Vancomycin-associated nephrotoxicity in non-critically ill patients admitted in a Brazilian public hospital: A prospective cohort study

Incidence of Acute Kidney Injury in Trough and AUC/MIC Vancomycin Dosing Strategies in a Large Tertiary Care Center: A Retrospective Cohort

Acute kidney injury (AKI) is a complication associated with vancomycin use. There is evidence that this was related to the presence of supratherapeutic vancomycin levels rather than the drug itself. The area under the curve over 24 h to minimum inhibitory concentration (AUC/MIC) dosing for vancomycin has replaced trough-based dosing, but the impact of this change on AKI rates remains unclear. A retrospective cohort study was conducted in a tertiary care teaching hospital. Patients from the trough cohort were recruited from January 1, 2019, to June 30, 2019, and the AUC/MIC cohort from July 1, 2021, to January 1, 2022. Sociodemographics, clinical characteristics, and concomitant medications were obtained. AKI was defined by The Kidney Disease Improving Global Outcomes. A total of 1056 patients were included, 509 in the trough cohort and 547 in the AUC/MIC cohort. The baseline rates of chronic kidney disease were 15.4% and 9.9%, respectively. The AKI rates were 15.9% and 11.9% for trough and AUC/MIC cohorts, respectively (P-value .045). The most frequent nephrotoxins were piperacillin/tazobactam (TZP), diuretics, and IV contrast for both groups. The rates of supratherapeutic levels were higher in the trough cohort (20.7%) than in the AUC/MIC cohort (6.6%). The multivariate logistic regression analysis showed that trough dosing was not associated with increased rates of AKI (OR = 0.96 CI 0.64-1.44). Supratherapeutic levels (OR = 4.64), diuretics (OR = 1.62), TZP (OR = 2.01), and ICU admission (OR = 1.72) were associated with AKI. Vancomycin AUC/MIC dosing strategy was associated with decreased rates of supratherapeutic levels of this drug compared to trough dosing, with a trend toward lower rates of AKI.

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.

Risk of Acute Kidney Injury Based on Vancomycin Target Trough Attainment Strategy: Area-Under-the-Curve-Guided Bayesian Software, Nomogram, or Trough-Guided Dosing

BACKGROUND

Guidelines support area-under-the-curve (AUC) monitoring for vancomycin dosing which may lower overall doses and reduce acute kidney injury (AKI).

OBJECTIVE

The aim of this study was to compare incidence of AKI across 3 vancomycin dosing modalities: AUC-targeted Bayesian pharmacokinetic software, AUC-targeted empiric dosing nomogram, and trough-guided dosing using clinical pharmacists' judgment.

METHODS

This retrospective study included adult patients with a pharmacy dosing consult who received ≥1 dose of vancomycin and ≥1 serum vancomycin level documented between January 1, 2018, and December 31, 2019. Patients with baseline serum creatinine ≥2 mg/dL, weight ≥100 kg, receiving renal replacement therapy, AKI prior to vancomycin therapy, or vancomycin ordered only for surgical prophylaxis were excluded. The primary analysis was incidence of AKI adjusted for baseline serum creatinine, age, and intensive care unit admission. A secondary outcome was adjusted incidence of an abnormal trough value (<10 or >20 μg/mL).

RESULTS

The study included 3459 encounters. Incidence of AKI was 21% for Bayesian software (n = 659), 22% for the nomogram (n = 303), and 32% for trough-guided dosing (n = 2497). Compared with trough-guided dosing, incidence of AKI was lower in the Bayesian (adjusted odds ratio [OR] = 0.72, 95% confidence interval [CI]: 0.58-0.89) and the nomogram (adjusted OR = 0.71, 95% CI: 0.53-0.95) groups. Compared with trough-guided dosing, abnormal trough values were less common in the Bayesian group (adjusted OR = 0.83, 95% CI: 0.69-0.98).

CONCLUSION AND RELEVANCE

Study results suggest that use of AUC-guided Bayesian software reduces the incidence of AKI and abnormal trough values compared with trough-guided dosing.

Impact of implementing a vancomycin protocol to reduce kidney toxicity: A comparative study

Introduction: Vancomycin is a frequently used antibiotic for treating severe infections caused by multidrug-resistant, Gram-positive pathogens. To ensure its effectiveness and minimize the risk of nephrotoxicity, safe administration and dose monitoring are crucial. Understanding the impact of vancomycin serum levels on clinical outcomes is of paramount importance, necessitating improved knowledge on its use, dose monitoring, nephrotoxicity, and safe administration. Objective: This study aimed to evaluate the incidence of acute kidney injury (AKI) in patients receiving vancomycin before and after the implementation of an institutional protocol for vancomycin administration in a public tertiary hospital in southern Brazil. Materials and methods: A cross-sectional study design was employed, analyzing data from the electronic medical records of 422 patients who received vancomycin. The patient population was divided into two independent cohorts: those treated in 2016 (pre-protocol) and those treated in 2018 (post-protocol), following the implementation of the institutional vancomycin administration protocol. Results: The study included 211 patients in each year of assessment. Patients from both cohorts had a Charlson Comorbidity Index (CCI) score of 4. The post-protocol cohort consisted of older individuals, with a mean age of 62.8 years. In addition, patients in the post-protocol year had higher baseline creatinine levels, higher rates of intensive care unit (ICU) hospitalization, and increased use of vasopressors. In the pre-protocol year, patients received vancomycin therapy for a longer duration. When comparing the incidence of AKI between the two groups, an intervention study revealed rates of 38.4% in group 1 and 20.9% in group 2, indicating a significant reduction (p < 0.001) in the post-protocol group. A logistic regression model was developed to predict AKI, incorporating variables that demonstrated significance (p ≤ 0.250) in bivariate analysis and those recognized in the literature as important factors for AKI, such as the duration of therapy, vancomycin serum level, and ICU hospitalization. The logistic regression classification performance was assessed using a receiver operating characteristic (ROC) curve, yielding an area under the curve of 0.764, signifying acceptable discrimination of the regression model. Conclusion: Implementation of the institutional protocol for vancomycin administration resulted in a significant and cost-effective impact, ensuring appropriate therapeutic dosing, reducing adverse events (e.g., nephrotoxicity), and improving clinical outcomes for patients in the study population.

Area-Under-Curve-Guided Versus Trough-Guided Monitoring of Vancomycin and Its Impact on Nephrotoxicity: A Systematic Review and Meta-Analysis

BACKGROUND

Conventionally, vancomycin trough levels have been used for therapeutic drug monitoring (TDM). Owing to the increasing evidence of trough levels being poor surrogates of area under the curve (AUC) and the advent of advanced pharmacokinetics software, a paradigm shift has been made toward AUC-guided dosing. This study aims to evaluate the impact of AUC-guided versus trough-guided TDM on vancomycin-associated nephrotoxicity.

METHODS

A systematic review was conducted using PubMed, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature, Google scholar, and Cochrane library databases; articles published from January 01, 2009, to January 01, 2021, were retrieved and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Studies that evaluated trough-guided or AUC-guided vancomycin TDM and vancomycin-associated nephrotoxicity were included. Random-effects models were used to compare the differences in nephrotoxicity.

RESULTS

Of the 1191 retrieved studies, 57 were included. Most studies included adults and older adults (n = 47, 82.45%). The pooled prevalence of nephrotoxicity was lower in AUC-guided TDM [6.2%; 95% confidence interval (CI): 2.9%-9.5%] than in trough-guided TDM (17.0%; 95% CI: 14.7%-19.2%). Compared with the trough-guided approach, the AUC-guided approach had a lower risk of nephrotoxicity (odds ratio: 0.53; 95% CI: 0.32-0.89). The risk of nephrotoxicity was unaffected by the AUC derivation method. AUC thresholds correlated with nephrotoxicity only within the first 96 hours of therapy.

CONCLUSIONS

The AUC-guided approach had a lower risk of nephrotoxicity, supporting the updated American Society of Health-System Pharmacists guidelines. Further studies are needed to evaluate the optimal AUC-derivation methods and clinical utility of repeated measurements of the AUC and trough levels of vancomycin.

Impact of combining vancomycin with proton pump inhibitors on the incidence of acute kidney injury

Vancomycin is a potent antibiotic against Gram-positive bacteria; however, its use can be limited by nephrotoxicity. Several reports showed that proton pump inhibitors (PPIs) are associated with renal impairment. Many hospitalized patients are prescribed both drugs. As the literature lacks data on the potential augmentation of acute kidney injury (AKI) risk with this combination, we aimed to assess such risk. This was a retrospective cohort study of hospitalized patients receiving either VAN-PPI or VAN alone for ≥72 h. Patients with a baseline serum creatinine (SCr) of ≥1.5 mg/dL were excluded. AKI incidence was assessed 3-5 days post VAN-PPI or VAN initiation. Of 300 patients, 186 were in the VAN-PPI group and 114 in the VAN group. The percentage of patients meeting AKI definition was not different between the two groups (11.8% vs. 7.9%; P = 0.277); however, the percentage change in SCr on Days 3-5 was only numerically higher in the VAN-PPI group (1% vs. -2.4%; P = 0.242). The distribution of patients meeting different RIFLE class criteria was not different (P = 0.320). Using VAN with PPI was not associated with augmented AKI risk. However, monitoring kidney function would still be recommended as a standard good clinical practice when either drug is used.

Experience of Vancomycin Therapeutic Drug Monitoring in Two Multidisciplinary Hospitals in Latvia

Background and Objectives: Management of infectious diseases is a huge burden to every healthcare system worldwide. Antimicrobial resistance, including antibacterial resistance, is an increasing problem worldwide; therefore, more new antibiotics are necessary to be discovered. Meanwhile, “old” antibacterial agents are still administered to fight infectious diseases caused by resistant bacteria. One of these antibacterial agents is vancomycin, which is effective in treating serious systemic infections caused by gram-positive bacteria. Thus, it is necessary to perform vancomycin concentration measurements in plasma due to its narrow therapeutic index. Various approaches are implemented for more precise therapy, including therapeutic drug monitoring (TDM) of vancomycin and with a supervision of a clinical pharmacist. The purpose of the study was to investigate if the TDM practice is improved with a local vancomycin TDM protocol applied in a hospital. The results of TDM in two multidisciplinary hospitals, one with a local TDM protocol implemented and applied and the other with no local TDM protocol implemented and applied, were compared. Materials and Methods: A retrospective study was performed in two multidisciplinary hospitals in Latvia. The data were collected for a time period of 4 years (2016−2020) in a hospital without a local TDM protocol and for a time period of 2 years (2018−2020) in a hospital with a local TDM protocol, starting with a period of time when the vancomycin TDM protocol was developed. The data about the patients included in the study were analyzed based on gender, age, body weight, and renal function. Vancomycin therapy was analyzed based on dosing schemes (vancomycin dose and dosing interval), data about loading and maintenance doses, vancomycin concentration, and details about vancomycin concentration (sampling time and concentration level). Results: Differences between the hospitals were found in terms of the initiation of vancomycin administration and concentration sampling. In the hospital with a TDM protocol compared with the hospital without a TDM protocol, more accurate initiation was found, alongside adaption of therapy (97.22% vs. 18.95%, p < 0.001), better performance of administration of a loading dose (22.73% vs. 1.29%, p < 0.01), and reaching of target concentration (55.56% vs. 35.29%, p < 0.01). Concentration sampling in the correct timeframe before the vancomycin dose and vancomycin administration did not show statistically better results in either of the hospitals (4.60% vs. 6.29%, p = 0.786). Conclusions: Better results of adequate adjustments of vancomycin therapy were achieved in the hospital with a TDM protocol. In the long term, sustainable results and regular medical professionals’ training is necessary.

Clinical Practice Guidelines for Therapeutic Drug Monitoring of Vancomycin in the Framework of Model-Informed Precision Dosing: A Consensus Review by the Japanese Society of Chemotherapy and the Japanese Society of Therapeutic Drug Monitoring

Background: To promote model-informed precision dosing (MIPD) for vancomycin (VCM), we developed statements for therapeutic drug monitoring (TDM). Methods: Ten clinical questions were selected. The committee conducted a systematic review and meta-analysis as well as clinical studies to establish recommendations for area under the concentration-time curve (AUC)-guided dosing. Results: AUC-guided dosing tended to more strongly decrease the risk of acute kidney injury (AKI) than trough-guided dosing, and a lower risk of treatment failure was demonstrated for higher AUC/minimum inhibitory concentration (MIC) ratios (cut-off of 400). Higher AUCs (cut-off of 600 μg·h/mL) significantly increased the risk of AKI. Although Bayesian estimation with two-point measurement was recommended, the trough concentration alone may be used in patients with mild infections in whom VCM was administered with q12h. To increase the concentration on days 1–2, the routine use of a loading dose is required. TDM on day 2 before steady state is reached should be considered to optimize the dose in patients with serious infections and a high risk of AKI. Conclusions: These VCM TDM guidelines provide recommendations based on MIPD to increase treatment response while preventing adverse effects.

Emergence of Meropenem Resistance Among Cefotaxime Non-susceptible Streptococcus pneumoniae: Evidence and Challenges

The principal causative agent of acute bacterial meningitis (ABM) in children and the elderly is Streptococcus pneumoniae, with a widespread increase in penicillin resistance. Resistance is due to non-synonymous single-nucleotide polymorphisms (nsSNPs) that alter the penicillin-binding proteins (PBPs), the targets for all β-lactam drugs. Hence, resistance against one β-lactam antibiotic may positively select another. Since meropenem is an alternative to cefotaxime in meningeal infections, we aim to identify whether nsSNPs in the PBPs causing penicillin and cefotaxime resistance can decrease the pneumococcal susceptibility to meropenem. Comparison of the nsSNPs in the PBPs between the cefotaxime-resistant Indian (n = 33) and global isolates (n = 28) revealed that nsSNPs in PBP1A alone elevated meropenem minimal inhibitory concentrations (MICs) to 0.12 μg/ml, and nsSNPs in both PBP2X and 2B combined with PBP1A increases MIC to ≥ 0.25 μg/ml. Molecular docking confirmed the decrease in the PBP drug binding affinity due to the nsSNPs, thereby increasing the inhibition potential and the MIC values, leading to resistance. Structural dynamics and thermodynamic stability pattern in PBPs as a result of mutations further depicted that the accumulation of certain nsSNPs in the functional domains reduced the drug affinity without majorly affecting the overall stability of the proteins. Restricting meropenem usage and promoting combination therapy with antibiotics having non-PBPs as targets to treat cefotaxime non-susceptible S. pneumoniae meningitis can prevent the selection of β-lactam resistance.

Impact of ascorbic acid in reducing the incidence of vancomycin associated nephrotoxicity in critically ill patients: A preliminary randomized controlled trial

Background Antioxidants show nephroprotective effect against vancomycin associated nephrotoxicity (VAN) in animals. This study aimed to assess the ascorbic acid nephro-protective role against VAN clinically.

Methods Forty-one critically ill patients were randomly assigned to one of two groups: intervention group (vancomycin IV plus ascorbic acid, n=21) or control group (vancomycin IV only, n=20). Primary outcomes were the incidence of VAN and the absolute change in creatinine parameters, while mortality rate was the secondary outcome. Nephrotoxicity was defined as an increase in serum creatinine (S.cr) by at least 0.5 mg/dL or 50% of baseline for at least two successive measurements. This study is registered at Clinicaltrials.gov (NCT03921099), April 2019.

Results Mean absolute S.cr increase was significant when compared between both groups, P-value = 0.036, where S.cr increased by 0.05(0.12) and 0.34(0.55) mg/dL in the intervention and control groups, respectively. Mean absolute Cr.cl decline was significant when compared between both groups, P-value = 0.04, where Cr.cl was decreased by 5.9(17.8) and 22.3(30.4) ml/min in the intervention and control groups, respectively. Incidence of VAN was 1/21(4.7%) versus 5/20(25%) in the intervention and control groups, respectively (RR: 0.19; CI: 0.024–1.49; P-value = 0.093). Mortality was higher in the control group; however, it was not statistically significant, P-value = 0.141.

Conclusion Co-administration of ascorbic acid with vancomycin preserved renal function and reduced the absolute risk of VAN by 20.3%, however, the reduction in VAN incidence didn’t reach statistical significance level. Further large multicenter prospective trials are recommended.

Candidates for area under the concentration-time curve (AUC)-guided dosing and risk reduction based on analyses of risk factors associated with nephrotoxicity in vancomycin-treated patients

OBJECTIVES

Compared with vancomycin trough concentration (C_min)-guided dosing, area under the concentration-time curve (AUC)-guided dosing is associated with decreased acute kidney injury (AKI). However, whether C_min-guided or AUC-guided dosing should be used in patients other than those with serious MRSA infections remains uncertain. The purposes of this multicentre study were to identify risk factors for early- and late-phase vancomycin-induced AKI and to identify candidates for AUC-guided dosing, rather than C_min-guided dosing, who require a more accurate dose titration to reduce the AKI risk.

METHODS

A multivariate logistic regression analysis was applied to identify risk factors for AKI. Additionally, the cut‑off day for AKI onset, cut-off C_min for AKI, safe C_min for reduced AKI risk and probability of AKI were calculated.

RESULTS

In total, 8.4% (159/1882) of patients developed AKI. AKI occurred within the first 7 days of therapy (early phase) in the vast majority of patients. Significant risk factors for AKI during the early phase were identified as C_min > 20 mg/L, ICU stay, concurrent diuretic or piperacillin/tazobactam use, and pre-existing renal dysfunction. A temporarily elevated C_min (>15-20 mg/L) was not associated with a greater risk of AKI. In patients with risk factors, the cut-off C_min for AKI and the estimated safe C_min for reduced AKI risk were 18.8-21.0 mg/L and <11.7-13.5 mg/L, respectively.

CONCLUSION

Patients with known AKI risk factors require a low target C_min. The presence of several risk factors for AKI may indicate a need for more accurate dose titration using AUC-guided dosing.

Validation of Methicillin-Resistant Staphylococcus aureus (MRSA) Risk Factors in Predicting MRSA Community-Acquired Pneumonia at an Academic Medical Center

Background: The 2019 Infectious Diseases Society of America community-acquired pneumonia (CAP) guidelines recommend antimethicillin- resistant Staphylococcus aureus (MRSA) therapy in patients with CAP based on previously identified risk factors for MRSA with an emphasis on local epidemiology and institutional validation of risk. Thus, we sought to assess the ability of guideline-recognized risk factors to predict MRSA CAP at our institution. Methods: This was a single-center, retrospective cohort study from January 2016 to March 2020. Patients were included if they were >18 years old, diagnosed with CAP, and had a MRSA nasal screen and respiratory culture obtained on admission. Patients were excluded if CAP diagnosis was not met, respiratory cultures were not obtained within 48 hours of antibiotic initiation, or they had cystic fibrosis. Sensitivity, specificity, negative predictive value, positive predictive value, and likelihood ratios (LR) were calculated using Vasser Stats 2019. Pre/post-test odds and pre/post-test probabilities were calculated using Excel 2019. Results: Of 705 screened patients, 221 were included. MRSA prevalence in CAP patients at our institution was 3.6%. History of MRSA isolated from a respiratory specimen had high specificity (98%), high positive LR of 20 (95% CI 5.3–74.8), and high post-test probability of 42.8%. Receipt of IV antibiotics during hospitalization within the past 90 days had a positive LR of 1.9 (95% CI 0.74–4.84). A positive MRSA nasal screen on admission had a positive LR of 6.9 (95% CI 4.0–12.1), negative LR 0.28 (95% CI 0.08–0.93), positive post-test probability of 20.7%, and negative post-test probability of 1.04%. Conclusion: Our study utilized institutional data to validate guideline recognized risk factors for MRSA CAP specifically at our institution. Risk factors including history of MRSA isolated from a respiratory specimen, and positive post-admission MRSA nasal screen were validated as significant risk factors; receipt of IV antibiotics during hospitalization within the past 90 days was not shown to be a risk factor for MRSA CAP based on our institutional data. Validated risk factors may help providers discern which patients with CAP at our institution would benefit most from empiric MRSA treatment.

The monitoring of vancomycin: a systematic review and meta-analyses of area under the concentration-time curve-guided dosing and trough-guided dosing

Background

This systematic review and meta-analysis explored the relationship between vancomycin (VCM) monitoring strategies and VCM effectiveness and safety.

Methods

We conducted our analysis using the MEDLINE, Web of Sciences, and Cochrane Register of Controlled Trials electronic databases searched on August 9, 2020. We calculated odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Adult patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia with VCM trough concentrations ≥15 μg/mL had significantly lower treatment failure rates (OR 0.63, 95% CI 0.47–0.85). The incidence of acute kidney injury (AKI) increased with increased trough concentrations and was significantly higher for trough concentrations ≥20 μg/mL compared to those at 15–20 μg/mL (OR 2.39, 95% CI 1.78–3.20). Analysis of the target area under the curve/minimum inhibitory concentration ratios (AUC/MIC) showed significantly lower treatment failure rates for high AUC/MIC (cut-off 400 ± 15%) (OR 0.28, 95% CI 0.18–0.45). The safety analysis revealed that high AUC value (cut-off 600 ± 15%) significantly increased the risk of AKI (OR 2.10, 95% CI 1.13–3.89). Our meta-analysis of differences in monitoring strategies included four studies. The incidence of AKI tended to be lower in AUC-guided monitoring than in trough-guided monitoring (OR 0.54, 95% CI 0.28–1.01); however, it was not significant in the analysis of mortality.

Conclusions

We identified VCM trough concentrations and AUC values that correlated with effectiveness and safety. Furthermore, compared to trough-guided monitoring, AUC-guided monitoring showed potential for decreasing nephrotoxicity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-05858-6.

Formononetin protects against cisplatin‑induced acute kidney injury through activation of the PPARα/Nrf2/HO‑1/NQO1 pathway

Acute kidney injury (AKI) is characterized by an abrupt deterioration of renal function. Formononetin (FOR) protects against cisplatin (CIS)‑induced AKI, and it has various potential pharmacological and biological effects, including anti‑inflammatory, antioxidative and anti‑apoptotic effects. The current study investigated the role of FOR in CIS‑induced AKI. Rats were treated with CIS to establish an AKI model, followed by treatment with FOR. HK‑2 cells were treated with CIS, FOR, GW6471 [a peroxisome proliferator‑activated receptor α (PPARα) antagonist], eupatilin (a PPARα agonist) and nuclear factor erythroid 2‑related factor 2 (Nrf2) small interfering RNA (siNrf2), and cell proliferation and apoptosis were determined by MTT and flow cytometry assays. The mRNA and proteins levels of PPARα, Nrf2, heme oxygenase‑1 (HO‑1) and NAD(P)H quinone dehydrogenase 1 (NQO1) were measured by reverse transcription‑quantitative PCR and western blotting. The results demonstrated that FOR attenuated the histopathological changes, the levels of blood urea nitrogen, creatinine, TNF‑α and IL‑1β, and the MDA content and MPO activity, whereas it enhanced CAT activity in the AKI rat model. Furthermore, FOR and eupatilin promoted cell viability and CAT activity, and increased the levels of PPARα, Nrf2 and HO‑1 and NQO1, but suppressed apoptosis and MPO activity, and reduced the levels of MDA, TNF‑α and IL‑1β in CIS‑treated HK‑2 cells. Notably, the aforementioned effects were reversed by GW6471 treatment or siNrf2 transfection. In conclusion, FOR protects against CIS‑induced AKI via activation of the PPARα/Nrf2/HO‑1/NQO1 pathway.

(-)-Camphene-based derivatives as potential antibacterial agents against Staphylococcus aureus and Enterococcus spp

Aim: To evaluate the activity of (-)-camphene-based thiosemicarbazide (TSC) and 4-hydroxy-thiosemicarbazone (4-OH-TSZ), alone and in combination against Gram-positive. Material & methods: MIC were determined for Staphylococcus aureus, Enterococcus spp. reference strains and clinical isolates. Drug combination, time-kill and cytotoxicity assays were also performed. Results: TSC and 4-OH-TSZ demonstrated potent inhibitory activity against S. aureus and Enterococcus spp., including multidrug-resistant isolates (MIC ranging from 1.9 to 31.2 μg/ml), and were bactericidal for the reference strains of both Gram-positive tested. The derivatives proved to be selective for the bacteria and synergistic with oxacillin and vancomycin. Conclusion: (-)-Camphene-based derivatives can represent promising drug candidates against critical pathogens, such as S. aureus and Enterococcus spp., including MRSA and vancomycin resistance Enterococcus spp. isolates.

Vancomycin in ICU Patients with Gram-Positive Infections: Initial Trough Levels and Mortality

Background

Vancomycin is one of the most common therapeutic agents for treating gram-positive infections, particularly in critically ill patients. The aim of this study was to identify factors associated with initial therapeutic vancomycin trough levels and mortality in a tertiary-care intensive care unit (ICU).

Methods

This retrospective study evaluated 301 adult ICU patients admitted to King Abdulaziz Medical City in Riyadh between October 1, 2017 and December 31, 2018 with confirmed gram-positive infections and received intravenous vancomycin. Vancomycin trough levels of 15–20 mg/L for severe infections and 10–15 mg/L for less severe infections were considered therapeutic.

Results

The patients were relatively older with a mean age of 60 (SD ±20) years. Initial vancomycin trough levels were therapeutic in 168 (55.8%). Factors associated with initial therapeutic vancomycin trough levels were female gender (adjusted odds ratio [aOR]=2.575), older age (aOR=1.024), receiving a loading dose (aOR=2.445), having bacteremia (aOR=2.061), and high platelet count (aOR=1.003). On the other hand, the increase of estimated glomerular filtration rate (eGFR) (aOR=0.993) and albumin levels (aOR=0.944) were associated with lower odds of initial therapeutic vancomycin trough levels. Factors associated with higher mortality were female gender (adjusted hazard ratio [aHR]=2.630), increased body weight (aHR=1.021), cancer (aHR=3.451), and high APACHE II score (aHR=1.068).

Conclusion

The study identified several factors associated with achieving initial therapeutic vancomycin trough levels (i.e. older age, female gender, receiving a loading dose, bacteremia, high platelets count, low eGFR and albumin level). These factors should be considered in the dosing of vancomycin in critically ill patients with gram-positive infections.

Relationship of vancomycin trough levels with acute kidney injury risk: an exposure–toxicity meta-analysis

Objectives

Nephrotoxicity represents a major complication of vancomycin administration, leading to high rates of morbidity and treatment failure. The aim of this meta-analysis was to evaluate the association between trough levels and risk of renal impairment, by defining an exposure–toxicity relationship and assessing its accuracy in predicting the development of acute kidney injury (AKI).

Methods

Medline, Scopus, CENTRAL, Clinicaltrials.gov and Google Scholar databases were systematically searched from inception. Studies examining the effects of trough levels on nephrotoxicity risk in adult patients were deemed eligible.

Results

The meta-analysis was based on 60 studies, including 13 304 patients. The development of AKI was significantly linked to both higher initial [standardized mean difference (SMD): 0.82; 95% CI: 0.65–0.98] and maximum (SMD: 1.06; 95% CI: 0.82–1.29) trough levels. Dose–response analysis indicated a curvilinear relationship between trough levels and nephrotoxicity risk (χ2 = 127.1; P value &lt; 0.0001). A cut-off of 15 mg/L detected AKI with a sensitivity of 62.6% (95% CI: 55.6–69.2) and a specificity of 65.5% (95% CI: 58.9–71.6), while applying a 20 mg/L threshold resulted in a sensitivity of 42.9% (95% CI: 34–52.2) and a specificity of 82.5% (95% CI: 73.9–88.8).

Conclusions

The present findings suggest that the development of vancomycin-induced AKI is significantly associated with higher initial and maximum trough levels. An exposure–response relationship was defined, indicating that increasing trough levels correlate with a significant rise of nephrotoxicity risk. Future studies should verify the effectiveness of individualized pharmacokinetic tools that would enable the attainment of trough level targets and minimize the risk of renal toxicity.