhibitory Concentration of Vancomycin on the Clinical Outcome of Enterococcus faecium Bacteremia

BACKGROUND/AIM

Vancomycin (VCM) is an antibiotic widely used in the treatment of resistant bacteria. In patients with methicillin-resistant Staphylococcus aureus (MRSA) infection, the clinical outcome differs according to the VCM minimum inhibitory concentration (MIC) of isolates. However, the effect of VCM MIC on the clinical outcome is unclear for bacterial species other than MRSA. This study evaluated the relationship between the VCM MIC and clinical outcomes in patients with Enterococcus faecium bacteremia.

PATIENTS AND METHODS

This study included patients who had E. faecium detected in at least one set of blood cultures between April 2011 and March 2022. The study assessed the outcome according to the VCM MIC. The primary outcome was the 30-day mortality rate. Measures of interest included the initial serum concentration of VCM, MIC, the area under the curve (AUC), and the AUC over 24-48 hours (AUC24-48 h).

RESULTS

A total of 26 patients were included in the study, of whom 5 died and 21 survived. The 30-day mortality was higher in patients with higher MICs and lower serum albumin levels. Patients with a serum albumin level <2.0 mg/dl and a MIC ≥1 μg/ml had significantly shorter survival than those who did not (p=0.013, log-rank test).

CONCLUSION

The 30-day mortality rate of patients with E. faecium bacteremia is associated with the VCM MIC of E. faecium isolates and the patient's nutritional status. Patients with albumin <2 mg/dl and MIC ≥1 μg/ml may have a poor outcome and require careful clinical monitoring.

Pharmacokinetic/pharmacodynamic analysis of vancomycin in patients with Enterococcus faecium bacteraemia: a retrospective cohort study

OBJECTIVES

The trough concentration of vancomycin and the area under the concentration-time curve (AUC)/minimum inhibitory concentration (MIC) ratio are crucial in determining vancomycin efficacy against methicillin-resistant Staphylococcus aureus. However, the use of similar pharmacokinetic principles in determining antibiotic efficacy against other gram-positive cocci is lacking. We performed a pharmacokinetic/pharmacodynamic analysis (association of target trough concentration values and AUC/MIC with therapeutic outcome) of vancomycin in patients with Enterococcus faecium bacteraemia.

METHODS

Between January 2014 and December 2021 we performed a retrospective cohort study of patients with E. faecium bacteraemia treated with vancomycin. Patients who received renal replacement therapy or had chronic kidney disease were excluded. Clinical failure, the primary outcome, was defined as a composite of 30-day all-cause mortality, vancomycin-susceptible infection requiring change of treatment, and/or recurrence. AUC24 was estimated using a Bayesian estimation approach based on an individual vancomycin trough concentration. The MIC for vancomycin was determined using a standardised agar dilution method. Additionally, classification was used to identify the vancomycin AUC24/MIC ratio associated with clinical failure.

RESULTS

Of the 151 patients identified, 69 were enrolled. All MICs of vancomycin for E. faecium were ≤1.0 µg/mL. The AUC24 and AUC24/MIC ratio were not significantly different between the clinical failure group and the clinical success group (432±123 µg/mL/hour vs 488±92 µg/mL/hour; p=0.075). However, 7 of 12 patients (58.3%) in the clinical failure group and 49 of 57 patients (86.0%) in the clinical success group had a vancomycin AUC24/MIC ratio ≥389 (p=0.041). No significant association between trough concentration or AUC24 ≥600 µg/mL×hour and acute kidney injury was observed (p=0.365 and p=0.487, respectively).

CONCLUSION

The AUC24/MIC ratio is associated with the clinical outcome of vancomycin administration in E. faecium bacteraemia. In Japan, where vancomycin-resistant enterococcal infection is rare, empirical therapy with a target AUC24 ≥389 should be recommended.

Impact of Pharmacist-Led Multidisciplinary Team to Attain Targeted Vancomycin Area under the Curved Monitoring in a Tertiary Care Center in Thailand

Vancomycin Area Under the Curve (AUC) monitoring has been recommended to ensure successful clinical outcomes and minimize the risk of nephrotoxicity, rather than traditional trough concentration. However, vancomycin AUC monitoring by a pharmacist-led multidisciplinary team (PMT) has not been well established in Southeast Asia. This study was conducted at Thammasat University Hospital. Adult patients aged ≥ 18 years who were admitted and received intravenous vancomycin ≥48 h were included. The pre-PMT period (April 2020-September 2020) was defined as a period using traditional trough concentration, while the post-PMT period (October 2020-March 2021) was defined as a period using PMT to monitor vancomycin AUC. The primary outcome was the rate of achievement of the therapeutic target of an AUC/MIC ratio of 400-600. There was a significantly higher rate of achievement of therapeutic target vancomycin AUC during post-PMT period (66.7% vs. 34.3%, p < 0.001). Furthermore, there was a significant improvement in the clinical cure rate (92.4% vs. 69.5%, p < 0.001) and reduction in 30-day ID mortality (2.9% vs. 12.4%, p = 0.017) during the post-PMT period. Our study demonstrates that PMT was effective to help attain a targeted vancomycin AUC, improve the clinical cure rate, and reduce 30-day ID mortality. This intervention should be encouraged to be implemented in Southeast Asia.

Pharmacokinetic/pharmacodynamic parameters of vancomycin for predicting clinical outcome of enterococcal bacteremia

Purpose

To find pharmacokinetic/pharmacodynamic parameters of vancomycin associated with the optimal outcome of severe infection due to Enterococcus species.

Methods

We retrospectively reviewed enterococcal bacteremia cases treated with vancomycin from January 2015 to December 2020. The primary outcome was 30-day mortality. We calculated cutoff values of the ratio of vancomycin area under the concentration–time curve over 24 h to the minimum inhibitory concentration (AUC₂₄/MIC) and trough concentration (C_trough) during the initial 72 h of treatment. The optimal cutoff value was determined using the Youden index. Binary variables created based on these cutoffs were further assessed using multivariable analysis.

Results

A total of 65 patients were included. The majority (87.7%) had solid or hematologic malignancies. Thirty-day mortality and nephrotoxicity occurred in nine (13.4%) and 14 (21.5%) patients, respectively. Both vancomycin AUC₂₄/MIC and C_trough showed fair performance in predicting 30-day mortality (AUC of receiver-operator curve for AUC₂₄/MIC, 0.712; 95% confidence interval [CI] 0.539–0.886; AUC for C_trough, 0.760; 95% CI 0.627–0.892; pairwise AUC comparison: p = 0.570). C_trough ≥ 13.94 μg/mL, but not AUC₂₄/MIC ≥ 504, had a significant association with 30-day mortality after adjusting for confounders (odds ratio, 8.40; 95% CI 1.60–86.62; p = 0.010).

Conclusion

Mean C_trough ≥ 13.94 μg/mL during the initial 72 h was associated with higher 30-day mortality in enterococcal bacteremia. Further studies are warranted to elucidate optimal pharmacokinetic targets for enterococcal bacteremia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07668-w.