850. External Validation of the Methicillin-Resistant Staphylococcus aureus Bacteremia Score

Abstract Background Predictive scoring systems, such as the Pitt Bacteremia Score (PBS) and Acute Physiology and Chronic Health Evaluation II (APACHE-II), can optimize clinical decisions and provide adjustment for confounding among patients with Methicillin-Resistant Staphylococcus aureus bacteremia (MRSAB). The recently introduced MRSAB score demonstrated superior discriminatory ability in mortality prediction compared to APACHE-II and PBS, however external validation is lacking. Methods Single center, retrospective cohort study of adult patients admitted to University of Colorado Hospital from 2013–2020 with initial episode of MRSAB were included. Patients transferred from an outside hospital, left against medical advice, or died/pursued comfort care within 24 hours of index culture were excluded. The primary outcome was discrimination of 30-day all-cause mortality. The discriminatory abilities of APACHE-II, PBS and MRSAB were compared using receiver operating characteristic (ROC) analysis. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were analyzed, and optimal MRSAB score was identified by Youden Index. Results Overall, 170 patients met study inclusion. The median (IQR) age was 57 (47-66) years, 69% were male, and 19% were in an ICU during blood culture collection. The most common infection sites were skin and soft tissue (41%), musculoskeletal (23%), and line-related (19%), whereas endovascular (14%) infections were less common. The median (IQR) PBS, APACHE-II and MRSAB scores were 2 (0-4),17 (12-23), and 6.5 (3-11), respectively. Thirty-day all-cause mortality was 12.9%. ROC curve analysis revealed an area (95% CI) for the APACHE-II, PBS, and MRSAB scores of 0.84 (0.77-0.92), 0.71 (0.57-0.85), 0.79 (0.68-0.90), respectively. A threshold MRSAB score of ≥10 was identified, whereby mortality was 3.6% with MRSAB < 10, and 30% with MRSAB ≥10. A MRSAB ≥10 had a sensitivity, specificity, PPV and NPV with corresponding 95% CIs of 0.82 (0.63-0.94), 0.72 (0.68-0.79), 0.30(0.19-0.42) and 0.96(0.92-0.99), respectively. Receiver operator characteristic (ROC) curves for the prediction of 30-day mortality Conclusion The MRSAB score is a useful predictive scoring model, with discriminatory ability comparable to APACHE-II, and excellent NPV at ≥10. Our findings support routine clinical and research application. Disclosures matthew miller, PharmD, Allergan (Speaker’s Bureau)Tetraphase (Speaker’s Bureau)

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1061. Comparison of the Acute Physiology and Chronic Health Evaluation (APACHE) II Score and the Pitt Bacteremia Score to Predict Mortality in Methicillin-Resistant Staphylococcus aureus Bacteremia

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy210.898 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S317-S318 ◽

Cited By ~ 1

Author(s):

Sarah Jorgensen ◽

Evan J Zasowski ◽

Trang D Trinh ◽

Abdalhamid M Lagnf ◽

Sahil Bhatia ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Predictive Value ◽

Methicillin Resistant Staphylococcus Aureus ◽

Apache Ii ◽

Apache Ii Score ◽

Health Evaluation ◽

Research Support ◽

C Statistic ◽

Sensitivity Specificity ◽

Research Grant

Abstract Background Methicillin-resistant Staphylococcus aureus bloodstream infection (MRSA BSI) is associated with high morbidity and mortality. The prediction of outcomes may have a profound impact on clinical decision making and risk stratification. The Acute Physiology and Chronic Health Evaluation (APACHE) II Score and the Pitt Bacteremia Score (PBS) have been repeatedly described as independent predictors of mortality in MRSA BSI. The APACHE II is complex to calculate and many of the variables may not be pertinent to MRSA BSI. The PBS is a simple score using readily assessable variables. The comparative predictive performance of the two models in MRSA BSI has not been evaluated. Methods Retrospective, observational, singe-center cohort study in adults with MRSA BSI between 2008 and 2018. Patients who did not receive active therapy ≤72 hours of index culture were excluded. APACHE II and PBS were calculated using the worst physiological values recorded ≤24 hours of blood culture collection. Discriminatory ability for 30-day mortality was assessed using the c-statistic and was compared using the Hanley and McNeil method. The best cut-off point in each scoring system was determined using the Youden Index (J). Results A total of 455 patients were included. The median (IQR) PBS and APACHE II were 2 (0, 3) and 18 (11, 23), respectively. All-cause 30-day mortality was 16.3%. The c-statistic (95% CI) for the APACHE II vs. PBS in the overall cohort and stratified by ICU status were: 0.813 (0.763, 0.863) vs. 0.717 (0.653, 0.782), P = 0.0035; ICU 0.729 (0.610, 0.848) vs. 0.570 (0.442, 0.699), P = 0.026; and non-ICU 0.821 (0.761, 0.881) vs. 0.700 (0.614, 0.786),P = 0.0046, respectively. The APACHE II with the maximum J value was 21; sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for 30-day mortality were 81.08%, 72.97%, 36.81%, and 95.21%, respectively. The PBS with the maximum J value was 3; sensitivity, specificity, PPV, and NPV were 66.22%, 72.18%, 31.61%, and 91.67%, respectively. Conclusion The APACHE II was superior to the PBS in predicting 30-mortality in patients with MRSA BSI in the overall cohort and stratified by ICU status at BSI onset. Future research to develop a more practical scoring model with high discriminatory power is needed. Disclosures M. J. Rybak, Allergan: Consultant, Grant Investigator and Speaker’s Bureau, Research grant and Research support. Achaogen: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Bayer: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Melinta: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Merck: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Theravance: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Sunovian: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Zavante: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. NIAID: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support.

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Impact of Prior-to-Admission Methicillin-Resistant Staphylococcus aureus Nares Screening in Critically Ill Adults With Pneumonia

Annals of Pharmacotherapy ◽

10.1177/10600280211023209 ◽

2021 ◽

pp. 106002802110232

Author(s):

Mariana G. Mallidi ◽

Giles W. Slocum ◽

Gary D. Peksa ◽

Joshua M. DeMott

Keyword(s):

Risk Factors ◽

Staphylococcus Aureus ◽

Hospital Admission ◽

Critically Ill ◽

Critically Ill Patients ◽

Predictive Value ◽

Methicillin Resistant Staphylococcus Aureus ◽

Methicillin Resistant ◽

Critically Ill Adults ◽

Sensitivity Specificity

Background The high negative predictive value (NPV) of a negative nasal methicillin-resistant Staphylococcus aureus (MRSA) result in suspected MRSA pneumonia is well established; however, data are limited on the NPV of samples collected prior to hospital admission for critically ill patients. Objective To evaluate the predictive characteristics of MRSA nares screening performed prior to hospital admission in critically ill adult patients diagnosed with pneumonia. Methods A retrospective analysis was conducted in critically ill patients with pneumonia and MRSA nares screening within 60 days of respiratory culture. The primary outcome was NPV of MRSA nares for MRSA pneumonia using samples within 60 days compared to in-hospital respiratory cultures. A sensitivity analysis was performed for samples within 30 days. Secondary outcomes were prevalence, positive predictive value (PPV), sensitivity, specificity, and MRSA pneumonia risk factors. Results The NPV for MRSA nares screening collected prior to hospital admission was high at 98% (95% CI = 96%-99%) for samples collected within 60 days (n = 243) and 99% (95% CI: 94%-99.9%) for samples within 30 days (n = 119). Specificity for MRSA nares collected 60 days prior to admission (96%, 95% CI: 93-98) and 30 days (96%, 95% CI: 91%-99%) were both high. PPV and sensitivity were lower. Risk factors for MRSA pneumonia were similar. Conclusion and Relevance MRSA nares screening within 60 days of intensive care unit admission has a high NPV and specificity for MRSA pneumonia in critically ill patients and may be a powerful stewardship tool for avoidance of empirical anti-MRSA therapy.

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