Vancomycin AUC24 /MIC Ratio in Patients with Methicillin-Resistant Staphylococcus aureus Pneumonia.

Vancomycin is the treatment of choice for serious methicillin-resistant Staphylococcus aureus (MRSA) infections. The area under the concentration-time curve from 0 to 24 hr (AUC24 )/minimum inhibitory concentration (MIC) ratio was recently introduced as a parameter for assessing clinical outcome by S. aureus. This study was purposed to apply the vancomycin AUC24 /MIC in patients with MRSA pneumonia. Forty-seven patients with confirmed lower respiratory infection caused by MRSA during 2011 were enrolled. All patients were treated with vancomycin. Clinical characteristics and laboratory data were collected. AUC24 /MIC values were calculated as previously reported and patients were divided into two groups based on the bacteriologic response, which was eradicated or not, and an AUC24 /MIC value (above or below 400). MRSA infections were eradicated in 39 patients but 8 patients had persistent MSRA infection in the following cultures. The mean AUC24 /MIC values and vancomycin concentrations were not statistically different between patients with and without MRSA eradication. All 13 patients with a vancomycin MIC of 2 mg/L had an AUC24 /MIC below 400. AUC24 /MIC might not be a reliable indicator for assessing treatment response of vancomycin in MRSA pneumonia. Relationship between vancomycin AUC24 /MIC and therapeutic outcome needs to undergo further studies, including sufficiently large sample size.

Ji M ，Kim HK ，Kim SK ，Lee W ，Sung H ，Chun S ，Kim MN ，Min WK ... -  《-》

Impact of area under the concentration-time curve to minimum inhibitory concentration ratio on vancomycin treatment outcomes in methicillin-resistant Staphylococcus aureus bacteraemia.

There have been few clinical studies on the association between the vancomycin 24-h area under the concentration-time curve (AUC24) to minimum inhibitory concentration (MIC) ratio and vancomycin treatment outcomes in methicillin-resistant Staphylococcus aureus (MRSA) infections. To examine this association and to establish a suitable cut-off value for AUC24/MIC, a multicentre prospective observational study was conducted in patients with MRSA bacteraemia. Data were collected on all patients aged ≥18 years with MRSA bacteraemia treated with vancomycin for ≥72 h without dialysis. The MIC was determined by broth microdilution (BMD) and Etest. Treatment failure was defined as (i) 30-day mortality, (ii) persistent bacteraemia (≥7 days) and (iii) recurrence (≤30 days after completion of therapy). AUC24 was estimated by a Bayesian approach based on individual vancomycin concentrations. The AUC24/MIC cut-off value for differentiating treatment success and failure was calculated by Classification and Regression Tree (CART) analysis. In total, 117 patients were enrolled, among which vancomycin treatment failure occurred in 38 (32.5%). In univariate analysis, high vancomycin MIC and low trough levels were unrelated to treatment outcomes. In the CART analysis, low vancomycin AUC24/MIC [<392.7 (BMD) and <397.2 (Etest)] was associated with treatment failure. In multivariate analysis, low AUC24/MIC was a risk factor for treatment failure [adjusted odds ratio (aOR)=3.50, 95% confidence interval (CI) 1.39-8.82 by BMD; aOR=5.61, 95% CI 2.07-15.24 by Etest]. AUC24/MIC is associated with vancomycin treatment outcomes in MRSA bacteraemia, and seeking individualised AUC24/MIC ratios above target (>400) may improve treatment outcomes.

Song KH ，Kim HB ，Kim HS ，Lee MJ ，Jung Y ，Kim G ，Hwang JH ，Kim NH ，Kim M ，Kim CJ ，Choe PG ，Chung JY ，Park WB ，Kim ES ，Park KU ，Kim NJ ，Kim EC ，Oh MD ... -  《-》

Predictive Value of Vancomycin AUC(24)/MIC Ratio for 30-day Mortality in Patients with Severe or Complicated Methicillin-Resistant Staphylococcus aureus Infections: A Multicenter Retrospective Study.

Although vancomycin is typically employed against methicillin-resistant Staphylococcus aureus (MRSA) infections, the optimal ratio of 24-h area under the concentration-time curve to minimum inhibitory concentration (AUC24/MIC) for severe or complicated infections lacks clear guideline recommendations. This study aimed to determine the target AUC24/MIC ratio associated with treatment outcomes of infections treated with vancomycin. This retrospective multicenter cohort study included adult patients receiving ≥ 5 days of vancomycin for severe/complicated MRSA infections (e.g., osteoarticular, pulmonary, endocarditis, etc.) between January 2018 and December 2023. The primary outcome was 30-day mortality, with secondary outcomes including clinical success, microbiological eradication, and nephrotoxicity. Receiver operating characteristic (ROC) curve analysis was used to identify the AUC24/MIC cutoff for 30-day mortality. Multivariate regression analysis was used to determine association between AUC24/MIC and outcomes. This study included 82 patients. ROC identified a target AUC24/MIC of ≥ 505 for 30-day mortality. The overall 30-day mortality rate (22.0%) was significantly higher for below average AUC24/MIC cutoff (34.1%) than for above AUC24/MIC cutoff group (9.8%). Multivariate analysis confirmed AUC24/MIC of < 505 as an independent predictor (adjusted odds ratio, 5.001; 95% confidence interval, 1.335-18.75). The clinical success rate differed significantly between below- and above-cutoff groups, whereas microbiological eradication tended to favor the above-cutoff group. The nephrotoxicity rates were comparable between groups. In treating severe/complicated MRSA infections, vancomycin AUC24/MIC ratio ≥ 505 was independently associated with favorable 30-day mortality. Given the retrospective nature of this study, further prospective studies are essential to confirm the reliability of the target AUC24/MIC ratios.

Hanai Y ，Hashi H ，Hanawa K ，Endo A ，Miyazaki T ，Yamaguchi T ，Harada S ，Yokoo T ，Uekusa S ，Namiki T ，Yokoyama Y ，Asakawa D ，Isoda R ，Enoki Y ，Taguchi K ，Matsumoto K ，Matsuo K ... -  《-》

A stewardship program's retrospective evaluation of vancomycin AUC24/MIC and time to microbiological clearance in patients with methicillin-resistant Staphylococcus aureus bacteremia and osteomyelitis.

Gawronski KM ，Goff DA ，Brown J ，Khadem TM ，Bauer KA ... -  《-》

Pharmacodynamics of vancomycin and other antimicrobials in patients with Staphylococcus aureus lower respiratory tract infections.

Moise-Broder PA ，Forrest A ，Birmingham MC ，Schentag JJ ... -  《-》