Shey-Ying Chen1, Po-Ren Hsueh2, Wen-Chu Chiang1, Edward Pei-Chuan Huang3, Ching-Feng Lin4, Chin-Hao Chang5, Shyr-Chyr Chen3, Wen-Jone Chen3, Shan-Chwen Chang6, Mei-Shu Lai7, Wei-Chu Chie8. 1. Department of Emergency Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan; Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan. 2. Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan. 3. Department of Emergency Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan. 4. Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan. 5. National Translational Medicine and Clinical Trial Resource Center, Taipei, Taiwan. 6. Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan. 7. Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan. 8. Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan. Electronic address: weichu@ntu.edu.tw.
Abstract
OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) isolates with an elevated vancomycin MIC ≥2 mg/L have been increasingly identified in many countries. We aimed to develop a clinical score to predict vancomycin MIC ≥2 mg/L in patients with community-onset MRSA bacteraemia. METHODS: This retrospective cohort study enrolled 394 patients with MRSA bacteraemia. Vancomycin MICs of all MRSA isolates were determined by agar dilution method. Clinical characteristics between patients with high (≥2 mg/L) and low (≤1 mg/L) vancomycin MIC MRSA bacteraemia were compared. Independent predictors of high vancomycin MIC isolate infection were identified and used to create a score-based predictive model. RESULTS: Among the 394 study patients, 56 (14.2%) had MRSA isolates with a vancomycin MIC ≥2 mg/L. The final regression model included 6 independent predictors: chronic liver disease (adjusted odds ratio [aOR], 2.99; 95% confidence interval [CI], 1.39-6.42), prior recovery of MRSA from respiratory tract specimen (aOR, 2.54; 95% CI, 1.15-5.61), end-stage renal disease (aOR, 2.53; 95% CI, 1.33-4.78), severe sepsis or septic shock on presentation (aOR, 2.39; 95% CI, 1.28-4.44), prior vancomycin exposure (aOR, 2.21; 95% CI, 1.13-4.30), and recent hospitalization within 3 months (aOR, 2.11; 95% CI; 1.01-4.40). All independent predictors had a value of one point. Youden's index statistics indicated a score of ≥3 as best cutoff value that had a sensitivity of 69.6% and specificity of 78.4%. CONCLUSIONS: Simple decision rule helps clinicians stratify the risk of high vancomycin MIC MRSA infection when deciding empirical therapy for patients with community-onset infections.
OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) isolates with an elevated vancomycin MIC ≥2 mg/L have been increasingly identified in many countries. We aimed to develop a clinical score to predict vancomycin MIC ≥2 mg/L in patients with community-onset MRSA bacteraemia. METHODS: This retrospective cohort study enrolled 394 patients with MRSA bacteraemia. Vancomycin MICs of all MRSA isolates were determined by agar dilution method. Clinical characteristics between patients with high (≥2 mg/L) and low (≤1 mg/L) vancomycin MIC MRSA bacteraemia were compared. Independent predictors of high vancomycin MIC isolate infection were identified and used to create a score-based predictive model. RESULTS: Among the 394 study patients, 56 (14.2%) had MRSA isolates with a vancomycin MIC ≥2 mg/L. The final regression model included 6 independent predictors: chronic liver disease (adjusted odds ratio [aOR], 2.99; 95% confidence interval [CI], 1.39-6.42), prior recovery of MRSA from respiratory tract specimen (aOR, 2.54; 95% CI, 1.15-5.61), end-stage renal disease (aOR, 2.53; 95% CI, 1.33-4.78), severe sepsis or septic shock on presentation (aOR, 2.39; 95% CI, 1.28-4.44), prior vancomycin exposure (aOR, 2.21; 95% CI, 1.13-4.30), and recent hospitalization within 3 months (aOR, 2.11; 95% CI; 1.01-4.40). All independent predictors had a value of one point. Youden's index statistics indicated a score of ≥3 as best cutoff value that had a sensitivity of 69.6% and specificity of 78.4%. CONCLUSIONS: Simple decision rule helps clinicians stratify the risk of high vancomycin MIC MRSA infection when deciding empirical therapy for patients with community-onset infections.